THE COURTSHIP OF BRITISH LYCOSID SPIDERS. 31 7

15. The Courtship of British Lycosid Spiders, and it9 probable By W. S. BRISTOWE, B.A., an(l G. H. significance.

LOCKET, B.A.* [Received February 17, 1996 : Read April 13, 1086.1

(Text-figures 1 - 10.)

INTRODUCTION. The original object of the present paper was to set forth the

observations of the authors on the courtship of some British spiders of the family Lycosids, but, bit by bit, various theories which have occurred to us in connection with the subject have crept in, until finally they have taken up quite a large portion of the paper. Since so little is known concerning the courtship of spiders, and since the few people who have made experiments have put forward such divergent views to explain the phenomena, we feel there is no need to apologise for this. We, the authors, have found ourselves in such perfect agreement both as to our observations, which were made quite independently, and also as to the conclusions at which we have arrived, that we have decided to collaborate in the hopc of thereby enhancing any value which may be attributable to our work. Where one of us alone is responsible for an observation, an opinion, or a section of the paper, his initials have been inserted alongeide.

I n this cotintry, literature on the subject of courtship in spiders is almost lacking, and i t is in America that the most complete observations have been made. The most extensive work is that carried out by Mr. and Mrs. Peckham on the family Attidae (30) t. I n this familythe spiders have comparatively good sight, and the males, which are often brightly coloured and provided with tufts of hair and other ornamentations, go through queer antics in front of the female. The Peckhams came to the conclusion that the sexes recognise one another by sight, and that the female chooses for a husbknd the most beautiful male. The males are numerous, and sexual selection of this Bind has, according to the Peckhams. resulted in the evolution of their bright ornamentations and their (lances so carefully designed to dibplay their charms. T. H. Montgomery (22), who worked chiefly on the American Lycosidae, denied the value of the male epigamic characters, and also the presence of any esthetic sense in the female by which she could choose the most beautiful male. His view was that

* Communicated by Prof, JULIAN HUXLEY, F.Z.S. t The numbers refer to the Bibliography given at the end of the paper. PROC. ZOOL. S0~.-1926, No. XXII. 22

318 MESSRS. W. 8 . BRISTO\VE AND Q. H . LOCKET ON THE

the male antics have arisen partly through the instinct of self- defence (e . g. legs raised), and partly through the great physio- logical excitement expei*ienced. H e aclmitted (25) that sight WAS used in the courtship of the Hunting Spiders, but believed that the sense of touch was of first importance in sex-recognition. Before setting out 0111- view, which differs from those we have nientioned above, we have thought it best to deal with the behavionr of the spiders me have had under our observation, thereby providing the necessmy evidence for our conclu~inns.

The paper is arranged as follows :- 1. Obserrations on the courtship of the British Lycosidz. 2. The sense of smell in spiders, and its relation to courtship. 3. The sense of hearing in spiders, and its relation to court-

ship. (W. s. B.) 4. Sexual selection and the evolution of courtship antics in

spiders, with a note as t o the possibility of applying similar theories to insects. (W. 8. B.)

5. Summary of results and conclusions. 6. List of the more important literature referred to in the

paper.

1 . OBSERVATIONS ON THE COURTSHIP OF BRITISH LYCOSIDB. TARENTULA BARBIPES Walck. (Text-fig. 1.) This is u. fairly conimon species on bandy heaths and other

situations where the vegetation does not grow high. Shallow burrows are formed, and the hpitlers often sit a t the entrance in a characteristic attitude with their front legs curled up under them, reqembling very closely their larger European relations, such as T. narbonensis, a species made famous by the writings of Fabre. The males of T. barbipes are to be found in a state of maturity most commonly from February onwards until May, by which time they are becoming scarce. They are handsome light- grey and black spiders. but the particular feature of the male is the enlarged and jet-bleck tibiae of the front pair of legs.

I n this species courtship is particularly marked, probably on account of the great ferocity of the female. When the male becomes aware of the presence of a female, with quivering front legs he paws the ground, and then, raising his cephalothorax by means of his second pair of legs, his palps and front pair of legs are raised (the latter in a bent position above his head) ; with a jerk they are raised higher still, and then the legs, trembling violently, are lowered to the ground ; a step is taken, and perhaps two or three if she is not in the immediate vicinity, and the front legs are drawn up ouce more into the queer posture we have attempted to describe above. Repeating this sequence of events over and over again, sometimes for hours on end, the male will court his ferocious spouse, circling round her, and sometimes

COURTSHIP O F BRITISH LYCOSID VPIDERS. 319

straying to a considerable distance, but in the end usually re- turning in her direction. When he arrives close to her, she rushes fiercely a t him, but he, with his superior agility, alwRys just inanages to escape her and, quite undaunted, renews his attentions. When he does arrive close enough to touch her, he extentls his front legs to her, and then she either drives him away or else, after a violent interplay of front legs, copulation ensiles. Copulation has been observed on two occasions (G. H. L.), on March 15th and 29th, and on each occasion it was a very short affair lasting between 20 :ind 30 seconds, during which time the palps were applied alternately four or five times.

Wheu n inde Tccreiatulcc crosses the track of a female, he touches the ground with his pelps and legs several times, and then, although the female may be out of sight, a tremor passes along his front legs, he pnws the ground, and the courtship motions are

T ~ ~ , t t u l a harbipes Walck. Male in ourtship attitude displaying his striking front l e p .

carried out. As a conclusive proof that sight is not used, the authors both discovered quite independently that the male will go through all his antics \vheii placed in a box from which a feinale has previously been removed. It was thought that threads trailed by the female might perhaps be the means by which she left proof of her identity, but her presence is still recognized if the same experiment is repeated after preventing her from spinning threads by means of a layer of collodion placed over her spinners ((3. H. L.). Water shaken round her box (G. H. L.), or loose particles of sand over which she has walked several times (W. S. B.), if placed in his box will excite him to action, as will threads spun by the fernale " 25 days previously. Threads dried and then baked, however, will not have any effect on him

* Males of several species of Lposid, and Attid also, have been seen " dancing " before other males of the same species, nnd in one case a male 2: bar6ipes started his performance after being placed in a box which had previously contained a inale (G. H. L. ) .

22"

320

(G.H.L.). This seems to show conclubively that tlie male Lycosid can recognize its mate by means of smell. That spiders possess a sense of smell has been known for many years *, but that it is used by the male to recognize the identity of the female does not appear to be R recognized fact f.

MESSRS. w. s. BRISTOWE AND GI. H. LOCKET ON THE

TARENTULA PULVERULENTA Clerck. (Text-fig. 2.) This species occurs in rather diverse kinds of habitat, and we

have, for example, found it on dry heathland, the drier portions of the Cambridgeshire Fens, and at the tops of mountains in Scotland (W.S.B.). I n this last locality it attains a much larger size, and was actually described by 0. P. Cambridge under the name of T. aculeata as a distinct species. The lowland variety might be described as being in appearance a small edition of

Tarenticla pdverulenta Clerck. Male walking about before a female with hunched-up legs and vibrating pnlps and abdomen,

T. barhips, but the legs of the male are not so markedly enlarged or black in aolour.

The courting display of this spider is not so striking as that of T. barbipes. I n the presence of a female the male moves his palps up and down, at first slowly, then more rapidly ; then his abdomen begins to move up and down for a short time, and finally he begins to walk about with jerky steps, his front legs hunched up under him and his pnlps and abtlomeii still moving u p xiid down. Performing these motions, he advances towards the female and walks backwards and forwards, a short distance a t a. time, gradually drawing closer. Every now and then he takes a rest, and when this occurs his ino0ioiis stop in tlie reverse order

* See Section 2. t. Montgomery (26) says that tonch is the dominant sense in ses-recognition,

though in Hunting Spiders sight is also used. ‘’ I t i s very doubtful nliether scent has any part in sex-recognition.” Petrunkevitch (31) says: “Tlie sense of sight, is beyond any doubt the only seiise that guider Hiiutiiig Spiders 011 their bunting excursions and in finding the females during the mating pwiod.” This was in ac- cordance with the Peckhams (30). Hewitt (14) foulid t h a t certam Aviculariid males became excited when they caiiie RCTOSS threads spaii by the female, but it was thought that this might be due to the keen tactile sense of the male.

COURTSHIP OF BRITISH LYCOSID SPIDERS. 321

to which they started-first he stops walking, then his abdomen stops pulsating up and down, and, last of all, his palps become stationmy.

W e found that this spider will start his display when placed in an empty box which recently contained a female, as did 1'. barb+es. H e feels the ground carefully with the tips of his legs and the upper side of his palps; then his palpe begin t o move up and down, n n d all the motions we have described above begin. The pulsations of the abdomen sometimes cause a distinct tapping sound as it hits the ground (W. 8. B.).

TAREXTULA CUNEATA Clerck. This spider is almost indistinguishable in the female sex from

Y'. pulwerulentn, but the inales are very distinct. In this species the male coloration is more like that of the female, and the front legs are peculiar for their bulbous tibirez The actions of the male, which were observed in May (G. H. L.), are very similar, indeed, to those of T. pulcewlemta. A s in that species, the palps are first moved, and then the spider begins to walk about with jerky steps, the front legs boinewhat crumpled under him, with the enlarged tibise displayed conspicuously.

TARENTULA MERIDIANA Hahn. On June 20t11, 1921, Dr. A. Randell Jackson, in company with

one of us (W. S. B.), came across this species (its second recorded occurrence in Britain) in a pine-wood clearing amongst bracken arid pine-needles at Coleman's Hatch (Ashdown Forest, Sussex). This species is smaller than the preceding ones and has a light reddish-grey band down its cephalothorax. The front portion of the abdomen is of the same colour with black (' shoulders," and the t ibie and tarsi of the legs are clothed with grey pubescence in the male.

When the sexes were placed together tlie male rapidly vibrated his palps and abdomen, and walked about, raibing Arst one leg and then the other. On arriving close to the feiiiale the vibrations of the pnlps and front legs became very rapid, and a t intervals of a few seconds lie gave a violent jerk of his whole body. H e kept on edging closer to the female j buk on each occasion she rushed fiercely a t him, and he fled. No copulation was observed (W. 5. B.).

TROCHOSA PICTA Hahn. The light pink and grey markings of t,liis species make it very

inconspicuous in the sandy localities whicii i t frequents. The male posseeses no epigamic ornamentations. The explanation of this may lie partly in the burrow-living life of the female, and it is certain that the protective coloration schenie woiild be impaired

322 MESSRS,. w. s. BKISTOWE AND o. H. LOCKET ON THE

if he did possess a.ny*. The male appears t o court t h e femtile chiefly i n t h e evening when she has retired t o her burrow, and, instead of '' dancing *' before her, he rippears to communicate by means of vibratioris, which she can probably .feel tlirough the burrow lining.

When t h e male of this species has come upon t h e trail of a female he reminds one of a hound following up a scent. He becomes very excited, and appears t o advance in n zigzag fashion along t h e trail, feeling t h e ground with his pelps and t h e tips of his legs, often touching t h e ground two or th ree times with t h e la t ter before a c t d l y put t ing tliem down. Having discovered t h e female's burrow, he advances with quivering abdomen. and, having reached t h e entnince, he draws iip liis legs and vibrates h i s abdomen very rapidly. He becomes excited, and at interrrds (after about six abdominal vibrations) a violent jerk of the whole body takes place. The femiile appeals t o heconie nwiire of his presence, and is often at t.he entrance to her burrow. After a, t ime he slowly advances, still vibrating his abdomen, aiirl, witjb his f ront legs waving in f ront of him, at.tempts t o touch her and also descends the burrow. Very often the female rushes foi+h, and sometimes he retreats, b u t usually she runs away followed by him for x short distance with legs outstretched " imploringly." After her withdrawal, he returns t o her burrow and takes posses- sion of it, even when she is still standing close a t hand. Her scent must be very strong here, and, t rust ing to his sense of smell ra ther than t o his eyesight, be explores i t carefully. After a short t ime she returns, but if he ip still in poFsession of her burrow she usually retreats. Courtship takes place at all times of t h e day, but copulation appears t o take place most frequently in t h e evening. Shortly after 7 P.M. on April I6th, 1921, R male WAS observed (W. 8. €3.) si t t ing near the burrow of a female vibrating his a.bdomen. The female, a t t h e entrance t o her burrow, lifted her f ront legs as though about t o repel him, but then moved them up and down exactly as he \ \ a s doing as he advanced t o meet her, t h e only difference being tha t she did not vibrate her abdomen. The male touched her with his f ront pair of legs, and then vihrated them very rapid.Iy: creeping over her at t h e same time. H e stopped, and with body raised moved fur ther over, and then with R dart, seized her round t h e junction between her abdomen and cephalotlio~.ax. Hfiving renched this position of mfety, he lent eyer to t h e right$ gently quivering his abdomen, nnd inserted a pall). This occurretl at 7.20. A t fairly regular intervals he changed his position from

* On many sandy heaths there is a Fossorial wasp ( P O ? ? I ~ ~ ? U S ) Psamvzockares uiaticw which hniita Lycosid spiders. The uraal prey is Trocliosa terricola, and ont of 36 spiders taken from these wafips in April 1021 at Oxshott and Ripley two were T. picta, one was T. barbipes. and tho remnilider T. terricola. T. picta iri cgmmon in those localities, and it may owemucli to its protective coloratioii. Pom- pilus plumbeus and probably other Ponipilid W I S P S also store their nests with

'

T yicta. (W. 8. R.)

COURTSEIP 04' BRITISH LYCOSID SPIDERS. 323

one side to the o ther as follows :-7.23, 7.25, 7.274, 7.306, and finally left h e r by springing away backwards at 7.334. Copu- lation was ohserved on two other occasions ((3. H. L.), but, since t h e female in neither case had been given time t o construct her burrow, t h e eoilditions were somewhat unnatural. In one case there were four and i n t h e other five applications of t h e palps, the total t ime taken being 41 and 64 minutes respectively.

Males of this species (as in t h e case of other species both of t h e Lycoside and Attidre) have been seen courting other T. pi& males and also immature forms of both sexes.

TROCHOSA RURICOLB Degeer. This is a ra ther plump, heavily-built brown spider which

is t o be found most commonly under stones and heaps of debris etc. i n fields. The male is like a d i m and d ight ly darker edition of the female, with black tihise and tarsi to the f ront pair of legs. W h e n excited by t h e presence of a female, these legs a r e alternately waved i n t h e air , nncl thereby this distinctij e

(Text-figs. 3 & 4.)

Trochosa ruricola Degeer. Male disrlayiiig oiie of his darkeired front legs to a feihale.

characteristic is prominently displayed. The u s i d proceeding is somewltat a s follows :- 011 being pl~ccci with a female, one leg is raised quiveri1;g above his Itend, and then slowly lowered and straightened i n f ront of him ; as i t is lowered, tiie last two joints, t h e tarsus and meta.tni.sus, a r e gently wa.ved up and down, moving loosely and reminding one r r f t h e graceful wavy arm-movements of some classical dancer ; having iwched t h e ground, t h e other leg i.s then raised in similar fn.shion, somewhat outwards and bent at t h e tarsus, and then lowered quivering and waving to t h e ground as before ; perforniing these motions a,nd with his palps vibrating and wit.h occasional abdominal pulsa,- tions, he slou.ly advances towards the female : sometimes he will

324 MESSRS. W. S. BRISTOWE AND Q. H. LOCKET ON THE

continue these antics for hours on end, re tur ing again and ngain a f te r being fiercely driven nwny by t h e female; when he is allowed t o come within “ arm’s length,” he stretches out both legs to: touch her, and tickles her, gently at first, and then more rapidly as he at tempts t o creep over her. On more t h a n one occasion, after each of which copulation WRS observed ( G . H. L.), she was seen t o reciprocate his leg-movements. Copulation lasted 1 hour 7 minutes, and during this t ime one palp was

Troc7tosa ruricola Degeer. Yale stretching out and gently waving one of his front legn.

inserted four, t h e other five, times, t h e applications lasting from 1-9 minutes. The female is often t o be found in little siik- lined hollows under stones, and, on one occasion, B male entered one of these and copulation took place.

Males mill begin their courtship motions after being pla.ced i n empty bores which had previously contained a female. By placing collodion over t h e female’s spinnerets t o prevent her from trailing a thread, it was shown t h a t her detection was effected by mea,ns of liis scent-organs. One male performed his antics i n it box previously occupied by a n immature half-grown female (G. H. L.).

TROCHOBA TERRICOLA Thor. (Text-figs. 5, 6, SS 7.) This species is very similar to T. ruricolu in general rrppearance,

b u t is often slightly more reddish in colour. It has a wider distribution, and i n Great Britn.in is f o n d under debris or stones on lieathland and i n moods, and is one of the commonest spiders on the islands u p t h e West Coast of Scotland (W. S. B.).

The courtship (W. S. €3.) though distinct from tha t of T. ruri- cola is very similar. W h e n placed with a female, t h e male raises both his f ront legs i n t h e shape of a n inverted U with t h e femur roughly Tertical, t h e patella and tibia horizontal, and t h e tarsus and metatarsus vertical. After strtying i n thin position for IL short time, one leg is miserl m d waved in a manner resembling T. ruricolu, and then lowered. Twitches of t h e male’s abdomen were observed as i n T. ruricola.

COURTSHIP OF BHITISH LYCOSID SPIDERS. 325

Trochosa terricola Thor. Male in the first courtship position.

T , * O C ~ O S U terricoln Thor. Male in the second courtship position wit]] one leg raised above the head.

Troclrosa terricola Tlior. Copulation position typical of the Lycosidae. Male leans over side of female and turns her abdomen slightly on one side. (Female shaded.)

326 MESCIHS. W. 5. BRISTOFE AND 0. II. LOCKET ON TEE

The only fenides available at the time the above observations were made were some pnralysed ones taken from a Fossorial wasp, Psanmochmres viaticus, so they could make no resistance to the attentions of the male. H e ndvanced with quivering front legs and placed them on her head. Then, with trembling body and legs, he crept over her and clasped her round the Maist.” After a short pause he leaned over to one side and inserted a palp. Starting a t 3.30 he clianged sides a t 3.47, 4.9, 4.26. 4.34, 4.45, and leEt her at 5.8. A lot of time was wnsted through the difficulty he experienced in raising hey abdomen sufficiently to enable him to insert her palp.

LYCOSA AMENTATA Clerck. (Text-figs. 8 & 8 CL)

‘L’he spiders of the genus Lycosa are usually smaller and less The niajority are brown robustly built thltn the preceding OIWS.

8 & 8 a. Lycosn amentata Clerck. Mals displays his black enlarged palps, alternately raising one and lowering the other. (Viewed from i n front.)

COURTSHIP OF BPI’ lSH LYCOSID SPIDEHS. 327

with rather indistinct markings, and t h e males resemble t h e females, b a t are usually slightly sliinnier and darker in ,colour. T h e f ront legs in t h e male a r e not enlarged or modified in any way, as they were i n Z’rochosa and Turentula, b u t their p d p s axe often a conspicuous sexual character, and these a r e prominently displayed when a female is at hand. We have watched the males of L. awentata courting t h e females on sevei-nl occasioiis in early summer (April and May). The male, standing rather high on hie legs, stretches his palps out sideways and raises one of them at a n angle of 45”, while t h e otlier is lowered a t :t similar angle. Stailding i n th i s posit,ion, with his striking black palps conspicuously tlispla.yed, he makes his palps and front pair of legs quiver violently, and occasionally liis abdomen quivers also. The palps are withdrawn and then stretched out with their positions reversed ; ttgaiii they a re witlidra.wn and stretched out-one raised, the other lowered. RepeaLing these ‘. seiiia- phore ” movenieiits over and over aga.in, he sloivly advances towards t h e female, until finally she either drives him away or else beats a Iiasty retreat herself. W h e n die has disappeared, he walks about a i t l i excited jerky steps, “feel ing” t h e ,ground with his palps and tlie tips of his legs. After courtship of this kind has been going 011 for varying periods, tlie female also becomes excited and vibrates her f ront legs niid aLdcinen mucli i n t h e same way ns he does.

LYCOSA NJGRICEPS Thor. This species iu lightish brown, a n d i n t h e male t h e digital

joints of t h e palps are R very conspicuous character, being

(Text-figs. 9, 9 u, & 9 b.)

enlarged and jet-black. As i n t h e l a s t species, the palps are waved about in a miinner which reminds one rather of a sema- phore signaller, bu t t h e motions a re easily d idnguished from

328 IERSRR. w. s . BRIBTOWE AND a. n. LOCKET ON THE

those of L. amentatn. The palps are waved in a rotat,ory motion, which is made up of a series of jerks so quick in succes- sion that they almost appear to form one continuous movement.

9, g n , & g 6. Lycosa Izigrieeps Thor. Male rotates his palps in a rapid series of jerks. (Viewed from in front. Legs and body omitted.)

Normally both palps move together-one in an upward, the other in a downward, direction,-but sometimes they move sillgly. Copulatioil lias been observed on one occasion after an interplay of front legs. One palp was inserted 9 times, the other 10, and each application lasted froni 12 to 27 seconds (G. H. L.).

LYCOSA PULLATA Clerck. There are no marked epigmiic characters in this small species,

a i d the male resembles the female except for a general darkening of his head and palps. When sexually excited the niale walks about in R curious jerky manner, '. feeling '' the ground with his pdp as he goes; but courtship movements scarcely seem to

COURTSHIP OF BRITISH LYCORID SPIDERS. 329

exist, and we have seen males leap on to the backs of females without any apparent preliminary warning. On two occasions (G. H. L.) we have seen males copulating with females which wera carrying their egg-sacs.

Copulation, in the one case observed (a. H. L.), lasted 14 hours, and it had begun before the spiders had been found. During this period each p d p was inserted 13 times ; 5-10 seconds was a fairly average time for each application, though in one case it lasted 3 mitiutes 50 seconds. The females of this genus seem but little affected by the process of copulation, and are often to be seen running about with the males on their backs.

LYCOSA PALUSTRIS Linn. The bpiders of the genus Lycosa attach their egg-sacs to their

spinnerets, and run about and hunt their prey in normal fashion. It is a well-known fact that if these egg-sacs are removed and a little wad of cotton-wool or other niaterial placed beside the spider, this will be carried about instead. Under natural conditions the spider i s seldom deprived of its eggs, so the discovery of .a specimen of this species running about with a very small empty snail-shell attached to its spinnerets is inter- esting (G. H. L.).

We have dealt with our observations on the courting move- ments of spiders belonging to three genera of the family Lycosida. Few as they are, they are sufficiently representative to show that there are considerable differences in the behaviour of the different niembers of the family-the complicated courtship of Tarentula bnrbipes, for instance, is very different fro111 the palpal motions of LycosLc anteittata. There is LI school of thought that the genera Tarentula, I'rochosa, and Lycosa (as ilsed in this paper) should be combined in one genus-Lycosa. NOW, if we were to take Tarentula bnrbipes and Lycosa aine,itata only. we would certainly be opposed to this view ; but when other species of these genera, and of other genera, are hrought into the question as well, we find that the generic characters, which were originally supposed to exist, become very flinisy and merge into one another. An examination of the courting antics 5eems to give the same result. Starting with the genus Lgco~a, we have shown that in L. wigriceps the male waves his palps, while in L. ainentatcc he vibrates liis front legs in addition. In Trochosa picta he vibrates his legs in a very similar manner to L. antentata, and in 2iwentula nzericliaita he rnrries the actions of T. picta a step further by raising his legs. The actions of t,he T. nzericliana male are not very different from those of Tareittula pulverulenta and Tarentzda cuneata, and those of T)*o- chosa tewicola are also r.rther similar but with fewer vibrations. From Tarentzda pulverulenta and Trochosa tewicola the relation- ship of Taarenttcla barbipes and Trochosa m.wicola respectively can

330 M&YSRS. W. S . IIRISTOWE AXD Q. H. LOCKET OX THE

be seen. I n the fornier ca.se the male movements are more active, and he raises his front legs higher ; in the latter, one leg is raised a t a time, and somewhat higher, but in rather the same fashion.

The position taken up during copulation is another guide to relationship. The male palpnl organ is very complicated, and i n order that i t may be iiisertd, one position, and in all probability one only, is possible for the male of any one species. Thus, as Prof. U. Gerhardt (11) points out (1924), i n the family Thoinisidre the TibeEZus male leans over the side of the female (in a position similar ta the Lycosirl), the Philoclronws male leans further over until his body is vertical, while in Xysticuh his body is also verticai, but lie is leaning over the end of the feinale abdomen, and in JIiszcmei~a he creeps right nnderneRth. Prof. Gerhardt shows that these positions are dependent on the body- structure.

The large, slim Hunting Spider, Pisaura nzirnbilis, wa.s placed in the family Lycodre by some early systematists, and here we give our observations on its mating habits to show how different they are from those we have been considering. This species is now included in the family Pisauridz.

PISAURA MIRBBILIS Clerck. (Text-fig. 10.) A inale was given a fly an(T placed in R box with a female.

He proceeded t o enwrap the fly with silk, and then wallred about with it in a jerky fashion until presently the attention of the

Text-figure 10.

Pisaura miruhilis Clerck. Copulntion positiou very different t o that taken up by the Lycosids. The feniale is eating 8 fly previously wrapped up and given her by the male.

female was attracted, and she approached him. He held out the fly to her and, after testing it with her falces, she seized hold of it. The male then crept to a position utmost undemreadh the female, a little to one side, and inserted his right palp. After

COURTSHIP OF BRITISH LYCOSID SPIDERS. 33 I

25 minutes lie withdrew his palp and joined the female at t he fly, and then, after some cnrious jerky movements, he inserted his left palp. This was x-ithclmwn after 16; minutes, but i twas applied again for mother 6$ minutes, and finally the right palp was applied for 163 minutes, the total time of mating being 1 hour 11 minutes.

On another occasion the male did not have time to wra.p up the fly, but the female lespt down to him and seized i t from him. Matiiig followed, but only one p d p was applied (for 18 minutes) before they separated. Throughout the mating the female sucked the fly. One male wliicli wns placed with a fly in a case where a female lincl just been, caught it and wmpt i t up a t once. On the following day he was given R fly, and ellclosed in a case where no fema.le had ever been. H e at0 the whole of it without making ;my n.ttempt to enwrap it. Another fly was given him, arid this time he was placed in d ie feniale’s empty case, all trace of her web having been removed, as far as possible, lest this should have some stimulating effect. The result was as before, and he proceeded, after walking about the case for a short time and “ feeling ” the ground, to wrap up the fly with silk (G. H. L.). I n Tarentula, scent was R sufficient stimulus to make him begin his courting display. I n Pisnum, sight does not appear to be so well developed, and the male possesses no epigtniic chamcters, so the Attid or Lycosid kind o‘f courtship would not be so suitable. It is interesting to find t1ia.t he is also shimulatecl by the scent of n female” to conimence his mode of courtship-namely the preparation of food as an offering. This is rather a romnrkalhle piece of instinct-a carnivorous creature like a spider deliberately giving up his food as an offering to the fetnale t. A rather pardlel case occurs Rmongst some of the Robber Flies of the family Einpidae, which always catch a fly to give their females before seeking to mate with them. A t the end of this paper some references to work on this subject will be found (see Aldricli (l), Hamm (13), Howlett (17), Poulton (32)). In some cases the present is enclosed in a silky covering produced by the male, and i t has become a kind of ornament or phything, but in other cases, and in Enapis livicla, as we have ourselves observed, the female devours the fly during copulation (W. R. B.).

Thus in Pisaura mirabilis not only is the courtship very different from that of the Lycosids, but also the mating position taken up, with the male almost underneath her and slightly to one side.

* The fresh flesh of a female smeared round his box does not stimulate him to wrap up the fly. t In one case, before the habits of the species were known to us, when the two sexes were placed together in a box, the female leapt upon the male and killed him. No fly had been provided (W.S.U.). Re “giving up his food” to the female, a male has been seen to wrap up the dried remains of a fly he had himself eabu, as his gift to a female! (G. H. L.).

(G. H. L.)

332 YESSRS. w. 8. BRISTOWE AND Q. H. LOCKET ON THE

The mating habits of Pisaura nairubilis have been described by earlier workers, and their descriptions tally very closely with ours given above. Van Hltsselt described the courtship in 1889 (Tijdschr. Entom. vol.xxxii.) and Prof. U. Oerhardt more recently, in 1924 (11). On one occasion Prof. Gerhardt saw two males courting the same female, one with a blue-bottle (CaZZz$hora) and the other with a spider as an offering. The female chose the Calliphoru, but whether on account of its greater size it is impossible to .say. On another occasion a hungry female jumped at and seized the fly held by a male just as we ourselves observed in one case.

2. TEE SENSE OF SMELL AND ITS RELATION TO COURTSHIP. In 1887, Mr. and Mrs. Peckhani (29) found that spiders

belonging to various families responded to essential oils, such as peppermint, lavender, cedar, cloves, and wintergreen, when these were brought close to them, by movements of the legs, palps, and abdomens. Pritchett (33) (1904) found that a Lycosid spider was repelled by both irritating and non-irritating oils, and move- ments of the mandibles and palps were noted, with the raising of each leg as the scent was placed below it. Attempts were made t o localise the scent-organs without much success. It was noted that the 1st pair of lees was raiwd highest, the 2nd pair the next highest, the 3rd pair next, and the 4th pair least of all, ns the scent was placed in turn immediately below each pair. This was thought t o indicate that the sense of smell was situated somewhere in the legs and that i t was strongest in the 1st pair, being followed in order by the,2nd, 3rd, and 4th pairs. The removal of spines and hairs appeared to make no difference, and mutilations only gave negative results. The experiments of McIndoo (21) (191 1) are of considerable interest. Having shown that spiders reacted in the manner recorded by earlier experi- menters, he tried to show that the lyriform organs constituted the organs of smell in spiders. The function of these organs had never definitely been established. In their position they are remarkably constant in all families, and are diqtrihuted fairly evenly all over the spider. I n addition to the legs nnrl palps, which have two or three to each joint, they occur on the mandibles, maxillq sternum, spinnerets, and the underside of the abdomen. McIndoo’s sections show them to consist of minute, flattened, funnel-shaped organs f t~rnisherl with grids and connected up with n group of nerve-cells. A varnish (vaseline) was carefully daubed over each of the larger lyriforrn orgms, Bncl the sense of ?me11 mas then fouiid to have been impaired, the time taken to react to the smells being considerably increased. Heivitt (14) (19161, 011 the other hand, experimenting with a Trapdoor Spider (Stasinzopzis sp.), came to the conc~usion that the scent-organs mere not spread all ovw the body, but were concen- trated in the tips of the legs, probably in the scopula hairs, By

\ COURI'SHIP OF BRITISH LYCOSID SPIDERS. 333

means of a hatpin dipped in various essential oils and then broiight close to various parts of the spider, he came to the con- clusion that the tips of the legs alone were sonsitive to smell. When the hatpin wab brought clove to the t ip of a leg, tha t leg was raised or withdrawn within a few seconds. If the tip was removed at the centre of the metatarsus, that leg did not respond, but, when removed at the centre of the tarsus, H. feeble response was noted. H e caine to the conclusion, like Pritchett, that the two front pairs of legs were more sensitive than the hind pairs, and, like McIridoo, tha t the sense of smell WRS more highly developed in the male than in the female.

W e have set forth a summary of the more important experi- ments on the sense of smell in bpiders, and, while they all point t o spiders possessing a sense of smell, one view holds that the sense is distributed over the greater portion of the body, and the other holds that i t is localized in the tips of the legs. Further, although they prove that spiders possess a sense of smell, they do not show that this sense is made L I S ~ of in sex-recognition; in fact, the writers on the subject assert the reverse (see footnote, p. 320). I n our experiments we have constantly noted tha t male spiders will repeatedly " feel " the ground with the tips of their legs and the uppw surface of the pnlps when a female spider has passed that way, and on several occasions we have seen mdes start their courtship motions after feeling the ground over which a female has passed *. On one occasion (W. S. B.) a female Trochosnpicta, after being placed in a large box, was made to walk over a certain piece of ground, and then she was renioved. Shortly afterwards a male was put in this box, and on crossing her track he immediately became very excited. After feeliiig the ground carefully, he advanced along the course she had taken, touching the ground wit,h the tips of his legs and palps on each side as he went, in a manner which reminded ong very much of a hound following a scent. I n captivity the female spider's tracks must, as a rule, be very confused, but under natural conditions i t seems probable that the male can follow the path taken by a female by means of his sense of smell. I n the family Attidse sight is more developed, so smell should not be so necesisary. The Peclrhams and Petrunkevitch assert that sight, and sight alone, is used, and Montgomery (25) tha t touch and sight are the two senfies used, the former being the more important; but, though we (W. 8. B.) have shown tha t the AttidE can recognize one another by sight alone (see p. 338), we have also found that they possess the power of recognizing the female by smell. If a male is placed in a box which recently held a female, he will become excited and feel the ground repeatedly, although he cannot be induced to perform his antics. A male Ediophaizzss

PXOC. ZOOL. S00.-1926, NO. XSIII. * T.pulverulenta, T. barbipe8, and T. ruricola.

23

33.1 MESSRS. W. S. BRISTOWE AX’D G . H. LOCKET ON THE

$avipes, placed in a box which contailled a female enclosed in R

dense silken cell, became very excited on feeling her web (W. S. l3.L I n other families, both web-builders (Epeirids) and hunters (Thomisids), the males appear to recognize the presence of R female by touching her web in the former case, or the ground over which sho has passed in the latter. W e have shown (G. H. L.) that the actual texture of the web is not the means by which the recognition is gained, as seemed feasible from Hewitt’s (14) observations, by preventing various Lycosids trailing their customary siken thread by applying collodion to the spinnerets. The kind of observations we have mentioned above all make one feel certain that male spiders possess smell- organs by which they can recognize the females, and that this sense is situated in the tips of their legs and palpi. W e (W. 8. B) have repeated the experiments of Peclrham, Prichett, and Hewitt, and found that spiders react to oils, such as wintergreen, clove, thyme, and pepperment, in the way they state, and that a hatpin dipped in one of these oils and then placed close to the tip of a leg will react in that leg very shortly being raised or withdrawn. The sense of smoll in the first t;rJo pairs of legs in the spider experimented on (Tffirelztula barbzpes) appeared to be more sensitive than the hind two pairs, and, after the removal of the tarsi, the sense Reemed to be very feeble indeed. I n one male the extreme tip of the palp and the tarsi of all the legs were removed under chloroform. I n twenty-four hours the spider had recovered almost completely, and caught a fly held out to i t in a pair of forceps. It was tested with a scented hatpin and was found to respond very feebly. It was plaaed in a box in which a female had recently been kept, and appeared to be just conscious of the fact, for at intervals a suspicion of a tremor passed down the legs. (A normal male had previously gone through the whole of his courting antics in this box.) Thus, this kind of experiment also points to the sense of smell being localized chiefly, at any rate, in the tips of the legs and palps. McIndoo’s experiments, in which he daubed the lyriform organs with vaseline, may be unsatisfactory in that the vaseline may have covered other sensory portions of the leg as well, especially as the vaseline is inclined to spread and form a film over the whole surface. The suggestion of Hewitt that the senbe of smell is situated in the scopula hairs is open to very serious difficulties. The acopula consists of a mass of truncated hairs apparently opening freely to the exterior, and it is more strongly developed in the front pairs of legs than the hind pairs, Now, in the Lycosids the scopula is highly developed, but in some families it appears to be absent, which seems to form rather a difficulty to our theory that the sense of smell is localized in the scopula. On the other hand, it must be borne in mind that the LycoRids are hunting spiders, and that to follow the trail left by a female passing over the ground once (as we believe actually takes place)

COURTSHIP OF BRITISH L Y C O S I D SPIDERS. 335

requires a more developed sense of smell than in a web-building family, for instmice, where the male has only got to recognize the web of the female. To put i t crudely, a few hairs or hairs less highly sensitive might be sufficient for this. If we accept this view, and we feel there is a certain amount of evidence for i t or, a t any rate, for the sense being largely IocaIized in the tips of the legs and the upper surface of the palps, we leave the lyriform organs without any identified function. The way in which the male spiders continually feel the ground suggests that the sense may be largely a sense of smell by touch-in fact, rather akin to taste, for the difference between the senses of smell and taste is only one of degree. McIndoo’s figures of his sections out through Iyriform organs preclude any ides that they might be glanduiar in function, either producing the distinctive specific odour or an oil to cover the body and prevent their sticking to their own web etc. I s it possible that they are also scent-organs-organs for recognition of smells from a distance and not merely close a t hand, and by actual contact as the tarsal organs would appear to be (W. S. B.)? Does the male web-builder, for instance, go on wandering about until he stumbles upon the web of a female, or is he able to detect the direction of a female at some distance like a male moth, for instance Z

That they are sensory seems certain.

3. THE SENSE OF HEARIXG AND ITS RELATION TO COURTSHIP. (W. S. B.)

Whether spiders can hear or not is a question which has never been definitely established. Dahl (6) (1883) believed that some of the hairs of spiders had an auditory function, and, according to him, they vibrated when a tuning-fork was placed close to them ; but Wagner (35) (1888) failed to repeat his results. Some spiders appertr to be conscious of the vibrations set dp by a tuning-fork not only when i t is placed in their webs, but also when it is brought close to them. Whether these vibrations are 6‘ felt ” o r “ heard ” is difficult to prove, as the difference is largely one of degree. The experiments of Mr. and M i x Peckham, McIndoo, Pritchett, etc., have been negative except in the case of the family Epeiride. W e ( w . S. B.) have found that the family Dictynids (Anzaurobius and D i c t p a ) also respond to a tuning-fork. One rather interesting experiment was carried out on Anaaurobius sinzilis. Tlie larva of a Staphyliil beetle (0cgpu.g &zs) was placed in the web of this spider. It wriggled and squirmed a lot in its attempts to get free, and although the apider canie to the entrance of its retreat, it refused to come out and investigate the cause of the commotion in its web. After nearly a quarter of an hour a tuning-fork was vibrated and placed in the web beside the wriggling beetle-larva. The owner of the web immediately rushed forth, and with considerable excitement

23*

336 NESSRS. W. S . BRISTOWE AND 0. H. LOCKET ON THE

seized upon t h e tuning-fork and wallred up i t , biting it con- tinually and t rying to find a tender spot. So excited was t h e spider tha t i t was lifted r ight out of its web, and not until t h e vibrations cea,sed did it a t tempt t o retire t o its home. The significance of th i s experiment is t h a t whether the spider ca.n lie:i,v or not, i t can differentiate between t h e different kinds of vibration set u p in its web. This fact is of considerable imporb ance t o t h e male spider, whose distinctive “tweaks ” and shalrings a re inimecliately recognized by the female.

Several types exist: biit for our purpose they can be divided into two chsses: (1) those which itre found equally developed in both sexes, and (2) those which a re found in t h e male sex, but which a re absent or only rutlinientnry in t h e femdes.

These spiders produce a. sound like a comb being rubbed against a. file when they are teased nnd p lmxl on the defensive. It seems probable t11a.t t h e function of the stridulating organs i n this case is t o frighten enemies. The Theridiitl= a re exrtmples of t h e second class, and the males possess some teeth on t h e front of t h e abdomen which a.re situated exactly opposite a, file-like process on the cephalotllornx. No sound has ever heen heard, biit suitable movemeiit,~ to bring t h e teeth into play with the file hare beeii observer1 (\V. S. R.) during courtship, which monld seem t,o intlica.te that, i t was R means of ina,king the female a.wni-e of his identity. The sounds produced may be very sma,II, or else out of range of hearing altogether, or t h e range of he:tring of spiders may be very limited, which would exphin their failure t o respond t o tuning-forks ; but we ( \V. S. R.) believe t h a t there is another nlterna.tive-that they c:wnot hear at n l l . W e hnve shown above tha,t the Avicnln.riidz, which possess stridulating orpa.ns in hoth sexes, probably use them to frighten away enemies mhich ca.n hew. I n this case i t is not essential t h a t they themselves shoiild possess any sense of henring. I n the other class, where stridula.ting organs, which nre possessed by t h e male only *, are never used apparently except ill tinies of courtship, i t seems obvious a.t first tha t they must convey some distinctive sound t,o t h e female by which she can recognize him. The TheridiidR are web-builders, and whether sound is producecl and heard or nott i t is certain tha t t h e gratiiig of t h e two pnrts of t h e body together will convey a distinct vibixtion through t h e legs mr l thence d o n g t h e web t o the female in t h e same way as, we believe, t h e vibrntions of the t,uning-fork were carried. The distinctive vibrations set up by t h e male web-builders when courting a female, whether i t be t h e tweakings of t h e web by t h e Epeir ida or t h e jerking by t h e Linyphiiclw etc., or, as we‘ suggest, vibrations set u p b y t h e stridulating organs, a r e recognized immediately, as is shown by t h e female’s behavionr, which is

Some spiders possess stridulating organs.

To the former class helong t h e Aviculariidze.

* Some of the females possess rudimentary stridulating orgnns.

CV UWLYHIP O F BRITISH LYCOSID SPIDEILS. 337

very different from that meted out to the orclinary intruder *. Some experimenters, and we amongst them, have found that some Epeirids will apparently become conscious of a tuning-fork if it is vibrate.d and then placed close to thein; but it is our experience that i t must be placed very close to them indeed, so close that the vibrations would almost certainly be felt by means of the spider’s sensitive tactile hairs, even if they were not heard in the ordinary meaning of the worcl. The Huntimg Spiders, whose livelihood does not depend on their tactile sense, appear to be unconscious of the presence of a tuning-fork placed close beside them.

Before leaving this subject of sound, there are one or two other observations which we ought to mention here. I n two cases we (W. S. B.) have noted sounds produced by spiders which d~ not possess stridulnting organs- Tnrentuba pulverulenta and E260ph?*yS frontalis, an Attid : in the case of the former by the pulsating ilbdomen sharply hitting the ground, and in the latter by the legs being raised, and then sharply lowered so that the tips of the second pair strike the ground with a click. Various Lycosicl i d e s vibrate their legs and pdps very rapidly when excited by the presence of a female, and an American species, Lycosn kochii, is said to produce a purring sound by these appendages strikiiig the ground (19). I n some British Lycosids both of the present authors have noticed the males pausing in the middle of their courting motions and convulsively rubbing their spiny legs together very rapidly. 30 sound was audible, and the ex- planation is doubtful?. Burrowing species of Lycosids, such as 1’. picta, and also of other faiuilies (d4typ26~ afiiltis, for instance) drum rapidly with their palps and legs on the ground a t the entrance to the female burrow. In some of these cases the vibrations will be felt by the female along the burrow-wall, and probably recognized by her, as in the web-builcling forms, ay the wo1.k of R suitoi..

4. SEXUAL SELEWIOX B K L , THE EVOLUTIOX OF ANTICS DURING COURTSHIP. (W. S. B.)

The majority can scarcely see further than they can feel with their outstretched legs, niid evidence is all in favour of the view that primitive spiders likewise had short sight. Now, the tips of their legs

* The female Garden Spider, Ep0iil.n Jiademata, is nil exceptionally rongh species. t T a r . barbipes, T.yulverulenta (W. S. lL aiid 0. H. L.), T . cuneata, Trocli. picta, Lyc. n i g r i c s p , L. amentata, and Pis. mirabilis (G. H. L.). Similar movements, but of n less pronounced nature, h a w been seen in some web-builders (Linyphia, for instance), and precisely siiiiilnr nioveiiieiits have been observed in the case o f Agsldiuc Zabyrinthica (G. H. L.). The action may be due merely to sexual excite- ment (G. H. L.), or, seeing that the legs contain sensory orgniis, i t may have tlie effect of sharpeiiiug the senses, and be eqniralent to blowing oiie’s u06e or taking off oiie’s gloves (W. S. B.).

Spiders are very short-sighted crea.tures.

338 MESSRS. W . S. BRISTOWE AND 0. H. LOCEET ON THE

possess a very acute sense of touch and also, we believe, smell, and many wandering spiders (DrassidE, Clubionide, and Dysderidae) stretch out their long front legs as they walk, much as a blind man stretches out his hands to feel the objects in front of him. I n these families of spiders, where sight is of little use, the male becomes ‘* conscious ” of the presence of tlie feinde 011 crossing her track, by means of his scent-organs. Having struck the trail, he attempts to find her, and by alternately feeling the ground with the tips of his legs 2nd raising them in a groping fashion, he can eventually discover her position. These motions, which one sees so often in the short-sighted wandering kinds, such as Drassus and Dysdera, are precisely what one would expect from it creature possessing both olfactory and keen tactile aenses in its legs. If he does happen to touch her before he is ’‘ coi~scions ” of her exact position, as often occurs, he is imme- liately aware of her identity, and is much more likely t o be able bo beat a hasty retreat, ik necessary, than he would have been had he walked straight into her. As sight develogetl, the males became less dependent on the senses of sinell and toucl: to recognize the female, and, in the extreme case of the Attide, the Peclrhams concluded that sight alone was used as a 1 ~ e a . m of recognition. Various Lycosid and Attid niales mill go through their courtship antics before one another, and they found that i1n Astic6 vittata nide would do so before its own image in n looking- glass. W e (W. 8. B.) have successfully repeated this experiment with I%kerillus v-insignitus, but have shown that recognition in the Atticls is also possible by smell. Though we have grounds for believing tha t the Lycosids can also recognize one mother by sight *, the sense in this family is not so highly developed, and, as we have showii, the sense of smell is still largely made use of. Now, although it seems probable that the antics of the males in :he long-sigh ted Lycosids and Attide originated in the groping movements of their short-sighted ancestors, the retention and coinplication of these moveriients has, we believo, subserved a direrent biological function, I n these families, correlated with increased vision axe epiganiic characters often of a very striking nature. I n the At t ids , wliere the females are in many cases dull- coloured, the males are bright and possess queer tufts of hair, enlarged front legs, and other ornamentations. The males perform antics before the females, and ta,ke up positions usually most suitable for the display of these features. I n tlie Lycosidse, where

* The male. after being “warned” by his smse of smell of the presence of a female in the neighbourhood, certainlv appears to recognize her, judging by the way his antics are directed towards her, au”d by the way lie hotly chases away otlier males, he also seems to recognize that sex by mems of his eyesight. Though r e are both of the belief that certaiu male Lycosids will Rtart their displays on sighting a female without having previouply been warned of her presence by smell, conclusive proof has up till now been lacking. 011 one occasiou a male T. barbipes was seen per- forming for the benefit of a male Trochosa ruricoln, which was separated from him by IL glass partition, and on the removal of tlie Troelosa his autics ceased. (G. H. L.)

COURTSHIP OF BRITlSH LTCOSID SPIDERS. 339

sight is also developed, but not to such a great extent, the ornamentations are present, but not to such a marked degree, and the antics though performed a.re not so spectacular. A. R. Wallace (36) attempted to explain the phenomena of the male coloration and displays a s being due to the greater vigour and higher vitality of the male at the mating season. I n the combats whicli occur between the male spiders (as in other creatures) the vigorous would survive and, if colour was correlated with vigour, colour also. T. H. Montgomery (22) and L. Berland (3a) followed Wallacian views as to the origin of the male ornamentations being outlets for his extra vigour. The former believed the courting a.ntics to be a mixture of physiological excitement and the instinct of self-defence, while the latter, after seeing the males of an Attid, Sffiitis bffirb+es, performing their antics when quite alone, came to the conclusion that they were nothing more than " l'interprktation externe de la granrle excitation physiologique." Mi.. and Mrs. Peckham followed the Darwinian theories of sexual selection. I n the mating season male Attids are often more numeroiis than the femdes, and they cnme to the conclusion that the males dancecl before a female, dis- playing their charms to the best of their ability, and that the female ultimately chose the most beautiful male. I n this way, they argued, by the continued selection over t i great period of years of the most beautiful males, that sex has acquired its present brilliant hues and complicated '' love dances." I f we look upon the ornamentations and a.ntics of these spiders as being distinctive, rather than pleusing, to the esthetic sense, ws approach very closely what appears to us to be part, at any rate, of the true explanation. The male adornments are so diverse and their antics so different, eren in species where the fema,les are very similar, tliat the male of any one species has a very distinctive appearance. Surely, therefore, this is a feasible explanation- that the male Ornamentations and poses are of use to him as being points by which the female ca.11 distinguish him from other spiders. In the short-sighted families the male sometimes touches the female before he has recognized her presence by means of his eyes. On contact he immediately recognizes her, and manages to escape the fierce onslaught which usually follows, by means of his superior agility and by reason of his approach having come entirely as a surprise to her. I n a longer-sighted species his approach would hzve been observed, and unless his appearance were different from that of other spiders, she would in all probability spring upon him immediately and kill him. Thus a bright pntch of colour on his head, or any of the other epigamic characters which actually do occur, would form a " landmark," a s it were, by which he could be distinguished. I n the Atticlse, sight has become developed to such an extent t8hat the male can recognize the female from some little distmce, but, in the inter- mediate stage of sight development, which we find in the

340 MESSRS. m. s. BRISTOWE AND Q. H. LOCKET ON THE

Lycosidre *, the male begins his courting antics imniediately he detects her presence by means of his scent-organs. H e does not wait until he actually sees her before commencing. Perhaps those that did perished ! An Attid or Lycosid can see further than it can leap; and if the male starts his antics outside the danger zone, he.will be recognized whilst in comparative safety, and later can advance without being treated as some insect to be eaten. H e is seldom “accepted” a t onca, but tlie apparently fierce onslaughts of the female should probably be looked upon as n “ refusal” rather than as an attack with murderous intent, for, in our experience, once a male has started his courtship he is never, or practically never, destroyed by the female. She has recognized him, but it takes a varying amount of importunity on his pnrt t o make her sufficiently excited to submit herself to him. Similarly, the female web-builder recognizes the male directly he begins to tweak her web, but it is usually some little time before these signals stimulate her sufficiently to allow him to mate with her. Different species, and the same species at different times of the year, require different amounts of st.imulation. The only occasion on which we have seen female Lyoosicl spiders kill males of the same species have been in cases where the latter have failed to advertise their identity by their usual courtship motions. A male Lycosid (2%reiztulcc burbipes) whose eyes ha,d been covered over with paraffin-wax, a n d the tips of whose legs had been severed, did not go through the usual sexual motions when placed close to a female. H e ivns immediately leapt upon by the female and killed (W. 8. B.). Another male of the same species was killed soon after copulation had taken place (G. H. L.). He, likewise, was not performing his courting antics. Male T. barbipes with the tips of their legs and palps severed did not take up their characteristic attitudes on being placed in a box which had previously contained a, female, their scent-organs-the necessary stimulus-presumably having been removed. When placed in cases with feniales, these males fled in apparent terror whenever they came face to face with them (W. S. B.).

Thus, t o sum up, we believe thRt t,he groping movements of the short-sighted male spiders in their ahtempts to find the females, by means of their tactile and olfactory senses, were the origin of t,he complicated courtship movements of the long- sighted Attidse and Lycosidre t. That, as sight developed. the males would still resort chiefly to their olfactory sense, and if the legs, which the males mere in the habit of mising, were brightly coloured or adorned with tufts of hair, these would form

* L. Rerland @a) noticed inales of the Attid, Bstiu barbipes, performing their displays in the absence of other males or females of the same species ; so it seems probable that some Attids will also start their antics without seeing a femnle, on coming acroes her tracks.

t Montgomery’s explanation, that motions of self-defence were tlie origin of the displays, would not be at all suitable in many c,ases, in the genus Lyeosa, for instance, where the palps alone are waved ahont, in T. pulrerulenta, etc.

COURTSHIP OF BBITISH LYCOSID SPIDERS. 34 1

a very distinctive kind of “landmark” for the female to see. The more distinctive the male, the more likely he would be to be recognized, and therefore the less likely to be killed. Having been recognized, his life is no longer at stake, but it still requires a varying amount of courtship on hie part to excite her sufficiently to submit herself to him. In this way sexual Eelection of a kind would operate, for the more conspicuous males would always tend to survive and propagate *.

Having formulated the above theory for spiders, the natural sequence is to see whether it will apply to other groups. I n considering the case of insects we must take two important points into account : first, that the male will not be killed by the female, if he is not recognized immediately, and, secondly, that the compound eyes of the female insect in all probability give but a blurred image, whereas the simple eyes of the spider, limited in range though they be, are considerably superior in this respect. Taking these points into account, we shall not expect either such complicated courtship or such elaborate ornamentations as nre found in the Attid spiders and to a less degree in the Lycosidce also. In insects as in spiders the coming together of the sexes is aided by smell and sight. It is the duty of the male to find the female, and he usually possesses either more highly-developed olfactory organs (antennce) or eyesight. Some male insects, the nocturnal moths for instance, prohbly use little elae than their sense of smell to find the female, and instances of a single female enclosed in a wire-gauze box attracting numerou8 males to the room from considerable distances are frequent. Other forms of Lepidoptera appear to use their sight to a considerable extent. Eltringham (9) found t h a t certain male butterflies flew down to dead specimens, only veering off’ when quite close ; they did not fly down when these had been dyed a different colour. Weismann (37) says that the less strongly-scented Lepidopfera have brighter colours, and Poulton (37) that the males of mimetic species are sometimes deceived by the similarity in appearance of the two species, and that they will sometimes chase the females of the wrong species. I n the Lepidoptera we have a group where

* It should be mentioned that male spiders appear to be more numerous than females, although this is not always obvious owing to their sudden disappearance, in many cases, after the brief mating period. Thia has feat confirmation to the popular belief that the females always eat the males, but natural caunes are probably largely responsible. We do believe, however, that the females sometimes kill the males after copulation, a t a time when their sexual instincts are at a minimum, especially towards the end of the mating season when the vigour of the males is departing and with it their powers of escape; and this would be a very economic state of affairs, comparable to thecustom of thenatives in Tierradel Fuego, who eat their old women in times of food scarcity (see C. Darwin’s ‘ A Naturalist’s Voyage Round the World ’). In the mating season male Attids and Lycosids appear to be much more numeroils than the females. During the right period, there are frequently 3 or 4 males to each web of the large Epeirid, Nephila clauipes, in Brazil, and I have s m as many as 7 males in the web of a single lirgiope trz asctata i n Madeira. I n a count of 41,749 specimens of Latrodectus mactans, dntgomery found the ratio of males to females to be A’19: 1 (W.S. B.).

342 MESSRS. W. S. BRISTOWE AND 0. H. LOCKET ON THE

the sexes are roughly equal in size and where the males probably meet with but little resistance. In the Hymenoptera, however, the males are usually smaller and less powerfully built, so recognition by the female might be expected to be of some advantage. An examination of a collection of Aculeate Hymeno- ptera will show that in a great number of cases the front portions of themales are brightly coloured, while the corresponding females are all dull. I n the genus Proscopis, for instance, while the female faces are all rather similar, in most cases black with two small yellow spots, the males vary considerably. Some have yellow faces, some have black faces and yellow antennre, and in some the tibire are yellow in front. Combinations and variations of the above characters make the species very distinct when viewed from in front. This is only one example of many genera whiehmight equally well have been taken from the Hymenoptera- Megochile, A?zdrencc, Cerceris, Crabro, etc., and, as the Rev. F. D. Morrice (27) says, ‘* i t is at least probnble that her notice mould be attracted by the spectacle, and that thus, bo to speak, the ice would be broken, and the road paved for further overtures.”

Although failure to advertise his identity will not result in death in the case of insects, the more conspicuous form will probably hold some slight advantage over his more ordinary fellow. The female will presumably recognize him more easily, and will therefore be less likely to pass him by or try to escape from him. Stimulation is probably necessary before she is willing to mate with him, and this is probably Rft’orded in some degree by her sight of him. I n the long run this should result in the more conspicuous males niating more frequently than their duller brethren. Sturtevant’s experiments (34) on Drosophilid flies are particularly interesting in this respect. I n the first place he found that the normal red-eyed males-the males to which the females are accustomed-when placed in eompany with mutant w hite-eyed males in the presence of females, managed to mate more frequently than the latter. Similarly, he found normal males with grey wings were more successful than a new mutant type with yellow wings. Flies of the genus Brosophila often have coloured markings on their wings, and their wings are moved up and down when the males ase in the presence of a female. The stimulating effect of this on the female is shown by another series of Sturtevant’s experiments, which may be summarized

(A) I n each of a number of vials one normal male and one normal female were placed. I n 12 minutes, copulation was taking place in 59 of these vials.

(B) In the same number of vials one male with wings cut off was placed with vne female. In 12 minutes, copulatioii \*as taking place in 25 of these vials.

thus :-

COURTSHIP OF BRITISH LYCOSID SPIDERS. 343

(c) In the same number of vials (125) one normal ua le a . i d one male with wings cut off' were placed with a female. In 12 minutes, copulation was taking place in every vial-72 of the normal mdes and 53 of the males with clipped wings.

The conclusion to be drawn from this is that the normal male's display so stimulated the female that she wits readier to accept either male.

! h e argument brought forward by Morgan (26) (1913) and others that sight plays only a minor rdle in courtship is probably true within limits. The actual direction and locality of a female may be detected by the sense of smell in many cases, and iu certain forms little else may be necessary; but in the longer- sighted insects there is no doubt whatever that sight is used to a consirlerable extent, and it is in these forms that tlie distinctive colorations and adornments of the males are found *.

Little work appears to have been clone on courtship in Crustacea, but the observations of A. S. Pearse (18) on tlie ha'bits of Fiddler Crabs are extremely interesting. In these crabs the males have one greatly enlarged claw which is always coloured a little differently from the rest of the body. They make burrows in mud flats etc., and if a female walks across an area in the breeding season where their burrows occur, every male stands a t the mouth of his burrow and waves his large chela wildly in the air, 31 else he may alternat,ely squat down and stand up. When the female is quite near. t'he male may dance and posture, holding a t intervals r2 statuesque pose with uplifted chela for 10 or even 20 minutes. The chela is never used to hold or grip the female, but if she half enters his burrow he niay try to push her in. Copulation always takes place inside the burrows. Thus the displiiy of these crabs appears to he coniparable with those of the spiders with which we dealt in the earlier portions of the present paper. The male Fiddler Crabs fight fiercely against one another, nncl in these fights the enlarged chelae are sometimes broken.

In the present, paper it is not proposed to deal with the C R I ~ S

of the higher animals more than merely to compare the signification of their displays a.ncl sexual adornments with that of the foregoing arthropods. I n the forms we have dealt with up till now the two important features of courtship have been recognition and stirnukction. We have tried to show that the former was vital in the case of male spiders and important in the ca,se of insects, while the latter was essential in both cases. I n the higher animals with their greater niental powers recog- nition is an insignificant factor: but st(imu1ation esseiitial. nlale

* Caremust he taken not t o confuse certaiu other secoiidary ResuaI iriale characters, spacial adaptations for clasping the feinnle and aiding tho iirale to c o p u l ; ~ , ni1d certaiii body-colorations also wlricl~ require n diflereiit espla~irctio~i.

344 MESSRS. W. S. BRISTOWE AND 0. El. LOCKET ON THE

epigamic characters in birds and other vertebrates appear to have na their function an exciting effect upon the female, this effect being iiecewary before copulation can take place. W. Finkler's (10) experiments on the Mountain Newt (%ton alpestvis) show it to be a very interesting example of the effect of the male disphy upon the feude . The male tleposits a sperma,tophore on tmhe grouncl in tlie presence of the feruale, anti then a forin of display takes place which finally excites her to such a pitch that she takes up the spermatophore. I n the absence of a displiiying male, spermatophores placed close to a female are not picked up by her.

J. S. Huxley (18) tells us that most birds are monogamous, and that in thein display does not occur until after pairing-up has taken place for the season. Thus strict Darwinian principles of sexual selection are only to be found in the rather rare cases of po!ygnmous birds. The display has mainly a stimulative fnnction ; competition amongst the males does not occur, but the bright coloration and display serve to regulate coition.

From this survey of animal courtship i t seems clear that the bright rolours and stai,tling displays of different male animals require slightly different explanations, but, whether. t<heir func- tion be to gain recognition, to stimulate tlie female, o r to compete directly with ot.lier males, they have one thing in common-they nppe:il to the ininrl of the female.

The courtship is a peculiar one.

SUMMARY. Mnle spideis of the families Attidae and Lycohidz possess

epiganiic characters, and during courtship perform various antics before their respective females. Both the senses of sight and smell stimulate the males to these antics. Lycosid males will begin in a box which previonsly contained a female, Attid males in front of a looking-glass. The sense of smell appears to be situated chiefly in the tips of the legs and palpi-possibly in the scopula-and by feeling the ground the males can follow the tracks of the female. The sense of hearing in the true sense inay not exist at all, in spite of the presence in many spiders of stridulating organs. These may be used in the Aviculariidse for frightening away enemies, and in the Theridiids RS a means of producing distinctive vibrations of the female web during courtship. The Attidse and Lycosids are hunting spiders with relatively good sight, and the males often possess striking epigamic cliaracters which are carefully displayed during the courtship antics. I n short-sighted spiders the males lift their legs and grope their way as they walk, often touching the female with their sense-tipped legs before they see her. In longer-sighted forms the females would leap upon the males and kill them'before this could occur. If the legs, which these males were in the custom of raising, were decorated conspicuously, tho females

' COURTSHIP OF BRITISH LTCOSID SPIDERS. 345

would be more likely to distinguish them from other spiders as they approached, and less likely to treat them as soniethiiig to be eaten. This is thought to have been the origin of the complicated courting performauces of the longsighted Attidae a n d Lycosith. The Lycosid eyesight is not so developed as that of the Attidg, and, having dibcovered by their sense of smell that a female is in the neighbourhood, they commence their antics. The Attid males, though excited by the scent of the female, trust to their eyesight before displaying their distinctive epigamic characters. Ha,ving once commenced his courtship, the rnttle spider is relatively safe, and it is probably very exceptional for the female to kill the male, but it taken a variable amount of importunity on his part to stimulate her to such a degree that, she will submit' herself to him. Becognition and stimz~lation. are both necessary before copidation can take place. The males possessing the most effective epigamic cliitracters and disp1a.y will, in the first place. be most easilydistingnisheil (and therefore will be less likely to be killed), and, in the second place, erect the necessary stimulation more rapidly. Sexual selection should operate along both these lilies to produce males with distinctive displays and, in the longel*- sighted forms such as the Lycosids aiid Attids, with conspicuous epigamic ornamentations. A brief survey of courtship in insects leads 11s to similar conclusions, but here (1) sight is probahly not so clear and epigamic characters need not be coniplicated, and (2) tlea.th does not await the unsuccessful suitor, so courtship methods need not be so highly developed. I n vertebrates, with their higher intelligence, the recognition factor is probably almost negligible, but stimulation is R. necessity. In polygamous f o r m the nialds wliich can stimulate the feinales most rapidly will tent1 to have the largest nninber of offspring. I n certain monogxmous vertebrates, in particular the n i n joritp of birds, competitioii amongst the niales does not a.ppew to exist to any appreciable extent, the function of the display being chiefly one of stirnulation, the display not occurring until :tfter pairing-up has taken place. Although the functions of the bright colorn.tion and displays of different male animals appear to be soinewhnt different. they all have one thing in comnion-namely, an appeal to the mind of the female.

In conclusion, the authors wish to convey their thanks to Professor J. S. Huxley for the interest he has taken in their results, and for his helpful suggestions iu the preparation of the

Fhe drawings were made by W. S. €%.-those for L. nigr icep Paper.

and P. mirabilis from notes supplied by G. H. L.

346 MESSRS. w. s. BRIYTOWE AXD a. H. LOCKET ON THE

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(Edited by A. C. Seward, onn part being written by A. Weismann, another by E. B. Poulton.)