Observations of Female Aggression Towards Males Within Hogna carolinensis Courtship

8/13/2019 Observations of Female Aggression Towards Males Within Hogna carolinensis Courtship

1/8

Observations of Female Aggression Towards Males WithinHogna carolinensis Courtship Wu

1

Observations of Female Aggression Towards Males

WithinHogna carolinensis Courtship

Chao Jimmy !un Wu

Project Tigrosa

"1 January "#1$


2/8


"

Abstra%t

Female aggression within the breeding rituals ofHogna carolinensis is a well &nown behavior within

the spe%ies' While in generality( female wolf spiders have a tenden%y to be sele%tive( they also have

other fa%tors whi%h lead to over aggression and defensive dispositions' These variables will be

dis%ussed within this arti%le' )ote that while aggression in itself is a variable within individuals( some

fa%tors do play a role in maintaining the balan%e between male and female wolf spiders'Hogna

carolinensis is a prime %andidate for these observations for it is widespread a%ross the *astern and

+outhern ,nited +tates' !i&ewise( the si-e and generali-ed environment ofHogna carolinensis also

allow this spe%ies to be perfe%t for en%losed observation'


3/8


.

Female Health

As a general rule( female health is of importan%e within the su%%ess of a breeding' While wolf spiders

have the %apability to survive for e/tended periods of time without food( a re%ently fed female is more

re%eptive to males' !i&ewise( females that stray away from the safety of a burrow 0or is evi%ted from a

burrow is less li&ely to be re%eptive 0though e/%eptions are available' !i2uid levels may play a %ertain

role within the re%eptiveness of the female' 3owever(Hogna carolinensis rarely ta&e li2uid dire%tly

from a water sour%e 0as observed'

Female Molt Cycle

This aspe%t is a lot harder des%ribe for males attempt to mate with relatively young or even immature

females' Observations between two pairs of immature females and two mature males e/pressed some

interesting results' The males began their mating ritual upon noti%ing the females 0drumming of legs

and pedipalps' 3owever( the females simply ignored them 0no responsive leg tapping' When the

males approa%hed and tapped the forelimbs of the females( the females responded 2uite passively by

running away in the opposite dire%tion' )ot on%e did the females e/press any level of aggression

toward the males' On one instan%e( the male attempted to mount the female prior to her maturity' +he

pushed him off and ran off' )ot on%e did any of the immature females e/press any sort of interest

either' Females did showed interest to males about one month post penultimate molt' 3owever( younger

adult females still had a level of aggression 0when %ompared to older females'

Female Virginity

This topi% has been greatly studied for males of some spe%ies of wolf spider have a uni2ue preferen%e

for virginal females' 4nH. carolinensisvirginity within females is a fa%tor whi%h only benefits the

males 0via my observations' Tena%ity within virginal females is usually lower than the levels within


4/8


$

mated females' !i&ewise( virginal females( &nowing possibly that they are still infertile( maybe more

willing to allow for mating' 4t also is important to note that female wolf spiders have the ability to store

male sperm within her epigastri% furrow for si/ or more months( thus %ontributing to a lower number of

available females for breeding' Mated females may often re5e%t the advan%es of males despite the male

being in top shape' More pu--ling( perhaps( is the inability for some males to reali-e the se/ual

disposition of the female' When matedH. carolinensis females were e/posed to adult males( many

aggressively stru%& at the males with reared fangs' Others( however( reared in a defensive posture near

the entran%e of her burrow but did not show physi%al violen%e' +till( some mated females simply

ignored the desperate drums of the male by hiding deep in her burrow 0whi%h %ould be up to a foot or

more in depth' On the opposite end( re%ently matured females also are more %autious to the advan%es

of the males 0perhaps their se/ual organs have not yet fully matured despite their bodily maturity'

6e%ently matured females( however( tend to stray away from the males7 sights by hiding away 0though

when e/posed( they will sometimes stri&e at the males' 4t seems thatH. carolinensismales %annot

determine whether the female is virginal or not for they %ontinue to be persistent mu%h of the time

despite the females7 aggressive atta%&s 0or perhaps they do &now and only hope for the best'

Population Density

From late May to late O%tober( maleH. carolinensis wander about during the night 0and the day in

sear%h of females( who usually are inside their sil& lined verti%al burrows' 4t is important to remember

that population densities vary from lo%ation to lo%ation' 3owever( males may have to wander for

meters upon meters before finding a female 0in general(H. carolinensis density is higher than native

)orth Ameri%an tarantulas 8Aphonopelma sp.9' +ome lo%ations have large 2uantities of females and

thus allow for males to have better su%%ess rates' 3owever( la%& of population density also means that

the females %an be%ome more sele%tive toward their males' What fa%tors %all for a su%%essful male is


5/8


:

not well &nown' The usual within ;lanet *arth will be si-e( strength( %olor or persisten%e' There also

may be the fa%tor of growth rate within a population ratio' As a general rule( males mature faster than

females'


6/8


>

environment with low food and moisture %ontent( their growth rate maybe slowed to the point where

they have to mature out in early O%tober 04n Tope&a( ?+( some males will mature e/tremely late due to

a la%& of food and water' 4f that is the %ase( and 4 have seen many %ases of this( the males7 %han%es of

breeding will be slowed' 4t is 2uite possible to &eep males beyond the winter months within %aptivity'

3owever( wild males have a mu%h harder time in doing so' +ometimes( males will wander into

buildings upon the onset of fall 0o%%asionally in large populations to es%ape the %old' While it is a

tolerant spe%ies( most males will perish if the temperature stays too high or low or if desi%%ation sets in'

As for general aggression( females within high densities have a tenden%y to be%ome less aggressive if

wandering males are low' 3owever( 4 have observed males 0deliberately released ne/t to a wild female

den be%ome shunned from the burrow when he tries to enter' Females %log the entran%e and rear her

fangs to prevent the male from mounting and breeding with her( in or out of the burrow' +ometimes( the

female will simply eat the male'

Male Size

!arger males have a smaller tenden%y to be%ome prey for the females may see them as more %apable

mates' 3owever( 4 have observed instan%es where even the largest males have fallen vi%tim to the bite

of a female' While females may not e/ert venom 0dry biting( physi%al damage from the stri&e itself

may be enough to &ill the male' 4n some instan%es( males will es%ape an aggressive female7s attempt to

%onsume@&ill him by shedding a leg' While self amputation is fairly rare in my observations( 4 have

seen o%%asional males do so in order to es%ape'


7/8


B

from &eeping away the grasping limbs of the female' ,ltimately( the male was &illed and eaten by the

female'

Presence of Female Silk

+il&en sheets allow for males to taste whether a female is nearby' Whereas Tigrosa wolf spider females

put out large amounts of sil&(Hognawolf spider females tend to not release large amounts' 4nstead(

only a small amount is produ%ed 0usually at the entran%e of her burrow' Males are more in%lined to

initiate breeding when sil& is present( therefore( a la%& of sil& may mean that males are less li&ely to

initiate the ritual'


8/8

Documents

Observations of Female Aggression Towards Males Within Hogna carolinensis Courtship