Upload
veldfloraed
View
217
Download
0
Embed Size (px)
Citation preview
8/6/2019 More common hawk moths
1/2
In a previous article on common
hawk moths* I described the general
characteristics of hawk moths (Sphingi-
dae or sphinx moths) and dealt in some
detail with the Common Striped Hawk and
the African Humming Bird Hawk. I shall now
introduce two other common hawk moths
that also turn up in many places including
private gardens, especially if there are food-
plants for their larvae on offer.
The Deaths Head Hawk
The most outstanding external feature of the
Deaths Head Hawk ( Acherontia atropos) isthe skull pattern on its thorax that may well
frighten somebody not familiar with this
harmless creature, but would hardly function
as a deterrent for predators. Females of this
heavy-bodied moth have a wingspan of up
to 120 mm, males on average being a little
smaller. The Deaths Head Hawk is unpopular
with apiarists because it burgles beehives
to feast on honey. Otherwise this nightly
visitor causes no damage or harm to the
bees. The moths nickname Bee Hawk should
not confuse this insect with the Oriental BeeHawk (Cephonodes hylas virescens) a day-
flying moth with translucent, hyaline wings
and a greenish-yellow body that resembles a
large bee, presumably to scare off potential
predators. I have occasionally found this
moth feeding on nectar from the flowers of
the Canary Creeper (Senecio tamoides) in my
garden in Sea Point.
The honey-stealing habit of the Deaths
Head Hawk stems from the fact that unlike
other hawk moths that possess a long hollow
tongue (proboscis) this hawk has a very short
proboscis, useless for imbibing nectar hidden
deep down in flowers. How this large moth
avoids being stung to death by the bees
when it enters a hive is not really known, but
it is believed that it
imitates sounds made
by the queen bee to confuse
the bees guarding the entrance to
the hive. Be that as it may, bee keepers have
told me that not all of these moths that enter
their bee hives leave unscathed and that they
have come across dead specimens left behind
in the hives and covered with propolis. These
unfortunate individuals must have died from
being stung too often by the irate bees.
The bees cover unfamiliar objects such as
dead moths that are too large to be physically
removed from the hive, with a dark, stickysubstance called bee-glue or propolis. Bees
manufacture propolis from resinous material
collected from plants, especially buds, and
use it in their hives as a crack filler to cover
up openings and gaps and to secure combs.
Another reason for the unpopularity of
this moth is that its greedy caterpillars feed
on the leaves of crop plants such as potato,
tomato, gooseberry and even on fresh leaves
of Cannabis. The larvae also feed on Lan-
tana, Salvia, Cape Honeysuckle (Tecoma) and
many others.When touched, the Deaths Head Hawk
squeaks, probably to frighten or confuse an
attacker. Even their larvae and pupae can
make audible scratchy noises when touched.
The large fully grown larvae reach a length
of about 150 mm and occur in various shades
of green, yellow and brown. (A possible
advantage to larvae of occurring in more
than one colour variety was referred to my
previous article* on common hawk moths.)
In spite of their large size and bright colours,
even fully grown larvae are not easily spotted,
where they cling against the underside of
leaves on which they feed. Prior to pupation
the mature larva burrows into the ground
and builds a safe chamber by compacting
loose soil around itself. During summer the
bulky, stout pupa takes about three weeks
to complete metamorphosis into the adult
moth that digs itself out of its chamber and
surrounding soil to reach the surface.
The pupa is often parasitized by large hairy
flies of the family Tachinidae that oviposit in
the moth larva and whose own larvae, after
first feeding on the non-essential parts of themoth larva, complete their development in
the pupa from which they eventually emerge
as adult flies.
The Fulvous Hawk
The Fulvous Hawk (Coelonia fulvinotata) or
Sphinx is similar in size, appearance, colour
and markings to the Deaths Head Hawk
but does not have the skull mark on its
thorax and, in contrast to the Deaths Head
Hawk, possesses a very long tongue, twice
its body length and equalled only by that ofthe Convolvulus Hawk (Herse convolvuli). The
spike on its rear end is much longer in the
larva of the Convolvulus Hawk and curved
upwards, while in the Deaths Head Hawk
larva it is quite short and more granular or
pimply in appearance. This moth is widely
distributed in Africa including South Africa. I
once found a dead specimen with a damaged
left wing in my back yard. I guess that it
had been attacked by a nightly predator.
Andrew Morton of Blue Bottle Guest House
in Muizenberg took photos of the larvae he
found feeding on tomato plants in his garden
More common hawk mothsThe Deaths Head Hawk and the Fulvous Hawk
by Andr Claassens
Deaths Head Hawk
(Acherontia atropos).Photo: A. Claassens.
BELOW LEFT: Deaths Head Hawk larva. Photo: J. Joannou.BELOW: Deaths Head Hawk. Photo: J. Joannou.
VELD&FLORA | JUNE 201178
8/6/2019 More common hawk moths
2/2
and reared the adult moth from them. My
younger granddaughters found, to their
great excitement, a large caterpillar feeding
on tomato in their garden in Newlands, Cape
Town. This larva duly pupated but being
parasitized, failed to produce the adult moth.
The larvae vary in colour, but green-yellow to
green individuals with dark oblique stripes
are common. Much lighter colour varieties
occur sometimes even on the same plant.
Like the larvae of the Deaths Head Hawk the
larvae of the Fulvous Hawk are polyphagous,
feeding on a wide variety of plants such as
Solanum species (Potato Creeper), tobacco,
Salvia, Cape Honeysuckle, Coleus, Lantana
and Convovulus. Anneke Kearney photo-
graphed a brown colour variety of the larva
that she found feeding on a Tree Fuchsia
(Halleria lucida) in Kenilworth, Cape Town,
which is probably a new food-plant record for
this moth. (See Veld & Flora, September 2009,
p. 162.) H. lucida was one of three indigenoustrees selected as Tree of the Year in 2009.
Before pupation the mature larva moves
down the food-plant onto the soil below
where it gathers some debris and sand around
itself, forming a loosely woven chamber in
which it completes pupation, a process that
takes eight to ten days. The 55 mm long
pupa at first has a shiny brown abdomen and
light green to yellow wing cases that, like
the abdomen, turn dark brown within a few
days. The prominent hook arched backward
over the front of the pupa houses the long
proboscis of the future adult moth or imago.
The posterior spike, a very characteristic
feature of the larva, is lost in the pupa. The
imago emerges after about three weeks in
summer, but during winter the pupa, like that
of other hawk moths and moths in general,
hibernates until the warmer days of late
spring or early summer.
Biological importance of hawk moths
Although hawk moth caterpillars can be a
nuisance in the garden because of their great
appetite for certain plants, the adult moths
with their long tongues (except of course
the Deaths Head Hawk) play an important
role in pollinating flowers with deep tubular
corollas, such as the Cape Honeysuckle, and
many other exotic flowers like petunias and
Wild Tobacco (Nicotiana) with its clusters of
trumpet flowers reminiscent of vuvuzelas.
Short-tongued insects avoid these flowers
and consequently do not pollinate them.
While the Humming Bird Hawk is confined
to Africa, the other hawk moths mentioned
not only occur throughout most of Africa,
but also in Europe and Asia. I remember as
a child catching Deaths Head Hawk Moths
in our garden in the humble village of Mill in
the south of Holland. The vast geographical
distribution of hawk moths is due to their
migrating habits, strong flight and wide
choice of food-plants, many of which occur
almost worldwide.
Biological control of hawk moths
We are not alone in the fight against
caterpillars because many vertebrate and
invertebrate insectivores provide free bio-
logical control by feeding on the larvae as
well as on the adult moths. The larvae are
also attacked by parasitoids such as certainwasps and flies whose larvae feed on non-
essential tissues of their prey, preventing it
developing into an adult moth. Moth eggs
are often attacked by tiny parasiti c wasps that
oviposit in them to allow their minute larvae
to complete development by consuming the
contents of the eggs and emerge from them
as a new generation of tiny parasitoids ready
to attack more newly laid moths eggs.
*Veld & Flora, 96(4), 170-171.
ACKNOWLEDGEMENTS
Thanks to Andrew Morton for the pictures of the
larva of the Fulvous Hawk; to Charles Botha for
allowing me to extract John Joannous picture of
the larva of the Deaths Head Hawk from the article
Gardening for Wildlife he wrote for Village Life 30,
June/July 2008, and to John Joannou for the picture
of the Deaths Head Hawk in natural position.
READING
Claassens, Andr. 2010. Common garden hawk
moths. Veld & Flora96(4), 170-171.
Kroon, D.M. 1999. Lepdidoptera of southern Africa.Host- plants and other associations. A catalogue.
Lepidopterists Society of Africa.
Pinhey, E.C.G. l975. Moths of southern Africa. Tafelberg,
Cape Town.
Pinhey, E.C.G. l962. Hawk moths of central and
southern Africa. Longmans, Cape Town.
Vari, L., Kroon, D.M. & Kruger. M. 2002. Classification
and checklist of the species of Lepidoptera recorded in
southern Africa. D.M. Kroon, Sasolburg.
WHAT DOES THAT MEAN?
oviposit Lay an egg or eggs.
proboscis A tube formed from the elongated
mouth parts of an insect, used for imbibing
liquid food such as nectar from flowers. Often
referred to as a hollow tongue. Derived from
the Greek word proboskis meaning trunk.
propolis Bee glue. Derived from the Greek
wordspro meaning for andpolis meaning city.
TOP: Fulvous Hawk with slightly damaged wing.Photo: A. Claassens.ABOVE: Fulvous Hawk larva - light green colour variety.Photo: A Morton.BELOW: Fulvous Hawk larva - dark colour variety. Photo: AMorton.BOTTOM: Fulvous Hawk pupa. Photo: A. Claassens.
LEFT: Oriental Bee Hawk. Photo: A. Claassens.
JUNE 2011 | VELD&FLORA 79