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Moths of the Amazon
and Andes
Tangerine
Bee-mimic
Cosmosoma sectinota
HAMPSON, 1898
Superfamily -
NOCTUOIDEA
Family - EREBIDAE
subfamily - ARCTIINAE
Tribe - CTENUCHINI
Cosmosoma sectinota, Manu cloudforest
1400m, Peru ©
Adrian Hoskins
Introduction
There are about 6000 known species of Arctiinae in the neotropical
region. Most are noxious to birds and have aposematic or diematic
warning coloration. The tribe Ctenuchini is entirely confined to the
Americas. It is comprised of 2 subtribes Ctenuchina and Euchromiina
which together account for a total of 2532 known species, of which
2496 are wholly neotropical in distribution. The remaining 36
species are partly or wholly North American in distribution. Almost
all of the genera within these two subtribes consist entirely of
species that mimic wasps or bees.
There are 187 known species in
the genus Cosmosoma. The moths are
restricted to the neotropics and southern limits of the nearctic,
with the greatest diversity and abundance in the rainforests and
cloudforests of Brazil, Ecuador and Peru.
Habitats
To be completed.
Lifecycle
To be completed.
Adult behaviour
As is usual with
nocturnal moths, males of Cosmosoma sectinota
are attracted by pheromones emitted by their females. As the male
approaches a female, he hovers above her, and discharges a burst of
very fine filaments which swirl in the air around her, and envelop
her body.
American biologists
Conner and Boada investigated the lifecycle and ecology of this
genus. They found that Cosmosoma males
are attracted to Eupatorium plants, and
sequestered alkaloids from juices seeping from the stems. Such
pyrrolizidine alkaloids are sequestered by a wide variety of
butterfly genera including Ithomia,
Pteronymia,
Oleria, Lycorea and
Danaus; and by several genera of moths
in the family Arctiidae. The PAs stored in the bodies of the insects
render them toxic or unpalatable to birds, and are a primary defence
method in aposematic species.
The researchers
found that in the case of Cosmosoma the
toxins seemed to be directed mainly at predatory spiders. Moths
caught in the webs of Nephila clavipes
were cut free from the webs by the spider, but moths which had been
deprived of the opportunity to sequester PAs were consumed.
Conner and Boada
found that PAs were passed to females via the discharged filaments,
and also via spermatophores delivered during copulation. The PA
toxins conveyed to females were found to provide them with
protection against predators during the following nights, enabling
them to lay their eggs unmolested. It was also demonstrated that the
toxins were passed to the eggs, and provided them with protection
against ants, Coccinellid beetles ( ladybirds ) and Chrysopid
larvae.
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