Poisoned Moths Poem by gershon hepner

Utatheisae ornatrices
are most enterprising moths,
for survival of this species,
caught in spiders’ web-made swaths,
is ensured by hidden presence
in their scales of alkaloids,
poison lurks in their quintessence,
which each spider then avoids.

Alkaloids are first ingested
by the mother moth and pass
into scales, and when molested
baby moths kill each badass
which, like spiders, try to eat it,
warfare’s biological:
predators are fast defeated,
logistics highly logical.

Thomas Eisner writes about Utatheisa ornatrix in the Science Times of the NYT, November 18,2003:

It widely known in biology that moths and butterflies, the lepidopterans, are covered with scales. But the purpose of those scales has remained a mystery to many. I have heard it said that scales trap a layer of 'dead air' next to the wing surface, giving the airborne insect additional lift. That sounds plausible. And I know from observation that scales can protect lepidopterans from getting stuck in spider webs. This is particularly true for moths, which have a denser scale cover, and whose scales come off easily. Insects become trapped in spider webs because they get stuck to the glue-coated silken strands. Moths are not trapped because they are never really detained by the web. As they fly into one and try to flutter free, they simply lose scales to the web's sticky strands and make their getaway.
Recently, while experimenting with a gaudily colored moth, Utetheisa ornatrix, a group of us found that scales can be impregnated with toxins. As a larva, Utetheisa feeds on leguminous plants of the genus Crotalaria, which has long been known to contain poisonous alkaloids. The larva is unaffected by these poisons, which it stores in its body and retains through metamorphosis into the adult stage. Some of the alkaloid in the adult is built into the scales, so the moth is unpalatable to spiders. Utetheisa therefore does not need to flutter free when it lands in a spider web; instead, it lies still and relies on the spider to cut it loose.

11/18/03