Mating moths (Tineidae, ditrysia, lepidoptera) preserved as frozen behavior inclusion in baltic amber (eocene)

Abstract

The investigation of amber inclusions provides a unique insight into the biology of animals living millions of years ago, due to their exceptional preservation in nearly lifelike conditions. This is not only true for morphological aspects, aspects of behavior can also be deduced from these fossils. Here, Microlepidoptera are reported from Eocene Baltic amber most likely as a first occurrence of fossil Lepidoptera found in copula. The moths belong to Tineidae (tineid moths includes clothes moths) and are described as a new species and new genus, Forcepsites michalskii. The clasping organ of the male is quite uncommon for moths from Baltic amber, with a ventral and dorsal part, each ending in two parallel, thorn-like protuberances, and seemingly not being formed by the valvae. The co-occur-rence of male and female, most likely in copula, allowed studying their sexual dimorphism directly, and there is evidence that the habitat of this species is the site of resin production in the Baltic amber forest. From sexual dimorphism of the antennae and eye morphology it is interpreted that the female was the calling sex for mating in this species.