The ecological scenario of Lepidopteran evolution

Abstract

Soil detritophagy has been hypothesized to be the ancestral feeding type of the Lepidoptera as evidenced by the larval feeding habits of Zeugloptera. The ancestral feeding type, as well as mycetophagy and other closely related types of feeding, is still retained in Hepialomorpha, many Tineiformes, and some Cossiformes. Two main trends in the evolution of larval feeding are recognizable. Larvae of non-ditrysian moths and primitive Ditrysia show the evolutionary trend from detritophagy and soil phytophagy to wood-eating and feeding on inner leaf tissues, and further to leaf-mining. Evolutionary transition to leaf-mining occurred independently in the main phylogenetic lineages, viz Aglossata, Heterobathmiina, Eriocraniomorpha, Adelomorpha, Nepticulomorpha, and Tineiformes + Yponomeutiformes + Gelechiiformes. Evolutionary transition to open-living phytophagous larvae occurred within Cossiformes. Both evolutionary trends are in accordance with the principle of enhancing the role of larval feeding correlated with a tendency to weakening of adult feeding (Mazokhin-Porshnyakov, 1954). Under these conditions, simple proboscis seems to have evolved as an adaptation to the exploitation of water and feeding on decaying organic matter. Subsequent coevolution of Lepidoptera and Angiospermae results in evolving of much more complex proboscis and high-energetic nectar feeding. The input of additional energy seems to be correlated with the origin of parental care in the order. Flower visiting has arisen at the evolutionary level of leaf-mining larvae (Adelomorpha), but the origin of true anthophily seems to be correlated with the evolutionary transition to open-living larvae (Apoditrysia). This correlation is evidenced by the fact that the most substantial functional modification of proboscis, namely the origin of new extensors CMx 5 is shared by all Apoditrysia.