The Diversity of Aphidlion-like Larvae over the Last 130 Million Years.

Abstract

Simple SummaryThe larvae of green lacewings and brown lacewings are called ‘aphidlions’, as they consume aphids. They play also an economic role as biological pest control. Aphidlions have, mostly, elongated spindle-shaped bodies, and similarly to most lacewing larvae, they possess a pair of venom-injecting compound jaws, also called stylets. Fossils that have been interpreted as aphidlions are known from amber of different ages (about 130, 100, 35, and 15 million years old). In this study, new aphidlion-like larvae are reported from about 100 million-year-old amber from Myanmar and about 35 million-year-old Baltic amber. The shapes of head and stylets were compared between the different time slices. With the newly described fossils and specimens from the literature, a total of 361 specimens could be included in the analysis: 78 fossil larvae, 188 extant larvae of brown lacewings, and 95 extant larvae of green lacewings. The results indicate that the diversity of head shapes stays about the same over time besides a certain increase in diversity of the head shapes in brown lacewing larvae. In certain other lacewings, a distinct decrease in the diversity of head shapes was observed in the larvae.Aphidlions are larvae of certain lacewings (Neuroptera), and more precisely larvae of the groups Chrysopidae, green lacewings, and Hemerobiidae, brown lacewings. The name ‘aphidlion’ originates from their ecological function as specialised predators of aphids. Accordingly, they also play an economic role as biological pest control. Aphidlions have, mostly, elongated spindle-shaped bodies, and similarly to most lacewing larvae they are equipped with a pair of venom-injecting stylets. Fossils interpreted as aphidlions are known to be preserved in amber from the Cretaceous (130 and 100 million years ago), the Eocene (about 35 million years ago) and the Miocene (about 15 million years ago) ages. In this study, new aphidlion-like larvae are reported from Cretaceous amber from Myanmar (about 100 million years old) and Eocene Baltic amber. The shapes of head and stylets were compared between the different time slices. With the newly described fossils and specimens from the literature, a total of 361 specimens could be included in the analysis: 70 specimens from the Cretaceous, 5 from the Eocene, 3 from the Miocene, 188 extant larvae of Chrysopidae, and 95 extant larvae of Hemerobiidae. The results indicate that the diversity of head shapes remains largely unchanged over time, yet there is a certain increase in the diversity of head shapes in the larvae of Hemerobiidae. In certain other groups of Neuroptera, a distinct decrease in the diversity of head shapes in larval stages was observed.