Metamorphosis Major Contributor to Insect Diversity

Scientists have found that metamorphosis is a major contributor to insect diversity, according to a new study. Given that these transforming insects diversify more quickly compared to other bugs, it is therefore the biggest influence on insect evolution.

Using a database of 1,500 fossil families - a third of which weren't added to the record until 1993 - biologists from the University of York compiled two new datasets on insect evolution, including timescales of origination and extinction of various families of insects.

The Natural Environment Research Council (NERC) funded both datasets, one created by former PhD student Dr. David Nicholson and the second compiled by PhD student James Rainford.

Researchers discovered from this updated fossil record that families of insects that undergo metamorphosis, a pupal stage separating two different juvenile and adult stages, are less likely to become extinct compared to other insects. This means that metamorphosing species like moths and butterflies (Lepidoptera), beetles (Coleoptera), wasps, bees, ants (Hymenoptera) and true flies (Diptera) will prosper in life, and probably outlive their non-mutating peers.

"Intuitively, people have long suspected that insects with metamorphosis have experienced different rates of diversification, because the richest insect orders mostly have metamorphosis," Dr. Peter Mayhew, who supervised the study, said in a statement.

But the details behind why exactly metamorphosis is important for insect evolution are still under speculation.

"Metamorphosis might reduce extinction, and promote speciation, in a number of different ways," Mayhew added. "It might reduce competition between larvae and adults, it might promote dietary specialization, it might reduce development times, it might improve survival in times of hardship, or something else. Future work needs to address this question."

This new research, which helped create the biggest and most detailed family tree of insects to date, paves the way for future studies looking into the role of metamorphosis in insect diversification.

The findings were published in the journal Proceedings of the Royal Society B: Biological Sciences.