Fossilized newborns, egg shells, and egg bursters preserved together in amber provide the first direct evidence of how insects hatched in deep time, according to a new article.
One of the earliest and toughest trials that all organisms face is birth. The new findings give scientists evidence on how tiny insects broke the barrier separating them from life and took their first steps into an ancient forest.
Trapped together inside 130 million-year-old Lebanese amber, or fossilized resin, researchers found several green lacewing newborn larvae, the split egg shells from where they hatched, and the minute structures the hatch-lings used to crack the egg, known as egg bursters. The discovery is remarkable because no definitive evidence of these specialized structures had been reported from the fossil record of egg-laying animals, until now.
The fossil newborns have been described as the new species Tragichrysa ovoruptora, meaning 'egg breaking' and 'tragic green lacewing', after the fact that multiple specimens were ensnared and entombed in the resin simultaneously.
Green lacewing larvae are small hunters which often carry debris as camouflage, and use sickle-shaped jaws to pierce and suck the fluids of their prey. Although the larvae trapped in amber differ significantly from modern-day relatives, in that they possess long tubes instead of clubs or bumps for holding debris, the studied egg shells and egg bursters are remarkably similar to those of today's green lacewings. Altogether, they provide the full picture of how these fossil insects hatched like their extant counterparts, about 130 million years ago during the Early Cretaceous.
The Tragichrysa ovoruptora larvae were almost certainly trapped by resin while clutching the eggs from which they had freshly emerged. Such behavior is common among modern relatives while their body hardens and their predatory jaws become functional. The two mouth-parts forming the jaws are not interlocked in most of the fossil larvae, which further suggests that they were recently born.