Earliest known example of brood care found in extinct insects from China

Bob Yirka is a research scientist at Phys.org.

The earliest example of brood care in an insect has been found at a dig site in China. The extinct water bugs are described in a paper by the group.

The oldest example of brood care in insects was from 122 million years ago. The water bugs found in China are over 160 million years old. They were found at a site in northeastern China. They found 30 fossils, all females and all with unique leg characteristics. Each of them had a mesotibia that extended from their left leg to hold eggs.

The ancient water bugs were distinguished by their body parts. There were rows of eggs on the left leg. It would have been possible for the female to lay her eggs on her leg after releasing sticky mucus to make sure they would bind to her. The researchers think the right leg was used to maintain balance as the bug went through the water. Studies show that the eggs jiggled as the water bug walked underwater, allowing for oxygen in the water to flow over the eggs.

The researchers note that the eggs were 12mm across and that they had not been seen before in insects or crustaceans. They discovered that the water bugs had a trapping mechanism that was similar to the one used in fairy shrimp.

More information: Yanzhe Fu et al, The earliest known brood care in insects, Proceedings of the Royal Society B: Biological Sciences (2022). DOI: 10.1098/rspb.2022.0447 Journal information: Proceedings of the Royal Society B

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