Living With Egg Rafts

Culex Eggs

Drawing of Culex pipiens eggs Image: Image: Beament and Corbet

Mosquitoes in the genus Culex lay eggs in groups that form rafts and float on the water. An ovipositing female mosquito will manipulate the eggs as they are laid such that the anterior end of the egg is facing downward. The anterior end contains the corolla, a structure that is wettable on the bottom and hydrophobic on top. Thus, the wettable portion of the corolla is below water level and anchors the egg. The hydrophobic portion resists wetting and floats due to the surface tension of the water. Individual eggs are top heavy and likely to tip. However, the female mosquito packages them in to egg rafts, clusters of several dozen eggs that cling together. The sides of the eggs contain tubercles, arm-like extensions of the egg that intercalate with each other. This holds the eggs in a cluster that has a stable base resistant to tipping.
egg raft

Culex Mosquito making an egg raft Image: Sean McCaan

About jjneal

Jonathan Neal is an Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
This entry was posted in Biomaterials, by jjneal, Environment. Bookmark the permalink.

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