Anal papilla (insect)

Rear part of a mosquito larva with breathing tube (above) and clearly recognizable anal papillae (below)

Anal papillae (from Latin anal or anus = "anus" and papilla = "wart") are leaf-shaped protuberances that surround the anus of various aquatic insects and that serve as a whole for osmoregulation . They occur among other things in the larvae of various mosquitoes such as mosquitoes and mosquitoes , dragonflies and water beetles .

function

The anal papillae are used to regulate the ion balance in aquatic animals (osmoregulation). The inside of the papillae, their lumen , is connected to the Mixocoel . Chlorine ions are actively absorbed from the water via transport proteins (Cl ^- ion pumps, carriers), which draw alkali ions along with them to balance the charge . In this way, the constant, osmotic ion loss is compensated, which is caused by the fact that the animals are hyperosmotic towards the surrounding water.

Freshwater insects and larvae, in which no active ion uptake is possible, must avoid the loss of ions or salt through a completely impermeable cuticle .

supporting documents

1. ↑ ^{a b c} Keyword "Analpapillen" In: Herder-Lexikon der Biologie . Spektrum Akademischer Verlag GmbH, Heidelberg 2003, ISBN 3-8274-0354-5 .