I never cease to be amazed by the things one can learn by observing nature and asking questions.
I photographed tiny pools of water containing dead insects on a gilled fungus and asked about it on the Western Australian Fungi Facebook Page.
I learnt that they are 6 legged fungi-eating Springtails (not insects!) on Cortinarius rotundidisporus (Elegant Blue Webcap). The group includes lucerne fleas, but are everywhere – even as innocuous residents in the house. As to the drowned ones, just read the extract from the Facebook site below.
"Temporary rain pools are a kind of trap for small surface-active springtails. Once they jump into such a pool they cannot easily escape from it. Due to the meniscus of the pool surface water at the edges, they will always slide back to the center of the pool. Eventually they will aggregate and form a kind of floating mass of crawling bodies from which some specimens will be able to escape by jumping away.
"If and when a sufficient number of individuals of the same species of Hypogastruridae gather together by accident on such a pool, another thing might happen. Adult females will release a sex pheromone to attract males. Also other females will be attracted by the pheromone signal. The more individuals gather together, the stronger the pheromone signal and more individuals will be attracted from a greater distance. This may eventually result in the spectacular mass aggregations typical for Hypogastruridae. 100,000s of individuals may aggregate as such. The purpose of these mass aggregations is to reproduce.
The pool party then becomes in fact a sex party! ;-)
OMG I posted springtail pornography!