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Archive for June 8, 2018

Newly-emerged Dragonflies Vulnerable

6-8-18 grackle with dragonflies2 _U1A5228When a dragonfly larva crawls up out of the water onto emergent vegetation or a rock to split its skin and emerge as a winged adult, it is in its most vulnerable state, for until its wings are pumped up and dry, it is incapable of flying.

Often for two or three hours a newly-emerged dragonfly will cling to the substrate, pumping hemolymph into its wings until they are fully expanded and then hang there defenseless while its exoskeleton and wings begin to harden. Only then does pigment in the dragonfly’s body become apparent, and its formerly pale, colorless head, thorax, abdomen and wings (see inset) assume their true colors.

The pictured Common Grackle has taken advantage of this precarious stage in a dragonfly’s life cycle and collected several dragonflies to feed to its offspring. The dragonflies’ lack of color indicates that this predation took place while the dragonflies were still flightless and before pigmentation was present.

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