A new generation of damselflies

June 18th, 2010 | Written by Lucy Brzoska.

Written by Lucy Brzoska

All round the pond, firmly stuck to the low concrete wall, were quantities of papery husks.  I immediately suspected what they might be, remembering the concentration of mating Western Willow Spreadwings (Lestes viridis) in the park last autumn.  It must have been a spectacular sight to see the nymphs emerge from the pond in such numbers and burst out of their unravelling skins.

One damselfly was still clinging to an exuvia, much smaller than itself. How could it fit inside?  Reading up, I found that once half out, they pause and inflate their wings and abdomen into shape with hemolymph, the insect equivalent of blood.

lestes-viridis-damselfly-with-exuvia

Looking closely at one of the exuvia, it appears like a Mutoid Waste sculpture. The long “snout” is the labial mask, or lower lip, which the nymph flips open to grab passing prey.

lestes-viridis-exuvia-showing-labial-mask

The nymphs do their work well. The two biology students who volunteer to keep algae levels at a  level acceptable for park authorities found no mosquito larvae in the pond at all.

After the mass metamorphosis, the damselflies had dispersed, but I did find one pristine young female clinging to a leaf.  Her wings had a pink shimmer and were still held close together, not at the 45 degree angle that gives the species its name.  With any luck, in a few weeks she would be laying eggs in the bamboo grove by the water’s edge.

lestes-viridis-damselfy-recently-emerged