In an attempt to avoid our local breezy, cool, overcast weather this morning, we went to investigate a new-to-us stretch of La Rigole, the cleverly constructed small canal that feeds the Canal du Midi with water from les Montagnes Noires. We’ve been Odonata hunting in its upper reaches but the valley looked like the best possibility for an improvement in conditions today. We arrived at a small man-made lake constructed in a bend in La Rigole. During the time it had taken us to make our circuitous way there, the skies had largely cleared and the sun was out. So were the damselflies and dragonflies.
In more southerly latitudes, it’s always worth looking more closely at blue-coloured damselflies since there are several species that look superficially similar but which might be subtly different and add to one’s photographic collection. Francine wandered off to retrieve a different lens as I dutifully began watching a small collection of blues flitting about a couple (literally) of plant stems protruding from the water. Since the main activity of damselflies when the sun is shining is sex, occasional tandem pairs of damsels arrived and alighted on the stems to form their copulation wheel.
After the copulation wheel, it’s time for a spot of ovipositing in the water. This pair of White-tailed damselflies (Platycnemis pennipes) very kindly demonstrated the most usually seen type of damselfly ovipositing behaviour: using vegetation as support, the male guards the female as she dips her abdomen beneath the surface to lay eggs. I know that, in some species, the female becomes almost submerged as she oviposits.
Almost! I watched a pair of damselflies alight on one of the plant stems and begin shuffling downwards until only the female’s head and thorax remained above the surface. So far so good. I continued watching in something approaching disbelief as the male released his hold on the female and she continued shuffling down the stem until she was completely submerged. Being completely gobsmacked took over as I watched her continue down the stem until she was out of sight in relatively clear water. By now Francine had returned and was watching with equal fascination as other pairs, all the same species, repeated this sequence, so it obviously was not an aberration. Francine had a good angle and grabbed this very clear shot including a completely submerged female.
The species involved in this submerging behaviour is the Goblet-marked Damselfly (Erythromma lindenii). These are the ones in the synchronized copulation wheels, above. We didn’t witness the resurfacing of any of the submerged females. Since my field guide makes no mention of this, I’ll have to try to do some research to see what I can find out about the life-cycle of the Goblet-marked Damselfly and see if this is a terminal act in an all-too-brief adult existence.
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