Tuesday, September 29, 2015
We spent a fascinating afternoon recently watching dragonfly behaviour at Ashes quarry at Stanhope in Weardale.
The most numerous dragonflies in the shallow, moss-edged pools there are common darters, Sympetrum striolatum. We watched them on their egg-laying flights, where the male tows the female around, attached by the tip of his abdomen to a point just behind her head.
Coupling up like this is the male's way of defending the female he has inseminated, preventing rival males from mating with her and displacing his sperm.
It's an unwieldy arrangement. At frequent intervals the male lowers his abdomen, forcing the female down to the water surface where she drops fertilised eggs from the tip of her abdomen.
That's an awkward manoeuvre, when the male momentarily hovers in this vertical position.
The males are fiercely defensive of their territory, often perching on a favourite stone or ....
... plant stem, ready to drive off rivals and pursue any passing female.
The second commonest dragonflies at this site are black darters Sympetrum danae. There seemed to be quite a lot of interspecific aggro - we watched several aerial battles between the two species.
These dragonflies land with their wings outstretched but ....
... finally come to rest with them in this swept-forward configuration.