In my last post I talked about Dragonflies, and in this one, I want to talk about their smaller counterparts, the Damselfly, but first the differences between the two..
Dragonflies have eyes that touch, or nearly touch at the top of the head, they are stocky, and have different sized wing pairs. When they perch, the wings are held open.
Damselflies have eyes that are clearly separated, one on each side of the head, they are long and slender, and have evenly sized wings, which are held close when they perch, as can be seen in the image below.
Damselflies are carnivorous insects that live and breed near a wide variety of freshwater habitats. They lay their eggs in water, and the immature damselflies spend the first several months or years as aquatic predators. These immature damselflies, called nymphs, have external gills that allow them to extract oxygen from the water. After undergoing metamorphosis, new adult damselflies fly away from the water for a brief period of several days to several weeks, after which they return to breed. Both adult and immature damselflies are predators whose diet consists primarily of insects. (Corbet, 1999; Silsby, 2001)
The mating behaviour of the damselfly is quite unique. Males have two sets of genitalia. To mate, the male must grasp the female behind the head, and curl his abdomen into a circle. In this position the male and female are said to be ‘in tandem’ – if the female is receptive, she will curl her abdomen forward to join the tip of her abdomen with the male’s second set of genitilia, sperm is then transferred from one to another. This position, called ‘the wheel’. After mating, the female will lay eggs usually below the water line, often guarded by the male
The average Damselfly, probably only lives between 3 to 4 weeks as an adult, but the damselfly nymphs can spend months in this early stage, depending on food source, temperatures and so on.
Damselfly do need a minimum temperature at which to fly – in the early mornings, they can be seen spreading their wings to dry out the morning dew, and warm up.
Damselfly and Dragonfly populations are good indicators of environmental quality and population levels are a good indicator of the health of the area.
They are the most ancient of insects, with evidence of them being found as fossils some millions of years ago.