Mark Leach is the Marketing Manager at the Society of Biology
Not being a biologist by trade means that my working day at the Society often provides opportunities for impromptu learning. As they say, ‘every day’s a school day’! A chance office conversation about the visit of a ‘weird blue dragonfly’ to my garden quickly revealed (in conjunction with the photo evidence on my phone) that our guest had in fact been a damselfly – a creature of which I had previously been unaware.
My interest piqued, I embarked upon some web research (however did we cope pre-Google?!) and learned that both dragonflies and damselflies (members of the order Odonata) are actually quite extraordinary.
As you might expect from a creature with two sets of wings, they are most at home in the air. As they eat other flying insects, they need to be able to outpace their prey, and hold their six legs in a ‘basket’ shape to catch them – not even landing to eat! They also manage to mate on the wing!
I was then encouraged to Google dragonfly larvae – go on, have a look – and this was when I really started to get interested. Odonata lay their eggs on calm water, and these hatch into ‘nymphs’, where they spend the majority on their life (typically more than a year in total). Resembling something that Doctor Who might have encountered (and not particularly enjoyably!), they have gills, and therefore breathe underwater, before crawling up the nearest plant stem, shedding their skin (exuvia, don’t you know?) and metamorphosing into an adult, where they spend the remaining two months of their life, searching for a mate and beginning the whole cycle again.
But how can you tell the difference? While the expert biologist will wax lyrical about the differences in appendages, or in the wing’s discalI cell, I have it on excellent authority that anyone can simply tell the difference between the stocky-bodied dragonfly and the longer, more slender damselfly. When they are at rest, damselflies will neatly fold their wings to the sides of their body, while dragonflies will always sit ‘wings akimbo’. A closer inspection will also reveal that a dragonfly’s eyes will be close together (or touching) at the top of the head, while the damselfly’s peepers will be clearly set at either side of the head.
So now I know!