The Atavism

Sunday, November 15, 2009

Sunday Spinelessness - damselflies

It's been a bit of a wintry Sunday here in Dunedin so I'll dedicate today's round of Sunday Spinelessness to a group of insects we should see a lot more of as summer takes hold, the Damselflies (Odonata:Zygoptera).


That's Xanthocnemis zealandica which is sometimes called the "common redcoat damselfly." It's certainly common enough, visit a pond or wetland in summer and you'll see hundreds of them skimming across the water to lay their eggs or perched on blades of grass or on trees (despite having an insect's full compliment of six legs those limbs are purely for perching - odonates can't walk).

You can probably tell just by looking at Xanthocnemis that damselflies are related to dragonflies, in fact the damsels and the dragons are two infra-orders in the medievaly themed order Odonata . You can tell a damselfly from a dragonfly thanks to the way they hold their wings - damselflies fold them up over their body when they land while dragonflies hold them open (kiwi naturalist Shelia Natusch describes this posture in a slightly morbid way: "wings extended, as though already pinned down on a collector's board") .

Damselflies are expert hunters - adults take small insects on the wing and their nymphs are pretty impressive aquatic predators - some will even take small fish. I don't know that any of the New Zealand species are quite as aggressive as all that but you can see photos of the nymphs thanks to Landcare Research and Waitakere City Council's website (which includes a 'profile' written in the first person).

There are six species of damselfly described in New Zealand - three more Xanthocnemis species (each of which are rare and restricted to a small area) , Austrolestes colensonis (which is blue and almost as comon as X. zealandica) and the self-introduced Ischnura aurora. Despite the lack of a red coat the next picture is likely another X. zealandica (it certainly isn't Austrolestes or Ischnura and as far as I can tel the other Xanthocnemis species aren't known from Dunedin.)
Damselfly perched on grass

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Posted by David Winter 5:30 PM



Thank you for this post which explained the difference between dragonflies and damselflies to me! Also, I used the image of the damselfly on my blog post.

If you read the post, you may notice that my focus on animals is somewhat different than your own. However, perhaps it might provide you with a different perspective!

Thanks again!

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