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Posts tagged “Odonata

Dragonflies Laying Eggs

8-27-14  black-tipped darner 133Never let it be said that Naturally Curious readers aren’t creative thinkers (see guesses on yesterday’s post) ! The vertical slits in the cattail leaves were made by female dragonflies that were in the process of laying their eggs. There are many different egg-laying strategies employed by dragonflies. Many females in the group of large, strong-flying dragonflies known as “darners” (such as the pictured Black-tipped Darner, Aeshna tuberculifera) use their lance-like ovipositors (see photo) to insert eggs into plants stems such as cattail, sphagnum moss, rotting wood or wet soil. However, most species of dragonflies possess non-functional ovipositors. The eggs of many of these species are washed off into water during flight as the female dips the tip of her abdomen into the lake, pond, river or stream.

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Twelve-spotted Skimmers

Twelve-spotted Skimmers are classified as “King Skimmers,” all members of which are large and conspicuous, often with distinctive wing patterns.   Male Twelve-spotted Skimmers (pictured) have a grayish bloom on their abdomens and each wing has three dark spots with white spots in between them.  Females have brown abdomens and no white spots on their wings.  All summer you can see males flying back and forth short distances along the shores of ponds and over water, hovering as well as perching.  They are territorial and patrol over water, loop-de-looping with competing males.  A small number of Twelve-spotted Skimmers occasionally take part in Atlantic Coast migrations.


Beaverpond Baskettail

Beaverpond Baskettail dragonflies have an early flight season, first appearing in May in the Northeast.  The males (pictured) cruise over the water (often beaver ponds, hence their name) as well as the shore in sexual patrol flight, flying back and forth over the same area repeatedly.  After mating, the female accumulates a large egg cluster at the tip of her abdomen, and as she drags it along the surface of the water, a long string of eggs is draped over plants.  Once these strings expand, they can be several feet in length and an inch or more in diameter.


Black-tipped Darner

I thought some people might like to see what the newly-emerged Black-tipped Darner dragonfly whose picture was posted three days ago  eventually looked like.


Dragonfly Eclosion – Emergence of Adult

8-4-11 Dragonfly  Eclosion – Emergence of Adult

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At the end of its larval stage, a dragonfly larva crawls out of the water where it’s been living and climbs up onto emergent vegetation, or a nearby rock, where it clings as its skin splits along its back and head.  The adult winged dragonfly pulls itself out of its larval skin through this hole, and grasps the skin (or vegetation or rock) while it pumps its body full of air and sends fluid into its wing veins.  This fluid causes the wings to enlarge — the wing expansion that is evident in these two photographs took place in less than ten minutes.  When it first emerges from its skin, a dragonfly is pale and soft, and the wings have a characteristic pearlescent sheen, as in these photographs.  Within a day or so the wings lose this sheen, the body hardens and colors start to develop.


Dragonflies and Temperature Control

Often on hot, sunny days you will see dragonflies perched facing away from the sun, with their abdomens raised high in the air above them.  This position actually has a name – the obelisk posture – and some dragonflies and damselflies assume this position to prevent overheating.  They raise their abdomen  until its tip points at the sun, minimizing the surface area exposed to it.  The name given this posture comes from the fact that when the sun is directly overhead, the vertical alignment of the insect’s body suggests an obelisk. The meadowhawk dragonfly in the photograph  assumed  the obelisk posture several seconds after the sun came out from behind  the clouds.  As soon as the sun was obscured by clouds again, the dragonfly would lower its abdomen to a horizontal position. It continued doing this for a considerable amount of time.  Sometimes abdomens are raised for reasons other than temperature control, including threat displays during conflicts.


Dragonflies Mating

7-19-11  Mating Dragonflies

Dragonflies (and damselflies) form what is called a “mating wheel” when they mate.  The male (top) grasps the female at the back of her head with the appendages at the tip of his abdomen. The female then curls her abdomen forward so that its tip reaches his sex organs and receives his sperm.  After mating, the male may continue to grasp the female and accompany her while she lays her eggs, to prevent another male from removing his sperm from the female and then mating with her.