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Damselflies

Damselfly or Dragonfly?

6-16-16  damselfy & dragonfly 178A visit to a pond will usually include sightings of dragonflies and the more delicate damselflies.  Both of these types of insects are in the order Odonata (Greek for “tooth,” referring to the serrated jaws of the adults).  They are separated into two suborders, due to their wing shapes and sizes. The wings of dragonflies differ in shape and size (hind wings are broader than forewings), whereas damselfly fore and hind wings are similar in shape, with the hind wings sometimes being smaller.

In addition to wing differences, damselflies have eyes that are separated by more than an eye’s width, whereas dragonfly eyes either touch or are separated by less than an eye’s width.  Damselflies are smaller and more slender than dragonflies and perch with their wings closed over their abdomens or held slightly spread.  Dragonflies at rest hold their wings out flat or downward.  In addition, dragonflies are more powerful and acrobatic in flight than damselflies.

Although these differences distinguish them, damselflies and dragonflies do have many similarities. Both are carnivorous, both spend most of their lives as aquatic larvae, and both lay their eggs in or near water.

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Dragonflies Eclosing

5-26-16  dragonfly eclosing2  347 The sudden hot weather seems to have triggered a mass emergence of dragonflies and damselflies.  The emerging vegetation along the shores of ponds is covered with larval Odonates (members of the order of insects that includes dragonflies and damselflies) metamorphosing into adults.  The adults, still in the skin of their last larval stage, crawl out of the water, climb up vegetation, rocks, etc., and split the back of their larval skin.  The adult flips backwards out of this opening, hangs upside down and then grasps the vegetation and/or empty larval skin while as its abdomen is released.  The dragonfly hangs in the breeze while it pumps air into its body, sending liquid into its wings.

To appreciate this process called eclosion, compare the size of the wings in the photo insert (recently-emerged adult) with those in the larger photograph, which was taken twelve minutes after emergence.  Within a day or so the sheen on the newly-formed wings goes away, the dragonfly’s body hardens and colors start to appear.

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Waxwings Supplementing Sugary Fruit Diet With High-Protein Insects

4-3-15 bohemian waxwing IMG_2383The diet of both Cedar and Bohemian Waxwings is primarily sugary fruits throughout most of year. Research shows that they can subsist on this diet exclusively for as many as 18 days. However, in winter when feeding on fruits, they also feed on buds and available insects. In warmer months, waxwings will fly out over water from exposed perches, much like flycatchers, and snatch emerging aquatic insects such as mosquitoes, midges, mayflies, caddisflies and dragonflies out of the air. They also glean for vegetation-borne insect prey, such as scale insects. At this time of year they are taking advantage of winter stonefly hatches over open streams. (photos: bohemian waxwing & stonefly)

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Damselfly Mating Wheel

2-14 Valentine's Day IMG_5890


Antlions Trapping Insects

8-14-14  antlions - 230The larvae of a predaceous group of winged insects (family Myrmeleontidae) that closely resemble dragonflies and damselflies are referred to as “antlions” – they have the ferociousness of a lion and prey mainly on ants. The manner in which an antlion traps its prey is ingenious. It excavates a conical pit in sandy soil (an antlion is also called a “doodlebug” because of the squiggly trails it leaves in the sand looking for just the right spot for a pit). Using its head as a shovel, it tosses out sand as it turns in a circle, digging deeper and deeper, until it forms a pit roughly two inches deep and three inches wide. The antlion lies at the bottom of the pit, covered by a thin layer of sand except for it pincer-like mandibles, which are ready to snatch prey at a second’s notice.

The slope of the sides of the pit is at the angle of repose – as steep as it can be without giving way – so when an ant accidentally steps over the edge of the pit and falls in, the sand beneath it collapses, carrying the ant to the bottom of the pit and into the pincers of the waiting antlion. If the ant tries to scramble up and out of the pit, the antlion tosses a load of sand at the ant, knocking it back down. The antlion then injects venom and digestive fluids into the prey via grooves in its mandibles, and drinks the innards of the ant through these same grooves.

The antlion’s anatomy is as unusual as its method of capturing prey. It has a mouth cavity, but no mouth opening, and no external opening for solid waste. Because digestion takes place outside of its body, the antlion doesn’t accumulate a lot of waste, but what it does accumulate stays inside of it until the antlion matures into an adult. This can be anywhere from one to three years, depending on the species. When fully developed, the antlion constructs a small, round pupal case out of silk and sand, in which it overwinters. It emerges from this case the following spring as a winged adult. (Thanks to Joan Waltermire and John Douglas for photo op.)

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Spreadwing Damselflies Mating & Laying Eggs

10-18-13 spreadwing damselflies 019Believe it or not, there are still damselflies (and dragonflies) that are flying, mating and laying eggs in the middle of October in northern New England. Certain damselflies known as “spreadwings,” unlike most other damselflies, perch with their wings partially open. (Another tell-tale spreadwing sign is that they often perch at roughly a 45 degree angle.) Spreadwings are weak flyers, and you usually see them flying low and for short distances. When sexually mature, the males tend to spend their days perched on vegetation along a pond’s shoreline. The females, like most dragonflies and damselflies, return to the water only when ready to breed. The pictured spreadwings (Spotted Spreadwings, Lestes congener, I believe) are one of the latest species of damselflies active in the fall; these two were resting before resuming egg-laying. The male (at top of photo) grasps the female’s “neck” (to prevent other males from replacing his sperm in her) while the female uses the sharp ovipositor at the end of her abdomen to slice into emergent vegetation and lay her eggs, which eventually end up in the water when the plants die.


Damselfly Reflections

Taken 10 minutes ago — sometimes no words are necessary. Have a glorious late summer weekend! 8-16-13  damselfly reflections 085


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