The American Rubyspot, Hetaerina americanaThe
American Rubyspot is certainly one of the most colorful insects in North
America. The red blaze on the wings is easily recognizable and cannot be
confused with any other species of damselfly. Males and females perch on
streamside or lakeside vegetation, usually overhanging the water, and
can be present in greater numbers than almost all other damsels. They
are very wary and difficult to approach.
The Damselfly (Suborder Zygoptera) is an insect in
the Order Odonata. Damselflies are similar to dragonflies, but the
adults can be differentiated by the fact that the wings of most
damselflies are held along the body when at rest. Furthermore, the
hindwing of the damselfly is essentially similar to the forewing, while
the hindwing of the dragonfly broadens near the base, caudal to the
connecting point at the body. Damselflies are also usually smaller,
weaker fliers than dragonflies, and their eyes are separated.
Damselflies undergo incomplete metamorphosis, with an aquatic nympal
stage. The female lays eggs in water, sometimes in underwater
vegetation, or high in trees in bromeliads and other water-filled
cavities. Nymphs are carnivorous, feeding on daphnia, mosquito larvae,
and various other small aquatic organisms. The gills of damselfly nymphs
are large and external, resembling three fins at the end of the abdomen.
After molting several times, the winged adult emerges and eats flies,
mosquitoes, and other small insects. Some of the larger tropical species
are known to feed on spiders, hovering near the web and simply plucking
the spider from its perch there.
Ebony Jewelwing, Calopteryx maculataThe Ebony
Jewelwing can be seen flitting about amidst the shadows of forest
clearings and underbrush near flowing water. Its iridescent green body
and jet-black wings make it an ethereal but showy insect when it happens
into direct sunlight - the iridescence lights up into startling glowing
neon green. Damselflies complete a life cycle in one
or two years. The adults mate over the shallow water, sometimes in
flight but often while clinging to the exposed portions of weed beds or
shoreline vegetation. Immediately after mating, the female will crawl
down the vegetation, and 'into' the water to lay her eggs on the
submerged portion of the vegetation. Once the eggs are laid she will
crawl back up the vegetation and repeat the process. When the eggs hatch
they do not go through the larva and pupa transformations. The newly
hatched damsel is just a smaller version of the later immature stages.
Thus they are simply called 'nymphs' until they actually hatch into
adults.
The damselfly nymph is predacious. Usually it lies in wait for other
aquatic bugs to get within range and then grabs them with its 'labium'
which is modified lower jaw. The nymph will proceed through 10 to 12
instars, or molts, before becoming fully developed and ready to emerge
as an adult. With each molt the nymph becomes somewhat darker in color.
Finally the nymph will swim towards the shore and crawl into shoreline
vegetation. While clinging to this vegetation the nymph's skin breaks
along the wing case and out crawls a shortened version of the adult.
Before taking flight, the new adult must pump body fluids into its
abdomen and wings. Depending on the species, the adult will live for
several weeks to several months before mating and dying.
The adult has four wings that fold over the back. The male of the most
common variety in the interior is blue while the female is more of a
slate color. For the nymph, a fairly large and bulbous head sits on a
tubular shaped body. The eyes of the damsel are fairly pronounced but
not as large or pronounced as the eyes of a dragonfly nymph. The tail is
three feathery looking appendages. The tail is called the "caudal
lamellae" and is actually three gills at the end of the abdomen. |
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Wide-set, large compound eyes give damselflies acute stereoscopic
vision, important for predators.
Argia apicalis Odonates are completely
harmless - they do not sting or bite. Indeed, they are beneficial in the
same respect spiders and other predators are beneficial - they keep the
burgeoning insect population in check. Many of these species prey on
each other; I often see dragonflies with damsels in their clutches.
Dragonflies are among the most ancient of living creatures. Fossil
records, clearly recognisable as the ancestors of our present day
odonates, go back to Carboniferous times which means that the insects
were flying more than 300 million years ago, predating dinosaurs by over
100 million years and birds by some 150 million. |
