Dragonflies and damselflies are some of the oldest insect types in the
world, having been around for at least 300 million years. In the time of the
dinosaurs, dragonflies and damselflies were much larger. Some prehistoric
dragonflies had 2 foot wingspans! However, size is the only characteristic
of these winged predators which has drastically changed over the years.
Dragonflies and damselflies are voracious predators, devouring other
insects, which often helps controlling pests like mosquitoes. This online
guide is designed to introduce you to dragonflies and damselflies which are
commonly found around Maryland. For a complete list of dragonflies and
damselflies found in Maryland, please check out our
Dragonflies and damselflies are classified as odonates (from
the Greek word for, "toothed"). Odonates are insects with large heads and
well developed compound eyes. They have 3 pairs of legs which are used like
a basket to scoop up prey and grab on to surfaces. Odonates also have long
abdomens and two sets of powerful wings. Often, the color of eyes and face
as well as markings on the thorax (segment between the head and abdomen) and abdomen color can help with odonate identification.
As juveniles, odonates are semi-aquatic or aquatic. The
odonate larvae, also known as nymphs, are carnivorous and feed on small
insects and other insect larvae, fish and tadpoles. Their jaws actually
shoot out of their mouths in one one -hundredth of a second to grab their
unsuspecting prey and pull it back into the mouth.
Compared to dragonfly
larvae, damselfly nymphs have longer abdomens with feather-like gills
protruding from their ends. Dragonfly nymphs, conversely, are short and
stout with gills on the inside of their abdomen. The larval stage can last
anywhere from one to six years. Eventually, the nymphs grow, shed their
larval skins and develop into flying adults.
Since odonates do not have an
intermediate stage between larvae and adults, odonates are characterized as
undergoing “incomplete metamorphosis”, also known as hemimetaboly.
When odonates mate, they couple together using special
clamp-like appendages at the end of their abdomens. This process is called
being ‘in tandem’, and the mating odonates often form a wheel or heart-like
shape. Depending on the species, the male may or may not stick around to
guard the female as she lays her eggs. The egg laying process is known as
ovipositing. Eggs can be placed on vegetation, in the water, in the soil or
even in rotting wood.
Dragonflies and damselflies are relatively easy to tell
apart once you know what to look for. The following list goes over common
differences between the two groups of odonates.
Body shape: Damselflies have slender bodies while dragonflies are much
Eyes: Damselflies have well separated eyes while dragonflies have eyes
that are close together and usually meet in the middle of the head. (see
Wings: Damselflies tend to hold their wings over their back when resting
while dragonflies tend to keep their wings open over their bodies. One
exception to this rule are spreadwing damselflies.
However, this group can
be separated from dragonflies by looking at their body shape and the space
between their eyes.
Kerry Wixted Wildlife and Heritage Service 580 Taylor Ave, E-1 Annapolis, MD firstname.lastname@example.org Phone: 410-260-8566 Fax: 410-260-8596
580 Taylor Ave, Annapolis MD 21401