HomeContact UsSite Map
Our Chapter Membership Conservation Field Trips Education Bird Information Special Events

Birds & Wildlife


Bats

Christmas Bird Counts

Rare Birds

Bird Problems

Where to Go Birding

Banded Birds

Sylvia's Trip Diaries

 

 

All About Dragonflies
 
Adult Dragonfly Anatomy

Odonates (dragonflies and damselflies) have the basic insect body parts which consist of a hard exoskeleton. Fashioned into a head, a thorax, abdomen, six legs, and four wings. Dragonflies are large, heavy-bodies, usually larger than damselflies.

HEAD
The head is relatively large and dominated by two large compound eyes that are oriented upward and to the sides. Each compound eye is composed of thousands of individual lenses or facets. The front of the face has chewing mouthparts below and is bordered above by a central plate.

THORAX
The thorax is divided into small segments attached to the head and bearing the front pair of legs, and the large sturdy midsection that houses the flight muscles and bears the wings and remaining two pairs of legs.

LEGS
The legs of odonates consist of the typical, jointed arthropod segments, most notably the femur, tibia, and tarsus which are tipped with two claws. Because of the forward positioning, the legs are of little use for walking; instead, they are used for perching, scooping up and handling prey, and in the case of the front legs for grooming the eyes and face.

WINGS
The large and many-veined wings of the dragonflies are held open & flat or down & forward when perched. Damselfly wings are positioned closed along the body.

ABDOMEN
The abdomen is divided into ten segments, numbered from one at the base to ten at the tip. Males-Three terminal abdominal appendages and a bump (genitalia) under the second abdominal segment. Females-Only two terminal abdominal appendages and often flanges for egg splashing and/or ovipositor.

 
Dragonfly Behavior

Adult dragonflies use vision as their primary means of assessing their environment. Dragonfly behavior has evolved in response to a few simple needs.

FEEDING BEHAVIOR
Dragonflies are voracious predators; they eat just about any animal they can catch and chew, including other dragonflies. Most prey of adult dragonflies are flying insects, taken on the wing.

ANTIPREDATOR BEHAVIOR
Dragonflies typically avoid aerial predators – birds, bats, and insects such as robber flies, wasps, and even other dragonflies – by an agile aerial maneuvering, as anyone who tries to net them can attest.

REPRODUCTIVE BEHAVIOR
Reproduction is the major goal of an adult dragonfly’s existence. After a few days or weeks of pre-reproductive life, during which it must feed, grow, and mature, it begins a programmed series of activities focused on reproduction.

REGULATE BODY TEMPERATURE (thermoregulation)
Dragonflies use a variety of behaviors in order to maintain an appropriate body temperature. Many of these movements and postures are designed to take advantage of solar regulation.

DISPERSAL
After emergence from the final larval stage, virtually all odonates disperse. For many this involves flying a distance from a few feet to a few miles away.

Life Cycles and Larva of Dragonflies

Dragonflies are amphibians in the same general sense as frogs, toads, and many salamanders. The familiar winged adults are the primary focus of the final, reproductive stage in the odonate lifestyle.

AQUATIC STAGE
Most of California’s odonates have a single generation per year. Adults emerge, mature, and lay eggs in the warmer months, primarily April through October. Eggs hatch within a few days or weeks, and the larvae grow through a series of about ten to 15 molts. The stage between molts is called instars.

Like adults, larvae are high-level predators, feeding on a wide range of aquatic invertebrates, including other odonates. Large, active larvae are capable of capturing and subduing small fish and tadpoles. Other unique features of odonate larvae are the gills they use to extract oxygen from the water in which they live.
In the final stage – the metamorphosis – the last larval instar leaves the water as an adult.

TERRESTRIAL PHASE
Mature adults, pair in wheel position (copulation). The next phase the female lays the eggs on either plants or on the surface of the water (ovipositing).

 
Watching Dragonflies

You can easily watch and enjoy many species of dragonfly with the naked eye. A pair of binoculars is very helpful. By carefully approaching a perched dragonfly from behind, you increase your chances of getting close to him. If you want to photograph dragonflies, you have to learn the skill of aerial shots (very challenging).
Kingdom  Animals
Phylum     Arthropods
Subphylum  Hexapods (Greek six legs)
Class  Insects
Order  Odonata Dragonflies and Damselflies

In both terrestrial and aquatic environments the ecosystems include communities made up a variety of species.

Resources:

Common Dragonflies of California by Kathy Biggs

Dragonflies and Damselflies of California by Tim Manolis

 
You can easily watch and enjoy many species of dragonfly with the naked eye. A pair of binoculars is very helpful. By carefully approaching a perched dragonfly from behind, you increase your chances of getting close to him. If you want to photograph dragonflies, you have to learn the skill of aerial shots (very challenging).

Kingdom  Animals
Phylum     Arthropods
Subphylum  Hexapods (Greek six legs)
Class  Insects
Order  Odonata Dragonflies and Damselflies

In both terrestrial and aquatic environments the ecosystems include communities made up a variety of species.

The following is a list of species that Mike has observed at the San Joaquin Wildlife Sanctuary


DRAGONFLIES:

Skimmers
Red Rock Skimmer
Flame Skimmer
Mexican Amberwing
Western Pondhawk
Blue Dasher
Red-tailed Pennant
Variegated Meadowhawk
Red Saddlebags
Black Saddlebags

DARNERS:
Common Green Darner
Blue-eyed Darner

POND DAMSELS:
Vivid Dancer
Pacific Forktailed
Familiar Bluet


posted 9/15/14

 


Sea & Sage Audubon Society
PO Box 5447 • Irvine, CA 92616 • 949-261-7963

http://www.seaandsageaudubon.org