Department of Entomology

Odonata (Dragonflies and Damselflies)

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Odonata - Brigham Young/VPI & SU PCD0330014

I. Background Information

A. Origin of name

1. odon, tooth
2. robust mandibles

B. Classification

1. Number of families and species in North America north of Mexico - 11 families, 415 species

C. Common names

1. Dragonflies, damselflies, mosquito hawks, devil's darning needles, horse doctors, horse stingers
2. many myths about them.

D. Type of metamorphosis - simple (hemimetabolous)

E. Phylogenetic relationships - paleopterous exopterygota

II. Biological Summary for Order

A. Life history

1. Eggs - usually several hundred to several thousand; either in water or in plants; usually hatch in several days to 1 month
2. Immature stages - nymphs; usually almost 1 year (ranges from 3 weeks to 5 years); usually 11 or 12 instars (ranges from 10 to 15)
3. Adults
a. most live 40 to 50 days
b. crawl out of water to molt
4. Number of generations per year - most univoltine (some semivoltine or merovoltine)
5. Time of emergence - most spring and summer (some early fall)
6. Delays in development - some inhabitants of temporary habitats diapause for up to 7 months as eggs in warm months

B. Habitat and habits

1. Adults - many disperse widely but return to spend most of adult life near preferred aquatic habitat (not necessarily the same one they came from); some fly almost all of the time, others perch for short periods between flights
2. Nymphs - dragonflies common in slow-moving flowing waters and standing waters; not many damselflies found in flowing waters; nymphs move rather slowly, if at all; lie in soft sediment or climb about in vegetation or plant debris

C. Food

1. Adults
a. capture insects with spines on front legs
b. large eyes, 360 degrees to capture prey
2. Nymphs - capture invertebrates (anything they can subdue - even Daphnia) with hinged labium

D. Respiration of immature stages

closed tracheal system with gills at end of abdomen; external in damselflies, internal in dragon flies

E. Behavior

1. adults - male dragonflies defend territories; unique copulatory loop; some males remain with females during oviposition

F. Significance

no adverse economic significance; some beneficial economic significance in control of biting Diptera (have been some attempts at mass rearings for biocontrol); important fish food in standing waters

III. Collecting and Preserving Adults

can only be collected by aerial netting while flying or perching; preserve dry on pins or in plastic envelopes; acetone can be used to preserve colors

IV. Other Web Sites

• Digital Dragonflies - Texas Agricultural Experiment Station