Phylum ArthropodaClass Insecta

Order OdonataDragonflies and Damselflies

Odonate Characteristics

• ‘Odonto’ refers to strong teeth on mandibles of adults• Aquatic larva -> terrestrial (aerial) adult• Highly predaceous larva or adult• Usually considered beneficial for the large number of

flying insects the adults eat• ~11 families and 407 species in NA• Hemimetabolous: egg -> nymph (naiad) -> adult• Some species are migratory• Adults often mate guard by flying in tandem after

copulating• “Devil’s Darning Needle”; mosquito hawk

Natural History• Habitat-almost all in lentic waters• Feeding-zooplankton->larger invertebrates->larger

items, even fish• Life history:

– Most have one generation/yr– Some require 2 years; a few require 3-6 yrs (in cold

climes)– Most oviposit in water; a few in plants above water line

with a sword-like structure– Hatch in several weeks; species of vernal pools may

enter diapause for 11 months– Larval stage averages 10 months (range-6 weeks to 6

years)– Molt 11-12 times (range 10-15)

More Natural History

• Stop feeding several days prior to emergence• Climb out of water• Emergence takes 1-3 hrs; a very vulnerable stage;

many emerge at night• Adults live 1 month (range: 2weeks-2 months)• Excellent vision; can rotate head almost 360• Catch food on the wing in leg basket• Males territorial; may lek

SubordersAnisoptera and Zygoptera

Dragonflies Damselflies

Adults

Larvae

•Labial mask for catching prey

•Rectal gills

•Stout body

•Labial mask for catching prey

•Three leaf-like gills at rear of abdomen

•Body long and slender

Dragonfly LarvaeFamily Differences

Aeshnidae Gomphidae Cordulugasteridae

Labial Mask

Often Identified by Wing Venation

Emergence: a dangerous time

Teneral Stage

Exuvium

Ovipositing