InstructionsUse the keyGroupsfamAnatomy
Phylum Arthropoda
Class Insecta
Order Odonata
Suborder Anisoptera
Family Cordulegastridae
Common Name Spiketail
Distinguishing Characteristics
  • Jagged and interlocking teeth on the palpal lobes (1)
  • Palpal lobes of labium form spoon-shaped structure (2)
  • Setae on palpal (2)
  • Females have a spike on the subgenital plate (3)
Additional Pictures
     A small Odonate family, Cordulegastridae has 1 genus and 9 species (1, 2). North American species are found in the eastern and western regions of the continent (2).

     Cordulegastridae are categorized as burrowers and sprawlers, burrowing deep into the substrate, exposing just their head (2). Clean sand and silt substrates in small lotic streams are preferred habitats (1, 2).
     In a Virginian stream, each species of Cordulegastridae observed had its own narrow niche where it lived except for Cordulegaster maculate, which had the broadest habitat of all, suggesting strength in the ability to adapt (4).

Life History
     Most species have life cycles lasting 3-5 years (1). The adult flying period is from spring to early summer, peaking in June (5). Males are very territorial and increase their territorial behavior based on the length of oviposition expressed by the female. An example of this observation was seen in Cordulgaster diadema where a female deposits her eggs in a male's territory in less than 10 seconds. Males in this species displayed less territorial behavior compared to males of other species where oviposition can take up to 30 minutes (5).
     Trapping air bubbles with the hairs along the body, females enter the water and descend towards the bottom (2). With an elongated and spike-like ovipositor the female deposits the fertilized eggs into the substrate comprised of sand or silt (1, 2).

Feeding Behavior
     As opportunistic feeders, Cordulegastridae consume any type of prey within their reach, even smaller larvae of the same species (4). This family is categorized as an ambush predator, capturing their prey by extending their labium (1).
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(1) Thorp, J.H. and A.P. Covich. 2010. Ecology and Classification of North American Freshwater Invertebrates, pp. 587-657. Elsevier Inc. Boston.

(2) Cummings, K.W. and R.W. Merritt. 1996. An Introduction to the Aquatic Insects of North America. Kendall and Hunt Publishing Company. Boston.

(3) Dijkstra, K.-D.B. and V.J. Kalkman. 2012. Phylogeny, classification and taxonomy of European dragonflies and damselflies (Odonata): a review. Organisms Diversity & Evolution.

(4) Burcher, C.L. and L.A. Smock. 2002. Habitat distribution, dietary composition and life history characteristics of Odonate nymphs in a blackwater coastal plain stream. The American Midland Naturalist 148:75-89.

(5) Poethke, H.J. and H. Kaiser. 1987. The territoriality threshold: a model for mutual avoidance in dragonfly mating systems. Behavioral Ecology Sociobiology 20:11-19.