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| 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). Habitat 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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