Dragonfly (Australian Emerald) Hemicordulia australiaeV
Species: Hemicordulia australiae
Common name: Australian Emerald, Sentry dragonfly
Hemicordulia australiae is an Australian dragonfly now common in New Zealand. It flies low over water, hovering stationary for periods and conducting sorties mostly close to the bank but occasionally out across open water. It may be seen far from water hawking above head height over bare ground in gardens and parks. Both adult and larvae dragonflies are predators of other insects. They require an aquatic habitat during the juvenile phase.
Male identification: A medium-sized dragonfly with a black abdomen, pinched near the base and fringed with orange crescent-shaped marks, the tips of which curve inward. Eyes on mature males are bright green and wings are completely transparent and unmarked. Black pterostigma (The pterostigma is a cell in the outer wing). See diagram below.
Female identification: Medium-sized with a broad and slightly tapering abdomen fringed with orange crescent-shaped marks, the tips of which curve inward. Reddish-brown eyes. Wing tips suffused brown. Black pterostigma.
Due to the unique nature of dragonfly copulation, the male must transfer sperm from his testes which are located on the underside of abdomen at segment 9 to his secondary genitalia, called the hamulus which is located in the underside of segments 2 and 3. The hamulus is a complicated organ that the male uses one part for removing the sperm deposits made by other males. Other parts of the hamulus are then used by the male to fertilize the female with his own sperm.
The terminal abdominal appendages of the male are called claspers. The claspers are formed by a pair of upper appendages, called cerci, and a single lower appendage, an epiproct. The male uses his legs to grasp the female by her head and thorax. He then curves his abdomen forward and uses his two cerci and the lower epiproct as a clamp and clasps the female by the back of her head. Mating is accomplished by the male arching his abdomen downward while the female arches her abdomen toward the male’s hamulus. Once connected the male commences he uses the hamulus to remove any sperm that the female may still be carrying from prior matings. This process ensures his genetic investment in the clutch of eggs that the female will soon lay.
Hemicordulia australiae in tandem copulating. Process described abiove.
A male Hemicordulia australiae with a body length of 50 mm. Males have emerald coloured eyes when matured but they are brown at an immature stage.
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