Mayflies

Code QE999999

See Key to Families of Australian Aquatic Ephemeroptera

A small order of insects, with no more than a few thousand species, with highest diversity in temperate areas. Adult with mouthparts reduced; large compound eyes, especially in male, and 3 ocelli; antennae filiform, sometimes multisegmented; thorax, particularly mesothorax, enlarged for flight, with large triangular fore wings and smaller hind wings, sometimes much reduced or absent; elongate fore legs in male used to seize female during mating flight; abdomen 10-segmented, typically with 3 long, multisegmented, caudal filaments consisting of a pair of lateral cerci and usually a median terminal filament.

Nymphs with 12-45 aquatic instars; fully developed mandibulate mouthparts; developing wings visible in older nymphs (as shown here for a leptophlebiid nymph); closed tracheal system lacking spiracles, with abdominal lamellar gills on some segments, sometimes elsewhere, including on maxillae and labium; with 3 usually filiform caudal filaments consisting of paired cerci and a variably reduced (rarely absent) median terminal filament. Penultimate instar or subimago (subadult) fully winged, flying or crawling.

Nymphs graze on periphyton (algae, diatoms, aquatic fungi) or collect fine detritus; few predatory on other aquatic organisms. Development takes from 16 days to greater than one year in cold and high latitude waters; some species are multivoltine. Subimago and adult are non-feeding and short-lived; exceptionally subimagos mate and adult stage is omitted. Nymphs occur predominantly in well-oxygenated, cool, fast-flowing streams, with fewer species in slower rivers and cool lakes; some tolerate elevated temperatures, organic enrichment or increased sediment loads.

There is a reported occurence of the otherwise New Zealand distributed family Siphlaenigmatidae in Australia (Luig-Ortiz & McCafferty, 1998) but the record is certainly incorrect, with label confusion with a New Zealand site.

Reference:

Luig-Ortiz, C.R. & McCafferty, W.P. (1998) First report of the genus Siphlaenigma Penniket and the family Siphlaenigmatidae (Ephemeroptera) from Australia. Proceedings of the Entomological Society, Washington 100 (2): 209-213.