Wednesday 25 August 2010

crane flies

If you see large mosquito-looking insects flying about the house or in the garden, particularly in the mornings, chances are, they are crane flies.

Crane flies
belong to the order Diptera (Family: Tipulinae). Also called daddy-long-legs, these fragile flies are well known for shedding their very long legs easily if caught. (and they really easy to catch) There are at least 4256 species of crane flies known to man, thus making the Tipulidae the largest family of Diptera.

They are unmistakable and easily identified by their long and gangly legs and slender abdomen. They are poor fliers and tend to wobble clumsily in unpredictable patterns during flight. They also vary size with the ones in the tropics being a lot larger then the temperate species. Cranes flies are mostly brown, black or grey with yellow or pale brown markings. The end of the abdomen is blunt and expanded in males, while females have a pointed ovipositor which resembles a stinger but is completely harmless.

They occur worldwide but are often found by water, or among damp vegetation, shaded woodland or pasture. The eggs are typically laid in soil and the larvae (called 'leather jackets) feed on roots and decaying organic material, fungal threads and mosses. Many adults are short-lived, fly at twilight and feed on nectar. Because of their diet, crane fly larvae are considered pests of crops, garden plants and lawns.

This particular species I saw at Mt Tengger is the Nephrotoma alterna. The adult flies are 10-16 mm in size. Body coloration of flies of this species is general yellow and conspicuously variegated by black, including three praescutal stripes; the outer pair curved lateral into an opaque black spot. The wing tips are darkened. This is a characteristic future for this species. This is a woodland species and is commonly found in the bottomland woods, and in the moist thickets along streams. Females were often observed ovipositing into wet soil in forest floor. Those that I saw were usually just resting on the leaves of plants or simply mating.

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