11_cook




George Cook
Crane Fly Larva, Posterior View, 2002

Photomicrograph; compound microscope; magnification approximately x200 at capture; Nikon CoolPix 990 camera

Rochester, New York, United States

The presence of aquatic organisms in water can be used as a determination of water quality. For this to be the case, the found organisms must first be identified. Insect larvae are identified by studying their body parts at magnifications up to ~500. Crane fly larvae are quite large and seldom require greater than 40, observable in a high quality stereomicroscope.

Crane flies are in the insect order Diptera and family Tipulidae. More than 1,500 species of such flies have been described in North America alone. Their life cycle includes metamorphoses in stages from eggs, larvae, pupae, and the adult flying and breeding phase. A typical crane fly larvae is grub-like and lives in a variety of habitats including fresh water streams, muddy soils with decaying plant material, and sometimes relatively dry soil such as those found in lawns. This photograph of the posterior of a crane fly larva is helpful in taxonomy for species identification. The arrangement of spiracles, or airways, surrounded by a ring of fleshy lobes varies from species to species, and easily visible in this magnification.

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