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Stream mayflies

These flat-headed mayflies are usually dark brown with clear wings and two long abdominal tails.

• IJEE CYCLE Lggs are laid in water. The nymphs are typically active and live under stones and vegetation or in debris. Some are poor swimmers and cling tightly to rocks and stones on the bottom of the habitat. Most scrape algae or eat fine particles of organic matter.

• OCCl JRRENCE Worldwide, except Australia and New Zealand; rare in South America. In and around ponds, lakes, and fast-

flowing streams.

NYMPHS are flat and dark. They are highly mobile swimmers.

Prongill mayflies

Most of these drab mayflies have dark, longitudinal veins on the wings. The males' eyes are divided into an upward-facing region with large facets and a downward-facing region with smaller facets. The abdomen carries three long tails.

• LlEE CYCLE Kggs are laid in water. The crawling nymphs may have a flat shape and live under stones and in debris. Most scrape algae or eat fine particles of organic debris; a few eat fish eggs.

• OCCURRENCE Worldwide. In streams and rivers; by the edges of ponds and lakes.

• REMARK The adults are used as models for artificial "flies" in trout fly-fishing.

NYMPHS look grasshopper-like from the side. The abdomen has forked gills.

large eyes typical smalt hiny black

U nOPHLF.nm VESI'F.RTINA is widespread three in Europe, near lakes and small streams. Here, abdominal a sub-imago mayfly rests on vegetation before 'ails molting into a shiny-winged adult.

KCDYONliRUS DISPAR is a common European mayfly. It prefers lake shores and stony-bottomed rivers. The dull winged sub-imago stage is seen here.

• very large eyes in males two long smalt t abdominal tails hindwings • • dull forewings

Damselflies and Dragonflies

^ UK 5,500 SPKCIKS and 30 families

_ in the order Odonata are better known as damselflies and dragonflies. The damselflies are represented here by a selection of families, from the (^alopterygidae to the Pseudostigmatidae. A selection of dragonflies follows, from the Aeshnidae to the Libellulidae.

The head of these insects has biting mouthparts, short antennae, and very large compound eyes. In damselflies, the head is broad, with widely spaced eyes, whereas dragonflies have rounded heads and eyes that are not widely separated. Both pairs of wings are more or less the same in damselflies, whereas the hindwings of dragonflies are broader than the forewings. At rest, damselflies fold their wings; dragonflies tend to bold them outstretched. Damselflies usually sit and wait for suitable prey, whereas dragonflies bunt prey in the air.

Males of both groups can curl their abdomen to transfer sperm from a genital opening on the ninth abdominal segment to a storage organ in the second or third. When mating, males may remove sperm from past matings. Eggs are laid in water and on aquatic plants. Metamorphosis is incomplete. The aquatic nymphs are predacious and have a hinged labium that can be shot forward to seize prey.

0rder Odonata

Family CALOPTKRYGIDAK

Broad-winged damselflies

I hcsc relatively large damselflies have wings that narrow gradually and appear to be unstalked. The wings may he dark and in males can have bright red marks at the bases or distinctive dark bands elsewhere. The pterostigma is small or may be absent altogether.

• LlFK CYCLK Kggs arc laid inside the tissues of various aquatic plants. Up to 300 eggs will be laid by a single female, and she may enter the water completely to do so. The nymphs hunt for prey in fast-flowing water.

• OCCl JRRKNCK Worldwide, especially in warmer regions; rare in Australia. In fast- and slow-flowing rivers and streams, and canals.

• RKMARK Adults may hunt some distance from water and prefer wooded areas.

Nymphs have a small head and three prominent, flaplike gill filaments.

Nymphs have a small head and three prominent, flaplike gill filaments.

thoracic segments angled backward as in all damselflies thoracic segments angled backward as in all damselflies

OPTERYX VIRGO, Beautiful Demoiselle, has metallic coloring. The male (seen here) is green-blue with dark wings; the green females have pale yellow-brown wings.

Wingspan K-lMin (2-4.5cm)

Nymphal feeding habits ^

No. of species j^q pterostigma is black and about three times • longer than its width

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