Thorne Moors – Page 2 – Yorkshire Dragonfly Group

Brown Hawker Aeshna grandis

Posted on 22 April 1994 by Paul Ashton

Length

73mm, Wings 102mm.

Males

Thorax brown; abdomen brown with bright blue spots at sides; wings characteristically honey brown colour; legs pale brown.

Females

As males except blue spots on abdomen replaced with yellow markings.

Habitat

Lakes, ponds, gravel pits, canals, ditches and slow-flowing rivers. Will tolerate moderate levels of pollution.

Behavior

Males are territorial, even defending territories away from water. They are often observed hawking along woodland rides and hedgerows. This is a difficult species to approach when settled, the first sign of their presence is usually the rustling of wings, as the fly up from roosting places in tall grasses. Copulation is lengthy, the female then ovipositing into emergent floating vegetation, or decaying floating logs, where several females may oviposit together. Larvae emerge two to four years later at night, with the maiden flight taking place before dawn.

Flight Period

Distribution Map

Locations

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Emperor Dragonfly Anax imperator

Posted on 22 April 1992 by Paul Ashton

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Length

78mm Wings, 106mm.

Males

Thorax bright green; abdomen blue with black central line; legs black; eyes green; wings clear with yellow costa.

Females

Generally greenish with thicker black central abdominal line.

Habitat

Ponds, lakes, gravel pits, dykes, canals and slow-flowing rivers with rich marginal vegetation, also tolerant of brackish conditions. Seldom found far away from water.

Behavior

Males are territorial, rarely more than one male is present at small locations. Constantly patrols its territory, which it defends vigorously. Will take prey as large as Four-spotted Chaser Libellula quadrimaculata. Copulation takes place away from water and lasts around ten minutes. The female then oviposits alone into submerged vegetation. Larvae emerge after two years on to tall emergent vegetation. Emergence is usually synchronous at site level.

Flight Period

Distribution Map

Locations

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Hairy Dragonfly Brachytron pratense

Posted on 22 April 1989 by Paul Ashton

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Male

The only ‘Hawker’ species flying during May and much of June, with a slight overlap with Southern Hawker at the end of June. Thorax and abdomen distinctly hairy. Side of the thorax predominantly green, lacking the paired thoracic stripes of other ‘hawker’ species, with tapering green antehumeral stripes on the top. Abdomen has small blue paired spots.

Female

Thorax and abdomen distinctly hairy. Side of the thorax predominantly green, lacking the paired thoracic stripes of other ‘hawker’ species, with restricted, or absent, antehumeral stripes on the top. Abdomen has small yellow paired spots.

Habitat

Ponds, lakes, canals, ditches, dykes and marshy fens with tall emergent vegetation, such as rushes, reeds and sedges. Requires abundant floating vegetation for oviposition.

Behaviour

Early flight period is characteristic. Quickly settles when the sun goes in, compared to other Aeshnidae species, making it less easy to find in dull conditions. Males are territorial and patrol in and out of vegetation at low level. Can be found away from water in sheltered areas, though males will generally not wander far. Females only come to water to find a mate and oviposit. Copulation is long, taking place in nearby trees and shrubs, or long vegetation along the banks. The female oviposits into decomposing floating vegetation.

Flight Period

Status

Mainly VC61 and VC63, currently expanding its range.

Distribution Map

Locations

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Four-spotted Chaser Libellula quadrimaculata

Posted on 22 April 1986 by Paul Ashton

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Length

43mm, Wings 76mm

Males

Thorax brown, no antehumeral stripes; abdomen brown, last 4 segments darker than the rest, yellow spots on sides; wings dark patches at nodes on leading edges and at bases of rear wings.

Females

Similar to males, main difference is the shape of the anal appendages.

Habitat

Prefers sites of still water consisting of lakes, ponds, bog pools, canals and dykes. Will tolerate brackish conditions. The largest concentrations are associated with acidic ponds and pools.

Behavior

Males are territorial, their noisy clashes are obvious where densities are high. Readily returns to the same perch on emergent vegetation, after sparring with other males, or after short patrols along the waters edge. Copulation is short taking place in flight, only lasting for 5-20 seconds. Female oviposits by flicking the abdomen tip downwards into the water. The eggs then sink and adhere to submerged vegetation. Males may stay close by to guard females during oviposition. Larvae live among the bottom debris, then emerge after two to four years. Emergence takes place amongst marginal vegetation during daylight hours.

Flight Period

Distribution Map

Locations

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Black-tailed Skimmer Orthetrum cancellatum

Posted on 22 April 1983 by Paul Ashton

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Length

50mm, Wings 78mm

Males

Thorax black, no antehumeral stripes; Abdomen top is blue with yellow spots towards sides, black tip; legs black.

Females

All yellow with 2 black bands on upper surface abdomen.

Habitat

Prefers lakes, ponds, gravel workings, slow rivers or marshes, with exposed mud, stones or bare patches where the male can perch.

Behavior

Highly territorial, males perch on bare areas of ground, typically on slightly raised areas such as stones, logs or bare soil, on the lookout for females and rival males. When patrolling over water they fly low, skimming over the surface. Copulation can take place in flight, where it will only last for a few seconds, though sometimes this can take place in vegetation where it may last up to 15 minutes. Oviposition occurs by dipping the abdomen into water, with the male often remaining nearby. Larvae live amongst the bottom silts, emerging after two to three years. Emergence usually takes place on vegetation, often several metres away from water.

Flight Period

Distribution Map

Locations

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Common Darter Sympetrum striolatum

Posted on 22 April 1981 by Paul Ashton

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Length

37mm, Wings 57mm.

Males

Thorax brown with yellow patches on sides; abdomen orange/red with black central line last 2 segments ; legs black/yellow; eyes brownish; black line on top of the frons only.

Females

Thorax pale brown with yellow side panels; abdomen yellow with black central line segments 9-10 and along sides. Old females tend to take on male colours.

Habitat

Preferences are quite catholic, including ponds, lakes, canals, ditches and slow-flowing rivers. It is tolerant of brackish conditions and peaty bog pools. Can be found away from breeding sites feeding in sheltered locations, like woodland rides and hedgerows.

Behavior

Males are territorial, spending a lot of time perched, only making short flights when disturbed or chasing off intruders. Basks on the ground, especially late in the season when temperatures are lower. Frequently found away from water in sheltered areas, especially females wanting to avoid attention from males. Copulation takes place at rest, lasting around 10-15 minutes. Oviposition regularly takes place in tandem, where the eggs are flicked into the water by dipping the abdomen onto the surface. Females will also oviposit alone. Larvae emerge after one year, this taking place during the morning, onto bare bank sides or emergent vegetation.

Flight Period

Distribution Map

Locations

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Ruddy Darter Sympetrum sanguineum

Posted on 22 April 1978 by Paul Ashton

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Length

34mm, Wings 55mm.

Males

Thorax brown with 2 thin black lines on sides; abdomen narrow waist, rich red colour; face red; legs all black; line over frons spreads down the sides.

Females

Yellowish throughout with black markings on sides of thorax and abdomen; legs all black.

Habitat

Marshes, ponds, lakes, canals and ditches, with plenty of tall emergent vegetation. Will tolerate brackish conditions, using woodland near to water bodies for shelter.

Behavior

Males are less aggressively territorial than Common Darter Sympetrum striolatum. They have a ‘skippy’ flight, being less direct than the latter species. Copulation lasts only a few minutes whilst perched on vegetation or the ground. The female will then oviposit either alone, or in tandem, amongst shaded vegetation. Larvae live among submerged plants and emerge after one year.

Flight Period

Distribution Map

Locations

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