North Cave Wetlands – Page 2 – Yorkshire Dragonfly Group

Common Blue Damselfly Enallagma cyathigerum

Posted on 22 April 1999 by Paul Ashton

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Length

32mm, Wings 36-42mm

Male

Bright blue body with black markings on upper surface of abdomen, segment 2 has lollipop mark; segment 8 and 9 all blue; broad antehumeral stripes on black thorax; eye spot linked by bar.

Female

3 colour forms:-
1) abdomen with black markings.
2) Green with black markings.
3) Brown with black markings. All have characteristic medial spine under segment 8, presumably puncturing plant material before inserting an egg.

Habitat

Large ponds and lakes are the main preference for this species. Can also be found along canals and rivers, but will also tolerate brackish conditions. The most abundant Zygoptera found in open areas.

Behavior

The most dominant species on large lakes and reservoirs, swarming over the waters surface far from the banks in sunny conditions. Readily settles on emergent vegetation and is aggressive towards others, even driving away larger species. Copulation lasts for around 20 minutes, frequently away from water. Oviposits into submerged and emergent vegetation, usually in tandem. If the female submerges the male will uncouple, guarding the area waiting for her to re-emerge. Females can submerge for up to an hour. Larvae live amongst submerged vegetation emerging after 1-3 years. They mature in surrounding areas over a period of around 12 days.

Flight Period

Status

Occurs on a wide range of varying water-bodies. Can be more conspicuous than the similar Azure Damselfly. Blue damselflies ranging far over open water are usually this species. Generally the most abundant blue damselfly at sites, where the Azure can be absent.

Distribution Map

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Southern Migrant Hawker Aeshna affinis

Posted on 22 April 1998 by Paul Ashton

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First recorded in 2018, with individuals present at Flamborough and Spurn.

Male Southern Migrant Hawker at Spurn, photographs courtesy of Daniel Branch

Flight Period

Distribution Map

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Common Hawker Aeshna juncea

Posted on 22 April 1997 by Paul Ashton

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Length

74mm, Wings 95mm.

Males

Thorax top is black , narrow yellow antehumeral stripes and sides are brown with 2 narrow yellow thoracic stripes; abdomen black with pairs of yellow and blue spots including segments 9 and 10; legs black; wings have brilliant yellow costa.

Females

Thorax brown; abdomen brown with paired yellow spots, sometimes green, rarely blue. Leading edge of the wing yellow.

Habitat

Prefers acidic conditions, consisting of bog pools, ponds and lake margins on moorland and heathland. Will also use slow-flowing sections of upland streams. Requires areas of emergent vegetation to breed.

Behavior

Males are territorial, regularly chasing off intruders of any species. They are relentless flyers and can often be found active in dull conditions. Copulation takes from 60-75 minutes, with pairs usually settling amongst the heather, shrubs or trees. The female oviposits alone, inserting the eggs into submerged vegetation. Oviposition may take place in dull weather, when the first sign of activity is the sound of rustling wings in low vegetation. Larvae develop over a period of two or more years amongst the submerged vegetation. They emerge, usually at night, on emergent plant stems. They regularly wander away from breeding sites to feed in sheltered areas, such as woodland rides.

Flight Period

Distribution Map

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Migrant Hawker Aeshna mixta

Posted on 22 April 1996 by Paul Ashton

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Length

63mm, Wings 87mm

Males

Thorax brown with broad thoracic stripes, with short indistinct antehumeral stripes; abdomen brown, yellow triangle mark on segment 2, separate pairs of blue spots along rest of abdomen; legs brown; eyes bluish; wings have brown costa.

Females

Thorax antehumeral stripes very restricted, often missing; abdomen brown with small yellow-brown spots; long anal appendages. Brown costa, leading edge to the wing.

Habitat

Still or slow-flowing waters including ponds, lakes, sand and gravel pits, reservoirs, slow-flowing rivers, canals and ditches. Will tolerate brackish conditions, though avoids acidic water.

Behavior

None territorial and often present in high densities with little sign of aggression. Frequently hovers, searching for females in marginal vegetation. Both sexes can be found well away from water in sheltered locations, such as woodland rides and hedgerows. Regularly found perched in the open. Copulation is lengthy and once complete, the female will oviposit alone. Oviposition usually occurs into emergent plants above the water, though occasionally in bare mud. Emergence usually occurs the following year, often during the night. Despite being abundant late in the season, few exuviae have been found. Those that have been recovered are usually found low down in thick vegetation. Due to the lack of breeding data, it would suggest that the majority of adults observed are migratory individuals.

Flight Period

Distribution Map

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Southern Hawker Aeshna cyanea

Posted on 22 April 1995 by Paul Ashton

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Length

70mm, Wings 98mm.

Males

Thorax – green and brown with broad green antehumeral stripes; abdomen – yellow triangle segment 2, green spots segments 3-8; undivided blue spots segments 9-10; wings brownish tinge; legs brown-black.

Females

Thorax – green and brown with broad green antehumeral stripes; abdomen brown with green spots, undivided green spots on segments 9-10.

Habitat

Lakes and ponds, including small garden ponds where it is the most likely Aeshnidae to be encountered. Also found along canals and ditches. Will feed away from breeding sites, sometimes being encountered in sheltered areas, such as woodland rides and hedgerows.

Behavior

Males are territorial, with a single male usually found at a small pond. There is however a constant change of males throughout the day. This is an inquisitive species, often approaching close to the observer. They can be active in dull weather, often on the wing late into the evening, even hunting when it is raining. Copulation takes place away from water, lasting for around two hours. The female oviposits into waterside vegetation, moss or bare soil above water, often in poor weather. Larvae emerge after two to three years on tall marginal vegetation. They mature away from water over a four to six week period, before returning to suitable sites to breed.

Flight Period

Distribution Map

Locations

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Brown Hawker Aeshna grandis

Posted on 22 April 1994 by Paul Ashton

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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

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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

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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

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Broad-bodied Chaser Libellula depressa

Posted on 22 April 1984 by Paul Ashton

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Length

44mm, Wings 76mm

Males

Thorax brown, pale, broad antehumeral stripes; brown patches at base of wings; broad abdomen blue with yellow spots at sides, legs brown, eyes brown.

Females

Thorax brown, pale, broad antehumeral stripes; abdomen yellowish brown with yellow spots along sides; wings brown base areas.

Immatures

Both sexes yellowish.

Habitat

Small lakes, ponds, garden ponds, ditches and canals with well-vegetated margins and sheltered sunny locations. Will use bog pools if they are not too acidic. Often, one of the first species to colonise new water bodies.

Behavior

Males are aggressively territorial, there seldom being more than one male at any small pond. They perch on stems of tall emergent vegetation, or on the ground, chasing off any intruding males that appear within their territory. Copulation takes place in flight, lasting for only a few seconds. The female oviposits by flicking the tip of her abdomen into the water rapidly, occasionally with the male guarding her nearby. Larvae live amongst the bottom debris, emerging after two to three years. Emergence at sites is usually synchronous on marginal and emergent vegetation.

Status

Widespread though scarce in VC65 Noert-east Yorkshire.

Flight Period

Distribution Map

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