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Conservation Status

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Very widespread species, especially in western North America (Lung and Sommer 2001).
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Cyclicity

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Flight season is from late June to mid September or October (Hutchings and Halstead 2011).
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Distribution

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Found from Alaska to Newfoundland and Labrador, south to northern California and Wisconsin, as well as some parts of northern United States. It is also found in northern Europe and Eurasia (Paulson 2009).
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General Description

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Approximately 3 centimeter meadowhawk with black and yellow patterns. Males are almost entirely black with few yellow stripes and have metallic face. Females have reddish-brown eyes with pale green colours. The thorax and abdomen is mostly yellow with black stripes on lateral sides and the costal veins on both wings are yellow. Immature adults are yellow with lighter black or brown patterns on thorax and abdomen, and will gradually turn darker as they become mature (Paulson 2009).
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Habitat

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Mountain areas (Cannings 2002), bogs, fens, and marshes with dense vegetations (Paulson 2009).
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Life Cycle

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The adults emerge around mid July to late August (Cannings and Cannings 1997). Unlike cherry-faced meadowhawks, the black meadowhawks are not territorial (Paulson 2009). The mating season is from August to early September (Cannings and Cannings 1997). Most of them mate away from the water, then come to water for oviposition in tandem by noon. Oviposition can happen either in tandem or alone. The female drop eggs from air into open water or on moss (Paulson 2009).
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Trophic Strategy

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Aquatic nymphs feed on many small soft body arthropods and vertebrates in water. Terrestrial flying adults feed on many small and soft bodied flying insects (Lung and Sommer 2001).
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Sympetrum danae

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Sympetrum danae, the black darter or black meadowhawk is a dragonfly found in northern Europe, Asia, and North America. At about 30 mm (1.2 in) long, it is Britain's smallest resident dragonfly. It is a very active late summer insect typical of heathland and moorland bog pools.

Members of the genus Sympetrum are known as darters in the UK and as meadowhawks in the US and Canada.[2]

Identification

Both sexes have black legs and pterostigmata and a very broad base to the hind wing. The thorax has yellow sides separated by a bold black panel in which are three yellow spots, resembling a highland darter (Sympetrum nigrescens).[3]

The male has a mainly black thorax and abdomen. The abdomen has small yellow marks on the side, that darken with age. The wings are clear.[3]

The female has black legs and brown eyes. The abdomen is mainly yellow, becoming browner with age. It has small yellow patches at the wing bases.[3]

Breeding

This darter is restricted to acidic shallow pools, lake margins and ditches in lowland heath and moorland bogs, usually with bog-mosses and rushes. Eggs are laid in flight by dipping the tip of the abdomen into the water.[4] The eggs hatch the following spring and the larvae develop very rapidly, emerging after as little as two months.[5]

Females tend to choose where to lay their eggs based on the appearance of the site. Female Meadowhawks also base the location of their oviposition on temperature. The females tend to gravitate more towards cooler climates rather than warmer climates. They are also likely to choose an oviposition site that contains little to no predators within the surrounding area.

Population and conservation

In the British Isles, this dragonfly is very locally distributed in the lowlands, but more widespread in the north-west and Ireland. It is often very locally abundant and maybe this triggers dispersal. Records from the south coast suggest that immigration from the continent does occur. Its main threats, however, are development, drainage, agriculture, and peat extraction.[3]

Diet

The immature Meadowhawk dragonflies feed on a various organisms that can be found in aquatic environments. Some of these insects include fly larvae, mosquito larva, mayfly larvae, shrimp, and other types of fish. The adult Meadowhawks feed on smaller, typically flying insects. Many of their diet consists of insects from the order Diptera. This includes mosquitoes, flies, moth, mayflies, and even insects like mites or termites.

Reproductive Structures

One factor that distinguishes the female dragonfly from the male is the presence of two spermatheca, this trait is absent in males. Females also obtain spherical bursa copulatrix. Male dragonflies, on the other hand, possess copulatory organs that aid them during sperm competition. During this process, the males have the capability of removing the sperm of previous mates from the female and replacing it with their own sperm. Males can also be distinguished by their genitalia which is uniquely four-segmented.

Development

The development of the Sympetrum danae is divided into seven different phases. The first phase begins with newly developed eggs. When eggs are first layer they are white in color, but after approximately 18 hours afte, they become a grayish color. The second phase takes place four days later when the structure of the yolk alters. It is then followed by the third stage on the eighth days. During this stage the germ plate becomes visible to the naked eye. The fourth stage occurs on the tenth day. This is when segmentation throughout the body becomes noticeable. Then, on the second week the fifth stage occurs. The eyes, mouthparts, and antennae develop during this particular stage. Many days later, on the 189th day, the sixth stage takes place and the embryo flips 180 degrees. Lastly, the seventh stage. This happens on the 197th day and it is when development is complete. The dragonfly typically hatches from its shell 217 days after it was oviposited.

Female v. Male Activity

Meadowhawk males are typically more active in the morning hours. They spent most of their mornings in search of females to mate with. Their activity lessens in the afternoon. Female Meadowhawks are the opposite. They tend to be more dormant in the early hours and more active at night. Male dragonflies are likely to be more active near ponds and bodies of water. Oppositely, females tend to be less active when near the water and prefer to be in areas with overgrown plants and grasses. Female dragonflies typically only go to the water when they are in search of a mate or if they are laying their eggs. Unlike female dragonflies, males have two different types of flight: search flight and patrol flight.

References

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Sympetrum danae: Brief Summary

provided by wikipedia EN

Sympetrum danae, the black darter or black meadowhawk is a dragonfly found in northern Europe, Asia, and North America. At about 30 mm (1.2 in) long, it is Britain's smallest resident dragonfly. It is a very active late summer insect typical of heathland and moorland bog pools.

Members of the genus Sympetrum are known as darters in the UK and as meadowhawks in the US and Canada.

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