Notable feature: Male Abdominal Segment 2 is partially green. This species can be confused with the more common Emerald Damselfly (Lestes sponsa) the male of which has a completely blue 2nd segment of the body.
Conservation Status: Not Evaluated
Where in the UK: Predominantly found in Norfolk, Kent & Essex
The Scarce Emerald Damselfly (Lestes dryas) is a native damselfly which has localised strongholds in south-east England; there are also a few scattered colonies at other locations in East Anglia.
Usually found within the dense vegetation of shallow pools and drainage channels and once thought to be extinct in the UK until it was rediscovered in 1983.
Male Scarce Emerald Damselflies have blue eyes and a bright metallic green body; the males 2nd abdominal segment is partially green; females in contrast have brown eyes and a duller green body. Often seen resting with wings half spread.
This species can be confused with the more common Emerald Damselfly (Lestes sponsa) the male of which has a completely blue 2nd segment of the body.
Size: Females 34mm in length, males slightly larger at 37mm in length
Life span: Biennial (or longer) life cycle; 2-3 years but mostly as larvae in ponds and ditches. The adults will feed and mate during summer but can not survive our winter temperatures and therefore overwinter as larvae.
Diet: Adults are aerial predators that feed on small flying insects like flies and midges. Nymphs are ambush predators of zooplankton, midge & fly larvae as well as other small invertebrates.
Reproduction: Adults will join together in the wheel position where the male holds the female below her head and she curls her body to collect the sperm that has been deposited on the males upper abdomen. They will remain joined for a few minutes until the transfer is complete. The male often stays attached in the tandem position to protect the female as she uses her sharp ovipositor to lay her fertilized eggs inside submerged plant material. The eggs hatch after 5-6 days. Larvae will spend 2 years feeding until ready to emerge.
When to see: June – Sept is the adults main flight period. Usually found within the dense vegetation of shallow pools and drainage channels. This species is unlikely to be seen flying over water. Larvae can be found in ponds and ditches all year round.
Population Trend: Unknown but listed as Near Threatened in the British Odonata Red List 2008.
Threats: Eutrophication (mineral/nutrient enrichment) of water bodies needed for larval stages. Habitat changes due to over-grazing or lack of management leading to unfavourable succession. Climate change causing drought or coastal flooding.
Fun Fact: Larvae will only crawl out onto land when conditions are right, so if the water isn’t warm enough or they haven’t fed sufficiently for incomplete metamorphosis they will remain in the water.
How you can help:
Buglife is working to increase awareness of invertebrates and the Scarce Emerald Damselfly through specific projects, including our current work at Canvey Wick and campaigns which have highlighted the importance of areas in the south-east including the Thames Gateway and brownfield sites, but we need your help!
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