Cordulia aenea (Linnaeus, 1758)
Common name: Downy Emerald
Preferred environment: oligotrophic to mesotrophic pools, lakes and canals especially in wooded areas.
Flight period: April to early August in southern Europe; mid-May to early August in northern part of range. Irish records only in mid June to mid July.
Adult habitat and habits: adults feed in woodland often at canopy level. Mature males occupy length of shoreline usually centred on bay for short periods of time. Males fly low and patrol regular beat with bouts of hovering. Other dragonflies are challenged. Unattached females are grabbed and taken to bushes where copulation takes place.
Oviposition site and behaviour: females oviposit alone, in shallow water margins, dipping abdomen on water surface and releasing batches of eggs.
Larval habitat and habits: Larvae are found amongst coarse leaf litter at bottom of pond, spending day time resting upside down under leaf fragment. Hunt by touch and feed at night. Larval stage takes 2-3 years.
Emergence behaviour: emergence occurs mainly in morning on surrounding vegetation up to 10m from pond and at any height up to 3m.
Range: central and northern Europe from French Pyrenees to northern Finland, across Asia to Japan. It is very local in Atlantic fringe of Europe. In Ireland confirmed breeding sites only in SW, around Killarney, There is one report of adults from near Glengarriff and an unconfirmed record from Connemara.
Determination of adults: species is keyed and male abdominal appendages are figured in Askew (1988) mature adults are illustrated in colour in Askew (1988) and Brooks (1997).
Determination of larvae: keys to mature larvae in Askew (1988) and Brooks (1997). Whole larva is figured in Askew (1988)and photograph of mature larva in Brooks (1997).
|Nelson, B., Thompson, R. & Morrow, C., 2000 (May 2). [In] DragonflyIreland http://www.ulstermuseum.org.uk/dragonflyireland/|