Broad-bodied Chaser, Libellula depressa

Size

Medium sized; body length 25mm to 20mm.

Colour-patterning

Males have a grey-brown ground colouration with a pair of yellowish bands on the thorax behind the eyes and a striking powder blue abdomen. The tip of the abdomen is black and there are a series of four or five yellow markings along either side of abdomen at mid-body. Both sets of wings have dark brown patches at their bases with those of the hind wings being larger and triangular in shape. Females are similarly patterned to the males but the males blue colouration is replaced with a duller yellow-brown colouration.

Behaviour

Males are very territorial and aggressive as they fly over their ponds and chase off not only rival males but also any other larger dragonflies that intrude into their territory. They adopt lookout perches to which they return consistently day after day in between territorial flights. Females are usually only seen over water when egg laying. Mating takes place in the air and the female lays her eggs in floating and submerged pondweeds. During egg laying the female hovers a few centimetres above the water surface and lays eggs individually onto the weeds as she swoops down repeatedly in a circular movement, lays her egg and returns to her hovering position.

Where to look for it

Broad-bodied Chasers prefer sheltered ponds or very slow moving water. They are not uncommonly associated with garden ponds and can even be found around brackish lagoons. They are always to be found over the ponds in Efford Marsh and Forder Valley Local Nature Reserves during the breeding season.

Distribution and status

The species is common and widespread throughout Plymouth.

When to look for it

Early May to August.

Similar species

Males could be confused with the far more slender Skimmers, Orthetrum spp, which lack both the yellow patches on the side of the abdomen and the darkened wing bases. Females could be confused with the similar looking Four-spotted Chaser, Libellula depressa, but this species has a dark posterior half to its abdomen and an extra pair of dark spots half way long the leading edge of each wing. Females could also be confused with the much more slender female Skimmers, Orthetrum spp, but they lack the yellow markings on the side of the abdomen.

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