Britain's bulkiest dragonfly: apple-green thorax, a bright yellow leading wing vein, and a black line down a sky-blue abdomen
Emperor dragonfly, male; the female is identical but green-bodied.
Nature · Insects & other invertebrates
Emperor dragonfly
Flies June–August · body length about 78 mm
Anax imperator — Aeshnidae (hawker dragonflies)
Britain's bulkiest dragonfly, a hawker that patrols a large pond all day and rarely settles, eating its prey on the wing. The male has an apple-green thorax and a sky-blue abdomen with a black line down the middle; the female is the same but green. It is identified in flight as much by manner as by colour — very large, the tail-end of the abdomen held slightly drooping — and it has spread strongly northwards since the 1990s, reaching Scotland in 2003.
How to spot them
- ▸Very large hawker with an apple-green thorax and a bright yellow leading wing vein
- ▸Male: sky-blue abdomen with a central black line. Female: green abdomen with the same black line
- ▸Rarely settles; patrols high and fast, and eats prey on the wing
- ▸In flight the rear of the abdomen is held bent slightly downwards
- ▸Large, well-vegetated ponds and lakes; the female lays eggs alone into floating pondweed
How to know it
It hardly ever settles, patrolling a large pond all day and eating its catch in mid-air, with the abdomen tip drooping
Emperor dragonfly — the drooping abdomen is a jizz feature for separating it from other hawkers.
Unusually for a dragonfly, the female lays her eggs alone, inserting them into floating pondweed with no male in attendance
Emperor dragonfly — most hawkers oviposit in tandem or with the male guarding.
Its larvae are the largest of any British dragonfly, at 45–56 mm
Emperor dragonfly — the larva spends one or two years in the pond.
Recorded in Scotland for the first time in 2003, having greatly expanded its British range since the 1990s
Emperor dragonfly — a clear climate-driven range shift, per the British Dragonfly Society.
Its imperial scientific name pairs a Greek word for 'lord' with the Latin for commander
Emperor dragonfly — Anax imperator.
Quick-fire facts
- •Anax imperator: Greek anax, 'lord' or 'chief', with Latin imperator, 'commander'
- •British Dragonfly Society: Britain's bulkiest dragonfly, about 78 mm long
- •A dragonfly, not a damselfly: at rest it holds its wings out flat, and its eyes meet on top of the head
- •Larvae are the largest of any British species at 45–56 mm, and are streamlined hawker-shaped
- •Its distribution has greatly increased since the 1990s; first recorded in Scotland in 2003
- •Males are strongly territorial and will drive other large dragonflies off a pond
- •Similar species are the vagrant emperor and the lesser emperor, both scarce migrants to Britain
- •It belongs to the Aeshnidae, the hawkers; the Anisoptera are the dragonflies and the Zygoptera the damselflies
Drill it — 7 cards
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Sources
- British Dragonfly Society — Emperor Dragonfly
- Paul D. Brock — Britain's Insects: A Field Guide to the Insects of Great Britain and Ireland