Lucilia caesar

Lucilia caesar

Description

This blow fly is bright iridescent green though like all the 'greenbottles' is becomes more bronze with age. It is very similar to other Lucilia species but has just two pairs of acrostichal bristles behind the suture line on the thorax and a dark basicosta.

Similar Species

There are seven very similar Lucilia species that can be found in our region. They can only be separated by close examination of features such as bristles. L. caesar can be distinguished from the more common L. sericata by having only two pairs of post suture acrostichal bristles and a dark basicosta, but there are other Lucilia species with these features.

Identification difficulty
ID checklist (your specimen should have all of these features)
  • dark basicosta
  • presence of a coxopleural streak (see ID Aids above)
  • 2 pairs of acrostichal bristles behind the suture line on the thorax
  • males have a frons (between the eyes) that is narrower than the parafacialia (facial areas between the eyes and the antennae)
Identification aids

A key feature needed to identify Lucilia caesar is the presence of a coxopleural streak - a small and subtle pale, buff-coloured line on the side of the fly.

Lucilia caesar coxopleural streak

Recording advice

This can only be separated from other Lucilia species by microscopic examination.

Habitat

Unlike its cousin the bluebottle, this species rarely comes into houses and is usually seen on flowers and vegetation, or sunning in a sheltered spot.

When to see it

April to October peaking in June.

Life History

The female lays her eggs on carcasses, seeking the soft parts that are shaded from the sun. Larvae live in carrion and also in wounds on living animals, eating away the flesh with alarming rapidity, and so can be a problem in sheep-rearing areas.

UK Status

Common and widespread in Britain.

VC55 Status

Common but under-recorded in Leicestershire and Rutland

Further Information

Leicestershire & Rutland Map

MAP KEY:

Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2025+ | 2020-2024 | pre-2020

UK Map

Additional images

All NatureSpot records