“BTB” Eutolmus rufibarbis (Meigen, 1820) common name: Golden-Tabbed Robberfly
Family: Asilidae
This is a large Robberfly and is not a common species in the UK. There are several similar species throughout Europe.
Scattered populations throughout the UK, scarcer in the north.
Months seen June to September.
As with all Robberflies the adults are predatory upon most other insects. They are impressive hunters of flying insects and this species has no trouble in catching large prey like bees, wasps, butterflies, beetles, dragonflies, damsel flies and grasshoppers. Using its very long and powerful spiny legs to grip and subdue prey, which is very often caught in flight. The Robberfly will characteristically find a blade of grass or a twig to suspend from by using one leg, then by piercing the prey using its proboscis the Robberfly injects a salvia containing neurotoxic and proteolytic enzymes which digests the insides of its prey. The Robberfly then proceeds to suck the liquefied juices through the proboscis. The mystax is very similarly placed on its face like a thick dense moustache of bristles which helps protects its face and eyes from the prey’s resistance.
The adult female will lay her eggs in soil or plants, the larvae are often found in decaying organic matter.
The larvae are omnivorous and will feed on the eggs and larvae of other insects, including beetles, grasshoppers, and flies.