miked's picture

3 flies whats going on

Observed: 15th May 2010 By: miked
iSpot team
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Description:

Some kind of Ménage à trois or is the lower fly actually being eaten?

Identifications
Species interactions

Comments

Urophora's picture

There is a lot of this going

There is a lot of this going on. The empids are mating, and the female is feeding on the third insect (maybe a Bibionid). This is common to see. I don't know if the male mounts her as she is distracted by the food, or the food is part of the mating sequence.

Martin Harvey's picture

wedding presents

In some groups of empidid flies the females won't mate unless they are provided with a 'wedding present' by the male, in the form of a nutritious insect on which to feed. In some cases it seems that this is an essential meal, providing proteins that help the female's eggs develop, while in others it may be that it is not actually necessary for the female's nutrition, but has become part of the mating ritual and is thus still essential to a successful courtship.

In at least one species it has been shown that the time spent in copulation depends on the size of the gift presented to the female - a larger, more nutritious prey item means the female spends longer mating.

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Entomologist and biological recorder