The dung fly rodeo
This is the infamous dung fly 'rodeo' - a well documented pre-copulatory mate guarding behaviour that most sepsid flies exhibit. This is the generalised summary:
Sepsid males wait near oviposition sites, eg fresh dung, and jump on any female that appears. The females usually copulate away from such sites, thus she will be a non-virgin and there to lay fertilised eggs. Due to physiological limitations, the female must complete oviposition before she can accept another spermatophore. Thus there is no attempt to mate, the male simply guards her while she lays her eggs. After this she walks away from the oviposition site, with male still holding on, and then begins the violent bucking and shaking in order to try and dislodge the uninvited male. Where a male is strong enough to hold on, the female finally submits and mating can occur. This ‘rodeo’ can last for some time – beyond 20 minutes has been observed in one species. Sepsid males who engage in this mate guarding have evolved opposing ridges and bristles/spikes on their fore tibiae and femora which help them clamp to the females' wing bases (see male pic below).
This couple look to be Parapalaeosepsis plebeia, the only common dung fly in Tasmania. Filmed in Hobart late October 2009 on a handycam.
The dung fly rodeo
This is the infamous dung fly 'rodeo' - a well documented pre-copulatory mate guarding behaviour that most sepsid flies exhibit. This is the generalised summary:
Sepsid males wait near oviposition sites, eg fresh dung, and jump on any female that appears. The females usually copulate away from such sites, thus she will be a non-virgin and there to lay fertilised eggs. Due to physiological limitations, the female must complete oviposition before she can accept another spermatophore. Thus there is no attempt to mate, the male simply guards her while she lays her eggs. After this she walks away from the oviposition site, with male still holding on, and then begins the violent bucking and shaking in order to try and dislodge the uninvited male. Where a male is strong enough to hold on, the female finally submits and mating can occur. This ‘rodeo’ can last for some time – beyond 20 minutes has been observed in one species. Sepsid males who engage in this mate guarding have evolved opposing ridges and bristles/spikes on their fore tibiae and femora which help them clamp to the females' wing bases (see male pic below).
This couple look to be Parapalaeosepsis plebeia, the only common dung fly in Tasmania. Filmed in Hobart late October 2009 on a handycam.