Natural History Photographs

The conopid flies (seven in total!) parasitize on Bombus species, making this an interesting photo! The bumblebee seems not worried at all - probably with good reason, since the flies attack only flying bumblebees.

Three widely different insects, sharing the same color pattern: black with yellow bands and spots, (fore)wing partially clouded. Could this be mimicry? If so, the aculeate wasp Gorytes is the most likely model, with its ability to sting. Left is a Ichneumonid wasp, right a thick-headed fly; if they lack a proper defense, they might achieve some protection from mimicing the wasp - this would be an example of Batesian mimicry. However, both could possibly be distasteful themsleves, and advertise this by the black & yellow color pattern. In that case, this would be an instant of Müllerian mimicry. The shared pattern would then enhance the speed of learning of predators. The more often a predator has an unpleasant experience with black & yellow colored prey, the faster it will learn to avoid all insects with this color pattern.

The name crabroniformis suggests a likeness to Vespa crabro. However, I find the likeness rather poor - in color pattern as well as in behavior. So mimicry as an explanation for the superficial likeness seems rather far-fetched to me.

The prey of this Robberfly is a small apterous wasp, probably Gelis agilis. Since this wasp normally runs on bare soil, this observation suggests that Dioctria cothurnata at least incidentally preys upon sedentary insects.

An unexpected guest in the polder, where peat and clay are the dominating soil types. However, I saw this fly on a sandy dike, close to a highway, also built on sand. Furthermore, the area close to the observation was rife with contruction activities, which all start with bringing sand to the area. So maybe this fly was accidentely introduced?