Asilidae, Assassin Robber Fly

With regard to the specificity of the trophic relationship Wood (1981) mentions the existence of some studies in the literature on the subject.Some genera have been found to be monophagic, but more generally the Asilidae manifest a more or less wide polyphagia with behaviors that vary from stenophagia to euriphagia. However, there are cases of stenohage asilids which if necessary focus their predatory activity against a species when this forms large populations.
Other studies conducted by Dennis, D. and Lavigne,(1975) have shown that the ratio between the size of the prey and the asilid varies from 1.8:1 to 3.7:1, with an average of 2. 6:1. The ratio tends to increase with decreasing size of the predator.
Egg-laying takes place, according to the species, with three different behaviors which relate to the structure and the morphology of the abdomen. Females with an undifferentiated ovipositor release eggs randomly and independently from the substrate. In other cases, however, the abdomen bears a differentiates, specialized ovipositor to lay eggs in the soil or sand, or lay them in cavities within plant tissues.