Top Tweets for #Machimus

about 2 years ago

About #robberflies, their #adaptations to the #predatory #lifestyle, their #phylogenetic position within the #Diptera and the #biology of the species #Tolmerus (#Machimus) #cingulatus. Robber flies (#Asilidae, #Diptera) are often noticed by humans in their natural habitat because of their size, strong #claws, "humped" thorax area and relatively large #eyes. We can usually identify these insects well due to their frequently observed behavior of remaining in a #lurking position at elevated vantage points, such as tree stumps, fences or building walls, and then flying up at lightning speed at the appropriate moment. The for their insect victims venomous Asilidae are adapted to kill their prey in flight. They are faced with the problem of having to hold onto the prey efficiently, but also kill it quickly so that they can start feeding on it straight away, which is then continued in a protected area. Losing prey that is still alive or dead would be a waste of energy that the animals cannot afford. A kind of stabbing apparatus has #evolved, formed mainly from the #hypopharynx and the #galeae, which impales the prey and holds it at the same time. The prey insect is grabbed with the claw legs, strong and densely growing #bristles in the area of the mouthparts additionally stabilize the prey in the claws of the robber fly. The eggs of the Asilidae hatch into #larvae that live #underground, in the galleries of other insects or under #treebark, and prey on the eggs or offspring of other arthropods. I have not yet found any literature evidence of phoretic mites or nematodes on the developmental stages of the Asilidae, but there is evidence of entomoparasitic #nematodes of the #Steinernematidae (Rhabditida) in Asilidae larvae in Bulgaria. The author D. Gradinarov (2003) described corresponding finds in larval representatives of two robber fly genera. Steinernematidae nematodes are interesting from an #evolutionary point of view and in terms of their life strategy, I.a., because they live in #symbiosis with #bacteria that they release inside the #host, which then kill the host, while the nematode feeds primarily on the bacteria that they bring with them, which thrive in large numbers. The robber fly species in my attached photo series is #Tolmeruscingulatus. This asilid species is widespread in the Palearctic region and is common in Central Europe. It is up to 15 mm long and inhabits forest edges and dry #meadows. The larvae develop in the soil. Although the species likes to prey in flight, the individual in photo 2 appeared to me to have landed next to potential prey, namely a grasshopper (#Chorthippus cf. albomarginatus) sitting on common #yarrow in #Berlin #urbanpark Rehberge. The asilid only landed after I discovered the grasshopper as a photo model, which gave me an interesting camera perspective. However, an attack by the fly did not happen. According to various authors, #systematically and #phylogenetically, the Asilidae belong to the superordinate taxon #Asiloidea, with subtaxa, whose relationships in detail are not yet well phylogenetically understood. The sister group of the Asiloidea are the bee flies Bombyliidae. The relationships within the Asilidae were reconstructed using molecular data, for example by the authors C. M. Cohen et al. (2021). © #StefanFWirth Berlin 2024 Sources: D. Gradinarov (2003): https://t.co/dqaUHQkvo6 C. M. Cohen et al. (2021): https://t.co/kIO68qXQd7 Photos: 1-4) Tolmerus (Machimus) cingulatus, 2) grasshopper Chorthippus cf. albomarginatus 1-4) © Stefan F. Wirth 2024, park Rehberge Berlin