![]() Each DCMD has its cell body in the protocerebrum of the brain, and its axon descends to the thoracic ganglia where it excites neurons controlling leg and wing movements. Looming-sensitive visual neurons have been found in a huge range of taxa, both vertebrate and invertebrate, ,, ,, ,, , but best understood among these is the single bilateral pair of DCMD neurons of acridid grasshoppers (including locusts). When a predator approaches, it can be perceived as a looming visual stimulus: its image expands over the eye of the viewer with a rate that increases as the time of collision nears. We then use simulated stimuli representing these attacks to investigate emergency behavioural responses triggered by a locust’s descending contralateral movement detector (DCMD) neuron, one of the most frequently studied identifiable visual neurons of invertebrates. Here we attempt to characterise the attacks of a natural predator of flying locusts. Where escape-triggering mechanisms have been studied during real or simulated predator attacks, these mechanisms confer a variable probability of successful escape, around 50% or less in many investigations, ,, perhaps reflecting the finely balanced arms-race between predator and prey. This means that it is often not possible to investigate escape-triggering mechanisms within the context of escape from a real predator. However, the characteristics of natural predator attacks, and the stimuli that they would provide to their prey, have rarely been described,. Such mechanisms presumably evolved as a result of selection pressures exerted by natural predators. The roles of identifiable neurons in triggering behaviour are particularly well understood in fast, reliable escape-triggering mechanisms such as those of several arthropods. However, the performance of this system is in line with expectations for a last-ditch escape response. Looming discs with or without wings triggered glides closer to the time of collision as l/|v| declined, and relatively infrequently before collision at very low l/|v|. However, adding wings to looming discs did slightly reduce high frequency DCMD spike rates in the final stages of object approach, and slightly delay glide initiation. Adding wings to looming discs to produce a more realistic stimulus shape did not disrupt the overall relationships of DCMD and gliding occurrence to stimulus l/|v|. Using simulated looming discs, we investigate these trends and show that both DCMD and behavioural responses are strong to stimuli with kite-like l/|v| ratios. Peak DCMD spike rate and gliding response occurrence are known to increase as l/|v| decreases for simple looming shapes. We estimate that the loom of a kite’s thorax towards a locust at these speeds should be characterised by a relatively low ratio of half size to speed ( l/|v|) in the range 4–17 ms. We analyse video of wild black kites attacking flying locusts, and estimate kite attack speeds of 10.8☑.4 m/s. To date it has not been possible to study glides in response to stimuli simulating bird attacks because such attacks have not been characterised. The DCMDs trigger ‘glides’ in flying locusts, which are hypothesised to be appropriate last-ditch responses to the looms of avian predators. ![]() ![]() Locusts possess uniquely identifiable visual neurons (the descending contralateral movement detectors, DCMDs) that are well-studied looming motion detectors. These mechanisms are important neuroethological models, but they are rarely investigated using predator-like stimuli because there is often insufficient information on real predator attacks. Scorpions live all around the world, especially in the Southern Hemisphere, in tropical areas, and to a lesser extent even in the Northern Hemisphere.Many arthropods possess escape-triggering neural mechanisms that help them evade predators. It can be used to sting with or without venom in offense or defense. This tail is known for its upward curved position. Scorpions represent a species of arachnids with 8 legs, pincers, and a thick segmented tail.
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