Video: Horsehead Grasshopper Reaches Across a Gap Between Two Rods
Posted on July 7, 2012
Researchers from the University of Sussex and University of Cambridge have shown that insects are capable of challenging neuronal tasks like visually targeted reaching. The researchers say the fact that insects can perform these behaviors challenges the idea that sophisticated behavioral capabilities necessarily require large numbers of neurons.
Visually targeted reaching to a specific object is a demanding neuronal task requiring the translation of the location of the object from a two-dimensional set of retinotopic coordinates to a motor pattern that guides a limb to that point in three-dimensional space. This sensorimotor transformation has been intensively studied in mammals, but was not previously thought to occur in animals with smaller nervous systems such as insects. The researchers studied horse-head grasshoppers (Orthoptera: Proscopididae) crossing gaps and found that visual inputs are sufficient for them to target their forelimbs to a foothold on the opposite side of the gap. High-speed video analysis shows these reaches were targeted accurately and directly to footholds at different locations within the visual field through changes in forelimb trajectory and body position, and did not involve stereotyped searching movements. Take a look:
Horsehead grasshoppers resemble walking sticks, but they are grasshoppers. They have large horse-like heads. You can find some photographs of them here. Here's a video of a person's pet horsehead grasshopper:
The research was published here in the Proceedings of the Royal Society B.