Web edition: September 7, 2012
Print edition: September 22, 2012; Vol.182 #6 (p. 11)
Galloping dung beetles
Pachysoma dung beetles in Africa have a gait never before described in insects — almost a gallop. Biologists hadn’t recognized the motion because it’s hard to see scuttling beetle legs, said Jochen Smolka of Sweden's Lund University. He videotaped beetle sprints and analyzed them in slow replays. Most insects move their six legs as two tripods. In one stride, the first and last legs on one side of the animal plus the middle one on the other side support the weight while the other legs step forward. In Pachysoma, the front two leg pairs power the gait, Smolka reported August 8. When the front pairs support the body, the middle pair bounds forward. The middle legs do the supporting when the front ones bound.
Hearing himself fly
The sounds of a male mosquito’s own wingbeats may help him catch the faint whine of a flying female. “Counterintuitive” is what Joseph C. Jackson of Scotland's University of Strathclyde called results he presented August 8 on mosquito hearing. Mosquito antennae are good for studying active listening: Nerve cells add their own mechanical oomph to signals of incoming sounds, which can amplify weak sounds or make hearing more selective. When a male hears a female, there’s a jump in his antennae's sensitivity. When listening to tones simulating his own wingbeats, that jump occurs sooner, Jackson found. Males should thus be able to lock on to even fainter sounds of females.