Meeting Abstract
97.2 Monday, Jan. 6 13:45 One antenna, two antenna; big antenna, small: in walking odor-tracking insects, bilateral input isn’t all. LOCKEY, JK*; WILLIS, MA; Case Western Reserve University, USA; Case Western Reserve University, USA jkl60@case.edu
Spatial tracking requires simultaneous comparisons across sensors to establish a spatial contrast in what is being tracked (e.g., light, sound, chemicals). American cockroaches (Periplaneta americana) are thought to use a spatial tracking strategy when searching for resources using windborne odor. P. americana uses its 4 cm-long antennae to locate odor sources, but it is not uncommon for individuals to lose portions of their antennae, yet still be able to track an odor to its source. In this study we asked what is the minimum antenna length needed to track an odor and how does loss of all or part of an antenna affect tracking behavior. If P. americana uses bilateral comparisons to maintain contact with the plume, the animals with shortened antennae should have narrower tracks, and removing one antenna should bias their turns to the direction of the remaining antenna. In a survey of 160 unilaterally antenectomized animals (80 left, 80 right) and 80 intact animals, with antennae of different lengths (4 cm, 2 cm, 1 cm, and 10 annuli), we found that animals with only one antenna are able to track to an odor source, suggesting that they are either not using a spatial tracking strategy, or there is a spatial map of the sensory hairs on each antenna. With the exception of the individuals with 10 segments in the flagellum of their antenna, all animals with bilateral inputs tracked to the odor source. The odds of unilateral-antentomized animals tracking decreased as antenna size decreased. Only four individuals (1.7%) with 10 annuli tracked. We demonstrate that while bilateral olfactory input is not necessary, it does improve tracking behavior. We thank Heather Voss-Hoynes and Jen Milligan for their assistance. This study was supported by NSF grant IOS-1121498 to MAW.
