Transsexual limb transplants in fiddler crabs and expression of novel sensory capabilities

We used transsexual limb transplants in fiddler crabs to examine how periph eral sensory structures interact with the central nervous system (CNS) to p roduce a sexually dimorphic behavior. Female and male chemosensory feeding claws were transplanted onto male hosts in place of nonfeeding, nonchemosen sory claws. Successfully transplanted claws retain donor morphologies and c ontain chemosensory neurons. Neurons in successfully transplanted female fe eding claws express the enhanced sensitivity to chemical cues seen in femal e, but not male, neurons in claws of normal animals. When chemically stimul ated, the transplanted claws evoke feeding behavior not observed in normal males, even though the sensory neurons in the transplanted limb project to the host's sexually dimorphic neuropil not known to receive chemosensory in put. Behavioral sensitivity is directly related to the sensitivity of perip heral neurons in the transplanted feeding claw. Thus, the interactions betw een peripheral neurons and their targets may restructure the CNS so that no vel sensory capabilities are expressed, and this can produce sexually dimor phic behaviors. (C) 2001 Wiley-Liss, Inc.