Meeting Abstract
Many ectoparasites move to and exploit specific body regions after hosts are acquired. Often, migration routes to these preferred regions are predictable, which suggests parasite movement is directed. We used a model system consisting of feather-feeding lice (Columbicola columbae) and their bird hosts (Columba livia) to understand how thermal cues influence microhabitat selection and to reveal the control mechanisms governing thermo-orientation. We first determined whether lice responded to thermal cues, then tested whether thermo-orientation helped guide their repeated migrations between flight feathers (where they hide from bird preening) and bird body regions (where they feed). We found that lice can accurately direct their movements towards heat targets, can distinguish between temperatures found on bird body regions and those found on the flight feathers, and will alter their temperature preferences when starved towards those found on bird body regions where they feed. Taken together, these results indicate that host-generated thermal cues play an important role in louse movement and microhabitat selection on their hosts. Finally, we exposed lice with two and one antennae to temporal and spatial heat gradients and analyzed their paths using motion-tracking software to better understand the control mechanisms governing thermo-orientation. We found that lice were capable of orienting to heat targets using only idiothetic (internally stored information) control mechanisms. However, they likely rely on a combination of idiothetic and allothetic (external information) control mechanisms during thermo-orientation.
