Zeroing in on an inconspicuous nest.
It is good to be back after a dry few weeks and it is a really nice paper to be back for:
Buelhlmann et al. report a neat series of experiments investigating ants’ use of plumes to localise nest entrances. With a logical series of experiments they show that: (i) ants localise their nest better from a downwind direction; (ii) That plumes aren’t nest specific; (iii) That a realistic concentration of carbon dioxide is sufficient for nest-plume-following. Their fourth finding is perhaps the most interesting. Because ants don’t seem to be using a colony specific plume to localise their nest, perhaps they run the risk of mistakenly following another nest’s plume. This risk would be mitigated if ants were able to use the state of Path Integrator as a contextual signal for proximity to their real nest. By manipulating the length of the residual home vector that ants had, when they experienced the plume, Buhlmann et al. were able to put the plume in conflict with ants’ PI systems. It was found that ants would not follow the plume unless their home vector was zero length. A really interesting question to follow this would be whether the interaction between these two cues happens centrally or whether purposeful motion, characteristic of PI following, means that ants won’t even ‘notice’ the CO2 plume, this second possibility would be a neat behavioural heuristic for solving the cue integration problem.
Buehlmann, Cornelia, Hansson, Bill S., and Knaden, Markus. (2012) Path Integration Controls Nest-Plume Following in Desert Ants. Current biology 22, 645-649.