Paying for information: partial loads in central place foragers.

A. Dornhaus, E. J. Collins, F.-X. Dechaume-Moncharmont, A. I. Houston, N. R. Franks, J. M. McNamara.
Information about food sources can be crucial to the success of a foraging animal. We predict here that this will influence foraging decisions by group-living foragers, who may sacrifice short-term foraging efficiency to collect information more frequently. This result emerges from a model of a central-place forager who can potentially receive information on newly available superior food sources at the central place. Such foragers are expected to return early from food sources, even with just partial loads, if information about the presence of highly valuable food sources is likely to become available. Returning with an incomplete load implies that the forager is at that point not achieving the maximum possible food delivery rate. However, such partial loading can be more than compensated for by an earlier exploitation of a superior food source. Our model does not assume cooperative foraging and could thus be used to investigate this effect for any social central-place forager. We illustrate the approach using numerical calculations for honey bees and leafcutter ants, which do forage cooperatively. For these examples, however, our results indicate that the benefit of partial loads for receiving information is minimal. Moreover, empirical data fit the predictions of a forager giving information better than an information receiving one as in our model. Thus we can conclude that in these two cases, giving information may be more important than receiving it.

Some key words:
central place foraging, information center, recruitment, partial loads, honey bees, Apis mellifera