Optimizing the Search for Resources by Sharing Information: Mongolian Gazelles as a Case Study

Abstract

We investigate the relationship between communication and search efficiency in a biological context by proposing a model of Brownian searchers with long-range pairwise interactions. After a general study of the properties of the model, we show an application to the particular case of acoustic communication among Mongolian gazelles, for which data are available, searching for good habitat areas. Using Monte Carlo simulations and density equations, our results point out that the search is optimal (i.e. the mean first hitting time among searchers is minimum) at intermediate scales of communication, showing that both an excess and a lack of information may worsen it. [7,8], and to pool information on resource locations when no single individual is sufficiently knowledgeable [9][10][11][12][13]. Communication among individuals frequently leads to group formation [14], which often has clear direct benefits such as reducing individual vulnerability to predators. Such strategies may, however, also have important incidental benefits. For example, an individual that has found a good foraging patch might try to attract conspecifics to reduce its risk of predation, but also provides its conspecifics with information on the location of good forage, thus increasing the foraging efficiency of those responding to the call.A variety of mammalian species are known to communicate acoustically over distances of up to several kilometers [3,15,16], but while group formation via vocalizations has been well studied [3,17,18], incidental benefits such as increased foraging efficiency have received little research attention. In contrast, research on foraging efficiency has focused largely on independent individuals [19][20][21][22][23][24][25], or on comparing foraging behavior across species [26]. In addition, recent theoretical work [27] has focused on the statistics of a population of independent random walkers, but an interaction mechanism, and its influence on search efficiency, has not been thoroughly studied. To date, very few models have examined the potential effect that long-distance communication [28]

Optimal search in interacting populations: Gaussian jumps versus Lévy flights

“…The model thus becomes an Ornstein-Uhlenbeck process, with individuals drifting randomly, but with an attraction to the location of the targets [30][31][32]. Following previous efforts [29,33], the interaction among individuals is given in terms of a nonlocal function defined as the superposition of the pairwise interaction between one individual and each one of the other members of the population,…”

“…While diverse observations suggest that such interactions occur in many taxa, including bacteria [23], insects, and mammals [24,25], previous studies have focused almost exclusively on how the collective movements of a group of animals can emerge from local interactions among individuals [26][27][28]. To our knowledge, only two recent studies have explored the effects of long-range communication mechanisms on a searching strategy [12,29]. In particular, [29] showed that when the communication range is intermediate, individuals tend to receive the optimal amount of information on the locations of targets, and search time is consequently minimized.…”

“…To our knowledge, only two recent studies have explored the effects of long-range communication mechanisms on a searching strategy [12,29]. In particular, [29] showed that when the communication range is intermediate, individuals tend to receive the optimal amount of information on the locations of targets, and search time is consequently minimized. Longer communication ranges overwhelm the searchers as they are simultaneously called from all directions, while shorter ranges do not provide enough information.…”

Collective foraging in heterogeneous landscapes

“…0 and g ¼ 2.5. In a study on the Mongolian gazelle [27], it was found that the gazelles exchange information about locations of resources at such distances that result in the optimal search. The authors also discussed possible disadvantages (other than search efficiency) that may result from communication at very short and long distances.…”

“…The role of information transfer in the recruitment of foragers has been studied in colonies of social insects [24][25][26]. Very recently, the influence of communication on the foraging pattern of gazelles was investigated [27]. The study showed that communication over intermediate length scales results in faster searches.…”