scholarly journals Sensitivity of density-dependent threshold to species composition in arthropod aggregates

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Pierre Broly ◽  
Quentin Ectors ◽  
Geoffrey Decuyper ◽  
Stamatios C. Nicolis ◽  
Jean-Louis Deneubourg
Keyword(s):  
Social Interactions ◽  
Total Population ◽  
Threshold Function ◽  
Population Densities ◽  
Mixed Species ◽  
Biologically Relevant ◽  
Similar Threshold ◽  
Aggregate Growth ◽  
Species Groups ◽  
Mixed Species Groups

Abstract How mixed-species groups perform collective behaviours provides unique insights into the mechanisms that drive social interactions. Herein, we followed the aggregation process of two isopod species under monospecific and heterospecific conditions at three population densities. Our experimental results show that the formation of both the monospecific and heterospecific groups responds to a similar threshold function. Furthermore, the two species contribute equally to the mixed-species aggregate growth and are not spatiotemporally segregated. However, we show that the cohesion is weaker and the probability of forming aggregations is lower in heterospecific groups than in monospecific populations. Thus, our results show that amplification processes are shared between species, but that the weighting given to conspecific and heterospecific information differs. We develop a theoretical model to test this hypothesis. The model reproduces our experimental data and shows that a relatively low level of inter-attractions between species is able to generate mixed-species aggregates. Moreover the greater the total population, the lower this parameter value is needed to observe aggregation in both species. This highlights the importance to study not only qualitatively but also quantitatively the heterospecific interactions in mixed-species groups. Finally, the patterns observed could be biologically relevant in favouring the association between species.

scholarly journals Individuals from different-looking animal species may group together to confuse shared predators: simulations with artificial neural networks

2006 ◽  
Vol 274 (1611) ◽  
pp. 827-832 ◽  
Author(s):  
Colin R Tosh ◽  
Andrew L Jackson ◽  
Graeme D Ruxton
Keyword(s):  
Animal Species ◽  
Empirical Work ◽  
Species Group ◽  
Mixed Species ◽  
Retinotopic Maps ◽  
Species Groups ◽  
Artificial Neural ◽  
Mixed Species Groups ◽  
Species Grouping ◽  
Prey Items

Individuals of many quite distantly related animal species find each other attractive and stay together for long periods in groups. We present a mechanism for mixed-species grouping in which individuals from different-looking prey species come together because the appearance of the mixed-species group is visually confusing to shared predators. Using an artificial neural network model of retinotopic mapping in predators, we train networks on random projections of single- and mixed-species prey groups and then test the ability of networks to reconstruct individual prey items from mixed-species groups in a retinotopic map. Over the majority of parameter space, cryptic prey items benefit from association with conspicuous prey because this particular visual combination worsens predator targeting of cryptic individuals. However, this benefit is not mutual as conspicuous prey tends to be targeted most poorly when in same-species groups. Many real mixed-species groups show the asymmetry in willingness to initiate and maintain the relationship predicted by our study. The agreement of model predictions with published empirical work, the efficacy of our modelling approach in previous studies, and the taxonomic ubiquity of retinotopic maps indicate that we may have uncovered an important, generic selective agent in the evolution of mixed-species grouping.

A mechanism mediating inter-individual associations in mixed-species groups

2016 ◽  
Vol 70 (5) ◽  
pp. 755-760 ◽  
Author(s):  
Tanja K. Kleinhappel ◽  
Oliver H. P. Burman ◽  
Elizabeth A. John ◽  
Anna Wilkinson ◽  
Thomas W. Pike
Keyword(s):  
Mixed Species ◽  
Species Groups ◽  
Mixed Species Groups

scholarly journals Can Mixed-Species Groups Reduce Individual Parasite Load? A Field Test with Two Closely Related Poeciliid Fishes (Poecilia reticulata and Poecilia picta)

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e56789 ◽  
Author(s):  
Felipe Dargent ◽  
Julián Torres-Dowdall ◽  
Marilyn E. Scott ◽  
Indar Ramnarine ◽  
Gregor F. Fussmann
Keyword(s):  
Field Test ◽  
Poecilia Reticulata ◽  
Parasite Load ◽  
Mixed Species ◽  
Species Groups ◽  
Mixed Species Groups

Moving Mixed-Species Groups in Different Taxa

2017 ◽  
pp. 27-57
Author(s):  
Eben Goodale ◽  
Guy Beauchamp ◽  
Graeme D. Ruxton
Keyword(s):  
Mixed Species ◽  
Species Groups ◽  
Mixed Species Groups

scholarly journals Suffixation influences receivers' behaviour in non-human primates

2015 ◽  
Vol 282 (1807) ◽  
pp. 20150265 ◽  
Author(s):  
Camille Coye ◽  
Karim Ouattara ◽  
Klaus Zuberbühler ◽  
Alban Lemasson
Keyword(s):  
Vocal Response ◽  
Adaptive Responses ◽  
Primate Communication ◽  
Mixed Species ◽  
Vocal Production ◽  
Vocal Responses ◽  
Cercopithecus Diana ◽  
Cercopithecus Campbelli ◽  
Species Groups ◽  
Mixed Species Groups

Compared to humans, non-human primates have very little control over their vocal production. Nonetheless, some primates produce various call combinations, which may partially offset their lack of acoustic flexibility. A relevant example is male Campbell's monkeys ( Cercopithecus campbelli ), which give one call type (‘Krak’) to leopards, while the suffixed version of the same call stem (‘Krak-oo’) is given to unspecific danger. To test whether recipients attend to this suffixation pattern, we carried out a playback experiment in which we broadcast naturally and artificially modified suffixed and unsuffixed ‘Krak’ calls of male Campbell's monkeys to 42 wild groups of Diana monkeys ( Cercopithecus diana diana ). The two species form mixed-species groups and respond to each other's vocalizations. We analysed the vocal response of male and female Diana monkeys and overall found significantly stronger vocal responses to unsuffixed (leopard) than suffixed (unspecific danger) calls. Although the acoustic structure of the ‘Krak’ stem of the calls has some additional effects, subject responses were mainly determined by the presence or the absence of the suffix. This study indicates that suffixation is an evolved function in primate communication in contexts where adaptive responses are particularly important.

scholarly journals Mixed-species groups in bats: non-random roost associations and roost selection in neotropical understory bats

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Detlev H. Kelm ◽  
Ulf Toelch ◽  
Mirkka M. Jones
Keyword(s):  
Information Transfer ◽  
Environmental Variability ◽  
Interspecific Interactions ◽  
Mixed Species ◽  
Interspecific Attraction ◽  
Roost Selection ◽  
Direct Benefits ◽  
Species Groups ◽  
Communal Roosting ◽  
Mixed Species Groups

Abstract Background Mixed-species groups in animals have been shown to confer antipredator, foraging and other benefits to their members that may provide selective advantages. In most cases, however, it is unclear whether functional benefits are a principal driver of heterospecific groups, or whether groups simply result from simultaneous exploitation of common resources. Mixed-species groups that form independently of environmental conditions may, however, evidence direct benefits of species associations. Bats are among the most gregarious mammals, with sometimes thousands of individuals of various species roosting communally. Despite numerous potential functional benefits of such mixed-species roosting groups, interspecific attraction has never been shown. To explore alternative explanations for mixed-species roosting, we studied roost selection in a speciose neotropical understory bat community in lowland rainforest in Costa Rica. Long term roost data were recorded over 10 years in a total of 133 roosts comprising both natural roosts and structurally uniform artificial roosts. We modelled bat roost occupancy and abundance in each roost type and in forest and pasture habitats to quantify the effects of roost- and environmental variability. Results We found that bat species presence in natural roosts is predictable from habitat and structural roost parameters, but that the presence and abundance of other bat species further modifies roost choice. One third of the 12 study species were found to actively associate with selected other bat species in roosts (e.g. Glossophaga commissarisi with Carollia sowelli). Other species did not engage in communal roosting, which in some cases indicates a role for negative interspecific interactions, such as roost competition. Conclusions Mixed-species roosting may provide thermoregulatory benefits, reduce intraspecific competition and promote interspecific information transfer, and hence some heterospecific associations may be selected for in bats. Overall, our study contributes to an improved understanding of the array of factors that shape diverse tropical bat communities and drive the dynamics of heterospecific grouping in mammals more generally.

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