scholarly journals Species-specific strategies increase unpredictability of escape flight in eared moths

2018 ◽  
Author(s):  
Theresa Hügel ◽  
Holger R. Goerlitz
Keyword(s):  
Food Intake ◽  
Single Individual ◽  
Mixed Species ◽  
Predator Detection ◽  
Predator Prey ◽  
Species Groups ◽  
Multiple Species ◽  
Species Specific ◽  
Mixed Species Groups ◽  
Over Time

ABSTRACTMany prey animals form mixed-species groups. Mixed-species groups provide various benefits ranging increased food intake to increased chance of predator detection. The escape-tactic diversity hypothesis predicts another benefit. It postulates that the overall unpredictability of evasive movement is increased if multiple species with different evasive tactics mix, resulting in enhanced predator protection for the whole group. Echolocating bats and eared moths are a textbook example of predator-prey interactions. Moths exhibit evasive flight with diverse tactics; however, the variability of their evasive flight within and between species has never been systematically quantified. We therefore recorded flight strength of eight moth species in response to the same level of simulated bat predation. We show species-specific and size-independent differences in both overall flight strength and in change of flight strength over time, confirming the escape-tactic diversity hypothesis for eared moths. Additionally, we show strong inter-individual differences in evasive flight within some species. This diversity in escape tactic between eared moths increases the overall unpredictability of their evasive flight in mixed-species groups, likely providing better protection against predatory bats for the single individual.

scholarly journals Mixed-species associations of Diana and Campbell's monkeys: the costs and benefits of a forest phenomenon

Behaviour ◽  
2003 ◽  
Vol 140 (3) ◽  
pp. 371-385 ◽  
Author(s):  
Sonja Wolters ◽  
Klaus Zuberbühler
Keyword(s):  
Resource Competition ◽  
Dilution Effect ◽  
Daily Basis ◽  
Species Group ◽  
Mixed Species ◽  
Predator Detection ◽  
Vocal Behaviour ◽  
Forest Strata ◽  
Species Groups ◽  
Mixed Species Groups

AbstractOne of the most striking behavioural patterns of many forest primates concerns their tendency to live in semi-permanent mixed-species groups. Functional investigations have ascertained that individuals obtain some antipredator benefits without paying the costs of intra-species resource competition. Despite these advances, very little is known about the subtle mechanisms that keep mixed species groups together on a daily basis. Our results showed that in the Diana-Campbell's monkey association both species benefited from each other in diverse and idiosyncratic ways. In the presence of Campbell's monkeys the conspicuous Diana monkeys were more likely to descend into the lower forest strata, increased their foraging behaviour, and individuals became less vigilant. The cryptic Campbell's monkeys, in turn, were able to use the higher forest strata and exposed areas more often, spread out over larger areas, were more likely to travel, and engaged in more conspicuous vocal behaviour when associated with Diana monkeys. These data suggested that both species benefited from each other in ways that went beyond passive group-size related antipredator benefits, such as a dilution effect and increased chances of predator detection. Instead, the increased safety of the mixed species group allowed individuals to exploit their ecological niche more broadly, to forage more efficiently, and to engage in more social behaviour, suggesting that the benefits of mixed species groups are much more varied and diverse than currently thought.

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 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.

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