Potential competitive interactions between larvae of Pseudophryne bibroni and P. semimarmorata (Anura : Leptodactylidae)

The two frog species Pseudophryne bibroni and P. semimarmorata are known to have allopatric distributions which meet in narrow hybrid zones in south-eastern Australia. A preliminary test is described of the hypothesis that interspecific competition plays a part in maintaining the narrow zones. Tadpoles from allopatric populations of each species were raised in single-species and mixed-species groups in experimental enclosures in a pool in the range of P. bibroni. Competitive superiority of P. bibroni was shown both in survival to metamorphosis and in size achieved at this stage. It is suggested that competition may be an important ecological component of the interactions taking place between the two taxa where their distributions meet.

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Fitness responses to co-infestation in fleas exploiting rodent hosts

Parasitology ◽

10.1017/s0031182015001006 ◽

2015 ◽

Vol 142 (12) ◽

pp. 1535-1542 ◽

Cited By ~ 4

Author(s):

IRINA S. KHOKHLOVA ◽

ELIZABETH M. DLUGOSZ ◽

BORIS R. KRASNOV

Keyword(s):

Reproductive Performance ◽

Egg Production ◽

Egg Size ◽

Experimental Treatment ◽

Single Species ◽

Mixed Species ◽

Species Groups ◽

The Mean ◽

Mixed Species Groups

SUMMARYTo understand mechanisms behind positive interspecific co-occurrences in flea infracommunities, we asked whether co-infestation results in an increase of flea fitness (quantity and/or quality of the offspring). We studied reproductive performance of Xenopsylla ramesis and Parapulex chephrenis when they exploited their characteristic host (Meriones crassus and Acomys cahirinus, respectively) either alone or together with another species. We used egg production, the number of new imagoes, pre-imaginal survival and egg size as fitness-related variables and predicted that fitness will be higher in fleas feeding in mixed- than in single-species groups. In both fleas, mean number of eggs produced per female flea did not depend on experimental treatment. No effect of single- vs mixed-species infestation on the mean number of new imagoes per female and the number of emerged imagoes per egg was found for X. ramesis, whereas both these numbers were higher in mixed- than in single-species groups for P. chephrenis. X. ramesis produced eggs of similar size independently of treatment, whereas eggs produced by P. chephrenis in mixed-species groups were significantly larger than eggs produced in single-species groups. We conclude that an increase in reproductive performance as a response to co-infestation may be one of the mechanisms behind aggregative structure of flea infracommunities. However, this response may vary among flea species.

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Cohesion, order and information flow in the collective motion of mixed-species shoals

Royal Society Open Science ◽

10.1098/rsos.181132 ◽

2018 ◽

Vol 5 (12) ◽

pp. 181132 ◽

Cited By ~ 10

Author(s):

Ashley J. W. Ward ◽

T. M. Schaerf ◽

A. L. J. Burns ◽

J. T. Lizier ◽

E. Crosato ◽

...

Keyword(s):

Gasterosteus Aculeatus ◽

Collective Motion ◽

Rutilus Rutilus ◽

Single Species ◽

Pungitius Pungitius ◽

Mixed Species ◽

In The Wild ◽

Threespine Sticklebacks ◽

Species Groups ◽

Mixed Species Groups

Despite the frequency with which mixed-species groups are observed in nature, studies of collective behaviour typically focus on single-species groups. Here, we quantify and compare the patterns of interactions between three fish species, threespine sticklebacks ( Gasterosteus aculeatus ), ninespine sticklebacks ( Pungitius pungitius ) and roach ( Rutilus rutilus ) in both single- and mixed-species shoals in the laboratory. Pilot data confirmed that the three species form both single- and mixed-species shoals in the wild. In our laboratory study, we found that single-species groups were more polarized than mixed-species groups, while single-species groups of threespine sticklebacks and roach were more cohesive than mixed shoals of these species. Furthermore, while there was no difference between the inter-individual distances between threespine and ninespine sticklebacks within mixed-species groups, there was some evidence of segregation by species in mixed groups of threespine sticklebacks and roach. There were differences between treatments in mean pairwise transfer entropy, and in particular we identify species-differences in information use within the mixed-species groups, and, similarly, differences in responses to conspecifics and heterospecifics in mixed-species groups. We speculate that differences in the patterns of interactions between species in mixed-species groups may determine patterns of fission and fusion in such groups.

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Vigilance of mustached tamarins in single-species and mixed-species groups—the influence of group composition

Behavioral Ecology and Sociobiology ◽

10.1007/s00265-009-0848-9 ◽

2009 ◽

Vol 64 (3) ◽

pp. 325-335 ◽

Cited By ~ 10

Author(s):

Mojca Stojan-Dolar ◽

Eckhard W. Heymann

Keyword(s):

Group Composition ◽

Single Species ◽

Mixed Species ◽

Species Groups ◽

Mixed Species Groups

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

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2006.3760 ◽

2006 ◽

Vol 274 (1611) ◽

pp. 827-832 ◽

Cited By ~ 15

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.

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