Interspecific aggression and behavioural dominance among four sympatric species of shrews

2006 ◽  
Vol 84 (3) ◽  
pp. 434-448 ◽  
Author(s):  
Leszek Rychlik ◽  
Rafal Zwolak
Keyword(s):  
Body Size ◽  
Dominance Rank ◽  
Interference Competition ◽  
Sympatric Species ◽  
Interspecific Aggression ◽  
Neutral Field ◽  
Subordinate Species ◽  
Defensive Behaviours ◽  
Sorex Minutus ◽  
Behavioural Dominance

Level of interspecific aggression should reflect intensity of interference competition, and large dominant and small subordinate species should develop aggressive and passive agonistic behaviours, respectively, to achieve stable coexistence. We tested these ideas, investigating interspecific behavioural dominance in a four-species community of shrews varying in body size (Sorex minutus L., 1766; Sorex araneus L., 1758; Neomys anomalus Cabrera, 1907; Neomys fodiens (Pennant, 1771)) by placing interspecific pairs in a neutral field. The order of dominance (determined on the basis of duration of offensive and defensive behaviours, total time spent in the shelter, and a "final shelter resident" index) corresponded to the order of body size: N. fodiens > N. anomalus > S. araneus > S. minutus. The highest number of conflicts and the least pronounced dominance of N. anomalus over S. araneus suggest that the interference competition was strongest between these species. The different social organization of N. anomalus (tolerant and gregarious versus intolerant and solitary in the other three species) did not decrease its aggressiveness and dominance rank. The larger Neomys species were more aggressive and initiated relatively more offensive behaviours, whereas the smaller Sorex species initiated more defensive behaviours. The presence of food and shelter did not intensify conflicts. Nevertheless, dominant species restricted the access of subordinate species to the shelter.

Allometry and Paleoecology of Medial Miocene Dwarf Rhinoceroses from the Texas Gulf Coastal Plain

Paleobiology ◽  
1982 ◽  
Vol 8 (1) ◽  
pp. 16-30 ◽  
Author(s):  
Donald R. Prothero ◽  
Paul C. Sereno
Keyword(s):  
Body Size ◽  
Coastal Plain ◽  
Sympatric Species ◽  
High Plains ◽  
Gulf Coastal Plain ◽  
Canine Tooth ◽  
Positive Allometry ◽  
Mammalian Faunas ◽  
The Common ◽  
Limb Proportions

Barstovian (medial Miocene) mammalian faunas from the Texas Gulf Coastal Plain contained four apparently sympatric species of rhinoceroses: the common forms Aphelops megalodus and Teleoceras medicornutus, a dwarf Teleoceras, and a dwarf Peraceras. Previous work has suggested positive allometry in tooth area with respect to body size in several groups of mammals, i.e., larger mammals have relatively more tooth area. However, dwarfing lineages were shown to have relatively more tooth area for their body size. Our data show no significant allometry in post-canine tooth area of either artiodactyls or ceratomorphs. Similarly, dwarf rhinoceroses and hippopotami show no more tooth area than would be predicted for their size. Limbs are proportionately longer and more robust in larger living ceratomorphs (rhinos and tapirs) than predicted by previous authors. Limb proportions of both dwarf rhinoceroses and dwarf hippopotami are even more robust than in their living relatives.The high rhinoceros diversity reflects the overall high diversity of Barstovian faunas from the Texas Gulf Coastal Plain. The first appearance of several High Plains mammals in these faunas indicates “ecotone”-like conditions as faunal composition changed. Study of living continental dwarfs shows that there is commonly an ecological separation between browsing forest dwarfs and their larger forebears, which are frequently savannah grazers. This suggests that the dwarf rhinoceroses might have been forest browsers which were sympatric with the larger grazing rhinos of the High Plains during the Barstovian invasion. The continental dwarf model also suggests that insular dwarfism may be explained by the browsing food resources that predominate on islands.

scholarly journals The isotopic niche of Atlantic, biting marine mammals and its relationship to skull morphology and body size

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Massimiliano Drago ◽  
Marco Signaroli ◽  
Meica Valdivia ◽  
Enrique M. González ◽  
Asunción Borrell ◽  
...  
Keyword(s):  
Body Size ◽  
Atlantic Ocean ◽  
Fisheries Management ◽  
Marine Mammals ◽  
Trophic Position ◽  
Sympatric Species ◽  
Isotopic Niche ◽  
Apex Predators ◽  
Skull Morphology ◽  
Ecosystem Based Fisheries Management

AbstractUnderstanding the trophic niches of marine apex predators is necessary to understand interactions between species and to achieve sustainable, ecosystem-based fisheries management. Here, we review the stable carbon and nitrogen isotope ratios for biting marine mammals inhabiting the Atlantic Ocean to test the hypothesis that the relative position of each species within the isospace is rather invariant and that common and predictable patterns of resource partitioning exists because of constrains imposed by body size and skull morphology. Furthermore, we analyze in detail two species-rich communities to test the hypotheses that marine mammals are gape limited and that trophic position increases with gape size. The isotopic niches of species were highly consistent across regions and the topology of the community within the isospace was well conserved across the Atlantic Ocean. Furthermore, pinnipeds exhibited a much lower diversity of isotopic niches than odontocetes. Results also revealed body size as a poor predictor of the isotopic niche, a modest role of skull morphology in determining it, no evidence of gape limitation and little overlap in the isotopic niche of sympatric species. The overall evidence suggests limited trophic flexibility for most species and low ecological redundancy, which should be considered for ecosystem-based fisheries management.

scholarly journals Chest beats as an honest signal of body size in male mountain gorillas (Gorilla beringei beringei)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Edward Wright ◽  
Sven Grawunder ◽  
Eric Ndayishimiye ◽  
Jordi Galbany ◽  
Shannon C. McFarlin ◽  
...  
Keyword(s):  
Body Size ◽  
Competitive Ability ◽  
Dominance Rank ◽  
Male Body ◽  
Honest Signal ◽  
Sexual Competition ◽  
Mountain Gorillas ◽  
Temporal Characteristics ◽  
Gorilla Beringei Beringei ◽  
Vocal Signals

AbstractAcoustic signals that reliably indicate body size, which usually determines competitive ability, are of particular interest for understanding how animals assess rivals and choose mates. Whereas body size tends to be negatively associated with formant dispersion in animal vocalizations, non-vocal signals have received little attention. Among the most emblematic sounds in the animal kingdom is the chest beat of gorillas, a non-vocal signal that is thought to be important in intra and inter-sexual competition, yet it is unclear whether it reliably indicates body size. We examined the relationship among body size (back breadth), peak frequency, and three temporal characteristics of the chest beat: duration, number of beats and beat rate from sound recordings of wild adult male mountain gorillas. Using linear mixed models, we found that larger males had significantly lower peak frequencies than smaller ones, but we found no consistent relationship between body size and the temporal characteristics measured. Taken together with earlier findings of positive correlations among male body size, dominance rank and reproductive success, we conclude that the gorilla chest beat is an honest signal of competitive ability. These results emphasize the potential of non-vocal signals to convey important information in mammal communication.

scholarly journals Interference competition pressure predicts the number of avian predators that shifted their timing of activity

2018 ◽  
Vol 285 (1880) ◽  
pp. 20180744 ◽  
Author(s):  
Yifan Pei ◽  
Mihai Valcu ◽  
Bart Kempenaers
Keyword(s):  
Species Richness ◽  
Body Size ◽  
Interference Competition ◽  
Relative Importance ◽  
Exploitation Competition ◽  
Predator Species ◽  
Avian Predator ◽  
Avian Predators ◽  
Time Partitioning ◽  
Competition Pressure

Being active at different times facilitates the coexistence of functionally similar species. Hence, time partitioning might be induced by competition. However, the relative importance of direct interference and indirect exploitation competition on time partitioning remains unclear. The aim of this study was to investigate the relative importance of these two forms of competition on the occurrence of time-shifting among avian predator species. As a measure of interference competition pressure, we used the species richness of day-active avian predator species or of night-active avian predator species (i.e. species of Accipitriformes, Falconiformes and Strigiformes) in a particular geographical area (assemblage). As an estimate of exploitation competition pressure, we used the total species richness of avian predators in each assemblage. Estimates of the intensity of interference competition robustly predicted the number of Accipitriformes species that became crepuscular and the number of Strigiformes species that became day-active or strictly crepuscular. Interference competition pressure may depend on body size and on the total duration of the typical active period (day or night length). Our results support—to some extent—that smaller species are more likely to become time-shifters. Day length did not have an effect on the number of time-shifter species in the Accipitriformes. Among the large Strigiformes, more time-shifter species occur in areas where nights are shorter (i.e. where less of the typical time resource is available). However, in the small Strigiformes, we found the opposite, counterintuitive effect: more time-shifters where nights are longer. Exploitation competition may have had an additional positive effect on the number of time-shifters, but only in Accipitriformes, and the effect was not as robust. Our results thus support the interference competition hypothesis, suggesting that animals may have shifted their time of activity, despite phylogenetic constraints on the ability to do so, to reduce the costs of direct interactions. Our findings also highlight the influence of body size as a surrogate of competitive ability during encounters on time partitioning, at least among avian predators.

scholarly journals Aggressive Behaviors of Adult Male Atlantic Spotted Dolphins: Making Signals Count during Intraspecific and Interspecific Conflicts

2021 ◽  
Vol 8 (1) ◽  
pp. 35-51
Author(s):  
Cassandra L. Volker ◽  
Denise L. Herzing
Keyword(s):  
Adult Male ◽  
Behavioral Plasticity ◽  
Bottlenose Dolphins ◽  
Sympatric Species ◽  
Aggressive Behaviors ◽  
Interspecific Aggression ◽  
Behavioral Types ◽  
Stenella Frontalis ◽  
Behavioral Type ◽  
Atlantic Spotted Dolphins

Some species exhibit behavioral plasticity by altering their aggressive behavior based on their opponent. Atlantic spotted dolphins (Stenella frontalis) and bottlenose dolphins (Tursiops truncatus) are two sympatric species resident to the northern Bahamas. We examined whether groups of adult male spotted dolphins demonstrated behavioral plasticity during two different types of aggressive interactions. We described and compared the types of aggressive behaviors used during intraspecific aggression and interspecific aggression with bottlenose dolphins. Between the years 1991-2004, twenty-two aggressive encounters (11 intraspecific (spotted only), 11 interspecific (spotted vs. bottlenose)) were behaviorally analyzed. Twenty-three specific aggressive Behavioral Events, further grouped into three Behavioral Types, were examined throughout these encounters. Similarities and differences in the use of the Behavioral Types occurred during intra- and interspecific aggression. Groups of male Atlantic spotted dolphins altered their behavior during aggressive encounters with male bottlenose dolphins. Spotted dolphins increased their use of the Pursuit Behavioral Type and did not use the Display Behavioral Type significantly more than the Contact Behavioral Type during interspecific aggression. The increased use of a more overt and energy intensive Behavioral Type, Pursuit, suggests that Atlantic spotted dolphins altered their behavior during aggressive encounters with bottlenose dolphins to compensate during fights with a larger species and/or to effectively communicate with a different species.

Another new, diminutive Rock Gecko (Cnemaspis Strauch) from Peninsular Malaysia and a discussion of resource partitioning in sympatric species pairs

Zootaxa ◽  
2010 ◽  
Vol 2569 (1) ◽  
pp. 55 ◽  
Author(s):  
L. LEE GRISMER ◽  
CHAN KIN ONN ◽  
EVAN QUAH ◽  
MOHD ABDUL MUIN ◽  
ANNA E. SAVAGE ◽  
...  
Keyword(s):  
New Species ◽  
Body Size ◽  
Endemic Species ◽  
Resource Partitioning ◽  
Sympatric Species ◽  
Southeast Asian ◽  
Peninsular Malaysia ◽  
Activity Period ◽  
Species Pairs

A new, diminutive species of Rock Gecko, Cnemaspis shahruli sp. nov. from Penang Island, Penang; Pulau Jerejak, Penang; Pulau Pangkor, Perak; and the adjacent mainland at Sungai Sedim, Kedah was previously confused with juveniles of the sympatric, endemic species C. affinis (Stoliczka) on Penang Island. Cnemaspis shahruli sp. nov. is diagnosed from all other Southeast Asian Cnemaspis on the basis of several unique aspects of squamation, coloration, and body size. It is proposed that this new species has a more extensive mainland distribution than is presented here based on its southernmost record on Pulau Pangkor, Perak. A pattern of resource partitioning on the basis of body size, habitat, and activity period among sympatric species pairs of Cnemaspis is discussed.

The Dynamic of Aggression: How Individual and Group Factors Affect the Long-Term Interspecific Aggression Between Two Sympatric Species of Dolphin

Ethology ◽  
2014 ◽  
Vol 120 (3) ◽  
pp. 287-303 ◽  
Author(s):  
Jessica A. Cusick ◽  
Denise L. Herzing
Keyword(s):  
Sympatric Species ◽  
Interspecific Aggression

scholarly journals Sexual dimorphism in mud crabs: a tale of three sympatric Scylla species

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10936
Author(s):  
Hanafiah Fazhan ◽  
Khor Waiho ◽  
Yushinta Fujaya ◽  
Nita Rukminasari ◽  
Hongyu Ma ◽  
...  
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis ◽  
Carapace Width ◽  
Sympatric Species ◽  
Sexually Dimorphic ◽  
Morphometric Characteristics ◽  
Mud Crabs

Sexual dimorphism is a common phenomenon in the animal kingdom. To test the consistency of sexual dimorphism patterns among sympatric species of the same genus, ten morphometric characteristics of mud crabs Scylla olivacea, S. tranquebarica and S. paramamosain were measured and compared using Discriminant Function Analysis (DFA). The descriptive analysis revealed that in all three species, body size dimensions and cheliped dimensions were significantly larger in males whereas the abdomen width was female-biased. Also, we described a morphological variation (carapace width, CW ≤ CW at spine 8, 8CW) that is unique to S. olivacea. Discriminant function analysis revealed that all nine morphometric characteristics were sexually dimorphic in S. olivacea, S. tranquebarica (except right cheliped’s merus length, ML) and S. paramamosain (except 8CW). The obtained discriminant functions based on the morphometric ratios (with CW as divisor) correctly classified 100% of adults of known sex of all three species. Further, based on the selected body traits, DFA was able to almost completely distinguish males (94%), but not females (74%), among the three Scylla species. This study highlights that congeneric species of portunids (e.g., Scylla spp.) show similar sexually dimorphic characteristics (body size and secondary sexual characteristics).

Aggression by red-winged blackbirds towards marsh wrens

1983 ◽  
Vol 61 (8) ◽  
pp. 1896-1899 ◽  
Author(s):  
Jaroslav Picman
Keyword(s):  
Interference Competition ◽  
Time Of Day ◽  
Two Dimensional ◽  
Ecological Specialization ◽  
Agonistic Interactions ◽  
Interspecific Aggression ◽  
Interspecific Territoriality

Marshes are simple, two-dimensional habitats that provide little opportunity for ecological specialization. This situation has most likely favored the evolution of interspecific aggression between red-winged blackbirds and marsh wrens. Redwings of both sexes are aggressive towards marsh wrens; however, the rate of redwing–wren agonistic interactions is determined by at least three factors: (i) sex of redwings (most interactions involved males); (ii) time of day (the rate of interactions is determined by territorial and foraging activities of these birds); and (iii) density of marsh wrens in an area (the rate of interactions increased with increasing density of marsh wrens in different areas). Since a consequence of this redwing aggression towards marsh wrens is partial interspecific territoriality, this behavior has presumably evolved as a mechanism reducing interference competition with marsh wrens.

Behavioral Interactions and Body Size Differences in Competition for Food among Juvenile Brown Bullhead (Ictalurus nebulosus)

1982 ◽  
Vol 39 (2) ◽  
pp. 316-320 ◽  
Author(s):  
W. Hubert Keen
Keyword(s):  
Body Size ◽  
Social Interactions ◽  
Growth Rates ◽  
Interference Competition ◽  
Size Difference ◽  
Food Level ◽  
Brown Bullhead ◽  
Exploitation Competition ◽  
Behavioral Interactions ◽  
Ictalurus Nebulosus

The effects of relative body size (larger or smaller fish), absolute body size differences, food level, and social interactions on the growth rates of juvenile brown bullhead (Ictalurus nebulosus) catfish were determined for pairs of fish. Overall growth rate of the larger fish was higher than for the smaller fish, although this difference did not depend on absolute body size difference within pairs. The reduced growth rates of both larger and smaller fish at limited food level was independent of both relative size difference and absolute body size difference within pairs. Both larger and smaller fish had highly variable growth rates. Size dominance and aggression were common within many pairs, yet this behavior was unrelated to food level and absolute body size difference. Aggression within pairs was not diminished by adding structural complexity to simple environments. It is suggested that the high variability in growth rates was due to differences in individuals within pairs with respect to the intensity of behavioral interactions. Social interactions within pairs offish were apparently unrelated to food level and were strong enough to mask both exploitative and interference mechanisms which may have been functional in competition for limited food.Key words: body size, dominance hierarchies, exploitation competition, food level, Ictalurus nebulosus, interference competition, behavioral interactions

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