Selective allocation of parental and infanticidal responses in rodents: a review of mechanisms
Page 421. CHAPTER 17 SELECTIVE ALLOCATION OF PARENTAL AND INFANTICIDAL RESPONSES IN RODENTS: A RE... more Page 421. CHAPTER 17 SELECTIVE ALLOCATION OF PARENTAL AND INFANTICIDAL RESPONSES IN RODENTS: A REVIEW OF MECHANISMS ROBERT W. ELWOOD and HAZEL F. KENNEDY Division of Environmental ...
Infanticide in the Mongolian gerbils: ontogeny, causation and function. I
The introduction of non-native species to new locations is a growing global phenomenon with major... more The introduction of non-native species to new locations is a growing global phenomenon with major negative effects on native species and biodiversity. Such introductions potentially bring competitors into contact leading to partial or total species replacements. This creates an opportunity to study novel species interactions as they occur, with the potential to address the strength of inter-and intraspecific interactions, most notably competition. Such potential has often not been realized, however, due to the difficulties inherent in detecting rapid and spatially expansive species interactions under natural field conditions. The invasive amphipod crustacean Gammarus pulex has replaced a native species, Gammarus duebeni celticus, in river and lake systems across Europe. This replacement process is at least partially driven by differential parasitism, cannibalism, and intraguild predation, but the role of interspecific competition has yet to be resolved. Here, we examine how abundance of an invasive species may affect spatial niche breadth of a native congeneric species. We base our analyses of niche breadth on ordination and factor analysis of biological community and physical parameters, respectively, constituting a summative, multidimensional approach to niche breadth along environmental gradients. Results derived from biological and environmental niche criteria were consistent, although interspecific effects were stronger using the biological niche approach. We show that the niche breadth of the native species is constrained as abundance of the invader increases, but the converse effect does not occur. We conclude that the interaction between invasive G. pulex and native G. d. celticus under natural conditions is consistent with strong interspecific competition whereby a native, weaker competitor is replaced by a superior invasive competitor. This study indicates a strong role of interspecific competition, alongside other known interactions such as differential intraguild predation, in rapid and expansive species replacements following biological invasions.
Animal Sentience: An Interdisciplinary Journal on Animal Feeling, 2022
The rigorous framework for research into potential pain in decapods was successful in allowing le... more The rigorous framework for research into potential pain in decapods was successful in allowing legislators in the United Kingdom to evaluate a complex scientific issue. However, it might produce problems for research. I discuss doubts about the usefulness of the eight criteria. Some have yet to receive any investigation and others do not allow much inference about pain. In addition, some existing studies are not covered in the framework. Most worrying, however, is the potential for stifling future research of novel areas that are excluded from the framework.
Reproduction in the littoral hermit crab, Pagurus bernhardus
Irish Naturalists' Journal, 1987
Discussion The results from this study indicate that small littoral P. bernhardus have a shorter ... more Discussion The results from this study indicate that small littoral P. bernhardus have a shorter breeding season than larger sublittoral specimens. It has been estimated that the female" incubates" the eggs for approximately 3 months (Pike and Williamson 1959) and ...
Do Fish Feel Pain? V Braithwaite (2010). Published by Oxford University Press, Great Clarendon Street, Oxford OX2 6DP, UK. 208 pp Hardback (ISBN 978-0-19-955120-0). Price £14.99, US$29.95
Animal Welfare, Feb 1, 2011
Comparison of the behavioural and physiological disposition across the Callitrichid family in captive versus free-ranging environments
Pain in response to tissue damage functions to change behaviour so that further damage is minimis... more Pain in response to tissue damage functions to change behaviour so that further damage is minimised whereas healing and survival are promoted. This paper focuses on the behavioural criteria that match the function to ask if pain is likely in the main taxa of arthropods. There is evidence consistent with the idea of pain in crustaceans, insects and, to a lesser extent, spiders. There is little evidence of pain in millipedes, centipedes, scorpions, and horseshoe crabs but there have been few investigations of these groups. Alternative approaches in the study of pain are explored and it is suggested that studies on traumatic mating, agonistic interactions, and defensive venoms might provide clues about pain. The evolution of high cognitive ability, sensory systems, and flexible decision-making is discussed as well as how these might influence the evolution of pain-like states.
How hermit crabs (Pagurus bernhardus) deal with obstructions in the apertures of shells
Irish Naturalists' Journal, 1990
Hermit Crabs – Information Gathering by the Hermit Crab, Pagurus bernhardus
Information gathering and decision-making during contests between male swordtails, Xiphophorus helleri
Animal contests may be settled on the basis of asymmetries in fighting ability (Resource Holding ... more Animal contests may be settled on the basis of asymmetries in fighting ability (Resource Holding Potential, RHP), resource value and prior ownership. Selection is expected to favour males that make accurate assessments of their chances of winning to reduce the costs of aggression. The presumption of opponent (mutual) assessment in contests has recently been questioned. Rivals can either assess their own RHP relative to their opponent or rely on assessment of own fighting ability (self assessment). We tested the predictions of these alternatives in order to determine the mechanism of assessment underlying decision-making in contests between male swordtail fish (Xiphophorus helleri). We staged dyadic territorial contests between males, from different stock populations, that had been visually isolated (to mediate the effects of experience and socially available information). We examined factors affecting contests outcome and relationships between measures of individual RHP and the cost of contest behaviour to distinguish between alternative assessment hypothesis. Our results support the mutual assessment hypothesis. Predictions of principal game theoretical models were also examined to ascertain which best fits contest behaviour in male swordtails.1 page(s
Do male swordtails assess opponents or rely on intrinsic factors during agonistic contests
Agonistic encounters are costly in terms of time, energetic resources expended and the risk of in... more Agonistic encounters are costly in terms of time, energetic resources expended and the risk of injury. Contestants are expected to reduce these costs by assessing their chances of winning and altering their behaviour accordingly. Until recently, the prevailing view of mutual (or opponent) assessment in contests, whereby rivals assess their own resource holding potential (RHP) relative to their opponent, remained unchallenged. The alternative of self- (or own-size) assessment, where individuals rely soley on assessment of their own fighting ability, was overlooked but recently gained some empirical support. We tested the predictions of these alternative modes of assessment behaviour in staged territorial encounters between pairs of male swordtails, Xiphophorus helleri. Males were isolated from social interaction prior to being released simultaneously into a test aquarium. Contests consisted of a combination of displays, includung the species typical S-threat behaviour, and direct fighting, followed by role reinforcement through chasing. We used relationships between measures of individual RHP and the cost of contest behaviour to distinguish between hypotheses and to determine the mechanism underlying contest decisions in swordtails. Initial results suggest opponent assessment occurs during contest between male swordtails.1 page(s
Sex differences in shell preferences in the hermit crab, Pagurus bernhardus L
Irish Naturalists' Journal, 1988
Parental states as mechanisms for kinship recognition and deception about relatedness
Kin Recognition, 1991
Dominance status and faecal and urinary cortisol in captive ring-tailed lemurs, lemur catta
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Papers by Robert Elwood