|
Wolfe Ml,. (1979). Feral horse demography: A preliminary report (Abstract).
|
|
Wolfe Ml,. (1979). Population ecology of the kulan.
|
|
Woodward Sl,. (1979). Population dynamics of a herd of feral burros (Abstract).
|
|
Zervanos Sm, K. R. (1979). Seasonal home ranges and activity patterns of feral assateague island ponies.
|
Cameron, E. Z., Linklater, W. L., Stafford, K. J., & Minot, E. O. (2000). Aging and improving reproductive success in horses: declining residual reproductive value or just older and wiser? Behav. Ecol. Sociobiol., 47(4), 243–249.
Abstract: In many mammalian species, female success in raising offspring improves as they age. The residual reproductive value hypothesis predicts that each individual offspring will be more valuable to the mother as she ages because there is less conflict between the current and potential future offspring. Therefore, as mothers age, their investment into individual offspring should increase. Empirical evidence for an influence of declining residual reproductive value on maternal investment is unconvincing. Older mothers may not invest more, but may be more successful due to greater experience, allowing them to target their investment more appropriately (targeted reproductive effort hypothesis). Most studies do not preclude either hypothesis. Mare age significantly influenced maternal investment in feral horses living on the North Island of New Zealand. Older mares, that were more successful at raising foals, were more protective for the first 20 days of life, but less diligent thereafter. Total maternal input by older mothers did not seem to be any greater, but was better targeted at the most critical period for foal survival and a similar pattern was observed in mares that had lost a foal in the previous year. In addition, older mothers were more likely to foal in consecutive years, supporting the hypothesis that they are investing less than younger mares in individual offspring. Therefore, older mothers seem to become more successful by targeting their investment better due to experience, not by investing more in their offspring.
|
Anderson, C., & Franks, N. R. (2001). Teams in animal societies. Behav. Ecol., 12(5), 534–540.
Abstract: We review the existence of teams in animal societies. Teams have previously been dismissed in all but a tiny minority of insect societies. “Team” is a term not generally used in studies of vertebrates. We propose a new rigorous definition of a team that may be applied to both vertebrate and invertebrate societies. We reconsider what it means to work as a team or group and suggest that there are many more teams in insect societies than previously thought. A team task requires different subtasks to be performed concurrently for successful completion. There is a division of labor within a team. Contrary to previous reviews of teams in social insects, we do not constrain teams to consist of members of different castes and argue that team members may be interchangeable. Consequently, we suggest that a team is simply the set of individuals that performs a team task. We contrast teams with groups and suggest that a group task requires the simultaneous performance and cooperation of two or more individuals for successful completion. In a group, there is no division of labor--each individual performs the same task. We also contrast vertebrate and invertebrate teams and find that vertebrate teams tend to be associated with hunting and are based on individual recognition. Invertebrate teams occur in societies characterized by a great deal of redundancy, and we predict that teams in insect societies are more likely to be found in large polymorphic (“complex”) societies than in small monomorphic (“simple”) societies.
|
Dall, S. R. X., Giraldeau, L. - A., Olsson, O., McNamara, J. M., & Stephens, D. W. (2005). Information and its use by animals in evolutionary ecology. Trends Ecol Evol, 20(4), 187–193.
Abstract: Information is a crucial currency for animals from both a behavioural and evolutionary perspective. Adaptive behaviour relies upon accurate estimation of relevant ecological parameters; the better informed an individual, the better it can develop and adjust its behaviour to meet the demands of a variable world. Here, we focus on the burgeoning interest in the impact of ecological uncertainty on adaptation, and the means by which it can be reduced by gathering information, from both 'passive' and 'responsive' sources. Our overview demonstrates the value of adopting an explicitly informational approach, and highlights the components that one needs to develop useful approaches to studying information use by animals. We propose a quantitative framework, based on statistical decision theory, for analysing animal information use in evolutionary ecology. Our purpose is to promote an integrative approach to studying information use by animals, which is itself integral to adaptive animal behaviour and organismal biology.
|
Dugatkin, L., & Alfieri, M. (1991). Tit-For-Tat in guppies (Poecilia reticulata): the relative nature of cooperation and defection during predator inspection. Evol. Ecol., 5(3), 300–309.
Abstract: Summary The introduction of game-theoretical thinking into evolutionary biology has laid the groundwork for a heuristic view of animal behaviour in which individuals employ “strategies” – rules that instruct them how to behave in a given circumstance to maximize relative fitness. Axelrod and Hamilton (1981) found that a strategy called Tit-For-Tat (TFT) is one robust cooperative solution to the iterated Prisoner's Dilemma game. There exists, however, little empirical evidence that animals employ TFT. Predator inspection in fish provides one ecological context in which to examine the use of the TFT strategy.
|
Dugatkin, L. A. (1991). Dynamics of the TIT FOR TAT strategy during predator inspection in the guppy (Poecilia reticulata). Behav. Ecol. Sociobiol., 29(2), 127–132.
Abstract: One well-known solution to the iterated Prisoner's Dilemma is the TIT FOR TAT strategy. This strategy has three “characteristics” associated with it. TIT FOR TAT is nice (cooperates on the first move of a game), retaliatory (plays defect against an individual that defected on the prior move), and forgiving (cooperates with an individual which has defected in the past but cooperates in the present). Predator inspection behavior in guppies (Poecilia reticulata) was examined in order to determine whether guppies displayed these three characteristics. Results indicate that while it can be quite difficult to translate the abstract concepts of niceness, retaliation, and forgiveness into measurable behaviors, the data support the hypothesis that guppies display the three characteristics associated with the TIT FOR TAT strategy.
|
Dugatkin, L. A., & Godin, J. - G. J. (1993). Female mate copying in the guppy (Poecilia reticulata): age-dependent effects. Behav. Ecol., 4(4), 289–292.
Abstract: Virtually all studies of mate choice to date have assumed that females choose mates independent of one another. Social cues, however, such as the mate choice of conspecifics, may also play an important role in such decisions. Previous work has shown that female guppies of similar age copy each other's choice of mates. Here we examine the effect of relative age on mate choice copying in the guppy, Poecilia reticulata, and examine whether younger individuals are more likely to copy the mate choice of older conspecifics than vice versa. Results indicate that younger females copy the mate choice of older females, but older individuals do not appear to be influenced by the mate choice of younger individuals.
|
