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31.
Eve?McDonald-MaddenEmail author Mark?A.?Elgar Kathrine?A.?Handasyde 《Behavioral ecology and sociobiology》2004,56(4):322-327
The costs of reproduction are widely recognised as a major selective force in the evolution of various behavioural and life-history characteristics. In particular, the behaviour of reproductively active animals is likely to change when breeding increases risk of predation. We investigated the effect of an experimentally derived threat on the vigilance and escape behaviour of female Trichosurus caninus with and without dependent offspring and at different stages of offspring development. Females with offspring showed a heightened response to the threat in comparison to females without offspring. In addition, females with offspring displayed a stronger response at earlier stages of their offsprings development.Communicated by P. Bednekoff 相似文献
32.
Ulrika?CandolinEmail author Heinz-Rudolf?Voigt 《Behavioral ecology and sociobiology》2003,55(1):42-49
The distribution of individuals is often the outcome of conflicting demands, such as between predator avoidance and reproduction. A factor that has seldom been considered in studies on habitat choice is time-dependent changes in risk-taking. We investigated the distribution of threespine sticklebacks, Gasterosteus aculeatus, over two breeding seasons and found it to change with time towards shallower areas with a more open habitat structure. Shallow and structurally less complex habitats were probably favorable due to a higher reproductive rate, but costly due to an increased risk of predation. Contrary to expectation, changing predation pressure was not a predictor of the shift in habitat use and, thus, not the proximate cue. Instead date was the main predictor. This suggests that increased risk-taking in relation to predation contributed to the habitat shift. The possibility was supported by a laboratory experiment that showed sticklebacks to take larger risks and prefer more predator-exposed areas at the end of the season than at the start of the season. These results demonstrate that temporal changes in risk-taking occur and can influence habitat choice, which points to the importance of considering risk-taking, in addition to predation pressure, when studying the effect of predators on distribution.Communicated by J. Krause 相似文献
33.
Marta C. Soares Sónia C. Cardoso Isabelle M. Côté 《Behavioral ecology and sociobiology》2007,61(7):1015-1022
Predation risk is amongst the most pervasive selective pressures influencing behaviour and animals have been repeatedly shown
to trade-off foraging success for safety. We examined the nature of this trade-off in cleaning symbioses amongst Caribbean
coral reef fishes. We predicted that cleaning gobies (Elacatinus evelynae and Elacatinus prochilos) should prefer fish clients that pose a low risk of predation (e.g. herbivores) over clients that may have more ectoparasites
but pose a higher risk (e.g. piscivores). Our field observations revealed that cleaners did clean preferentially client species
with more parasites but predatory and non-predatory clients had similar ectoparasite loads. Despite the lack of a foraging
advantage for inspecting predators, cleaners did not avoid risky clients. On the contrary, a larger proportion of visiting
predators than non-predators was inspected, gobies initiated more interactions with predatory clients, and predators were
attended to immediately upon arrival at cleaning stations. This preferential treatment of dangerous clients may allow the
rapid identification of cleaners as non-prey item or may be due to the effect of predators on the rest of the cleaners’ clientele,
which avoided cleaning stations whilst predators were present. Dealing with potentially risky clients may allow gobies to
regain access to their main food source: non-predatory clients. 相似文献
34.
Brian?D.?WisendenEmail author Mike?S.?Pollock Robyn?J.?Tremaine Jeff?M.?Webb Monique?E.?Wismer Douglas?P.?Chivers 《Behavioral ecology and sociobiology》2003,54(5):485-490
Chemical and visual sources of information are used by aquatic prey during risk assessment. Here, we test the behavioral response of littoral prey fish to combinations of chemical alarm cues (skin extract) and the visual presence of a fish shoal. We scented minnow traps with either alarm cues or water (control) placed inside the trap, a jar that contained either a fish shoal or nothing (control), and recorded the number and species of fish captured. We predicted that chemical alarm cues would reduce the number of fish captured and that a fish shoal would increase the number of fish captured. The predicted effect of chemical and visual cues combined depended on the nature of the interaction. We found that the lowest catch rate was for the combination of alarm cue + no shoal, but the highest catch rate occurred for the combination of alarm cue + shoal. Fish shoal + water had the second highest catch rate and no shoal + water had the second lowest catch rate. We conclude that chemical alarm cues induce area avoidance in the absence of a shoal, but a strong behavioral proclivity to increase shoal cohesion in the presence of a shoal. The presence of a shoal in the traps induced alarmed fish to shoal with them and thus, enter the traps. This occurred even though traps were the source of the alarm cue.Communicated by A. Mathis 相似文献
35.
Predation risk affects courtship and attractiveness of competing threespine stickleback males 总被引:6,自引:3,他引:6
Ulrika Candolin 《Behavioral ecology and sociobiology》1997,41(2):81-87
The effect of predation risk and male-male competition on male courtship behaviour and attractiveness to females was studied
in the threespine stickleback (Gasterosteus aculeatus) by presenting dummy or live females to solitary and competing males under different predation risks. In the presence of
a predator, males decreased courtship activity. Different courtship components were, however, adjusted to different extents
and in opposing directions to predation risk, probably because the single components may have varied in riskiness. The presence
of a competing male decreased overall courtship activity, but increased the frequency of zigzags, suggesting zigzagging to
be a competitive strategy against other males. In the presence of a predator male courtship activity was not affected by a
competitor. Female mate choice correlated with the males' previous frequency of zigzags towards a dummy female. However, when
a live female paid attention to a male, the male decreased zigzagging and instead increased leading and fanning behaviours,
probably trying to attract the female to the nest to mate. Predation risk affected the attractiveness of males as females
reduced their attention to a male when he faced a predator and reduced his courtship activity. As females instead increased
their attention to a competing male that had increased his courtship activity, due to decreased competition, males clearly
are balancing mating opportunities against predator avoidance. When males vary in their susceptibility to predators, predation
risk may thus affect mating success of competing males.
Received: 31 January 1997 / Accepted after revision: 15 April 1997 相似文献
36.
Mark R. L. Forbes Robert G. Clark Patrik J. Weatherhead Terry Armstrong 《Behavioral ecology and sociobiology》1994,34(2):79-85
We tested several predictions of nest defense theory by observing variation in flushing distance and probability of nest abandonment within and between six species of waterfowl. In these species, only the females incubate eggs and attend offspring. First, we examined whether flushing distance by females varied in relation to clutch size, stage of incubation, and time of season, after controlling for the number of visits made to nests by observers. Revisits by observers appeared to affect flushing distance by females for reasons unrelated to the relative value of the current clutch. We found that as incubation progressed, females allowed observers to approach more closely before flushing from the nest. In some species, females with larger clutches allowed closer approaches to nests before flushing which was also consistent with nest defense theory. In contrast, time of season (Julian date) did not relate to flushing distance for any species. When species were compared, we found that species with moderate to high yearly mortality and high reproductive output per breeding attempt (e.g., northern shoveler and blue-winged teal) were less likely to abandon nesting attempts and exhibited riskier behavior (remained at nests when approached closely by observers) than species that had lower yearly mortality (e.g., mallard). Our results show that flushing distance and patterns of nest abandonment by female ducks conform to several predictions of nest defense theory.Correspondence to: M.R.L. Forbes 相似文献
37.
Nina Peuhkuri 《Behavioral ecology and sociobiology》1999,46(5):307-312
Similarity among group members may serve as a defence against visually hunting predators that preferentially attack individuals
who are phenotypically different from the group majority. The presence of such odd individuals in an otherwise homogeneous
group may, however, increase the vulnerability of the other group members as well. Individuals might thus be expected to form
uniform groups in order to decrease predation risk, not only in trying to avoid being odd in a group, but also when attempting
to avoid being accompanied by odd individuals. This hypothesis was tested with small and large three-spined sticklebacks,
Gasterosteus aculeatus. Focal fish were offered the choice between a shoal consisting of conspecifics that were all similar in body length to the
focal fish (matching shoal) and a shoal in which one or a few individuals differed in body length from the focal fish (non-matching
shoal). In the control experiment, all individuals in the non-matching shoal differed in size from the focal fish. The control
confirmed that individuals preferably joined the matching shoal when the alternative option was to be odd in another one.
However, when the alternative for size-assortative shoaling was to belong to the majority in a mixed shoal, the shoal choice
of individuals appeared on average to be random. Visual contact with a live pike, Esox lucius, did not affect the shoal choice pattern. Furthermore, despite the frequency-dependent nature of the oddity effect, varying
the number of odd individuals in the non-matching shoal did not have a significant effect on individual's shoaling decisions.
These results suggest that size-assortativeness in fish shoals is not a result of individuals avoiding being among the majority
in a mixed group.
Received: 2 September 1998 / Received in revised form: 12 May 1999 / Accepted: 29 May 1999 相似文献
38.
Guy Cowlishaw 《Behavioral ecology and sociobiology》1999,45(1):67-77
This paper investigates the determinants of individual spacing behaviour in a desert baboon population (Papio cynocephalus ursinus). Patterns of neighbour proximity and neighbour density were examined among adults in four groups under different ecological
and social conditions (through instantaneous sampling during focal follows). Initial analysis of these data shows that (1)
the use of vertical substrates (refuges such as tall trees and cliff faces) can confound patterns of spacing, and (2) individual
differences in spacing can depend on the spatial scale over which it is measured. To minimise these substrate and scale effects,
this analysis focuses on animals which are off refuges and examines spacing behaviour through its underlying statistical `dimensions'
(identified through factor analysis). Analysis of these dimensions indicates that sex, group size, activity-habitat and female
reproductive state can all have independent effects on spacing: (1) males are more dispersed than females in smaller groups,
(2) male and female dispersion increases with time spent in foraging habitats, and (3) female dispersion is reduced during
lactation. According to the hypotheses tested, these results indicate that feeding competition only affects spacing behaviour
during foraging while predation risk plays little or no role in spacing. Most aspects of spacing behaviour are best explained
by male reproductive strategies and their social repercussions.
Received: 25 May 1998 / Accepted after revision: 18 July 1998 相似文献
39.
Matthias Bandilla Teija Hakalahti-Sirén E. Tellervo Valtonen 《Behavioral ecology and sociobiology》2008,62(6):975-982
Mating is essential for sexually reproducing species to pass on their genes. For sexual parasites, this implies a need to
switch the host in the search for a mate when potential partners are not available on the same host, although host switching
includes risks like starvation and predation. Studies of mate-searching behavior predict that commonly only one sex searches
for mating partners while the other remains stationary. In the present work, we experimentally infected rainbow trout (Oncorhynchus mykiss) with the fish ectoparasite Argulus coregoni and determined whether the sex, age and the presence of mating partners influenced the host switching activity. Our results
show that increased host switching by A. coregoni occurred only after the parasite reached the adult stage and a difference between the sexes was also recorded. Host switching
by mature males was enhanced when no mating partners were present on the same host, whereas females remained mainly stationary
on their host regardless of male presence or absence. Our data therefore support the hypothesis that there is a strategic
difference in reproductive behavior between males and females; males invest energy in mate searching while females are rather
stationary and invest into body size and hence increased fecundity. Our data also showed that leaving the host to find a mate
is potentially costly in terms of predation since a substantial number of free-swimming parasites were eaten by fish. 相似文献
40.
Insect larvae increase in size with several orders of magnitude throughout development making them more conspicuous to visually
hunting predators. This change in predation pressure is likely to impose selection on larval anti-predator behaviour and since
the risk of detection is likely to decrease in darkness, the night may offer safer foraging opportunities to large individuals.
However, forsaking day foraging reduces development rate and could be extra costly if prey are subjected to seasonal time
stress. Here we test if size-dependent risk and time constraints on feeding affect the foraging–predation risk trade-off expressed
by the use of the diurnal–nocturnal period. We exposed larvae of one seasonal and one non-seasonal butterfly to different
levels of seasonal time stress and time for diurnal–nocturnal feeding by rearing them in two photoperiods. In both species,
diurnal foraging ceased at large sizes while nocturnal foraging remained constant or increased, thus larvae showed ontogenetic
shifts in behaviour. Short night lengths forced small individuals to take higher risks and forage more during daytime, postponing
the shift to strict night foraging to later on in development. In the non-seasonal species, seasonal time stress had a small
effect on development and the diurnal–nocturnal foraging mode. In contrast, in the seasonal species, time for pupation and
the timing of the foraging shift were strongly affected. We argue that a large part of the observed variation in larval diurnal–nocturnal
activity and resulting growth rates is explained by changes in the cost/benefit ratio of foraging mediated by size-dependent
predation and time stress. 相似文献