| 1. |
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| 2. |
- Fuller, Rebecca, et al.
(författare)
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Behavioral responses of a sex-role reversed pipefish to a gradient of perceived predation risk
- 1996
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Ingår i: Behavioral Ecology. - 1045-2249 .- 1465-7279. ; 7:1, s. 69-75
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Tidskriftsartikel (refereegranskat)abstract
- Conspicuous behaviors such as courtship and mating often make animals susceptible to predation. When perceiving themselves at an elevated level of risk, animals frequently reduce conspicuous behaviors in trade-off for a decrease in probability of being preyed upon. In the present study, we used two experiments to examine the effect of perceived predation risk from cod (Gadus morhua) on nonreproductive and reproductive behaviors in the sex-role reversed pipefish (Syngnathus typhle). In the first experiment, no differences due to predation risk were detected in the nonreproductive behaviors of either males or females. In the second experiment, predation risk had significant effects on reproductive behaviors. Pipefish were allowed to court and copulate at four different predation levels. We created predation levels differing in perceived predation risk by controlling the number of sensory modes through which pipefish could detect the presence of a cod. As predation risk increased, pipefish copulated and courted less frequently, swam alone (displayed and searched for conspecifics) less often, and waited longer before commencing courtship. These changes in behavior minimized the amount of time spent above the eelgrass and presumably reduced conspicuousness to visual predators. Pipefish also copulated after a smaller amount of courtship as predation risk increased, indicating that they may trade information concerning mate quality for a reduction ill predation risk. No differences were found in any response variable between males and females. The role of operational sex ratios and intersexual competition in determining which sex assumes greater costs in mate acquisition is questioned.
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| 3. |
- Nilsson, Anders, et al.
(författare)
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Foraging among cannibals and kleptoparasites: effects of prey size on pike behavior
- 1999
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 10:5, s. 557-566
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Tidskriftsartikel (refereegranskat)abstract
- The northern pike (Esox lucius) is an important and selective piscivore that chooses smaller prey than predicted from energy / time budgets. In a laboratory experiment, we investigated pike predatory behavior to explain this selectivity. Northern pike feeding on different prey sizes in aquaria were observed when foraging alone, when in the presence of chemical cues from similar-sized or larger conspecifics, and when in the presence of conspecifics that were allowed to interact with the focal pike. The results show that prey handling time increases with prey size and that the duration of manipulating and handling prey inflicts a risk of exposure to cannibals and kleptoparasites on the pike. Therefore, the risk of falling victim to cannibals or kleptoparasites increases with prey size. Attracting and experiencing intraspecific interactors can be regarded as major fitness costs. Chemical cues from foraging conspecifics have only minor effects on pike foraging behavior. Furthermore, the ability to strike and swallow prey head first improves pike predatory performance because failing to do so increases handling time. Our findings emphasize the increasing potential costs with large prey and explain previous contradictory suggestions on the underlying mechanisms of behavior, selectivity, and trophic effects of northern pike predation.
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| 4. |
- Olsén, K. Håkan, 1952-, et al.
(författare)
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Aggressiveness and kinship in brown trout (Salmo trutta) parr
- 1996
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Ingår i: Behavioral Ecology. - : Oxford University Press. - 1045-2249 .- 1465-7279. ; 7:4, s. 445-450
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Tidskriftsartikel (refereegranskat)abstract
- In a series of experiments, kin-biased behavior of young brown trout (Salmo trutta) was observed. The aggressiveness shown by groups of familiar siblings (siblings reared together since fertilization) and groups of unfamiliar siblings (siblings reared apart since fertilization) was significantly lower compared to that of mixed groups of two unrelated sibling groups (offspring of two different pairs of parents). The evolution of kin-biased behavior, as shown by a reduction in aggressiveness, is assumed to have evolved through a kin-selective mechanism.
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| 5. |
- Svensson, Erik, et al.
(författare)
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The trade-off between molt andparental care: a sexual conflict in the blue tit?
- 1997
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 8:1, s. 92-98
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Tidskriftsartikel (refereegranskat)abstract
- Breeding activities and molt are generally thought to be mutually exclusive in birds since both are energetically costly and are normally separated in time. However, sometimes molt overlaps with breeding to some degree. A trade-off between adult somatic maintenance functions (feather renewal) and parental care is then to be expected. The consequences of this are largely unknown, and there are few studies that have shown any fitness costs of molt-breeding overlap. We investigated the consequences of molt-breeding overlap by removing first clutches of blue tit Parus caeruleus pairs, thereby inducing late repeat clutches. Among the delayed pairs, a high proportion of males and some females started their molt already during incubation or nestling feeding. Molting males fed their nestling to a lesser extent than non-molting ones, and nestling mortality increased as a direct result of the early timing of male molt. Furthermore, the ability to raise an experimentally enlarged brood was negatively coupled to the molt stage of the male. Our data thus protide evidence that molt-breeding overlap leads to fitness costs, and we discuss the results within the context of sexual conflict and the implications for optimization of avian reproductive decisions.
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| 6. |
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| 7. |
- Fiske, P, et al.
(författare)
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Mating success in lekking males: a meta-analysis
- 1998
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Ingår i: BEHAVIORAL ECOLOGY. - : OXFORD UNIV PRESS INC. - 1045-2249. ; 9:4, s. 328-338
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Traits that are correlated with mating success are likely to be subject to sexual selection. In lekking species, a male's mating success can be estimated as the number of females that he copulates with. Earlier reviews of sexual selection in lekking speci
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| 8. |
- Forsman, A, et al.
(författare)
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Visual predators impose correlational selection on prey color pattern and behavior
- 1998
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Ingår i: BEHAVIORAL ECOLOGY. - : OXFORD UNIV PRESS INC. - 1045-2249. ; 9:4, s. 409-413
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Several lines of indirect evidence suggest that selection imposed by predators may favor certain combinations of prey coloration and behavior at the expense of other combinations, but this hypothesis has never been tested experimentally. We manipulated co
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| 9. |
- Fuller, R, et al.
(författare)
-
Behavioral responses of a sex-role reversed pipefish to a gradient of perceived predation risk
- 1996
-
Ingår i: BEHAVIORAL ECOLOGY. - : OXFORD UNIV PRESS INC. - 1045-2249. ; 7:1, s. 69-75
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Conspicuous behaviors such as courtship and mating often make animals susceptible to predation. When perceiving themselves at an elevated level of risk, animals frequently reduce conspicuous behaviors in trade-off for a decrease in probability of being pr
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| 10. |
- Komers, PE, et al.
(författare)
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Age at first reproduction in male fallow deer: Age-specific versus dominance-specific behaviors
- 1997
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Ingår i: BEHAVIORAL ECOLOGY. - : OXFORD UNIV PRESS INC. - 1045-2249. ; 8:4, s. 456-462
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The argument that an optimal age at first reproduction evolves where the benefits of reproduction outweigh the costs implies that where conditions change, age at first reproduction should also change. We studied six captive populations of allow deer (Dama
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