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501.
Many mammals warn conspecifics with alarm calls about detected predators. These alarm calls are either functionally referential,
urgency based, or they can have multiple functions, including predator deterrence. The taxonomic distribution of these alarm
call systems is uneven, with primates providing the best-known examples for a functionally referential system and rodents
most examples of an urgency-based system. Reports of different alarm call systems in lemurid primates prompted us to examine
the anti-predator behavior of two additional lemur species. In an experimental field study we exposed adult redfronted lemurs
(Eulemur fulvus rufus) and white sifakas (Propithecus verreauxi verreauxi) to playbacks of vocalizations of their main aerial and terrestrial predators, as well as to their own alarm calls given
in response to the presentation of these predators. We scored the subjects' immediate behavioral responses, including alarm
calls, from video recordings made during the first minute following a playback. We found that both species gave specific alarm
calls only in response to raptor playbacks and the corresponding alarm calls, whereas calls given in response to carnivores
and the corresponding alarm calls were also observed in other situations characterized by high arousal. Other behavioral responses,
such as gaze and escape directions, corresponded to the hunting strategies of the two predator classes, suggesting that the
corresponding vocalizations were categorized correctly. These two lemur species, which represent different families, have
therefore independently evolved a mixed alarm call system, characterized by functionally referential calls for diurnal raptors,
but not for carnivores. Electronic supplementary material to this paper can be obtained by using the Springer LINK server
located at http://dx.doi.org/10.1007/s00265-001-0436-0
Electronic Publication 相似文献
502.
503.
Nathaniel T. Wheelwright Cheryl B. Schultz Peter J. Hodum 《Behavioral ecology and sociobiology》1992,31(4):279-289
Summary To determine the effects of male mating status on female fitness, we compared the reproductive success, survival, and future fecundity of female Savannah sparrows (Passerculus sandwichensis) mated to monogamous vs. polygynous males in a 5-year study on Kent Island, New Brunswick, Canada. The proportion of males with more than one mate varied from 15 to 43% between years and sites. Polygynous and monogamous males fledged young of equal size in every year of the study. Females who shared paternal care with other females laid as many eggs per clutch and clutches per season as monogamously mated females. In most years polygynously mated females showed no delay in laying a second clutch, and they suffered no reduction in fecundity the following year. Recruitment of a female's offspring into the breeding population was generally independent of her mating status. Fitness costs of being mated to a polygynous male were only apparent in one year of the study, during which females mated to polygynous males had higher over-winter mortality than those mated to monogamous males. That same year, young raised by polygynous males were only one-third as likely to survive to reproductive maturity (as inferred by returns) as those raised by monogamous males. A male's mating status had no effect on his own survivorship. A male's mating status did not necessarily reflect his contributions to raising nestlings, which may partially explain why monogamously and polygynously mated females had equal fitness. At 35 nests the proportion of food deliveries brought by individual males varied from 0 to 75%; on average, males brought fewer than 30% of all food deliveries. Yet parental care by polygynous males was no less than that of monogamous males, at least at the nests of their primary females. Secondary females tended to receive less male assistance during the nestling stage, but their reproductive success was indistinguishable from that of primary females. Females feeding young without male assistance made as many food deliveries/h as did pairs in which males brought at least 30% of all food deliveries. Unassisted females did not suffer diminished fledging success or produce smaller fledglings. The benefits of polygyny for male Savannah sparrows are clear: polygynous males recruit more surviving offspring into the breeding population than monogamous males. The fitness of females, on the other hand, appears to be unaffected by whether their mate was monogamous or polygynous except in occasional years. Polygyny may be maintained in this population by the constraints of a female-biased sex ratio, the inability of females to predict a male's paternal care based on his morphology or behavior, the poor correlation between a male's mating status and his assistance at the nest, and inconsistent natural selection against mating with a polygynous male.
Correspondence to: N.T. Wheelwright 相似文献
504.
505.
Many predators hunt using the social and waste odors of their prey. It is unknown, however, whether potential prey modify
their behavior in response to the risks of predation associated with accumulations of conspecific odor. We examined this question
by measuring foraging trade-offs of wild house mice (Mus domesticus) in the field where we increased both predation risk and conspecific odor at artificial food patches in a two-factor design.
Mouse giving-up densities (GUDs) were significantly higher in open habitats than in closed habitats but did not differ with
the addition of mouse odors. Fine-scale behavioral observations of captive mice confirmed their attraction to the conspecific
odor in an enclosure experiment, without any change to the GUD. These results indicate that house mice continue to visit and
forage at food patches despite accumulations of predator-attracting odors. This most likely occurs for the social benefits
obtained from conspecific odor exploration; however, such behavior may cause mice to become vulnerable to considerable olfactory
exploitation by their predators. Future work must therefore focus on how mice trade off the social benefits of investigating
odors that also attract their enemies. 相似文献
506.
Francis C. Neat Peter J. Wright Alain F. Zuur Iain M. Gibb Fiona M. Gibb David Tulett David A. Righton Robert J. Turner 《Marine Biology》2006,148(3):643-654
Atlantic cod stocks are subdivided into geographically and biologically discrete populations; some being locally resident,
others migratory. The reasons for the variation in migration pattern and the consequences it may have for population structuring
is poorly understood. We studied a group of cod from the coastal waters of the Shetland Isles in the northern North Sea. During
the spawning season, electronic tags that record depth and temperature over time were implanted into 133 individuals and the
fish released within a few kilometres of where they were captured. Thirty-nine cod have been recaptured up to 608 days later,
throughout the year and, in all but two cases, within 15 km of their release site. Geolocation methods based on temperature
and bathymetry also suggested that the cod had a limited home range, remaining resident year-round in coastal waters. The
cod were deeper during the winter and moved to shallower water in late spring and summer. They showed diel, fortnightly and
monthly cycles in depth movement that varied much within and between individuals over the season. Residency and the individual
variability in vertical movement may reflect a combination of locally complex depth strata, variable seabed substrate and
the wide range of seasonally available prey resources. 相似文献
507.
508.
In situ measurements comparing vertical SO42− profiles in vegetated and non-vegetated sediments showed that SO42− concentrations in vegetated sediments increased significantly at the beginning of the growing season and then gradually decreased during the rest of the growing season. Throughout the growing season, SO42− concentrations remained higher in the vegetated sediments than in the sediments without plants. The higher SO42− concentrations in the vegetated sediments indicate that oxygen release from roots and evapotranspiration-induced advection by plants play an important role in the dynamics of sulfur species in sediments. Since the total pool of solid-phase sulfide is relatively large compared to the mass of SO42− in the sediments, the gradual decrease of SO42− concentrations may result from limitation of the solid-phase sulfide that is in direct contact with or very close to the roots and rhizomes. This would mean that the main pool of solid-phase sulfide and associated trace metals are not affected by the oxygen release from roots, and the associated trace metals will not become bioavailable during the growing season. 相似文献
509.
The high frequency of extra-pair paternity in tree swallows is not an artifact of nestboxes 总被引:6,自引:0,他引:6
C. A. Barber Raleigh J. Robertson Peter T. Boag 《Behavioral ecology and sociobiology》1996,38(6):425-430
A common criticism of nestbox studies is one of creating artificial nesting conditions and breeding behavior different from
what would be seen under natural conditions. We assessed the frequency of extra-pair paternity (percentage of broods with
at least one extra-pair young) in 25 families of tree swallows (Tachycineta bicolor) nesting in natural cavities and compared it to that in a nestbox population. We found that 84% of females nesting in natural
cavities obtained fertilizations from extra-pair males. These extra-pair males fathered 69% of all nestlings. Studies of tree
swallows breeding in nestboxes have shown that 50–87% of broods contained extra-pair young, with extra-pair males fathering
38–53% of all the young. In broods with extra-pair paternity, natural cavities contained a significantly greater proportion
of extra-pair young than did nestboxes. Despite differences in nesting habitat and female age structure, the frequency of
extra-pair paternity did not differ significantly between the natural-cavity and nestbox populations. Therefore, the presence
of extra-pair paternity in tree swallows is not an artifact of nestboxes or of artificial nesting conditions.
Received: 2 May 1995/Accepted after revision: 14 January 1996 相似文献
510.
Peter D. Dijkstra Renske Hekman Rüdiger W. Schulz Ton G. G. Groothuis 《Behavioral ecology and sociobiology》2007,61(4):599-609
The nature of the costs maintaining honesty of sexual signalling in inter- and intrasexual interactions remains a contentious
issue. For carotenoid-based colour ornaments, it has been hypothesized that the honesty of the signal is enforced when carotenoid
allocation to colour expression is traded off against carotenoid availability for immunocompetence. In addition, honesty is
enforced if androgens required for colour expression are immunosuppressive. We tested whether there is a trade-off between
colour expression and immunocompetence in a lek-breeding haplochromine cichlid fish, Pundamilia nyererei, from Lake Victoria with a carotenoid-based nuptial dress. First, we showed that expression of red nuptial colouration and
social rank in a group were positively correlated. We then successfully manipulated the level of colour advertisement by socially
stimulating individually housed males with a rival male: Stimulated males developed larger areas of red nuptial colouration
and had higher levels of circulating 11-ketotestosterone (11-KT) than non-stimulated males. We subsequently tested the humoral
immune response to a novel antigen (sheep red blood cells). There was no overall significant effect of social stimulation
on antibody production, but in the stimulated males, the degree of red colouration and the antibody response were negatively
correlated. This significant interaction between colour and treatment thus shows that the negative correlation between colouration
and antibody production is dependent on the (manipulated) social environment. This study provides correlational and experimental
evidence for a trade-off between expression of a sexual trait and one component of immune function in fish. We found no evidence
for a direct effect of 11-KT on antibody production, and we discuss alternative mechanisms that could mediate the trade-off. 相似文献