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981.
T. R. Pope 《Behavioral ecology and sociobiology》2000,48(4):253-267
Evaluation of evolutionary mechanisms proposed to promote cooperative behavior depends on the relative influence of the behavior
on the reproductive success of individuals, the reproductive success of the group in which they interact behaviorally, and
the degree of gene correlation among cooperators. The genetic relationship within cooperative coalitions of female red howler
monkeys was examined for three populations with different densities and growth rates. Patterns of gene correlation change
within coalitions is documented using data from the mitochondrial and nuclear genomes, and long-term census monitoring. Differences
in fecundity and infant survivorship within and between groups of unrelated (rˉ=0) and related (rˉ≥ 0.25) females are compared. Females that emigrate from their natal groups form coalitions with other migrant females. These
coalitions attempt to establish a territory and, once successful in producing offspring, exclude other females from feeding
resources. Females in these coalitions had different mtDNA haplotypes and a genetically estimated mean r of 0, supporting demographic data on emigration patterns indicating that these females rarely have the opportunity to form
coalitions with kin. Patterns of recruitment and rate of matriline development within social groups supported behavioral data
indicating that females actively attempt to promote their own matriline as breeders over that of other females, and that some
matrilines are more successful at this than others. Mean r among females was significantly higher in coalitions established as social groups for several generations (rˉ=0.44). In these groups, females all shared the same mtDNA haplotype, and mtDNA haplotype divergence was significantly higher
between than within groups. Females in coalitions with kin had significantly higher reproductive success than females in unrelated
coalitions in all populations. This difference was not a function of coalition size, number of males, socionomic sex ratio,
or primiparity, although anecdotal evidence suggests that allomothering may compensate for inept new mothers in related coalitions
more often than in unrelated ones. Differences in territory quality could not be ruled out as a potential causal factor in
the saturated populations, but were unlikely in the low-density, growing population. There were substantial differences among
long-established coalitions in overall reproductive output in all three populations, and this was significantly correlated
with the number of breeding females. Increase in coalition size was a function of both group age and the behavioral tolerance
among females. Regardless of the underlying reasons for the patterns observed, reproductive success clearly increases with
degree of gene correlation among females within cooperative coalitions, and coalitions that recruit more daughters produce
more offspring. The nature of the cooperative relationship among group females directly influences both of these outcomes.
This is associated with substantial genetic differentiation among social groups within populations, creating conditions in
which genetic tendencies towards cooperative behavior can become tightly associated with group reproductive success.
Received: 15 September 1999 / Revised: 27 April 2000 / Accepted: 27 May 2000 相似文献
982.
Characteristics that influence male reproductive success on a lek of Lethrinops c.f. parvidens (Teleostei: Cichlidae) 总被引:1,自引:1,他引:0
Sexual selection has long been proposed as a mechanism leading to the diverse cichlid (Teleostei: Cichlidae) fauna of Lake
Malawi, Africa. Many of the shallow-water, sand-dwelling, bower-building cichlid species are particularly well suited for
studies of sexual selection because they participate in leks. Since females in lekking systems appear to acquire only genetic
material from their mates, it has been suggested that leks are ideal systems to study female mate choice. The objectives of
the investigation were to examine Lethrinops c.f. parvidens male bower characteristics (i.e., bower size and location) as well as other male characteristics (i.e., length, gular color,
and duration on the lek) for their influence on male mating success as measured by the number of visits, circles, and eggs
laid by females. These measures are nested in that a visit by a female may or may not lead to circling, and circling by a
female may or may not lead to egg-laying. We found increased bower height and higher numbers of conspecific neighbors (analogous
to shallow-water, near-shore bower positions) to be positively, significantly associated with the number of visits by females.
The only significant correlate with the number of circles was visits, and similarly circles was the only significant correlate
with the number of eggs laid. The R
2 value for the egg-laying regression was quite low (19.8%) compared with visits (54.3%) and circling (78.9%), suggesting that
females may be using additional cues, that we failed to measure, when in close proximity to males or simply that a small proportion
of the females were ready to spawn. Both indirect selection and direct selection pressure due to egg predation may have influenced
female choice on the lek.
Received: 10 April 1999 / Received in revised form: 26 July 1999 / Accepted: 18 September 1999 相似文献
983.
A recently favored hypothesis is that duetting in birds has a mate-guarding function: a male responds vocally to his partner’s
song, thereby forming a duet that repels males who are attracted to her song. Previous studies have not provided unambiguous
tests of the mate-guarding hypothesis because: (1) the probability of a male answering his partner’s song has not been shown
to increase specifically when the female is fertile, and (2) the probability of a male answering his partner’s song has not
been assessed separately from simply a higher song initiation rate. We investigated extra-pair paternity, mate-guarding, and
duetting in the socially monogamous Australian magpie-lark (Grallina cyanoleuca). DNA fingerprinting revealed that 3% of young were the result of extra-pair paternity, and we found that males guarded fertile
females by staying close to them. However, males did not initiate songs at a higher rate when females were fertile and actually
reduced their probability of replying to female song during this period. We conclude that although male magpie-larks did guard
fertile females in an attempt to prevent extra-pair copulations, they did not use duetting for this purpose.
Received: 10 May 1999 / Received in revised form: 27 September 1999 / Accepted: 2 October 1999 相似文献
984.
Ectoparasites of house sparrows (Passer domesticus): an experimental test of the immunocompetence handicap hypothesis and a new model 总被引:2,自引:0,他引:2
Conspicuous secondary sexual traits may have evolved as handicap-revealing signals or as badges of status. We present results
of an experiment using males of the sexually dimorphic house sparrow (Passer domesticus), that support the idea that the male-specific bib can be both a handicap-revealing signal and a reliable badge indicating
the physical condition of the bird. In a test of the immunocompetence handicap hypothesis, wild-caught adult male house sparrows
were studied in captivity. Birds implanted with elevated doses of testosterone were more dominant, had higher circulating
levels of both testosterone and corticosterone and they also harboured relatively larger ectoparasite loads. Higher parasite
loads were also associated with individuals showing lower immunocompetence and larger changes in bib size. A new model for
immunocompetence effects in sexual selection is introduced, integrating actions that the hypothalamopituitary axis exerts
on gonads, adrenals and the thyroid gland. The ”integrated immunocompetence model” synthesizes both the ”handicap” (i.e. survival-decreasing)
and ”badge of status” (i.e. survival- enhancing) models for evolution of secondary sexual traits.
Received: 15 May 1999 / Received in revised form: 2 November 1999 / Accepted: 6 November 1999 相似文献
985.
Experimental evidence of a testosterone-induced shift from paternal to mating behaviour in a facultatively polygynous songbird 总被引:5,自引:2,他引:3
Previous studies have suggested that testosterone (T) profiles of male birds reflect a trade-off between mate attraction behaviours
(requiring high T levels) and parental care activities (requiring low T levels). In this study, we experimentally elevated
T levels of monogamous males in the facultatively polygynous European starling (Sturnus vulgaris), and compared mate attraction and paternal behaviour of T-treated males with those of controls (C-males). T-males significantly
reduced their participation in incubation and fed nestlings significantly less often than C-males. Females paired to T-treated
males did not compensate for their mate’s lower paternal effort. The observed reduction in a male’s investment in incubating
the eggs was accompanied by an increased investment in typical female-attracting behaviours: T-males spent a significantly
higher proportion of their time singing to attract additional females. They also occupied more additional nestboxes than C-males,
although the differences just failed to be significant, and carried significantly more green nesting materials into an additional
nestbox (a behaviour previously shown to serve a courtship function). T-males also behaved significantly more aggressively
than C-males. During the nestling period, the frequency of mate-attracting behaviours by T-treated and control males no longer
differed significantly. Despite the reduced paternal effort by T-males and the lack of compensation behaviour by females,
hatching and breeding success did not differ significantly between T- and C-pairs.
Received: 7 February 2000 / Revised: 10 August 2000 / Accepted: 3 September 2000 相似文献
986.
Weather-mediated natural selection on arrival time in cliff swallows (Petrochelidon pyrrhonota) 总被引:2,自引:0,他引:2
An unusually long period of cold weather in May 1996 caused extensive mortality among insectivorous cliff swallows (Petrochelidon pyrrhonota) in the northern and central Great Plains. We analyzed how viability selection affected spring arrival time in a migratory
Nebraska population by comparing capture histories of survivors with those of birds known to have died and by documenting
how arrival time changed in the year following the selection event. Surviving birds had significantly later first-capture
dates (an index of arrival time) in the years prior to selection than those that died; a significant selection differential
suggested directional selection for birds that arrived later. Colony sites were occupied significantly later following the
selection event, and the distribution of first-capture dates in the season after selection was significantly shifted toward
later arrivals. Offspring of the survivors tended to arrive later than birds of the same age prior to the selection event.
While major weather-caused mortality events of this magnitude are rare in the study area, spells of cold weather severe enough
to cause limited mortality are frequent in April and early May. At least 25 probable mortality events of varying severity
were identified in the last 50 years based on climatological data. Periodic weather-mediated selection against early arrival
constrains the cliff swallow’s breeding season and may partly prevent directional selection for earlier nesting.
Received: 19 October 1999 / Received in revised form: 15 January 2000 / Accepted: 24 January 2000 相似文献
987.
T. Lubjuhn Wolfgang Winkel Jörg Thomas Epplen Jörg Brün 《Behavioral ecology and sociobiology》2000,48(1):12-17
One of the most interesting aspects of the mating system of pied flycatchers is the regular occurrence of polygyny. Here we
present data on the reproductive success of polygynously paired pied flycatcher males compared to monogamous males based on
paternity analyses through DNA fingerprinting. Males paired with two females suffered a higher loss in reproductive output
per female compared to monogamous males due to (1) a greater proportion of unhatched eggs in their broods, (2) greater nestling
mortality and (3) a greater probability of being cuckolded. Nevertheless, the number of fledglings was significantly greater
for polygynous males. Based on the number of nestlings that returned for subsequent breeding seasons, however, the reproductive
success of monogamous and polygynous males did not differ significantly. These data raise the question as to why males attempt
polygyny.
Received: 16 August 1999 / Received in revised form: 15 March 2000 / Accepted: 18 March 2000 相似文献
988.
989.
990.
Assessing the Geographic Representativeness of Genebank Collections: the Case of Bolivian Wild Potatoes 总被引:5,自引:0,他引:5
R. J. Hijmans K. A. Garrett Z. Huamán D. P. Zhang M. Schreuder M. Bonierbale 《Conservation biology》2000,14(6):1755-1765
Abstract: Genebank collection databases can be used for ecogeographical studies under the assumption that the accessions are a geographically unbiased sample. We evaluated the representativeness of a collection of wild potatoes from Bolivia and defined and assessed four types of bias: species, species-area, hotspot, and infrastructure. Species bias is the sampling of some species more often than others. Species-area bias is a sampling that is disproportionate to the total area in which a species is found. Hotspot bias is the disproportionate sampling of areas with high levels of diversity. Infrastructure bias is the disproportionate sampling of areas near roads and towns. Each of these biases is present in the Bolivian wild potato collection. The infrastructure bias was strong: 60% of all wild potato accessions were collected within 2 km of a road, as opposed to 22%, if collections had been made randomly. This analysis can serve as a guide for future collecting trips. It can also provide baseline information for the application of genebank data in studies based on geographic information systems. 相似文献