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891.
Peter D. Dijkstra Ole Seehausen Boye L. A. Gricar Martine E. Maan Ton G. G. Groothuis 《Behavioral ecology and sociobiology》2006,59(5):704-713
It has been suggested that sympatric speciation can be driven by sexual selection on male mating traits alone. However, a
fundamental problem for this process is the lack of ecological differentiation that would stabilize the coexistence of incipient
species through frequency-dependent selection. Such selection can also occur if male aggression is primarily directed towards
similar rather than towards dissimilar phenotypes, so that rare male phenotypes would enjoy a negatively frequency-dependent
fitness advantage. We experimentally tested such an aggression bias in two recently diverged, ecologically and anatomically
similar sympatric cichlid species pairs of the genus Pundamilia from Lake Victoria. Territorial males of a pair of partially reproductively isolated species with red and blue nuptial coloration,
respectively, studied in the laboratory were confronted simultaneously with both colour types enclosed in transparent tubes.
Red males were more aggressive to red stimuli under white light but not when colour differences were masked under green light.
Blue males were equally aggressive to both stimuli in both light conditions. Males of two apparently fully reproductively
isolated species, again one with red and one with blue nuptial coloration, studied in the field, both directed more aggressive
behaviour towards conspecific than towards heterospecific stimulus males. The differential allocation of aggression would
create an advantage for males of the less abundant phenotype or species, thereby potentially supporting stable coexistence
of the phenotypes. The finding that this effect was less clear in the partially reproductively isolated species pair than
in the fully isolated species pair is discussed. 相似文献
892.
Bart Kempenaers G. R. Verheyen André A. Dhondt 《Behavioral ecology and sociobiology》1995,36(1):33-42
This study investigates the importance of mate guarding for males and females in the facultatively polygynous blue tit Parus caeruleus. We present observational data in combination with a paternity analysis using DNA fingerprinting to show that (1) male blue tits guard their mate, since they stay closer to their mate, initiate fewer flights and follow their mate more often during the female's presumed fertile period; (2) polygynous males do not suffer more from lost paternity despite lower mate guarding; (3) in monogamous pairs there is either no relation or a positive relation (depending upon the variable measured) between measures of mate guarding intensity and the proportion of extra-pair young in the nest; and (4) monogamous males that are more often followed by their fertile female suffered less from lost paternity. We conclude that, despite mate guarding, paternity seems to be largely under female control and unattractive males guarding their mate are making the best of a bad situation. Experimental evidence is provided showing that when males were temporarily removed from their territory, their mate suffered from increased harassment from neighbouring males that intruded in the territory and tried to copulate with the female. Almost all of these copulation attempts were unsuccessful because females refused to copulate. We conclude that mate guarding may be beneficial for females because harassment by neigbouring males is prevented. 相似文献
893.
We examine the evolutionary consequences of copying mate choice using models in which the preferences of younger females are affected by the mate choices that they observe older females making. We introduce two models of copying, termed single mate copying and mass copying, corresponding to situations in which immature females imprint on the choices of only one or of a very large number of older females, respectively. Female mating preferences are assumed to evolve only through cultural evolution, while the male trait on which they act is inherited either via a haploid autosomal or a Y-linked locus. Results show that the preference and male trait can rapidly coevolve, with a positive frequencey-dependent advantage to the more common male trait allele. This process can cause a display trait that lowers male viability to increase in a population. Mass copying results in stronger frequency dependence than does single mate copying. Mass copying and, under some conditions, single mate copying lead to two alterative stable equilibria for the male trait. Neither copying model supports variation at the male trait locus, and copying makes it more difficult for a novel male trait phenotype to spread.
Correspondence to: M. Kirkpatrick 相似文献
894.
Hanna Kokko 《Behavioral ecology and sociobiology》1997,41(2):99-107
In various models of sexual selection mediated by the viability indicator (“good genes”) mechanism, a sexually selected trait
will truly reflect male quality if its expression is costly for the male. However, in long-lived species, the expression of
a trait often increases with age while the genotype of the male remains unchanged. This fact may obscure the indicator mechanism.
Hitherto, game theory models of honesty in sexual advertisement have not taken life-history effects into account, whereas
life-history models of reproductive effort have only seldom considered the dependence of mating success on the actions of
other individuals. Here, the two approaches are combined, and I examine whether honesty is maintained if males can divide
their advertisement effort over their lifetime. The model shows that an increase in the expression of the sexually selected
trait over several years is an evolutionarily stable strategy (ESS) under a wide range of situations, so that a correlated
preference for old age can emerge through a viability indicator mechanism. Honesty in the strict sense is not preserved: an
optimally behaving low-quality male will in some cases advertise more than a high-quality male of equal age, to the extent
that the strongest advertisement found in the population can be associated with a low-quality male. Due to life-history trade-offs,
however, honesty in an average sense holds true over the lifetime of individuals: “cheater” age classes will remain small
enough, that a female will obtain a higher expected mate quality if she trusts in the trait as an indicator of viability.
Received: 25 June 1996 / Accepted after revision: 15 April 1997 相似文献
895.
A. Peters K. Delhey W. Goymann B. Kempenaers 《Behavioral ecology and sociobiology》2006,59(5):666-673
The proximate basis of sexual traits can suggest mechanisms maintaining honesty in signalling. A central role hereby has been
attributed to testosterone, although its importance for brightly coloured plumage has been questioned. We determined circulating
testosterone levels in male blue tits captured at the start of breeding and demonstrated an age-dependent relationship between
testosterone and male crown UV/blue coloration. In yearling males, testosterone increases with increasing ornamentation (higher
UV chroma, higher chroma, more UV-shifted hue), whereas in older males, this relationship is negative, with less UV-ornamented
males having higher testosterone. This pattern is robust since it occurred in 2 years, before and after egg laying, and in
males sampled during the day and during the night, despite a tenfold difference in testosterone levels. Since more UV-ornamented
young males gain higher within-pair paternity, while less UV-ornamented older males achieve more extra-pair matings, the results
imply that higher testosterone is associated with reproductive success and attractiveness in both age classes. We hypothesise
that this relationship could result from causal effects of testosterone on coloration or through associations with behaviour
and suggest ways to test these hypotheses. Our results caution against premature dismissal of a potential role for testosterone
in maintaining honesty of plumage signals. 相似文献
896.
To maximize reproductive success, reproductive behaviors have to be adjusted to environmental conditions. The breeding habitats
of the threespine stickleback Gasterosteus aculeatus are presently changing in the Baltic Sea due to eutrophication and enhanced growth of filamentous green algae. Earlier studies
show that high algae density reduces mate encounter rate and the intensity of selection on a few sexually selected traits,
but the willingness of males to nest under the new conditions, and their investment into reproduction, have not been investigated.
Here, we investigated the effect that increased algae growth has on nesting behavior of sticklebacks. We allowed males to
build nests in aquaria with either a sparse or a dense vegetation structure and recorded male nest building behavior and nest
characters. Males that nested in dense vegetation showed a longer latency before commencing nest building and also completed
nest building later since there was no difference in time spent building. There was no effect of vegetation cover on nest
characters. These results suggest that males prefer to nest in sparser vegetation, but that they eventually nest in dense
vegetation if more open habitats are not available. This may arise from a negative effect of vegetation on visibility and
mate encounter rate and thus on expected reproductive success. This implies that human-induced changes in the environment
may force sticklebacks to breed in non-preferred habitats. Since the intensity of sexual selection is reduced in these areas,
this could influence the further evolution of the population. 相似文献
897.
898.
A Synthesis of Marine Conservation Planning Approaches 总被引:3,自引:1,他引:3
HEATHER M. LESLIE† 《Conservation biology》2005,19(6):1701-1713
899.
David?R.?TarpyEmail author David?C.?Gilley Thomas?D.?Seeley 《Behavioral ecology and sociobiology》2004,55(6):513-523
The extended phenotype of a social insect colony enables selection to act at both the individual level (within-colony selection) and the colony level (between-colony selection). Whether a particular trait persists over time depends on the relative within- and between-colony selection pressures. Queen replacement in honey bee colonies exemplifies how selection may act at these different levels in opposing directions. Normally, a honey bee colony has only one queen, but a colony rears many new queens during the process of colony reproduction. The replacement of the mother queen has two distinct phases: queen rearing, where many queens develop and emerge from their cells, and queen elimination, where most queens die in a series of fatal duels. Which queens are reared to adulthood and which queens ultimately survive the elimination process depends on the strength and direction of selection at both the individual and colony levels. If within-colony selection is predominant, then conflict is expected to occur among nestmates over which queens are produced. If between-colony selection is predominant, then cooperation is expected among nestmates. We review the current evidence for conflict and cooperation during queen replacement in honey bees during both the queen rearing and queen elimination phases. In particular, we examine whether workers of different subfamilies exhibit conflict by acting nepotistically toward queens before and after they have emerged from their cells, and whether workers exhibit cooperation by collectively producing queens of high reproductive quality. We conclude that although workers may weakly compete through nepotism during queen rearing, workers largely cooperate to raise queens of similar reproductive potential so that any queen is suitable to inherit the nest. Thus it appears that potential conflict over queen replacement in honey bees has not translated into actual conflict, suggesting that between-colony selection predominates during these important events in a colonys life cycle.Communicated by A. Cockburn 相似文献
900.
Abstract: Conspecific attraction, the tendency for individuals of a species to settle near one another, is well described in colonial species, especially birds. Although this behavior may occur in territorial birds, evidence has been lacking. If territorial birds do exhibit this behavior, it would have major conservation implications. Birds could potentially be attracted to specific sites with artificial stimuli, making conservation of those species more efficient. In 2001 and 2002, we tested whether conspecific attraction occurs in an endangered, territorial songbird, the Black-capped Vireo ( Vireo atricapilla ) by playing vireo vocalizations in unoccupied habitats at Fort Hood, Texas. We were successful in attracting 73 birds to five experimental sites in 2001 and 75 birds to seven experimental sites in 2002. No birds settled on comparable control sites. Many birds attracted to the vocalizations paired and bred. At most research sites the primary threat to the species, the brood-parasitic Brown-headed Cowbird ( Molothrus ater ), was controlled, allowing vireos to achieve high nesting success relative to a nearby, unmanipulated population. Second-year birds were more responsive to conspecific vocalizations than older birds, as they were more common on experimental sites than in the established population. In 2002 birds recolonized experimental sites from 2001 where vocalizations were not played in 2002, indicating that 1 year of playbacks may be sufficient to establish a population. Our results provide the first experimental evidence that territorial songbirds use the presence of conspecifics when deciding where to settle and suggest that conspecific attraction may provide a valuable conservation tool. 相似文献