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661.
Male European starlings Sturnus vulgaris sing long complex songs that appear to be important in the courtship of females but which also influence competitive interactions
between males. We tested the hypothesis that females choose mates on the basis of the complexity of their songs, rather than
on the quality of the territories the males defended. In order to determine whether certain territories were preferred over
others, the first set of birds to settle in the experimental nest-boxes was removed and a second set allowed to settle. Consistent
preferences for certain nest-boxes were indicated by correlations between the settlement patterns of the first and second
sets of birds. However, males with the most complex song did not necessarily occupy the most preferred nest sites. Males with
more complex song acquired mates faster. This relationship remained significant when nest-site preference was statistically
controlled, indicating that female starlings chose males with complex song rather than those that defended preferred nest
sites. A number of morphological variables were also found to be uncorrelated with female choice. Song complexity in European
starlings increases with age, and the evolution of song complexity in this species is consistent with an age-indicator model
of sexual selection. Males with larger repertoires were also in better condition, indicating that females obtain high-quality
mates by choosing on the basis of male song.
Received: 29 April 1995/Accepted after revision: 9 September 1995 相似文献
662.
C. Macías Garcia Georgina Jimenez Beatriz Contreras 《Behavioral ecology and sociobiology》1994,35(4):253-259
Handicap models of sexual selection predict that ornaments must be costly to produce and/or to wear and maintain; only then can they evolve as reliable signals of genetic quality. We investigated in the laboratory one potential cost of possessing ornaments, using the viviparous fish Girardinichthys multiradiatus and its natural predator, the snake Thamnophis melanogaster. We found that female G. multiradiatus show preferences for males with larger fins, as measured from body correlates. Males with a morphology attractive to females, however, were more likely to be captured by snakes than were other males (Fig. 5). Greater vulnerability to snakes cannot be explained as a result of snake visual preferences, because snakes responded similarly to males and females (Fig. 6). Finally, males, particularly dominant ones, were more likely to inspect foraging snakes than were females (Fig. 7). We conclude that male Girardinichthys multiradiatus experience a sexually-selected handicap due to reduced mobility resulting from having enlarged fins. 相似文献
663.
密切值法在污水土地处理工程选址中的应用 总被引:4,自引:0,他引:4
本文对密切值法在污水土地处理工程选址中的应用进行了探讨,通过实例分分析看出该方法科学可行且简易。 相似文献
664.
A differential equation was employed in modelling deforestation by human population interactions to yield an explicit mathematical model. The theoretical relation and many possible models were applied to the grid cell data in Hiroshima Prefecture, and relative appropriateness of each model was evaluated by Akaike's information criterion (AIC) using raw data. Intensive further verification was executed bythe bootstrap method. It was demonstrated that the theoretical relation was in the best agreement among many other models in comparison. 相似文献
665.
Costs of searching for a mate are an important component of models of sexual selection, yet they have rarely been examined in wild populations of vertebrates. In this paper, we report an experiment in which we handicapped female tree swallows by clipping some flight feathers. This manipulation increased the costs of flight and searching for extra-pair mates. Despite these costs, handicapped females had the same level of extra-pair mating (percentage of extra-pair young, percentage of broods with extra-pair young, and the number of extra-pair sires per brood) as control females. However, handicapped females were more likely to have young sired by extra-pair males that lived closer to her nest than control females. This change in the distribution of extra-pair mating was most likely due to female choice rather than male coercion, and it suggests that extra-pair mating has significant benefits to females. One important implication of our study is that ecological and social factors that influence search costs could affect the spatial distribution of extra-pair sires and, consequently, the intensity of sexual selection. These effects may have been overlooked in previous studies that did not identify extra-pair sires. 相似文献
666.
Troy G. Murphy 《Behavioral ecology and sociobiology》2007,61(6):911-918
Both males and females of many avian species maintain elaborate plumage traits, and elaborate monomorphic plumage may convey
adaptive benefits to one or both sexes as inter- or intraspecific signals. Both sexes of the turquoise-browed motmot (Eumomota superciliosa) are elaborately plumed with long racket-tipped tail. I investigated whether the racketed tail functions as a sexually selected
signal in one or both sexes by testing the predictions that males and/or females with the largest tails have: (1) greater
pairing success, (2) greater reproductive performance (clutch-initiation date, clutch size, and hatching success), and (3)
greater reproductive success. Yearling males with longer denuded rachises (wires) on the central tail feathers had greater
pairing success. In addition, adult males with longer wires paired with females who laid larger clutches, had greater hatching
success independent of clutch size, and fledged more young. There was no relationship between female tail plumage and pairing
success, reproductive performance, or fledgling success. These results are consistent with the hypothesis that male tail plumage
functions as a mate choice or status signal, but that the tail of the female does not function in a sexually selected context.
I discuss alternative hypotheses for the evolutionary maintenance of the elaborate female tail plumage. 相似文献
667.
Kathrin P. Lampert Ximena E. Bernal A. Stanley Rand Ulrich G. Mueller Michael J. Ryan 《Behavioral ecology and sociobiology》2006,59(6):796-804
In most sexually reproducing animals, the behavior of one or both sexes during courtship critically influences the success
at mating of the opposite sex. This behavior is often interpreted as “mate choice,” and there is great interest in why such
choices are exercised. The explanation for the evolution of mate choice that has received the most attention and generated
the most controversy is based on assumed genetic effects. In this study, we investigated whether female túngara frogs, which
choose mates based on acoustic cues, have a preference for genetically less related males. Specifically, we determine if there
is disassortive mating based on microsatellite markers, if there is information in the advertisement call that could be used
to assess genetic similarity, and if females exhibit acoustic-based mating preferences that would promote choice for genetic
diversity. Using seven microsatellite markers, we found no correlation of male call similarity and male genetic relatedness.
Female choice experiments showed no female preference for calls of less related males, and there was no evidence for inbreeding
avoidance in the field. Our results do not support the hypothesis of mate choice based on information about genetic relatedness
conveyed by acoustic signals in túngara frogs. 相似文献
668.
Family insurance: kin selection and cooperative breeding in a solitary primate (Microcebus murinus) 总被引:1,自引:0,他引:1
Lactation imposes substantial physiological costs on mothers and should therefore not be directed towards foreign offspring. Such allonursing, however, is common in mammal species that share roosts. Hypotheses to explain allonursing among such plural breeders include misdirected parental care, milk evacuation, brood parasitism, reciprocity, and kin selection. The necessary behavioral data, in combination with data on kinship and kin recognition, have rarely been available to distinguish among these explanations, however. In this study, we provide evidence for cooperative nursing and adoption by plural-breeding females in a nocturnal primate, the gray mouse lemur (Microcebus murinus), in which females forage solitarily during the night, but form day-time sleeping groups with one to two other females. We observed 34 resident females in an 8 ha study area in Kirindy Forest, Madagascar, over three consecutive annual breeding seasons and determined genetic relationships among all members of this population. Five sleeping groups of adult females were filmed inside their roosts during one breeding season after females gave birth. The composition of groups changed substantially across years, but they always consisted of close maternal relatives. All females within a group gave birth to one to three infants. They regularly transferred only their own offspring among roosting sites, demonstrating an ability to discriminate between their own and other’s offspring, but they regularly groomed and nursed related offspring other than their own and adopted related dependent young after their mother’s death. Kin selection may therefore be the main selective force behind cooperative breeding among these closely related females with a high mortality risk, providing each of them with family insurance. 相似文献
669.
Martin?PlathEmail author Jakob?Parzefall Kay?E.?K?rner Ingo?Schlupp 《Behavioral ecology and sociobiology》2004,55(6):596-601
In many species, females prefer large males as mating partners. Male size can easily be determined visually. We examined how such mate choice evolves when individuals are deprived of sensory information previously used to determine male quality. Using a cave-dwelling population of Atlantic mollies, Poecilia mexicana, as a model, we asked whether the female mating preference for large male body size still occurs in this cave fish, or whether it is lacking due to the absence of visual communication in the cave environment. In simultaneous choice tests we compared the time females spent with a large or a small male. In the river-dwelling and cave-dwelling fish, as well as the population originating from the cave entrance, we found a significant preference for large males in light. Hence, the ancestral mating preference of surface-dwelling mollies has been maintained during the evolution of the cave form. However, only the cave population exhibited a mating preference in darkness. Determination of male body size appears to have been taken over by a non-visual sensory system, probably the lateral line.Communicated by K. Lindström 相似文献
670.
Ornamentation predicts reproductive success in female pipefish 总被引:5,自引:0,他引:5
Anders Berglund Gunilla Rosenqvist Patricia Bernet 《Behavioral ecology and sociobiology》1997,40(3):145-150
In the sex-role reversed pipefish Syngnathus typhle females compete for access to males and males are choosy. Females develop a temporary ornament when competing over mates
with other females and when performing nuptial dances with males. This ornament is an amplification of the normal striped
pattern in these fishes. We here show experimentally that (1) the contrast of this normal pattern forecasts the extent to
which the ornament is shown, (2) contrast and ornamentation honestly signal female quality (egg numbers), (3) contrast and
ornamentation accurately predict female mating success, (4) contrast is a phenotypically plastic trait specifically exaggerated
under situations of female – female competition, and (5) neither contrast nor ornament are energetically expensive to the
females (i.e., they are independent of short-term nutritional status). Hence, as predicted in sex-role reversed species, ornament
design is constrained by costs to female fecundity: an energetically demanding ornament would impair on a female's ability
to produce eggs. The type of ornament described here is the expected one, costly for reasons other than being energetically
expensive to produce.
Received: 4 April 1996 / Accepted after revision: 27 October 1996 相似文献