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101.
Reproductive isolation and speciation can result from female choice for particular males. Isolation can also result, however, from male mating preferences or from aggressive encounters which then influence mating decisions. In this study, we use laboratory discrimination trials to study the behavioral mechanisms of population discrimination in sagebrush lizards (Sceloporus graciosus). We specifically ask three questions about population-level discrimination: (1) Does it vary in strength in relation to the geographic distance between the populations? (2) Is it more apparent in inter- or intra-sexual interactions? (3) Does it take the form of attraction or avoidance? We ran 890 trials that tested the ability of male and female sagebrush lizards from one population to discriminate their own population from four other populations. In addition, we utilized both sequential and simultaneous-choice designs, which enabled us to distinguish between attraction and avoidance. We found that most population-level discrimination was exhibited by male lizards preferring to associate with particular types of females, as well as female avoidance of particular types of males. The strength and direction of both discriminations depended on the populations compared and on whether the tests were conducted as sequential- or simultaneous-choice tests, producing a complex relationship between geographic distance and behavioral discrimination. Our results suggest that there are roles for male attraction and female avoidance in population discrimination, reproductive isolation, and speciation. 相似文献
102.
实数编码遗传算法的评述 总被引:6,自引:1,他引:6
遗传算法是一种基于自然选择和遗传变异等生物进化机制的全局优化搜索算法.使用实数表示基因的实数编码遗传算法常用于求解连续函数优化等问题.本文阐述了实数编码遗传算法研究的有关工作进展,讨论了算法框架及特点,对实数编码遗传算法中常用的选择、交叉和变异算子进行了比较全面的形式化描述,并介绍了其未来研究方向. 相似文献
103.
Biological markets: supply and demand determine the effect of partner choice in cooperation,mutualism and mating 总被引:12,自引:0,他引:12
The formation of collaborating pairs by individuals belonging to two different classes occurs in the contexts of reproduction and intea-specific cooperation as well as of inter-specific mutualism. There is potential for partner choice and for competition for access to preferred partners in all three contexts. These selective forces have long been recognised as important in sexual selection, but their impact is not yet appreciated in cooperative and mutualistic systems. The formation of partnerships between members of different classes has much in common with the conclusion of trade agreements in human markets with two classes of traders, like producers and consumers, or employers and employees. Similar game-theoretical models can be used to predict the behaviour of rational traders in human markets and the evolutionarily stable strategies used in biological markets. We present a formal model in which the influence of the market mechanism on selection is made explicit. We restrict ourselves to biological markets in which: (1) Individuals do not compete over access to partners in an agonistic manner, but rather by outcompeting each other in those aspects that are preferred by the choosing party. (2) The commodity the partner has to offer cannot be obtained by the use of force, but requires the consent of the partner. These two restrictions ensure a dominant role for partner choice in the formation of partnerships. In a biological market model the decision to cooperate is based on the comparison between the offers of several potential partners, rather than on the behaviour of a single potential partner, as is implicitly assumed in currently accepted models of cooperation. In our example the members of one class A offer a commodity of fixed value in exchange for a commodity of variable value supplied by the other class, B. We show that when the B-class outnumbers the A-class sufficiently and the cost for the A-class to sample the offers of the B-class are low, the choosiness of the A-class will lead to selection for the supply of high value commodities by the B-class (Fig. 3a). Under the same market conditions, but with a high sampling cost this may still be the evolutionariy stable outcome, but another pair of strategies proves to be stable too: relaxed choosiness of class A coupled with low value commodities supplied by class B (Fig. 3b). We give a number of examples of mating, cooperative and mutualistic markets that resemble the low sampling cost situation depicted in Fig. 3a. 相似文献
104.
Kazuki Tsuji 《Behavioral ecology and sociobiology》1994,35(2):109-113
The queenless ant Pristomyrmex pungens has an unusual social structure, in which all workers reproduce parthenogenetically and help others. Laboratory experiments manipulating the proportion of post-reproductive foragers in the colony at various rates suggested that colonies with 5–10% forager ratios had the maximum efficiency per-worker. This result suggests that the cooperative colonies may be maintained by colony-level natural selection. Non-cooperative mutants that oviposit but do not forage should increase in relative frequency in the colony in the short term. However, decreased colony productivity and the resulting competition among colonies might eliminate colonies dominated by such mutants in the long term. P. pungens has a viscous population without migration between colonies, which may facilitate this process. 相似文献
105.
F. Mougeot J. Martínez-Padilla L. Pérez-Rodríguez G. R. Bortolotti 《Behavioral ecology and sociobiology》2007,61(5):741-751
Among the most familiar sexual signals are red, yellow, and orange sexual traits pigmented by carotenoids. Many birds can
detect near-ultraviolet (UV) light, and UV signals can play key roles in mate choice. Grouse (Tetraonidae) exhibit bright
carotenoid-dependent sexual ornaments, their supra-orbital combs, which to humans appear orange-red. Combs also reflect in
the UV, which is not visible to humans but is likely to be visible to grouse. In male red grouse Lagopus lagopus scoticus, we show that comb UV reflectance decreases with increasing comb size and redness. By removing the epidermis of combs, where
carotenoid pigments are, we show that the UV reflectance is a property of the dermis, underneath the red pigmented epidermis.
Carotenoid pigmentation of combs acted as a mask to reduce reflectance by the dermis in the range 400–550 nm and in the UV,
300–400 nm. Patagium skin (non-ornamental skin under the wing) also reflects in the UV, but epidermis removal on this bare
part tended to reduce UV reflectance, whereas removal of the red epidermis of combs increased UV reflectance. Males in better
condition (greater body mass relative to size) had bigger and redder combs, but with less UV. Thus, carotenoid pigments of
grouse combs are deposited on a white background with significant UV reflectance, which can influence how the signal is perceived
by conspecifics. Carotenoid-based traits exhibit UV reflectance in a number of species, but how UV reflectance and carotenoid
pigmentation influence colour remains little known for integumentary ornaments compared to plumage traits. UV vision is not
uncommon in birds and other animals, so future studies should investigate how UV reflectance influences the perception of
carotenoid-based signals of quality. 相似文献
106.
Joel W. McGlothlin Deborah L. Duffy Jessica L. Henry-Freeman Ellen D. Ketterson 《Behavioral ecology and sociobiology》2007,61(9):1391-1399
Sexually selected traits that act as signals of quality often display some degree of condition dependence. In birds, condition
dependence of ornamental plumage is often mediated by production costs related to acquisition or allocation of dietary resources.
White plumage ornaments, however, have often been assumed to be inexpensive because their production requires neither pigment
nor specialized feather structure. In male dark-eyed juncos (Junco hyemalis), the size of a white patch on the tail contributes to attractiveness and mating success. Using captive males, we examined
the effects of diet quality on the size and brightness of the tail-white patch. After removing four tail feathers to induce
replacement, we maintained subjects on a subsistence (low-protein) or enriched (high-protein) diet while induced feathers
grew. Birds that received an enriched diet grew their feathers more quickly and grew larger, brighter white patches. Feather
growth rate was positively correlated with the increase in the size of the tail-white patch, a relationship that was stronger
in the subsistence diet group. However, within diet treatments, faster-grown feathers were slightly duller. Taken together,
these results suggest that variation in diet quality may lead to condition-dependent expression of tail white and that condition
dependence may be stronger in more stressful environments. We suggest a mechanism by which increased feather growth rate may
lead to an increase in the size of the tail-white patch and discuss potential trade-offs between signal size and brightness. 相似文献
107.
Abstract: The Iberian Peninsula harbors about 50% of European plant and terrestrial vertebrate species and more than 30% of European endemic species. Despite the global recognition of its importance, the selection of protected areas has been ad hoc and the effectiveness of such choices has rarely been assessed. We compiled the most comprehensive distributional data set of Iberian terrestrial plant and vertebrate species available to date and used it to assess the degree of species representation within existing protected areas. Existing protected areas in Spain and Portugal reasonably represented the plant and animal species we considered (73–98%). Nevertheless, species of some groups (amphibians, reptiles, birds, and gymnosperms) did not accumulate in protected areas at a rate higher than expected by chance ( p > 0.05). We determined that to conserve all vertebrate and plant species in the Iberian Peninsula, at least 36 additional areas are needed. Selection of additional areas for conservation would be facilitated if such areas coincided with sites of community importance (SCI) designated under the European Commission Habitats Directive. Additional areas required for full representation of the selected plant and animal species all coincide with SCI in Spain. Nevertheless, the degree of coincidence varies between 0.3% and 74.6%, and there is a possibility that important areas for conservation occur outside the SCI. Our results support the view that current SCI can be used for prioritization of areas for conservation, but a systematic reevaluation of conservation priorities in Spain and Portugal would be necessary to ensure that effective conservation of one of European's most important biodiversity regions is achieved. 相似文献
108.
When Good Animals Love Bad Habitats: Ecological Traps and the Conservation of Animal Populations 总被引:15,自引:2,他引:15
JAMES BATTIN† 《Conservation biology》2004,18(6):1482-1491
109.
110.
Recent studies have demonstrated that mating with multiple males can be beneficial for females and her offspring even if males contribute nothing but sperm. This was mainly established for species in which sperm from several males mix in the reproductive tract of the female, thus allowing sperm competition and/or female sperm choice. However, in species with last male sperm precedence, female re-mating decides against the previous male by strongly limiting his reproductive success. We tested the effect of female re-mating behaviour using the cellar spider Pholcus phalangioides, which shows strong last males sperm precedence and moderate levels of polyandry under natural situations. We predicted that females prevented from remating even though they are receptive would show reduced reproductive success compared to females that accept two copulations and females that reject a second male, since the latter two treatments were allowed to behave according to their decisions. However, if the number of matings per se had an effect on oviposition or on offspring performance, double-mated females should perform better compared to both treatments of once-mated females. We measured female fecundity and fertility over a period of 140 days, comparable to the species' natural reproductive peak season. Two thousand one hundred and fifty-two offspring from 67 first egg sacs were reared under two feeding levels. We registered development time and survival, and measured offspring adult size and mass. We found a positive effect of double mating, as in this treatment, oviposition probability was higher compared to the other treatments. Interestingly, adult female offspring of the DM treatment that were raised under low food level had a higher condition index compared to those from FS and RM, but development time, size and mass at adulthood were not affected by mating treatment. Female choice only seemed to affect hatching latency of the offspring. Overall, the main predictor of female reproductive output and success was female body size. 相似文献