首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   17篇
  完全免费   5篇
  2019年   1篇
  2017年   2篇
  2014年   1篇
  2013年   1篇
  2012年   4篇
  2011年   1篇
  2010年   1篇
  2009年   3篇
  2007年   1篇
  2006年   2篇
  2003年   1篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1997年   1篇
排序方式: 共有22条查询结果,搜索用时 102 毫秒
1.
The evolution of obligate interspecific brood parasitism in birds   总被引:2,自引:1,他引:1  
We present a simple analytical model to investigate the conditionsfor the evolution of obligate interspecific brood parasitismin birds, based on clutch size optimization, when birds canlay more eggs than their optimal clutch size. The results showthat once intraspecific parasitism has appeared (i.e., femalesstart to spread their eggs over their own and other nests) the evolutionarily stable number of eggs laid in its own nest decreases.Two possible ESSs exist: (1) either the evolutionarily stablenumber of eggs laid in its own nest is larger than zero, anda fraction of the total number of eggs is laid parasitically(i.e., intraspecific parasitism); and (2) either the evolutionarilystable number of eggs laid in its own nest is zero and all eggs are laid parasitically. Since all females lay parasitically,this could favor the evolution of obligate interspecific broodparasitism. The key parameter allowing the shift from intraspecificto obligate interspecific parasitism is the intensity of density-dependentmortality within broods (i.e., nestling competition). Strongnestling competition, as in altricial species, can lead toan ESS where all eggs are laid parasitically. Altricial speciesare, therefore, predicted to evolve more easily toward obligate interspecific parasitism than precocial species. These predictionsfit the observed distribution of brood parasitism in birds,where only one species out of 95 obligate interspecific parasitesexhibits a precocial mode of development. Different nestlingsurvival functions provided similar findings (i.e., obligatebrood parasitism is more likely to evolve in altricial species),suggesting that these results are robust with respect to themain assumption of the model.  相似文献
2.
鹰鹃在橙翅噪鹛巢中寄生繁殖   总被引:1,自引:1,他引:0       下载免费PDF全文
2011年和2012年每年的5月到8月,在甘肃莲花山地区共发现了5例鹰鹃(Hierococcyx sparverioides)在橙翅噪鹛(Garrulax elliotii)巢中寄生繁殖的案例.鹰鹃卵为椭圆形,浅蓝色,卵壳上没有斑点.测量了其中2枚卵,卵重分别为6.9g和7.2g,长径×短径分别为29.76 mm×20.40 mm和28.40mm×21.68 mm.鹰鹃幼鸟在出壳后的第20天离巢.  相似文献
3.
Poysa  Hannu 《Behavioral ecology》2006,17(3):459-465
Conspecific nest parasitism (CNP) is a widespread alternativereproductive tactic in birds. Several hypotheses have been putforward to explain the evolution and occurrence of CNP, butno generally applicable hypothesis exists. Recent experimentalresults from the common goldeneye (Bucephala clangula), a cavity-nestingduck, have revealed that parasitic females preferentially layeggs in safe nest-sites, implying that nest predation risk isan important ecological determinant of CNP. The present studyfocuses on the mechanisms by which parasites identify safe nest-sites.Predation risk of a given nest-site was predictable betweensuccessive breeding seasons. At the end of the nesting season,females prospected active nest-sites more frequently than nest-sitesthat did not have a nest in the current season. Nest-sites thathad been prospected more frequently by females in year t hada higher probability to be parasitized in year t + 1. The resultssuggest that the use of public information, derived throughnest-site prospecting, enabled parasites to target safe nests.These findings provide a new and potentially generally applicableperspective to understand the evolution and occurrence of CNP.  相似文献
4.
Preferences by parasites for particular hosts may have important implications for the functioning of host–parasite systems, however, this parasitic life-history trait remains little studied. No detrimental effect of Louse Fly Crataerina pallida parasitism has been found on Common Swift Apus apus nestling hosts. Host selection choices may be mediating the effect this parasite has and account for this apparent avirulence. Two aspects of parasite host selection were studied at a breeding colony of Common Swifts during 2008; (1) intra-brood differences in C. pallida parasitism were studied to determine the influence of nestling rank, (2) differences in male and female C. pallida parasitism were investigated, as they may result in varying costs of parasitism to hosts. C. pallida populations were found to preferentially parasitize higher rather than lower ranking nestlings within broods of both two and three chicks. Greater proportions of females were seen upon nestlings than at the nest, and upon higher ranking than lower ranking nestlings within broods. These results indicate that host selection occurs and this may thus account for the lack of parasitic virulence reported within this host–parasite system.  相似文献
5.
6.
The intensity of biotic interactions varies around the world, in such a way that mortality risk imposed by natural enemies is usually higher in the tropics. A major role of offspring attendance is protection against natural enemies, so the benefits of this behaviour should be higher in tropical regions. We tested this macroecological prediction with a meta‐regression of field experiments in which the mortality of guarded and unguarded broods was compared in arthropods. Mortality of unguarded broods was higher, and parental care was more beneficial, in warmer, less seasonal environments. Moreover, in these same environments, additional lines of defence further reduced offspring mortality, implying that offspring attendance alone is not enough to deter natural enemies in tropical regions. These results help to explain the high frequency of parental care among tropical species and how biotic interactions influence the occurrence of parental care over large geographic scales. Finally, our findings reveal that additional lines of defences – an oftentimes neglected component of parental care – have an important effect on the covariation between the benefits of parental care and the climate‐mediated mortality risk imposed by natural enemies.  相似文献
7.
2010年4~8月在甘肃安西极旱荒漠国家级自然保护区,采用样点法对荒漠伯劳(Lanius isabellinus isabellinus)的繁殖生态进行了研究,采用单因素方差分析(ANVON)对荒漠伯劳卵体积与卵序之间的关系进行了研究,用二元Logistic回归对雏鸟生长曲线进行拟合。结果表明,荒漠伯劳的繁殖时间为4月底至8月初,每巢产卵3~6枚,平均窝卵数为4.67±0.57(n=21),卵体积为(3.14±0.32)cm3(n=95),卵鲜重(3.48±0.20)g(n=20),卵体积随着产卵顺序显著减小(R=-0.427,P=0.021,n=29),其采取的是"窝雏减少"的繁殖策略。雌鸟产首枚卵后即开始孵卵,雄鸟负责情饲及警戒。温度自动记录仪测量平均孵卵温度为(38.19±0.77)℃(n=2),雌鸟在巢率为93.95%。平均孵卵时间为(15.33±0.52)d(n=6)。荒漠伯劳雏鸟留巢期12~15 d,幼鸟离巢后亲鸟继续饲喂幼鸟,整个育雏期最长达31 d。研究地区荒漠伯劳种群的孵卵率为82.50%(n=80),卵成功率为46.25%(n=80),雏鸟离巢率为56.06%(n=66),巢成功率58.62%(n=29)。在2010年环志标记的12对繁殖鸟中只有1对繁殖了第二窝。  相似文献
8.
The parasitic relationship between a black fly, Simulium annulus, and the common loon (Gavia immer) has been considered one of the most exclusive relationships between any host species and a black fly species. To test the host specificity of this blood‐feeding insect, we made a series of bird decoy presentations to black flies on loon‐inhabited lakes in northern Wisconsin, U.S.A. To examine the importance of chemical and visual cues for black fly detection of and attraction to hosts, we made decoy presentations with and without chemical cues. Flies attracted to the decoys were collected, identified to species, and quantified. Results showed that S. annulus had a strong preference for common loon visual and chemical cues, although visual cues from Canada geese (Branta canadensis) and mallards (Anas platyrynchos) did attract some flies in significantly smaller numbers.  相似文献
9.
We examined the rate of parasitism and sex ratio of the cuckoo wasp Chrysura hirsuta (Gerstaecker) (Hymenoptera: Chrysididae) that emerged from nests of the mason bee Osmia orientalis Benoist (Hymenoptera: Megachilidae) in Nara, Japan. Nests of O. orientalis were found in empty shells of two snail species, Satsuma japonica (Pfeiffer) and Euhadra amaliae (Kobelt). The percentage of parasitism by cuckoo wasps per all collected cocoons tended to be high (20–50%) even though interannual variation and the average number of cocoons per nest did not differ across snail shell species within each year. Our results from three years of observation, combined with previous reports, showed that the adult sex ratio of C. hirsuta was strongly female‐biased, which suggests that the species reproduces by thelytokous parthenogenesis.  相似文献
10.
Nest predation limits avian fitness, so ornithologists study nest predation, but they often only document patterns of predation rates without substantively investigating underlying mechanisms. Parental behavior and predator ecology are two fundamental drivers of predation rates and patterns, but the role of parents is less certain, particularly for songbirds. Previous work reproduced microhabitat‐predation patterns experienced by Yellow Warblers (Setophaga petechia) in the Mono Lake basin at experimental nests without parents, suggesting that these patterns were driven by predator ecology rather than predator interactions with parents. In this study, we further explored effects of post‐initiation parental behavior (nest defense and attendance) on predation risk by comparing natural versus experimental patterns related to territory density, seasonal timing of nest initiation, and nest age. Rates of parasitism by Brown‐headed Cowbirds (Molothrus ater) were high in this system (49% nests parasitized), so we also examined parasitism‐predation relationships. Natural nest predation rates (NPR) correlated negatively with breeding territory density and nonlinearly (U‐shaped relationship) with nest‐initiation timing, but experimental nests recorded no such patterns. After adjusting natural‐nest data to control for these differences from experimental nests other than the presence of parents (e.g., defining nest failure similarly and excluding nestling‐period data), we obtained similar results. Thus, parents were necessary to produce observed patterns. Lower natural NPR compared with experimental NPR suggested that parents reduced predation rates via nest defense, so this parental behavior or its consequences were likely correlated with density or seasonal timing. In contrast, daily predation rates decreased with nest age for both nest types, indicating this pattern did not involve parents. Parasitized nests suffered higher rates of partial predation but lower rates of complete predation, suggesting direct predation by cowbirds. Explicit behavioral research on parents, predators (including cowbirds), and their interactions would further illuminate mechanisms underlying the density, seasonal, and nest age patterns we observed.  相似文献
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号