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1.
Christopher N. Anderson Gregory F. Grether 《Proceedings. Biological sciences / The Royal Society》2010,277(1700):3669-3675
Aggression between species is a seldom-considered but potentially widespread mechanism of character displacement in secondary sexual characters. Based on previous research showing that similarity in wing coloration directly influences interspecific territorial aggression in Hetaerina damselflies, we predicted that wing coloration would show a pattern of character displacement (divergence in sympatry). A geographical survey of four Hetaerina damselfly species in Mexico and Texas showed evidence for character displacement in both species pairs that regularly occurs sympatrically. Hetaerina titia, a species that typically has large black wing spots and small red wing spots, shifted to having even larger black spots and smaller red wing spots at sites where a congener with large red wing spots is numerically dominant (Hetaerina americana or Hetaerina occisa). Hetaerina americana showed the reverse pattern, shifting towards larger red wing spots where H. titia is numerically dominant. This pattern is consistent with the process of agonistic character displacement, but the ontogenetic basis of the shift remains to be demonstrated. 相似文献
2.
The biting midge Culicoides sonorensis Wirth and Jones (Diptera: Ceratopogonidae) transmits pathogens to both livestock and wildlife. Biting midge surveillance relies heavily on light traps for collection; however, little is known about the light spectra preferences of C. sonorensis midges. A light assay arena was constructed and light‐emitting diodes (LEDs) of various light spectra were used as light sources to evaluate midge photoattraction. A comparison of responses to light spectra indicated the highest proportions of C. sonorensis were attracted to ultraviolet (UV) light and that midges differentiated 10‐nm differences in wavelength. Stronger intensities of UV light resulted in greater attraction. Midges exhibited both sugar‐seeking and escape behaviours under different conditions of sugar supplementation before and during the experiment. These behaviours occurred with lights of 355 nm and 365 nm in wavelength. Based on the results of this study, the attraction of C. sonorensis to light traps can be improved through the use of bright LEDs at 355 nm or 365 nm. 相似文献
3.
In many ecological situations, resources are difficult to find but become more apparent to nearby searchers after one of their numbers discovers and begins to exploit them. If the discoverer cannot monopolize the resources, then others may benefit from joining the discoverer and sharing their discovery. Existing theories for this type of conspecific attraction have often used very simple rules for how the decision to join a discovered resource patch should be influenced by the number of individuals already exploiting that patch. We use a mechanistic, spatially explicit model to demonstrate that individuals should not necessarily simply join patches more often as the number of individuals exploiting the patch increases, because those patches are likely to be exhausted soon or joining them will intensify future local competition. Furthermore, we show that this decision should be sensitive to the nature of the resource patches, with individuals being more responsive to discoveries in general and more tolerant of larger numbers of existing exploiters on a patch when patches are resource-rich and challenging to locate alone. As such, we argue that this greater focus on underlying joining mechanisms suggests that conspecific attraction is a more sophisticated and flexible tactic than currently appreciated. 相似文献
4.
Wenjun Geng Jinggong Xiangyu Xiuzhen Li Zhongning Zhang Deyuan Han Yongwei Li 《Insect Science》1997,4(4):364-368
Abstract Field trials by sex pheromone of aphid to trap peach aphids Myzus persicae have been carried out in 1995 and in 1996. Suitable time and the effect of ratio of two components nepetalactone and nepetalactol to apply the lure have been observed. 相似文献
5.
Nancy C. Pratt Allison C. Alberts Kathryn G. Fulton-Medler John A. Phillips 《Zoo biology》1992,11(3):153-163
This study investigated the morphological, physiological, and behavioral components of social dominance important for mate attraction in male green iguanas (Iguana iguana). A group of 9 male and 11 female adult green iguanas was studied in a large semi-natural enclosure during one reproductive season (October–January). Four of the nine males never initiated aggressive encounters; the other five were observed to display aggressively toward each other and were ranked in a linear dominance hierarchy. Head size was the most important factor influencing fighting success. Head size and display frequency were positively correlated with plasma testosterone levels. Dominance rank directly influenced ability to monopolize areas containing resources used by females. The quality of a male's home range, measured as his access to a large basking rock in the enclosure, was related to the proportion of potential mates found within his home range. One male greatly surpassed the others in his ability to defend a home range of high quality and attract potential mates. These data suggest that physiological and morphological factors, through their influence on social behavior, may ultimately affect male reproductive fitness. © 1992 Wiley-Liss, Inc. 相似文献
6.
Susan M. McLernon Stephen D. Murphy Lonnie W. Aarssen 《American journal of botany》1996,83(9):1168-1174
The cumulative (season-long) incidence of heterospecific pollen transfer (HPT) was examined using nine sympatric species in a midsuccessional old field. Inflorescences were collected weekly during the flowering season, and the proportion of foreign pollen/stigma was recorded. Flowering phenologies of sympatric species and ovule and seed counts of study species were also recorded. Heterospecific pollen was detected on some stigmas of each species. Medicago sativa (Fabaceae) received the most foreign pollen; in some cases, all of the grains on a stigma were heterospecific. Lotus corniculatus (Fabaceae) received the least amount of foreign pollen; the incidence of heterospecific pollen was near zero in most cases. The mean and range of foreign pollen received varied by as much as an order of magnitude between species. The six species with zygomorphic flowers, all Fabaceae, received more heterospecific pollen than the three species with actinomorphic flowers, Potentilla recta and P. simplex (Rosaceae) and Ranunculus acris (Ranunculaceae). This probably reflects a bias because our data were analyzed on a cumulative basis and the Fabaceae had longer flowering phenologies. HPT was not correlated with the species' relative abundance within the community. Proportion of foreign pollen received varied temporally within species, and this variation generally was not related to phenology of any sympatric taxa or the species' own phenology. Pollen grain diameter was positively related to levels of foreign pollen received by species. This might be caused by poor adhesion of large pollen grains to small stigmatic papillae or if generalist pollinators carrying large amounts of heterospecific pollen visit the large-grained species and specialists with little foreign pollen visit the small-grained species. The large proportions of heterospecific pollen on stigmas of many species indicate that HPT occurs frequently in the community we studied and the implications may include reduced seed set because of occlusion by foreign grains. As yet, however, it is unclear how important a factor HPT is in mediating pollen limitation of reproductive success. 相似文献
7.
The snare web is used as a medium for communication betweenindividuals within colonies of social spiders and has thereforebeen suggested as necessary for the evolution of sociality inthe Araneae. The social spider Diaea socialis (Thomisidae) isan exception because it does not build a snare web. Experimentsdemonstrate that silk attracts all spiders and that a chemicaldeposited onto the silk attracts adult female spiders, suggestingthat the group living of this species is mediated by a pheromone.The pheromone attracts spiders differentially: females are notattracted to juvenile silk, and it repels gravid females. Thepheromone appears to be stable but volatile, is ether-soluble,and retains its viability after dissolution. Molecular-ionicmasses for 7-8 different compounds were found in the range 220281atomic units; the pheromone may be one or a combination of severalof these. 相似文献
8.
具有节点偏置的高阶神经网络模型 总被引:1,自引:0,他引:1
在汪涛文献基础上提出了一个具有节点偏置的高阶神经网络模型、给出了模型的哈密顿量和学习算法,证明了学习算法的收敛性,该模型能对每一神经元自动引入一个节点偏置使得网络能够存储所有学习图样包括相关图样,其存储容量远高于Hebb—rule—like学习算法下的高阶神经网络模型.对由30个神经元组成的二阶神经网络进行了计算机仿真,结果证实了上述结论.此外,对初始突触强度对学习效果的影响和不同存储图样数目下的平均吸引半径进行了仿真计算并分析了所得结果.新模型的特点使其具有良好的应用前景 相似文献
9.
黄山雄性短尾猴换群行为的研究 总被引:5,自引:2,他引:3
1986至1992年对安徽黄山一群短尾猴连续进行7年的换群行为研究表明:雄性的换群行为发生在临近交配期开始前后,大多数为成年个体;这些个体与换群前的顺位无关,且未受到迁入新群的其它个体更多的攻击,迁入雄体还倍受雌体青睐。据此推测,外群雌性的性吸引是雄性短尾猴换群的直接原因。雄性短尾猴换群的结果,降低了种群的近亲繁殖率,增加了不同种群间的基因交流,对种群遗传多样性的保存和发展具有重要意义.因此,进化选择压力有利于换群行为的发展。 相似文献
10.
Do anthocorid predators respond to synomones from Psylla-infested pear trees under field conditions?
Because Y-tube olfactometer experiments in the laboratory showed a response of anthocorid bugs to odour fromPsylla-infested leaves, it was of interest to assess its relevance under field circumstances. This was done by measuring the density
of predatory bugs on pear trees adjacent toPsylla-infested or control trees that were covered with fine mesh gauze-screens. In this way odours from these caged trees could
spread through the screen, while contact with thePsylla prey in the cage was prevented. The density of anthocorid predators around cages with heavily infested trees was significantly
higher than around uncaged control trees and around cages containing uninfested or little infested trees. Covering a cage
withPsylla-infested trees by an airtight plastic sheet led to an immediate drop in the density of anthocorid predators, whereas removal
of the sheet led to predator aggregation again. The results of these field experiments strongly support the hypothesis that
anthocorid predators respond to volatile chemicals emanating fromPsylla-infested pear trees. 相似文献