Male mate-locating behavior inEuphydryas chalcedona (Lepidoptera: Nymphalidae) related to pupation site preferences

Males of the checkerspot butterfly (Euphydryas chalcedona)patrol and perch near but not on the larval foodplant in search of females. Experiments with tethered butterflies show that searching males chase virgin females for longer times than they do mated females or males. The larvae leave the larval food-plant to pupate. The correspondence between the distance from the larval foodplant to pupation sites and where males search for females suggests that male mate-locating behavior has evolved to maximize the rate of encounters with newly emerged, virgin females. These conclusions are compared to a recent analysis of butterfly mating systems by Odendaal et al. (Am. Nat. 125: 673–678, 1985).     

Conspecific discrimination in an object-choice task in African grey parrots (Psittacus erithacus)

Living in social groups presents the opportunity to use information provided by other individuals. Several animal species emit specific vocalizations when they find food. Here, we investigate whether African grey parrots (Psittacus erithacus) use vocal and non-vocal information provided by a conspecific in order to find a hidden food source. One subject was attracted by the presence or the vocalizations of a subordinate conspecific, but not of a dominant, which brings us to hypothesize that parrots could be capable of individual vocal discrimination.     

DOCUMENTATION STANDARDS FOR WILDLIFE SOUND RECORDINGS

ABSTRACT

Shearwaters are nocturnal seabirds that rely on olfaction and acoustics to communicate at night. Although previous studies have described the vocal repertoire of some shearwater species, there is a need for more precise experimental data investigating the biological relevance of these acoustic signals in this seabird group. The present paper focuses on the vocal behaviour of the Yelkouan shearwater Puffinus yelkouan, a poorly studied species which produces a single major call composed of two notes, a noisy note and a clear one. A quantitative analysis of the calls allowed to extract the acoustic parameters supporting both sexual and individual signatures. Playback experiments were conducted during the incubation period to test the ability of the Yelkouan shearwater (1) to vocally identify the sex of the emitter, and (2) to discriminate the mate from a non-mate. We showed that birds discriminate the sex of the emitter, calling back almost exclusively to calls of birds of the same sex. Among the few birds replying to calls of the opposite sex, females responded to calls of their partner only, whereas males responded equally to calls of the partner or to calls of a non-partner, suggesting that females are vocally more selective than males.     

使用RAPD分析辨别印度半岛的五种结鱼

用RAPD分析研究了结鱼种组(黄鳍结鱼Tor putitora,结鱼Tor tor,库德里结鱼Tor khudree,Tor mosalmahanadicus和墨脱四■魮Neolissochilus hexagonolepis)5个物种的遗传关系。在所测试的69个随机引物中,11个引物能够在所有5个物种中扩增出稳定的条带。RAPD带型显示,综合使用这些RAPD标记能够区分这5个物种,但Tor mosal mahanadicus和黄鳍结鱼享有相似的带型。UPGMA分析揭示出3个独特的分支,第一支由黄鳍结鱼、Tor mosal mahanadicus和结鱼组成,第二支是库德里结鱼,第三支是墨脱四■魮。Tor mosal mahanadicus的分类地位在不同学者间存在分歧,被认为是库德里结鱼或结鱼的亚种,但我们的结果表明,相对而言,Mahanadi河中的Tor mosal mahanadicus与黄鳍结鱼的进化关系更近,因此有必要对其系统分类地位进行重新评估。     

Partial Distributional Canonical Discriminant Analysis

A canonical discriminant technique is proposed which is unrelated to particular distributional assumptions. This approach allows for a data generated choice between ordered, partially ordered and unordered outcomes and remains identifiable in each dimension of the canonical model. The concepts of allocatability and distinguishability of categories are investigated. Maximum likelihood parameter estimation is conducted and inferential tests for the assessment of the dimensionality of the canonical model are derived. The model is applied to the perioperative prediction of risk of death from peritonitis, using real data.     

Temporal threshold and response bias in the discrimination of empty intervals by cats

Cat's differential duration threshold was investigated by the method of limits in a schedule of discrimination of empty durations. The standard stimulus was 4 sec long throughout the experiment. The comparison stimulus was reduced from 10 to 5 sec by 1 sec steps in successive blocks of 5 sessions. Standard and comparison stimuli, delimited by 50 msec auditory signals, were equiprobably distributed, in a random sequential order of presentation in each trial. After a 2 sec delay, an auditory signal indicated that reinforcement was available upon a response on one of two levers. Weber fractions around .25 were obtained. Strong response bias developed in most cats. Some consequences of the inhibition of responding induced by the procedure were considered.