摘要:

In a field study conducted in the Parco Nazionale del Gran Paradiso, Valle d'Aosta, Italy, acoustic signals were categorized as follows: single whistle (SW), a loud cry that was not repeated, and multiple whistle, a series of whistles which could be uttered in brief (BMW) or in numerous long lasting bouts (LMW). In 438 hr of direct observations I demonstrated that: (1) single whistles were associated significantly with flying stimuli and multiple whistles with terrestrial stimuli; (2) the signals interrupted the foraging behaviour of 22 individually recognized adults; BMW seemed more disturbing than SW when coming from the same or near colony and less alarming when coming from a distant colony. Evidence for true semanticity and honest advertisement is discussed.

ISSN:0394-9370    

DOI:10.1080/08927014.1992.9525334

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This study evaluates some morphological, ecological and behavioural aspects of fallow deer mothers and fawns during the calving season in order to know the antipredator tactics selected in this species living in a particularly open habitat at Donana National Park. In this area fallow deer give birth in synchrony during the first fortnight of June. At this time they move away from their matriarchal groups. A concentration of births in the early afternoon was detected, coinciding with the minimal activity of predators in the area. Mothers groom their offspring and ingest the birth remains to prevent the attraction of predators. During the first days of life fawns remain hidden keeping motionless.

ISSN:0394-9370    

DOI:10.1080/08927014.1992.9525335

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The social organization and the potential correlates of social status were investigated in 18 adult female Dama gazelles and 23 adult female Cuvier's gazelles living in captivity at the Estación Experimental de Zonas Aridas in Almen'a (Spain). A linear hierarchy, positively correlated with age, was observed in Cuvier's gazelles but not in Dama gazelles. Physical characteristics (birth weight, adult weight, body length and horn length) had no effect on the social status of Dama gazelles, but adult body weight and horn size are good indicators of social status in Cuvier's gazelles. High social status was reinforced by aggression for both Dama and Cuvier's gazelles, but in Dama gazelles dominance was contested by the submissive. After the stability of dominance ranks was established, the effects of social status on the components of reproductive success were analysed (age at first birth, fecundity and annual survival of offspring). Results showed a reduction in fecundity and offspring survival and an increase in the age at first birth for low ranking Cuvier's gazelles but no effect was observed in Dama gazelles. The differential effect of rank on reproduction between the gazelles studied is discussed.

ISSN:0394-9370    

DOI:10.1080/08927014.1992.9525336

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We examined the behavioural responses of two closely related, but ecologically different species of tadpoles,Bufo bufoandBufo calamita, to seven predator and control chemical stimuli. All tadpoles were hatched and reared in the laboratory to eliminate experience from natural habitats. In the presence of all predator and control stimuli,B. bufosignificantly shifted its use of microhabitat in experimental containers from the open-water and benthic refuge to the edge. Conversely,B. calamitasignificantly shifted its use of microhabitat from the edge to the open-water or refuge. Neither species responded differently to any of the predator or control treatments, nor was there an interaction between species and predator treatment. Our results indicate that tadpoles may possess innate general defensive responses to sudden changes in chemical or tactile stimuli that signal potential danger. We suggest that the divergent responses of each species may be adaptive in its present ecological environment of ponds with and without fish.

ISSN:0394-9370    

DOI:10.1080/08927014.1992.9525337

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The aims of this paper are to recall and to illustrate one of the validity range boundaries of behavioural ecology and the evolutionary theory of games, within the field of neo-darwinian theory. The principles underlying these two disciplines can apply at the minimum condition that the pure or mixed strategy, which must remain at selective equilibrium, reproduces its kind. This important restriction has been explicitly stated by evolutionary games theorists, but not so clearly in the case of frequencyindependent selection which is also considered by behavioural ecologists. In sexual populations, this precludes in particular all the cases where the expected optimal or evolutionarily stable strategy is achieved in hétérozygotes, as hétérozygotes produce homozygotes at each generation.

ISSN:0394-9370    

DOI:10.1080/08927014.1992.9525338

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The substance secreted by the gland associated with van der Vecht's organ ofParapolybia indicaapplied to the nest petiole during the rubbing behaviour has an antrepelling effect.Parapolybiais the only genus of the independent-founding polistines for which the ant repelling function of the rubbing substance had not previously been demonstrated.

ISSN:0394-9370    

DOI:10.1080/08927014.1992.9525339

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The decoding process of distress calls uses many parameters. In our experiment we establish that amplitude modulation was not taken into consideration by the birds in the experiment, even if other parameters were altered. The decoding process that discards amplitude modulation appears well adapted to transmission at long range because amplitude modulation is always subject to degradation.

ISSN:0394-9370    

DOI:10.1080/08927014.1992.9525340

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The concentration of plasma testosterone was studied in a number of territorial male Red-backed Shrikes,Lanius collurio, during a breeding season in the Italian Pre- Alps. Testosterone levels were highest at the time of the birds' arrival and declined abruptly after a few days. This indicates that high levels of circulating testosterone are needed to sustain aggressive motivation while much lower levels may be sufficient for sexual behaviour in this species. Moreover, it also appears that males of Red-backed Shrikes have very high testosterone blood levels well before they gain their breeding sites.

ISSN:0394-9370    

DOI:10.1080/08927014.1992.9525341

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

When medium workers of the leaf-cutting antAtta sexdens sexdensare presented with the compounds 3-ethyl-2,5-dimethylpyrazine and methyl 4-methylpyrrole-2-carboxylate in various proportions in a trail-following bioassay, they show the highest performance for the 14:1 mixture over other mixtures or the pure compounds. This preferential mixture corresponds with the proportion of both compounds described for the venom gland, which is the source of the natural trail pheromone in these leafcutting ants.

ISSN:0394-9370    

DOI:10.1080/08927014.1992.9525342

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Ecological relationships of plants and animals. By Henry F. Howe And Lynn C. Westley. ISBN 0-19-506314-7, 1990, XIII+ 273 pp., Oxford paperbacks, price £ 13.50.

ISSN:0394-9370    

DOI:10.1080/08927014.1992.9525343

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor