摘要:

We hypothesise that marine algae and various common microbes of the atmosphere (spora) use chemical induction of water condensation to enable or increase their wind dispersal between their aquatic, terrestrial or epiphytic growth sites. Biogenic chemical cloud condensation nuclei (CCN) and ice nuclei (IN), sometimes co-occurring in single species (e.g.Pseudomonas syringae), release heat energy of phase change, thus contributing to local air movements that can be used both for lofting and for lateral dispersal of their producers. The phase-change catalysis may occur on the microbial surface (e.g.P. syringae) or may happen more distantly through the release of chemical precursors for suitable ions (e.g. plankton-derived dimethylsulphide [DMS] forming atmospheric sulphate). Small phytoplankton and bacteria take off from water through bubble-burst processes especially in “white-caps”, these often themselves caused by convective winds.

ISSN:0394-9370    

DOI:10.1080/08927014.1998.9522867

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper providesthe first description and comparison of courtship behavioursin males of four species of tragopans in captivity. Inter-specific comparisons of each of the five displays (frontal, lateral, wing whir, flight, and lappet dropping) were similar with one main difference; Temminck's and Satyr tragopans assumed an arched posture, in addition to the upright posture during the lateral display. All frontal and lateral displays were performed only in front of females and most likely have a sexual function. In contrast, wing whir, flight, and lappet dropping displays were also performed in front of other males. Therefore, these displays are most likely to be sexual and aggressive in function and may also be a form of comfort behaviour in the lappet display. The first female displays are described for this genus. Intra- and inter-specific lateral displays in females were only directed towards other females and probably function as a threat display. Because of the similarities of the five displays among the four species of tragopans studied, courtship displays do not appear to serve as behavioural isolating mechanisms in zones of sympatry. However, lappet dropping, flight, and frontal displays are unique to this genus and probably function to reduce intergeneric hybridization. Female choice is probably based on differences in plumage colouration, lappet pattern and colouration, and vocalizations rather than display characteristics, as the former characteristics have diverged considerably as a result of sexual selection.

ISSN:0394-9370    

DOI:10.1080/08927014.1998.9522868

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

During an 8-year study, the clutches most frequently laid by Night HeronsNycticorax nycticoraxand by Little EgretsEgretta garzettawere 1-egg smaller than the most productive ones, and this contrasts with the idea that natural selection maximises reproduction. The productivity of the largest clutches in these two herons seems to be proximately limited by their inability to hatch successfully clutches above four and six eggs, respectively. Major losses seem to involve hatching failures due to the parents' inability to incubate clutches above a certain size, or to early chick mortality due to competitive aggression among siblings. Clutch size and fledgling success were stable or slightly increased during the season, an unusual trend that may be linked to a late peak in food availability. Among the hypotheses put forward to explain the discrepancy between most frequent and most productive clutches in birds, the evidence for Night Herons and Little Egrets contrasts with the predictions of the “predation”, the “bad years”, and the “insurance” hypotheses. A clutch size modification experiment, the first one accomplished on a ciconiiform species, was conducted for 3 years, and its results contrasted with the predictions of the “individual optimum” hypothesis. The limited information now available suggest that the “incubation capacity” and the “adaptation in progress” hypotheses may be applicable to these herons, who find particularly abundant food resources in the rice fields of this study area

ISSN:0394-9370    

DOI:10.1080/08927014.1998.9522869

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Spiders in the genusArgiopefrequently decorate their webs with highly visible silk structures. To investigate the possible function of these curious decorations in the foraging behavior ofArgiope appensa, several free-ranging populations were studied on Guam, Mariana Islands. The mean area of decorated webs was consistently and significantly smaller than the mean area of undecorated webs. Decorated webs also suffered significantly more damage per unit area than undecorated webs and decorated upper web quadrants tended to exhibit more damage patterns than undecorated quadrants. Estimates of individual foraging success, however, showed no significant difference between decorating and non-decorating spiders. These data suggest thatA. appensais engaged in a mixed foraging strategy with two alternative tactics. Spiders which spin smaller, decorated webs achieve similar foraging success to those which spin larger, undecorated webs.

ISSN:0394-9370    

DOI:10.1080/08927014.1998.9522870

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In bird species, several behavioural strategies have evolved to facilitate the avoidance of cuckoldry, such as mate guarding, frequent copulation, territory defence, and song signals. The present study describes mate guarding in the chiffchaff,Phylloscopus collybita, and reports an experimental manipulation aimed at discovering whether females engage in extra-pair copulations in the absence of their males. The data indicate that the males were responsible for maintaining and increasing pair proximity during the period just before the females start laying their eggs. Also, most successful pair copulations took place in the days immediately before egg laying. These findings are consistent with the predictions of the sperm competition hypothesis, i.e. the male achieves mate guarding by maintaining close proximity and following the female during her fertile period constitute mate guarding. However, the female-advantage hypothesis cannot be refuted because the female could be inducing male proximity through contact calls. Also, during the experimental removal of the male from the territory, females did not leave the territory and were unwilling to accept extra-pair copulations (EPC). This immediate female rejection may be evidence that there is a cost to the female in engaging in an EPC. It is suggested that mate guarding could have other functions besides paternity assurance.

ISSN:0394-9370    

DOI:10.1080/08927014.1998.9522871

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The allodapine beeExoneura bicolorconstructs linear nests in pithy centres of dead plant material. Brood is reared progressively. During winter, nests usually contain one mated female with large ovaries and several subordinate females with small ovaries. The dominant female pheromonally inhibits ovarian enlargement of subordinate females. During the foraging season, dominant females guard the nest, while subordinate females undertake the more risk prone foraging activities. During winter, virtually no foraging occurs. Therefore, guarding might be the most dangerous activity during winter. In this paper we investigate whether the position of females in the nest during winter is related to dominance. Females did not change relative position frequently and the position of females decreased near monotonically with ovary size, with the dominant female closest to the nest entrance. It is concluded that: (1) dominant females do not move about in the nest to ensure spread of their pheromones among nestmates, or to behaviourally inhibit ovarian enlargement of subordinates; (2) dominant females do not force subordinates to guard the nest. Because the guard is probably the female that is most subject to predation during winter, guarding by the dominant should have some payoffs. Potential benefits are: (a) contamination of incoming air with volatile pheromones; (b) preventing intruders from entering the nest; (c) controlling nestmates leaving and entering the nest. The latter may enable females to control food that is brought back into the nest, and to prevent mating by subordinate females. Our results indicate that social structure within these nests is influenced by the linear structure of the nest burrows.

ISSN:0394-9370    

DOI:10.1080/08927014.1998.9522872

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Genotypes of a queen and the first brood of workers of 20 colonies ofPolistes chinensis antennaliswere electrophoretically analyzed. We found allelic polymorphisms in two loci which encodes two enzyme, i.e., creatine kinase (CK) and isocitrate dehydrogenase (IDH). The genotype array of the first brood of workers in five colonies could not be explained by monoandry of the queen. Two to four suggested multiple mating of the queen, and one to three suggested replacement of the queen. Although multiple matings of some queens is apparent, the mean estimate of relatedness of the first brood of workers from the genotype frequency data, 0.648, is ambiguous, because it is not significantly different from 0.75 (one singly-mated queen) nor 0.545 (one doubly-mated queen).

ISSN:0394-9370    

DOI:10.1080/08927014.1998.9522873

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

More than 500 male-male interactions were recorded in a population of 560 fallow deer in order to evaluate the importance of fight duration as an index of risk and benefit. Fight duration was affected by rank, presence or absence of parallel walk in the fight sequence and, to a lesser extent, presence of females. Higher-ranking bucks fought for longer than low-ranking ones, probably because parallel walks were more common during fights among high-ranking than lowranking bucks. The high level of competition in this population may explain why fights were shorter in the presence of does, which can be considered a shortterm resource: fighting for too long could mean a lost mating opportunity.

ISSN:0394-9370    

DOI:10.1080/08927014.1998.9522874

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor