摘要:

Productivity, choice between colonial and solitary nest spacing and, mate fidelity were studied in the European tree sparrowPasser montanusL. in a suburban area of Budapest, Hungary. Nestboxes were arranged in five plots, in each plot, 25 were placed at 50 m intervals to simulate solitary breeding and 25 were placed 3-5 m apart to simulate colonial breeding. We recorded parental condition, number of eggs and fledglings, recruitment and life-span in the study area. Females raised most fledglings and recruiting offspring and reached their longest life span in the study area when they bred colonially for the first breeding year and they moved to solitary for all subsequent breeding seasons. The shift in nest spacing was influenced by low productivity in the colonial nests and the poor condition, as assessed by body mass, at the end of first breeding year. Both productivity and the condition of the females improved in the second breeding year if they took new partners which had greater previous breeding experience than themselves. Males produced most fledglings and recruiting offspring and reached their longest life-span if they bred in colonies throughout their lives in the study area. For all males, in all breding years, it was more advantageous to maintain the pair bond rather than to take a new partner. Males had a lower productivity and shorter life-span than did females.

ISSN:0394-9370    

DOI:10.1080/03949370.2000.9728439

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Independent-founding polistine wasps build exposed, single-comb nests that are attached to the substrate by a narrow pedicel. These wasps coat the pedicel with a glandular repellent that helps protect the brood against predation by ants. In contrast, most swarm-founding wasps build nests that are broadly attached to the substrate and covered with an envelope. The envelope restricts access to the brood to a narrow entranceway, which is guarded against ants by the large worker force comprising the founding swarm. The combination of enclosed nest and founding by swarms suggests that these wasps rely on active defense to keep ants from the brood and do not use chemical defense. We show this to be the case forPolybia sericea, a swarm-founding species for which we found no evidence of an ant repellent applied to the nest.

ISSN:0394-9370    

DOI:10.1080/03949370.2000.9728440

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Two-chick broods of the blue-footed booby develop a dominance relationship during the junior chick’s first 2 weeks of life, when behaviour of the subordinate chick is conditioned through aggression by its 4-day-older sibling. We used natural and experimental situations to test the Challenge Hypothesis, which predicts a rise in testosterone to regulate aggression only in socially unstable situations, and to investigate the role of corticosterone in the development of submissive behaviour in subordinates. In unmanipulated broods during the first 12 days, we found no differences among singletons, dominants and subordinates in testosterone levels, and corticosterone levels did not differ significantly. In experimental pairings of singleton/dominant and singleton/subordinate, testosterone was not detected and corticosterone increased significantly in dominants and singletons, but not in subordinates. These results indicate that the Challenge Hypothesis does not apply to these young birds. Whether or not circulating corticosterone regulates aggression in chicks awaits further experimentation.

ISSN:0394-9370    

DOI:10.1080/03949370.2000.9728441

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Many species of tropical social wasps initiate colonies by means of a swarm of queens and workers. Swarms either bud from mature colonies (reproductive swarms) or form from the entire adult population when it evacuates following destruction of the nest by predation or accident (absconding swarms). Colonies giving rise to founding swarms of either type may have males in their populations. Swarms emigrate along a chemical trail to a site selected by scouts, where the workers begin building a new nest. Published analyses of newly-founded colonies indicate that such colonies occasionally contain males. This raises the question of whether these are alien males who joined the new colony shortly after its founding, or are siblings of the females, having emigrated with them from the natal nest site. We used a double censusing technique to determine whether males of the Neotropical social wasp,Polybia occidentalis, emigrate with females in absconding swarms. Nine absconding swarms in Costa Rica were censused and sexed directly before they emigrated and were shown to contain males as well as females. When the swarms departed for the new site, males remained behind, and when the swarms were censused again soon after reaching their new sites, none contained males. Thus males of this species cluster temporarily with absconding females, but fail to emigrate with them. We suggest that the males’ failure to join pre-emergence colonies is in the best interest of both sexes.

ISSN:0394-9370    

DOI:10.1080/03949370.2000.9728321

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Morphological analyses of female wasps collected at different points in the development of the colonial life cycle showed that inPolybia occidentalis,P. paulistaandP. scutellaris, caste differences progressively increase because larger queens appeared in more abundance in later stages of the colony cycle. Possibly, the mechanism can be of selective importance in the onset of the cyclical oligogyny, which is presently well documented in the life cycle of many swarm-founding polistine wasps. Males and uninseminated females with developed ovaries (intermediates) only occurred at the later stages of a colony’s developmental cycle.

ISSN:0394-9370    

DOI:10.1080/03949370.2000.9728322

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Dufour’s gland contents of the queens of the slave-making ant speciesPolyergus rufescensand its host,Formica cunicularia, were analysed by gas chromatography-mass spectrometry. InP. rufescens, the gland contains a mixture of several esters, one of which, decyl isobutyrate, was consistently present in large quantities (constituting more than 80% of glandular contents). Glandular contents in the host species, were found to be different, containing, in addition to two substances also found inP. rufescens, a mixture of acetates and several hydrocarbons. Decyl isobutyrate was not present. We discuss the possible role of these substances in the life history ofP. rufescens.

ISSN:0394-9370    

DOI:10.1080/03949370.2000.9728323

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

This laboratory study examined responses of Israeli blind subterranean mole rats (of theSpalax ehrenbergisuperspecies) to food odours (Narcissus tazettaandUrginea maritimabulbs) and assessed to what extent mole rats’ odour preferences are indicative of their food preferences and whether these preferences influence their foraging behaviour. Prior to odour testing, mole rats ateNarcissusbulbs preferentially and avoidedUrgineabulbs when both types of bulbs were available, as is the case in nature. In phase 1, mole rats (n = 20) spent significantly more time sniffing the odour ofNarcissusbulbs than the odour ofUrgineabulbs, indicating a preference for the odour of the preferred bulb. In phase 2 in a six-tunnel radial arm maze, the presence of preferred or non-preferred food odours at the ends of the 20 em tunnels did not affect mole rats’ (n = 12) movement into the tunnels. The results suggest that mole rats can identify food items by their odours and thus can discriminate between edible (e.g.,Narcissus) and poisonous (e.g.,Urginea) bulbs without the necessity of biting into them. Because there is limited air movement in mole rats’ sealed tunnel systems, the food odours do not travel far underground, and thus mole rats probably do not use detection of airborne food odours to facilitate their foraging underground. Our results suggest that mole rats could use food odour discrimination to select edible food items for collection and to sort food items in their nest stores.

ISSN:0394-9370    

DOI:10.1080/03949370.2000.9728324

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The homing ability ofEmys orbicularisliving in a canal was tested on adult specimens whose home range had been previously assessed. Homing success was very high both from land and water (93 and 80%, respectively). Turtles released near the canal tend to initially move directly toward the nearest water, and then orient toward home. In contrast, turtles released further from the canal initially orient toward their home ranges. Homing cannot be entirely explained on the basis of topographic orientation.

ISSN:0394-9370    

DOI:10.1080/03949370.2000.9728325

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0394-9370    

DOI:10.1080/03949370.2000.9728326

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0394-9370    

DOI:10.1080/03949370.2000.9728327

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor