摘要:

Feeding ecology of individually marked male and female Herring gulls breeding at the colony of Trébéron (France) has been compared for two successive periods. During the first period (1983–1988), most of the breeders intensively used a nearby refuse tip which was the main feeding site of the colony. At the refuse tip. food supplies were more abundant and predictable than at the other available feeding sites. In the second period (1989–1990), an incinerator was running so that the amount of food dumped at the tip decreased by 80%.

ISSN:0394-9370    

DOI:10.1080/08927014.1994.9523003

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Foragers of the ponerine antEctatomma ruidumRoger can be classified into two behavioural subcastes: prey-hunting and nectar-collecting ants. Observations on foraging activities of nectar-collecting workers specialized on the extrafloral nectaries of the orchid,Spathoglotis plicata, were made in a neotropical forest located in Guadeloupe, using marked ants. Although foraging activity was mainly diurnal, the activity rhythm of these specialized workers showed a shift at the end of the afternoon, before sunset. Most foragers come back to the nest at this time but, by contrast, those collecting nectar on orchids increase their activity. This increase is linked with the secretion cycle of extrafloral nectaries which exhibit a strong activity at this time. Behavioural and ecological implications of the spatial and temporal learning involved in this food site fidelity are discussed.

ISSN:0394-9370    

DOI:10.1080/08927014.1994.9523004

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Thousands of vanishing bearings of homing pigeons observed at 28 and 10 release sites, respectively, around two home lofts in southern Germany, Würzburg and Andechs, were analysed with respect to their spatial relationships to nearby villages and forests. Pigeons from Würzburg showed a statistical preference to fly over built-up areas rather than open fields and a less distinct preference for open rather than wooded country. The same kind of analytical method did not reveal such preferences in pigeons from Andechs. Thus, responses to the landscape appear to depend on conditions at the home site. It is concluded that trivial factors such as topographical features may, and often do, contribute to the appearance of the initial-orientation pattern observed at a given release site. Therefore, such patterns should not be interpreted as sole manifestations of less trivial orientation processes, e.g. home-related navigation.

ISSN:0394-9370    

DOI:10.1080/08927014.1994.9523005

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Underwater television with time lapse video recording was used to record in situ activity of the tellinacean bivalveDonax vittatuson West Sands Beach, St Andrews on the east coast of Scotland. Individuals emerged from the sand most frequently immediately before and after low water, when wave action in shallow water caused disturbance of the sediment. During this period, emergence was most frequently followed by ‘leaping’ and/or transport by waveinduced currents. Emergence or partial emergence during mid-tide periods was more frequently followed by surface or subsurface crawling. These activities resulted in a redistribution of the population which affected up to 44% of individuals during each tidal cycle. In all cases, reburial followed quickly. The number of emergence, ‘leaping’, and reburial events in each 30 min time interval showed a positive, and the number of crawling events a weak negative, correlation with the degree of disturbance by wave action. The separate inhalant and exhalant siphons, used to draw in the feeding current, remained extended and visible at the sand surface continuously except for periods when wave action was so strong as to stir the sand into suspension, causing intermittent withdrawal. The significance of these activities is discussed in relation to potential predation risks.

ISSN:0394-9370    

DOI:10.1080/08927014.1994.9523007

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Trail following is a well established feature of the behaviour of gastropods. UsingLimax pseudoflavusas an example, experiments with naturally laid trails and re-laid trail extracts have shown that the trail following substances are of a low molecular weight, soluble in both water and methanol and volatile. There are differences between the behaviour of dried methanol extracts and dried aqueous extracts which indicate that more than one substance is involved. An artificial trail of 5 ppm propionic acid induced trail following and it is speculated that this substance may form a component of a trail following cocktail.

ISSN:0394-9370    

DOI:10.1080/08927014.1994.9523008

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Motographic recordings using time-lapse photography have been carried out on the intertidal limpetPatella rusticaon the boulders of a breakwater in central Italy. The reconstruction and analysis of the individual paths allowed a detailed description of the geometry of foraging excursions of this algal grazer.P. rusticaat Cala Calera showed a consistent homing pattern and reuse of the same home scar over long periods. Foraging excursions were scattered around the scar, but longest excursions were upwardly polarized, minimizing the overlap of grazing area with respect to other species (P. caeruleaandP. aspera) coexisting on the same shore. The segmentai analysis of the foraging routes pointed out a typical tri-phasic pattern of activity: relatively fast outward trip, slow and randomly oriented grazing in the central part of the path, and fast locomotor activity during the homeward lag. Limpets showed an extensive use of intra-individual trail following during the return phase of each excursion, while very low overlap appeared between successive excursions of the same individual. On the other hand, the long term monitoring of spatial activity showed a persistent fidelity to the home scar and relative constancy of the individual feeding area.

ISSN:0394-9370    

DOI:10.1080/08927014.1994.9523009

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Nucella lapillusis an ideal subject for investigating general aspects of foraging behaviour under field conditions. When foraging, it moves short distances and feeds principally on barnacles and mussels, taking from several hours to days to handle each prey item. Consequently, marked snails can be followed daily and accurate diet histories compiled. Such studies reveal great variation in foraging behaviour, both within individuals at different times and among individuals during any one period of time. This variation can only be explained by a comprehensive account of endogenous and exogenous factors, requiring combined physiological, behavioural, ecological and genetical approaches. Dynamic programming is a modelling technique that readily accommodates such an interdisciplinary approach and we have used it to examine the effects of endogenous (gut fullness, level of energy reserves) and exogenous factors (perceived risk of mortality) on the foraging behaviour ofN. lapillus. While these factors account for a significant proportion of variation in the foraging behaviour ofN. lapillus, there remains much that is not explained. We suggest that the cycle of resource allocation to reproduction and its interaction with risk of mortality when foraging will prove to have an important influence on the foraging behaviour of this intertidal gastropod.

ISSN:0394-9370    

DOI:10.1080/08927014.1994.9523010

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Sacoglossan opisthobranchs are suctorial feeders and the majority of species feed on the cytoplasm of siphonalean green algae. All shelled sacoglossans feed on the morphologically variable, but anatomically strictly monosiphonaceous algal genusCaulerpa. Thus stenophagy is plesiomorphic within the group. After losing the shell, an adaptive radiation of diets has taken place. Most shellless species are stenophagous, but some, in particular species with temperatt distributions, are relatively euryphagous.

ISSN:0394-9370    

DOI:10.1080/08927014.1994.9523011

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Foragers which recruit or immigrate into a new area explore it, and thereby gradually establish a home-range or territory. We hypothesized that the rate of area acquisition is determined by the costs of movement relative to its benefits. To test this hypothesis, we explored the movement patterns ofPatella caerulealimpets, transplanted onto panels in a fully crossed, replicated laboratory experiment. Experimental treatments were high and low food, high and low limpet density. The limpets gradually increased their home-ranges during the 14 days of experiment. In spite of only few observed aggressive encounters, the home ranges were largely exclusive, hence constitute territories. Territories increased faster at high than at low food densities. At low food densities territories increased faster with high than with low limpet density. Territory formation was slowest in low food-low limpet densities. We propose that the limpets mark territories with mucus trails. When food is abundant, the benefit of foraging is higher than the costs of locomotion and marking, favouring high movement rates and large territories. When food is scarce but competitors are many, limpet movement leads to marking rather than foraging, and they monopolize prospective resources by increasing their territories. When both food is scarce and competitors are few, the reward of either foraging or marking is low, making for slow territory-formation rates. Thus, prospective benefits are involved in the determination of territory-formation rates.

ISSN:0394-9370    

DOI:10.1080/08927014.1994.9523012

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Gastropods, particularly the opisthobranchAplysia, represent an optimal biological model for system analysis in feeding behaviour.

ISSN:0394-9370    

DOI:10.1080/08927014.1994.9523013

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor