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1.
In our previous study, we constructed a lattice model of termite tunnel pattern to explore the relationship between tunnel geometry and foraging efficiency. The model was based on experimental data obtained from homogeneous soil substrates without food resource. In the present study, we adopted a more general rule in the model to determine branching tunnel lengths. The rule was described by two variables, the probability of tunnel branching, Pbranch, and the probability for a branching tunnel to terminate, Pterm. With the modified model, we explored the influence of the geometry of branching tunnel on foraging efficiency, γ, for two termite species, Coptotermes formosanus and Reticulitermes flavipes (Isoptera: Rhinotermitidae). For C. formosanus, γ map consisting of the two variables were partitioned in three regions by the level of γ value, while γ for R. flavipes was categorized as two regions: higher γ and lower γ. This result was discussed in termite foraging strategy. 相似文献
2.
The possible effects of foraging strategy on the relationship between vigilance and group size were studied in three species
of waders with different foraging strategies. I predict that (1) pause–travel species should show no relationship between
scanning and group size, because these species scan for prey as well as for predators; (2) continuous-tactile foraging species
should show a positive relationship between flock size and vigilance level, because in their large groups vigilance towards
other birds could be used to avoid interference and aggression; and (3) continuous-visual searching species should show the
general pattern of decreasing vigilance when group size increases as predicted by both the 'many eyes' and the 'predatory
risk' hypotheses. Results support the predictions for the influence of foraging strategy on the relationship between vigilance
level and group size. The mutual exclusion of foraging and scanning can determine the importance of the 'many eyes' hypothesis.
Such exclusion seems to be determined by foraging strategy. The influence of foraging on scanning must be taken into account
in future studies on the group-size effect.
Electronic Publication 相似文献
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两种鼠耳蝠回声定位叫声的比较 总被引:4,自引:3,他引:4
对鼠耳蝠属两种蝙蝠飞行状态下的声发射进行了比较研究.结果表明两种鼠耳蝠声发射信号的声谱图都呈调频(FM)型,但在波形及频率范围上有明显差异.大鼠耳蝠(四川亚种)的声脉冲宽度很小(1.6±0.3ms),能率环较低(4.0%),其主频率(DF=44.6±4.3kHz)也较低;而水鼠耳蝠的声脉冲宽度较大(4.2±1.6ms),能率环(9.6%)及主频率(DF=83.0±4.0kHz)也较高.文中结合两种蝙蝠的形态及食性分析了回声定位对捕食生境及捕食策略的适应性. 相似文献
5.
Partitioning seasonal time: interactions among size, foraging activity and diet in leaf-litter frogs
This study investigates hypotheses about partitioning of food resources among all species and several size classes in an
assemblage of diurnal leaf-litter frogs in central Amazonia. All species in this assemblage change the type and size of prey
as they grow. An ordination of diet composition was significantly associated with frog size and species-specific behaviour.
However, a partial Mantel analysis indicated that species explained about 1.5 times more of the variation in diet overlap
between individuals than frog size. Diet and foraging activity are correlated in juveniles, but not in adults, and this result
holds whether species are considered as statistically independent observations or whether relationships are analysed using
phylogenetically independent contrasts. This study showed that the partitioning of food resources between species changes
with the population size structures. Thus, intraspecific and interspecific changes in diet, coupled with different patterns
of juvenile recruitment, cause diet segregation among species due to temporal segregation of equivalent size classes.
Received: 25 August 1997 / Accepted: 1 April 1998 相似文献
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Oliver T. Coomes 《Biodiversity and Conservation》2004,13(2):351-360
Does the use of non-timber forest products (NTFPs) lead to species conservation and protection of the tropical rain forest? This paper examines the use and fate of the chambira palm (Astrocaryum chambira) – a prime candidate for ‘conservation-through-use’– around a traditional peasant community in northeastern Peru where land scarcity has forced households to draw increasingly on NTFPs to supplement their incomes, including palm fibre for the production of handicrafts. Using household survey data (n = 36), we identify the specific factors that influence handicraft production, household use and economic reliance on palm fibre-based handicrafts, and the planting (semi-domestification) of the chambira palm. Our findings question the promise of rain forest ‘conservation-through-use’ and indicate the scope of challenges for species conservation, particularly among the rural poor. 相似文献
8.
Joan Navarro Jacob González-Solís Olivier Chastel 《Journal of experimental marine biology and ecology》2008,358(1):14-19
The knowledge of ecophysiological responses in relation to foraging effort is crucial to understanding feeding strategies, survival and reproductive trade-offs, as well as to obtain reliable indicators of an excessive workload. We present an integrative approach that examines a suite of ecophysiological parameters in relation to increased workload. We experimentally increased wing loading of 10 Cory's shearwaters Calonectris diomedea, a medium-sized pelagic seabird, by adding 45 g extra weight and compared their ecophysiological responses with 10 control birds. Among all the parameters analysed, the only significant response to overloading was a longer foraging trip, a lower rate of mass gain whilst at sea, and an increase in plasma levels of creatine kinase and lactate dehydrogenase activity indicating muscular damage. The analyses on these muscular enzymes open new opportunities to measure the impact of instruments on birds and to understand physiological responses in relation to foraging activity. 相似文献
9.
Critical thermal limits in Mediterranean ant species: trade-off between mortality risk and foraging performance 总被引:9,自引:0,他引:9
1. In Mediterranean ant communities, a close relationship has been found between activity rhythm in the period of maximum activity and position in the dominance hierarchy: subordinate species are active during the day, when conditions are more severe, while dominants are active during the afternoon and the night.
2. Results obtained in this study confirmed that the species foraging at higher temperatures were closer to their critical thermal limits than the species foraging at lower temperatures.
3. This enabled two extreme strategies of foraging in relation to temperature to be distinguished: (1) heat-intolerant ant species behaved as risk-averse species, foraging at temperatures very far from their critical thermal limits; and (2) heat-tolerant ant species behaved as risk-prone species, foraging very near their critical thermal limits and running a high heat mortality risk.
4. Heat-tolerant species benefited from this strategy by having better foraging performance at high temperatures.
5. This wide range of thermal niches may be one reason why Mediterranean ant faunas are so diverse in the face of limited diversity in vegetation and habitat structure: the daily range of temperature may be sufficiently great to meet the requirement both of heat-adapted and cold-adapted species as well as a spectrum of intermediate forms. 相似文献
2. Results obtained in this study confirmed that the species foraging at higher temperatures were closer to their critical thermal limits than the species foraging at lower temperatures.
3. This enabled two extreme strategies of foraging in relation to temperature to be distinguished: (1) heat-intolerant ant species behaved as risk-averse species, foraging at temperatures very far from their critical thermal limits; and (2) heat-tolerant ant species behaved as risk-prone species, foraging very near their critical thermal limits and running a high heat mortality risk.
4. Heat-tolerant species benefited from this strategy by having better foraging performance at high temperatures.
5. This wide range of thermal niches may be one reason why Mediterranean ant faunas are so diverse in the face of limited diversity in vegetation and habitat structure: the daily range of temperature may be sufficiently great to meet the requirement both of heat-adapted and cold-adapted species as well as a spectrum of intermediate forms. 相似文献
10.
J.-B. Charrassin C. A. Bost K. Pütz J. Lage T. Dahier T. Zorn Y. Le Maho 《Oecologia》1998,114(2):194-201
For oceanic birds like king penguins, a major constraint is the separation of foraging areas from the breeding colony, largely
because swimming increases foraging costs. However, the relationship between foraging strategy and breeding stage has been
poorly investigated. Using time-depth recorders, we studied the diving behaviour of two groups of king penguins that were
either incubating or brooding chicks at Crozet Islands (Southern Indian Ocean) at the same period of the year. Although birds
with chicks had the highest predicted energy demand, they made foraging trips half as long as incubating birds (6 vs. 14 days)
and modified their time and depth utilisation. Birds with chicks dived deeper during daylight (mean maximum depth of 280 m
vs. 205 m for those incubating). At night, birds with chicks spent twice as much time diving as those incubating, but birds
at both stages never dived beyond 30 m. Movements to greater depths by brooding birds are consistent with the vertical distribution
of myctophid fish which are the main prey. As chick provisioning limits trip duration, it is suggested that it is more efficient
for parents to change their diving patterns rather than to restrict their foraging range.
Received: 23 June 1997 / Accepted: 3 November 1997 相似文献
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F. E. Grosclaude J. A. Núñez 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1998,183(1):61-68
When conditioned honeybees collect sucrose solution delivered at a range of low-profit flow rates for the hive, they increase the pause length between successive visits. If sucrose solution was delivered continuously, it accumulated at the food source in an amount proportional to the pause length and the flow rate of nectar. When the flow rate of sucrose solution was further decreased but kept constant throughout the day, a threshold level was attained in which oscillations in the length of the pauses were observed. The relationship between the amount of accumulated nectar and subsequent pause length at this threshold level can be depicted by means of a power function. The best fit allowed the calculation of the values of parameters that quantitatively describe the control system regulating foraging activity. The importance of foraging pauses as a strategy to cope with changing nectar availability is discussed. Accepted: 7 January 1998 相似文献
13.
In this study, the interactions between two semi-aquatic mammals, the endangered Pyrenean desman Galemys pyrenaicus and the Eurasian water shrew Neomys fodiens, were investigated through the analysis of their summer diet using next-generation sequencing methods, combined with analyses of prey selectivity and trophic overlap. The diet of these predators was highly diverse including 194 and 205 genera for G. pyrenaicus and N. fodiens respectively. Overall, both species exhibited rather non-selective foraging strategies as the most frequently consumed invertebrates were also the most frequent and abundant in the streams. This supported a generalist foraging behaviour for G. pyrenaicus and N. fodiens in the study area. The Pianka index (0.4) indicated a significant but moderate dietary overlap as G. pyrenaicus mostly relied on prey with aquatic stages whereas prey of N. fodiens were mainly terrestrial. Moreover, no difference in G. pyrenaicus prey consumption was found in presence or absence of N. fodiens. A differential use of trophic resources through mechanisms such as plastic feeding behaviour or differences in foraging micro-habitat are likely to facilitate the coexistence between these two mammal species. 相似文献
14.
Invertebrates are the main source of protein for many small-to-medium sized monkeys. Prey vary in size, mobility, degree of protective covering, and use of the forest, I.e. Canopy height, and whether they are exposed or embed themselves in substrates. Sex-differentiation in foraging patterns is well documented for some monkey species and recent studies find that color vision phenotype can also affect invertebrate foraging. Since vision phenotype is polymorphic and sex-linked in most New World monkeys - males have dichromatic vision and females have either dichromatic or trichromatic vision - this raises the possibility that sex differences are linked to visual ecology. We tested predicted sex differences for invertebrate foraging in white-faced capuchins Cebus capucinus and conducted 12 months of study on four free-ranging groups between January 2007 and September 2008. We found both sex and color vision effects. Sex: Males spent more time foraging for invertebrates on the ground. Females spent more time consuming embedded, colonial invertebrates, ate relatively more "soft" sedentary invertebrates, and devoted more of their activity budget to invertebrate foraging. Color Vision: Dichromatic monkeys had a higher capture efficiency of ex posed invertebrates and spent less time visually foraging. Trichromats ate relatively more "hard" sedentary invertebrates. We con clude that some variation in invertebrate foraging reflects differences between the sexes that may be due to disparities in size, strength, reproductive demands or niche preferences. However, other intraspecific variation in invertebrate foraging that might be mistakenly attributed to sex differences actually reflects differences in color vision. 相似文献
15.
贺兰山马鹿冬季食性分析 总被引:11,自引:0,他引:11
2003年11月-2004年2月在宁夏贺兰山国家级自然保护区和内蒙古贺兰山国家级自然保护区,利用粪便显微组织学分析技术结合野外啃食调查对马鹿阿拉善亚种(Cervus elaphus alxaicus)冬季食性进行了研究.从7个沟系中一共收集了219堆马鹿粪便中捡拾粪粒,组成14个复合样本进行分析,其结果表明,灰榆(27.37%)、山杨(11.75%)、蒙古扁桃(9.83%)、金露梅(8.12%)、锦鸡儿(6.52%)等植物的当年枝和落叶以及禾本科草本植物(7.51%)是马鹿冬季主要食物,其中灰榆为大宗食物,针叶树种(杜松、油松、青海云杉)和其他草本植物所占比例均较小.马鹿对灰榆、山杨、蒙占扁桃、金露梅、锦鸡儿和杜松有正选择性;而对禾本科草本植物、油松和青海云杉有负选择性.马鹿对它们选择性的强弱顺序为:山杨>杜松>锦鸡儿>蒙古扁桃>金露梅>灰榆>禾本科草本植物>油松>青海云杉.马鹿取食乔木36.8%、灌木44.7%、禾本科草本植物8.0%和非禾本科草本植物10.5%,这4类植物的利用性与可利用性存在极显著差异,乔木和灌木的利用性高于可利用性;禾本科草本植物和非禾本科草本植物的利用性低于可利用性,说明马鹿的食物以木本植物镲为主,草本植物为辅.Spearman相关分析得出马鹿对食物的选择性与水分、灰分、粗蛋白、粗脂肪、粗纤维和无氮浸出物之间无明显的相关关系.被啃食植物中粗蛋白含量较高,蛋白质不是越冬马鹿的限制因子,而能量可能是影响冬季马鹿采食较为关键的因子.马鹿冬季采食策略主要是以最小的能量消耗获取最大的能量收益. 相似文献
16.
The red palm weevil (RPW), Rhynchophorus ferrugineus, is a serious pest of date palms. Its larvae bore deep into the trunk disrupt the vascular tissues and kill the infested trees. Behavioral features of entomopathogenic nematodes (EPNs), reflected by attraction and distribution patterns, are fundamental aspect in determining their parasitic ability and potential management of RPW. We studied the attraction behavior of the EPNs Steinernema carpocapsae and Heterorhabditis bacteriophora to the RPW under simulated natural conditions in tubes to evaluate their infective potential. In all experiments, a certain proportion of infective juveniles (IJs) (16–20%) stayed near the inoculated site and a major proportion (38–48%) was attracted to the host end. Both H. bacteriophora and S. carpocapsae were efficient crawlers, climbing up and descending when locating their insect host. They were efficiently attracted to the various larval sizes and stages of the RPW life cycle. Host localization by ascending movement was more prominent in S. carpocapsae than in H. bacteriophora. In general, H. bacteriophora is classified as a cruiser forager and S. carpocapsae as an ambusher. However, in this study, we discovered a higher percentage of cruiser foragers among S. carpocapsae IJs. They dispersed much faster and their cruising behavior was prominent characteristic in controlling the cryptic RPW concealed in organic habitats. 相似文献
17.
Synopsis We examined the diel chronology in food consumption and dietary composition, and in the local distribution of yellow perch,Perca flavescens, at 3 h intervals over two 24 h periods during the summer at Baptiste Lake, Alberta. Feeding intensity, as indicated by changes in stomach fullness, increased throughout the day, peaked in late evening, and almost ceased after sunset. Changes in perch densities at the sampling site reflected the pattern of feeding intensity, indicating that movements into the littoral zone are correlated with foraging. Perch diet composition, analyzed as percent occurrence, relative numerical abundance, and percent contribution by weight, differed significantly between times of day, particularly between day and night, and between sampling periods. These differences could be related both to prey behavior and distribution, and to changes in perch foraging behavior in response to light intensity. In terms of biomass, forage fish, amphipods, chironomids, and trichoptera were the most important food items on both sampling dates. 相似文献
18.
Abstract The circadian rhythm in the flight activity of a tropical microchiropteran bat Taphozous melanopogon responds at all phases with delay phase shifts to single light‐on steps (DD/LL transfers). The circadian rhythm responds at all phases with advance phase shifts to single light‐off steps (LL/DD transfers). Phase shifts were measured from the delays or advances of the onsets of flight activity on days following DD/LL and LL/DD transfers relative to the temporal course of the onsets of activity in controls. The magnitude of the phase shifts was a function of the phases in which the transfers were made. The On‐PRC and Off‐PRC plotted from such data are mirror‐images in their time‐course and wave‐form. The phase shifts of the circadian rhythm in either direction were accompanied by changes in period (for the duration of our recordings after die transfer). The period lengthened following a delay shift and it shortened following an advance shift. The phase shifts are abrupt and discernible in the first cycle after perturbation. There are no transients. 相似文献
19.
Darrell Moore Patrick Doherty 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2009,195(8):741-751
Forager honey bees can associate the time of day with the presence of food at locations outside the hive. It is thought that
this time-memory enables the bee to make a spatio-temporal match between its behavior and floral nectar secretion rhythms.
Despite a long tradition of research, the mechanisms by which the time-memory becomes established are unknown. We investigated
the influences of two experiential factors on the acquisition of time-memory: (1) the number of collecting visits made by
the forager within a feeding bout during a restricted time of day and (2) the number of days of exposure to the restricted
feeding time. Our results indicate that these two factors control different processes. The number of days of experience influences
the temporal accuracy of reconnaissance behavior to the food source. The cumulative number of collecting visits within the
feeding bouts has no apparent effect on time-accuracy but, instead, determines the probability of exhibiting food-anticipatory
behavior and, if that overt behavior is performed, the intensity of its expression.
This paper is dedicated to the memory of Prof. James L. Larimer. 相似文献
20.
1. Feeding behaviour of generalist and specialist predators is determined by a variety of trophic adaptations. Specialised prey‐capture adaptations allow specialists to catch relatively large prey on a regular basis. As a result, specialists might be adapted to exploit each item of prey more thoroughly than do generalists. 2. It was expected that obligatory specialist cursorial spiders would feed less frequently than generalists but for a longer time and, thus, that their foraging pause would be longer. First, the feeding frequencies of three generalist spider species (Cybaeodamus taim, Harpactea hombergi, Hersiliola sternbergsi) were compared with those three phylogenetically related specialist species: myrmecophagous Zodarion rubidum, and araneophagous Nops aff. variabilis and Palpimanus orientalis. 3. Generalists captured more prey, exploited each item of prey for a significantly shorter time, and had a shorter foraging pause than was the case for specialists. Generalists also gained significantly less relative amount of prey mass than did specialists. 4. Second, the study compared the prey DNA degradation rate in the gut of generalists and specialists by means of PCR. The degradation rate was not significantly different between specialists and generalists: the detectability half‐life was estimated to exist for 14.3 days after feeding. 5. This study shows that the feeding strategies of cursorial generalist and obligatory specialist spiders are different. Obligatory specialists have evolved a feeding strategy that is based on thorough exploitation of a few large prey, whereas generalists have evolved a strategy that is based on short exploitation of multiple small items of prey. 相似文献