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1.
Adaptive superparasitism and patch time allocation in solitary parasitoids : the influence of pre-patch experience 总被引:3,自引:0,他引:3
Marcel E. Visser Jacques J. M. van Alphen Henk W. Nell 《Behavioral ecology and sociobiology》1992,31(3):163-171
Summary Dynamic optimal diet models predict that host selection decisions and patch time allocation are influenced by the resource value of the habitat. We tested these predictions using the solitary' parasitoid Leptopilina heterotoma. Assuming that travel times between patches, the quality of previously visited patches and parasitoid density affect the parasitoids' estimation of the resource value of the habitat, different treatments were given before introducing parasitoids singly to a patch containing 5 unparasitized and 15 parasitized hosts. The decision to superparasitize is only slightly influenced by the rate of patch encounter. The quality of the previously visited patch has a strong influence. When a poor patch has been visited on the previous day, more superparasitism is observed in the partly depleted patch than when a rich patch has been searched. More superparasitism is also observed when the parasitoids are kept with conspecifics before the experiment than when they are kept alone. Increasing patch residence times are observed as the quality of the previously presented patch decreases. Host selection decisions and patch time allocation are thus clearly influenced by the pre-patch experience of the parasitoid, as predicted by dynamic optimal diet models. This can also explain why females that have never oviposited in unparasitized hosts will superparasitize readily.
Correspondence to: M.E. Visser 相似文献
2.
Marianne J van Dijken Pam van Stratum Jacques J M van Alphen 《Behavioral ecology and sociobiology》1992,30(2):77-82
Summary In parasitoid wasps, self-superparasitism (oviposition into a host already parasitized by the female herself) often contributes less to the reproductive success of the parasitoid than oviposition into a host previously parasitized by a conspecific (conspecific superparasitism). It could therefore often be profitable for parasitoids to avoid self-superparasitism. This requires a mechanism for either (1) the avoidance of previously searched areas and/or (2) the rejection of hosts containing eggs laid by the searching female. We investigated whether the solitary parasitoid Epidinocarsis lopezi is able to avoid self-superparasitism. We show that visits to previously searched patches were shorter than visits to unsearched patches and conclude that E. lopezi females leave a trail odour on patches they have searched. No differences were found between the time on patches previously searched by the wasp itself and on patches visited by conspecifics. However, E. lopezi superparasitizes fewer hosts previously parasitized by itself than hosts parasitized by a conspecific. Thus, they recognize an individual-specific mark in or on the host. We discuss how patch marking and host marking enable E. lopezi to avoid self-superparasitism. 相似文献
3.
Yin-Quan Liu Carlos Bernstein Andra Thiel 《Behavioral ecology and sociobiology》2009,63(10):1459-1469
Foraging animals usually keep track of how costly it is to reach new resource patches and adjust patch residence time and
exploitation rate accordingly. There are at least two potential factors, which are not necessarily closely linked, that animals
could measure to estimate costs of traveling: the time the forager needs to reach the next patch and the amount of energy
it has to invest until arrival. In the parasitoid wasp Venturia canescens, females forage for hosts from which their offspring can develop. Two different types of this parasitoid exist. The thelytokous
type lives in anthropogenic habitats where flight is not necessarily linked with foraging. The arrhenotokous type lives under
field conditions and shows frequent flight activity. We tested whether the wasps would use time or energy needed to assess
patch availability, by either confining them into vials or letting them travel actively in a flight mill between patch visits.
Our results show that in thelytokous lines, time is a sufficient cue influencing patch exploitation and an additional effect
of the energy needed was not visible. In the arrhenotokous wasps, however, only the number of rounds flown in the mill influenced
subsequent behavior, while mere time spent traveling did not.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
4.
Andra Thiel Gerard Driessen Thomas S. Hoffmeister 《Behavioral ecology and sociobiology》2006,59(5):614-623
The parasitic wasp, Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae), has two reproductive modes, namely, thelytoky or arrhenotoky, and occurs in habitats
with highly variable or relatively stable host abundances, respectively. Since information processing is costly, we expected
that information indicating resource availability would be mainly used by the thelytokous wasps and less so by the arrhenotokous
type. This idea was explored by two different approaches. In a study on patch-time allocation, we used females from ten populations
and measured patch-residence times of individuals that visited multiple patches at different encounter rates. In a more detailed
approach, thelytokous and arrhenotokous females from a single location were observed continuously while foraging, and all
behaviors were recorded. Wasps of both reproductive modes (i.e., both habitat types) used information for the assessment of
habitat quality. However, the way that the information was used differed between them. Whereas thelytokous females used foraging
information to maximize their efficiency at high patch-encounter rates, arrhenotokous females merely reduced the number of
offspring produced without changing patch times. The behavior of the arrhenotokous females should result in a spreading of
offspring across the habitat and, thus, reduced sib-mating. The foraging strategy of these wasps might therefore be an adaptation
to reduce costs associated with inbreeding. 相似文献
5.
In solitary parasitoids, in which only one individual can emerge per host, the adaptive value of conspecific superparasitism is a function of the survival probability of the egg laid by the superparasitizing female. In the few cases which these probabilities are compared, the oldest immature has an advantage over the other individuals. We measured the acceptance rate of parasitized hosts and survival rate of supernumerary larvae in Anaphes victus (Hymenoptera: Mymaridae) in relation to the interval between ovipositions. When this interval was 5–7 days, the first immature was at the prepupa and pupa stage respectively, and female Anaphes victus changed their oviposition behavior markedly. They killed the developing parasitoid of their own species before ovipositing in it. The progeny of these females, which are normally primary parasitoids, developed thereafter as hyperparasitoids. Indeed, in contrast with other species, the survival of the second female's progeny increased with the time interval between ovipositions. This type of facultative intraspecific hyperparasitism is different from autoparasitism in Aphelinidae and has never been mentioned in other parasitoids; it would be adaptive if females of this short-lived species encounter low-quality patches. 相似文献
6.
Maryse Barrette Guy Boivin Jacques Brodeur Luc-Alain Giraldeau 《Behavioral ecology and sociobiology》2010,64(4):593-598
Models of prey choice in depleting patches predict an expanding specialist strategy: Animals should start as specialists on
the most profitable prey and then at some point during patch exploitation switch to a generalist foraging strategy. When patch
residence time is long, the switch to a generalist diet is predicted to occur earlier than when patch residence time is short.
We tested these predictions under laboratory conditions using female parasitoids (Aphidius colemani) exploiting patches of mixed instars aphid hosts (Myzus persicae, L1 and L4). The duration of patch exploitation was manipulated by changing travel time between patches. As predicted, patch
residence times increase with travel time between patches. Our results provide empirical support for the expanding specialist
prediction: Parasitoid females specialized initially on the more profitable hosts (L4), and as the patch depleted, they switched
to a generalist diet by accepting more frequently the less profitable hosts (L1). The point at which they switched from specialist
to generalist occurred later when travel times and hence patch residence times were short. By affecting the patch exploitation
strategy, travel time also determines the composition of hosts left behind, the “giving up composition.” The change in the
relative density of remaining host types alters aphid populations’ age structure. 相似文献
7.
Yannick Outreman Anne Le Ralec Eric Wajnberg Jean-Sébastien Pierre 《Behavioral ecology and sociobiology》2005,58(2):208-217
The present study aimed to address how an insect parasitoid makes patch-departure decisions from various types of host patches and how previous patch experiences in the environment modify this decision-making process. Experiments were done with the parasitic wasp Aphidius rhopalosiphi attacking the grain aphid Sitobion avenae. In the experiments, wasps were observed in a laboratory environment containing several patches of various host densities, and behavioural records were analysed using a Coxs proportional hazards model. Consideration of the effect of the within-patch experience gave a classic pattern of patch-leaving decision rules in parasitoids: A. rhopalosiphi used local information on host quality (i.e. numbers of ovipositions or rejections) and availability (i.e. patch density) to determine departure decision. However, consideration of previous patch experiences provided evidence that these departure rules are fundamentally dynamic, responding to the physiological state of the animal and the information it has about its environment. Results showed that A. rhopalosiphi decreased its tendency to leave the visited patch after an oviposition. However, when a female has already laid several other eggs in the environment, such an incremental mechanism gradually switched to a decremental one. Hence, A. rhopalosiphi responded to egg-load depletion by leaving the visited patches sooner and by depositing a smaller number of eggs in those patches, which probably led to a decreased level of superparasitism. Results also indicated that previous experiences enabled wasps to estimate spatial host distribution and then to adjust their behavioural decisions accordingly. Thus, A. rhopalosiphi was shown to adjust its patch residence time according to the quality and the number of the patches previously visited. These proximate mechanistic rules adopted by A. rhopalosiphi females are discussed in the context of general predictions from optimality models.Communicated by D. Gwynne 相似文献
8.
Bernard D. Roitberg Karen Zimmermann Thomas S. Hoffmeister 《Behavioral ecology and sociobiology》2010,64(4):627-637
Despite the multitude of work on patch time allocation and the huge number of studies on patch choice in the face of danger,
the patch leaving response of foragers perceiving cues of danger has received relatively little attention. We investigated
the response of parasitoid insects to cues of danger both theoretically and experimentally. Using stochastic dynamic theory,
we demonstrate that patch-leaving responses in response to the detection of danger should be seen as a dynamic decision that
depends upon reproductive options on the current host patch and on alternative patches that might be found after leaving the
current patch. Our theory predicts a sigmoidal response curve of parasitoids, where they should accept the danger and stay
on the patch when patch quality is high and should increasingly avoid the risk and emigrate from the patch with decreasing
patch quality and decreasing costs of traveling to an alternative host patch. Experiments with females of the drosophilid
parasitoid Asobara tabida that were exposed to a puff of formic acid (a danger cue) at different times through their patch exploitation confirmed the
theoretical predictions (i.e., a sigmoid response curve); however, the predicted curve was significantly steeper than observed.
We discuss the impact of dynamic patch-exit decisions of individual foragers on population and community dynamics. 相似文献
9.
The parsnip webworm, Depressaria pastinacella, specializes on wild parsnip, Pastinaca sativa, and several species of Heracleum, hostplants rich in toxic furanocoumarins. Rates of furanocoumarin metabolism in this species are among the highest known
for any insect. Within its native range in Europe, webworms are heavily parasitized by the polyembryonic parasitoid wasp Copidosoma sosares. In this study, we determined whether these parasitoids are exposed to furanocoumarins in host hemolymph, whether they can
metabolize furanocoumarins, and whether parasitism influences the ability of webworms to detoxify furanocoumarins. Hemolymph
of webworms fed artificial diet containing 0.3 % fresh weight xanthotoxin, a furanocoumarin prevalent in wild parsnip hosts,
contained trace amounts of this toxin; as well, hemolymph of webworms consuming P. sativa flowers and fruits contained trace amounts of six of seven furanocoumarins present in the hostplant. Thus, parasitoids likely
encounter furanocoumarins in host hemolymph. Assays of xanthotoxin metabolism in C. sosares failed to show any ability to metabolize this compound. Parasitized webworms, collected from populations of Heracleum sphondylium in the Netherlands in 2004, were on average 55 % larger by weight than unparasitized individuals. This weight is inclusive
of host and parasitoid masses. Absolute rates of detoxification (nmoles min−1) of five different furanocoumarins were indistinguishable between parasitized and unparasitized ultimate instars, suggesting
that the intrinsic rates of metabolism are fixed. Thus, although parasitized larvae are larger, detoxification rates are not
commensurate with size; rates in parasitized larvae expressed per gram of larval mass were 25 % lower than in unparasitized
larvae. 相似文献
10.
Vicarious sampling: the use of personal and public information by starlings foraging in a simple patchy environment 总被引:6,自引:0,他引:6
Group foragers may be able to assess patch quality more efficiently by paying attention to the sampling activities of conspecifics
foraging in the same patch. In a previous field experiment, we showed that starlings foraging on patches of hidden food could
use the successful foraging activities of others to help them assess patch quality. In order to determine whether a starling
could also use another individual’s lack of foraging success to assess and depart from empty patches more quickly, we carried
out two experimental studies which compared the behaviour of captive starlings sampling artificial patches both when alone
and when in pairs. Solitary starlings were first trained to assess patch quality in our experimental two-patch system, and
were then tested on an empty patch both alone and with two types of partner bird. One partner sampled very few holes and thus
provided a low amount of public information; the other sampled numerous holes and thus provided a high amount of public information.
In experiment 1, we found no evidence of vicarious sampling. Subjects sampled a similar number of empty holes when alone as
when with the low and high information partners; thus they continued to rely on their own personal information to make their
patch departure decisions. In experiment 2, we modified the experimental patches, increasing the ease with which a bird could
watch another’s sampling activities, and increasing the difficulty of acquiring accurate personal sampling information. This
time, subjects apparently did use public information, sampling fewer empty holes before departure when with the high-information
partner than when with the low-information partner, and sampling fewer holes when with the low-information partner than when
alone. We suggest that the degree to which personal and public information are used is likely to depend both on a forager’s
ability to remember where it has already sampled and on the type of environment in which foraging takes place.
Received: 31 January 1995/Accepted after revision: 11 September 1995 相似文献
11.
Summary Among insect parasitoids, superparasitism is said to occur when a second clutch of eggs is laid on a previously parasitized host. Ovicide occurs when a parasitoid destroys a clutch of eggs laid on a host by a previous female. Here, general models are constructed to predict the conditions which favor superparasitism and ovicide. Major predictions for the ovicidal model were that ovicide is more likely to occur if the time necessary to kill eggs is short, if travel times and the proportion of parasitized hosts increases and if the competitive advantage of a first clutch is large. The predictions of the models were tested by examining superparasitism and ovicide in Bracon hebetor (Say), a gregarious, ectoparasitoid of phytisiine moths. Using a wild and eye color mutant of B. hebetor to distinguish first and second clutches, it was found that the competitive advantage of a first clutch over a second clutch increased with the time between ovipositions. Patterns of superparasitism and ovicide in B. hebetor were in qualitative agreement with the major predictions of the model. Most notable, ovicide increased in frequency with a decrease in the overall rate of host encounter and an increase in the proportion of parasitized hosts encountered. 相似文献
12.
Status signals are traits that advertise an individual’s competitive abilities to conspecifics during aggressive disputes.
Most studies of status signals in birds have focussed on melanin-based plumage signals, but recent research shows that carotenoid-based
signals may also play a role in aggressive signaling. We assessed the relative importance of melanin- and carotenoid-based
plumage patches as agonistic signals in a small passerine, the golden whistler (Pachycephala pectoralis). Display signals in male golden whistlers include an unpigmented white throat patch, a carotenoid-based yellow breast and
nape band, and a melanin-based black chin-stripe. We found that only the white throat patch was correlated with contest-related
attributes. Males possessing large throat patches defended larger territories and commenced breeding earlier. When caged males
with either experimentally reduced, or unmanipulated throat patches were presented to conspecifics, those with experimentally
reduced patches attracted less aggression from male subjects. Focal males also responded faster to caged males with throat
patches similar in size to their own, suggesting that they may assess relative throat patch size before engaging in aggressive
encounters. Females did not discriminate between “reduced” or “control” treatments. Our data strongly suggest that only the
unpigmented throat patch functions as a status signal. As this signal is unlikely to have significant development costs, honesty
may be maintained through social costs. 相似文献
13.
Ideal free distribution (IFD) models are perhaps the group of mathematical models of behavior that have been the most widely
and successfully applied by empiricists. These models can be applied to nearly any situation in which consumers compete—by
any mechanism—for resources that are patchily distributed in their environment. Although IFD models have come to be broadly
accepted, experiments that simultaneously test more than a single prediction are rare. Instead, investigators normally either
test (1) for a relationship between the distribution of consumers and the distribution of resources or (2) whether average
fitnesses are equal across resource patches. We conducted experiments with pea aphids (Acyrthosiphon pisum Harris) feeding on two patches of fava beans (Vicia faba L.) to fully independently parameterize an IFD model with interference competition and then test quantitative predictions
about aphid spatial distributions and the payoffs of patch choice. We found a precise fit between aphids’ predicted and observed
reproductive successes. Furthermore, by varying patch “quality” in two ways, we were able to show that aphid distributions
vary with the mode of resource variation in the predicted manner: aphids (1) matched resources when patches varied in size
but not quality and (2) overmatched the good patch when patches varied in quality but not size (predicted as a consequence
of weak interference). The close correspondence between quantitative predictions of the model with observed behaviors suggests
that IFD theory is a framework with more explanatory power than is generally appreciated. 相似文献
14.
Munjong Kolss Thomas S. Hoffmeister Lia Hemerik 《Behavioral ecology and sociobiology》2006,61(2):291-304
A female parasitoid searching for hosts in a patch experiences a diminishing encounter rate with unparasitized and thus suitable hosts. To use the available time most efficiently, it constantly has to decide whether to stay in the patch and continue to search for hosts or to search for and travel to another patch in the habitat. Several informational cues can be used to optimize the searching success. Theoretically, encounters with unparasitized hosts should lead to a prolonged search in a given patch if hosts are distributed contagiously. The results of empirical studies strongly support this hypothesis. However, it has, to date, not been investigated theoretically whether encounters with already parasitized hosts (which usually entail time costs) provide a parasitoid with valuable information for the optimization of its search in depletable patches, although the empirical studies concerning this question so far have produced ambiguous results. Building on recent advances in Bayesian foraging strategies, we approached this problem by modeling a priori searching strategies (which differ in the amount of information considered) and then testing them in computer simulations. By comparing the strategies, we were able to determine whether and how encounters with already parasitized hosts can yield information that can be used to enhance a parasitoid’s searching success.
相似文献
Munjong KolssEmail: Phone: +41-26-3008856Fax: +41-26-3009698 |
15.
For a facultative kleptoparasite, the decision to allocate time and energy to search for a prey or for a kleptoparasite opportunity could be influenced by its prior experience. In this study, we investigated the influence of experience on the proportion of the facultative kleptoparasitoid Eupelmus vuilleti females choosing an unparasitized host or a host parasitized by Dinarmus basalis. When exploiting hosts previously parasitized by D. basalis, a large proportion of E. vuilleti females reused the hole drilled by the D. basalis female, which led to a reduction in the time needed to reach the host. When submitted to successive choice tests between an unparasitized host and a host parasitized by D. basalis in a natural host-plant system, the proportion of E. vuilleti females which choose the parasitized host increased with the female experience. The same experiment carried out with an artificial host-plant system allowing an easy access to the host did not show a variation of the females’ choice with experience. A reward—here a faster access to the host through the hole drilled by the D. basalis female—seems necessary to mediate the associative learning expressed by the preferential choice of the parasitized host. 相似文献
16.
Arne Janssen Jacques J. M. van Alphen Maurice W. Sabelis Kees Bakker 《Behavioral ecology and sociobiology》1995,36(4):229-235
Although there are many examples of the role of volatile infochemicals in interactions between trophic levels of insect communities, surprisingly little is known of volatile interactions between species within the third trophic level. Recently it was found that Leptopilina heterotoma, an endoparasitoid that attacks Drosophila larvae, avoids one type of patches (decaying stinkhorn mushrooms) when parasitoids of another species (L. clavipes) are present on these patches. L. heterotoma is able to smell the presence of L. clavipes from a distance (Fig. 1). In this paper we investigate the source of the odour that induces avoidance behaviour, by varying the host species and parasitoid species present on stinkhorn mushrooms, and by using another type of patch (sap-fluxes of wounded trees). L. heterotoma was found to avoid stinkhorn patches with conspecific as well as heterospecific parasitoids (Fig. 2). Hosts had to be present in the patch to elicit avoidance, but avoidance behaviour was also found with another host species present in the patch (Fig. 3). No avoidance behaviour was found with sap-flux patches with hosts and parasitoids on them (Fig. 4). Avoidance of stinkhorn patches only occurred when the parasitoids present on the patch were able to contact hosts (Figs. 5 and 6). The exact source of the odour that elicits avoidance is still unclear, so that one can only speculate on the function of the signal. However, there is a clear benefit to the receiver, because it is able to avoid superior competitors. Avoidance can lead to non-aggregated parasitoid distributions. The importance of avoidance behaviour for population dynamics and stability of parasitoid-host systems is discussed. 相似文献
17.
Diane Lefebvre Jacqueline Pierre Yannick Outreman Jean-Sébastien Pierre 《Behavioral ecology and sociobiology》2007,61(11):1707-1715
The patch living rules of a pollinator, the bumblebee Bombus terrestris L., are studied here in the framework of motivational models widely used for parasitoids: The rewarding events found during
the foraging process are supposed to increase or decrease suddenly the tendency of the insect to stay in the current patch
and therefore to adjust the patch residence time to the patch profitability. The foraging behaviour of these pollinators was
observed in two environment types to determine their patch-leaving decisions. The rich environment was composed of male-fertile
flowers, offering pollen and nectar, and the poor one of male-sterile flowers, offering little nectar and no pollen. The experimental
design consisted of a patch system in which inflorescences were evenly arranged in two rows (1 m distance). Residence times
of foragers inside inflorescences and rows were analysed by a Cox proportional hazards model, taking into account recent and
past experience acquired during the foraging bout. Most of the results showed a decremental motivational mechanism, that is,
a reduction in the residence time on the inflorescence or in the row related to exploitation of flowers within inflorescences
and inflorescences within rows These results indicate that bumblebees tend to leave the patch using departure rules similar
to those found in parasitoids. The results also provide information on the memory, learning and evaluating capabilities of
bumblebees especially when rich and poor environments were compared. The patch-leaving mechanism suggested by this study is
consistent with the central place foraging theory. 相似文献
18.
Within the framework of optimal foraging theory, models assume that parasitoid insects are able to evaluate the quality of the patch in which they are currently searching for hosts and the travel time between patches. They can adjust their residence time in consequence. Simple and more realistic decision mechanisms that induce behavior compatible with the predictions of these models have been proposed for a number of species. Most of these decision mechanisms only take into account the presence of unparasitized hosts. Here, we studied the consequences for leaving patches containing different proportions of unparasitized and parasitized hosts. We support the hypothesis that parasitoids sample their environment and we propose a binomial sequential model, based on the type of host encountered (unparasitized or parasitized) instead of on the time spent in a patch, to explain the giving-up behavior of a parasitoid in a patch. A motivational incremental/decremental stochastic process is proposed to explain a possible mechanism of the apparent sampling scheme followed by the insect. The empirical data support the hypothesis of a sequential, decisional, binomial sampling scheme performed with a limited memory. This memory is, in fact, more an effect of habituation than the "true memory" of the parasitoid. The theoretical model was applied to real data obtained with an encyrtid parasitoid. These data were also compared to realizations of the incremental/decremental process. 相似文献
19.
Summary The parasitic wasp, Telenomus remus, lays her eggs in diserete patches of moth eggs, where her offspring develop and mate before dispersal, satisfying conditions for local mate competition (LMC). In the presence of other ovipositing females, wasps lay a higher sex ratio (proportion males), as predicted by LMC theory, and achieve this by a combination of two mechanisms, (1) avoidance of superparasitism and a sequence of sex allocation initially biased towards males and (2) a direct increase in sex ratio in the presence of other wasps, sex ratio increases with the proportion of previously parasitized hosts, as predicted by LMC theory. In both cases, chemical traces left by foraging wasps are indicated as the stimuli causing wasps to increase the proportion of males allocated to hosts. 相似文献
20.
Oded Berger-Tal Shomen Mukherjee Burt P. Kotler Joel S. Brown 《Behavioral ecology and sociobiology》2009,63(12):1821-1827
Theory states that an optimal forager should exploit a patch so long as its harvest rate of resources from the patch exceeds
its energetic, predation, and missed opportunity costs for foraging. However, for many foragers, predation is not the only
source of danger they face while foraging. Foragers also face the risk of injuring themselves. To test whether risk of injury
gives rise to a foraging cost, we offered red foxes pairs of depletable resource patches in which they experienced diminishing
returns. The resource patches were identical in all respects, save for the risk of injury. In response, the foxes exploited
the safe patches more intensively. They foraged for a longer time and also removed more food (i.e., had lower giving up densities)
in the safe patches compared to the risky patches. Although they never sustained injury, video footage revealed that the foxes
used greater care while foraging from the risky patches and removed food at a slower rate. Furthermore, an increase in their
hunger state led foxes to allocate more time to foraging from the risky patches, thereby exposing themselves to higher risks.
Our results suggest that foxes treat risk of injury as a foraging cost and use time allocation and daring—the willingness
to risk injury—as tools for managing their risk of injury while foraging. This is the first study, to our knowledge, which
explicitly tests and shows that risk of injury is indeed a foraging cost. While nearly all foragers may face an injury cost
of foraging, we suggest that this cost will be largest and most important for predators. 相似文献