共查询到20条相似文献,搜索用时 31 毫秒
1.
Resource value is often considered the most important nonstrategic variable in the fighting behavior of invertebrates. In
our study, we tested whether the experience of shells of a given quality, occupied in the recent past, might affect the agonistic
behavior of the hermit crab Pagurus longicarpus. We analyzed the fights battled by 84 test crabs against size-matched unknown rivals before (premanipulation phase) and after
(postmanipulation phase) having modified the quality of the domicile shell of the contestants. Specifically, we compared the
behavior of crabs that had been subject to either a worsening or an improvement in the quality of their shell with crabs that,
although being similarly subject to a shell manipulation, occupied a shell of the same quality as in the premanipulation phase.
We found that the crabs subject to a worsening in the quality of their shell were more aggressive than those subject to its
improvement and that the former were even more aggressive than those that occupied a bad quality shell also in the premanipulation
phase. Crabs seemed not to gather information about the opponent’s shell during fights or not to use this information, most
often behaving in accordance with the quality of the domicile shell. These results are clear in showing the role played by
the experience of a previously occupied shell, also confirming that the agonistic behavior of P. longicarpus is mainly based on decision rules of the type “own resource value dependency.” 相似文献
2.
We examined the impact of dominance on crayfish social spacing and resource control. Spatial distributions of individual crayfish,
Orconectes propinquus, were recorded from five sample sites in Douglas Lake, MI, USA. Crayfish populations from each site were collected and then
immediately transferred to artificial ponds in order to reproduce potential dominance hierarchies. After 15 h of observation
in the artificial ponds, hierarchies were found to stabilize and dominance for each crayfish was scored based on the percentage
of total fights an individual won. These dominance scores were then regressed against nearest neighbor distance obtained from
field data, crayfish size, and shelter evictions observed during hierarchy formation. Dominant crayfish were found to have
greater nearest neighbor distances than lower ranking crayfish. In addition, as the difference in dominance score between
nearest neighbors increased, the distance between them also increased. Although claw size was an accurate predictor of dominance,
size did not correlate with nearest neighbor distance. Factors such as social dynamics may thus play a larger role in natural
crayfish populations than previously thought. Dominant crayfish also performed more shelter evictions during hierarchy formation,
which were correlated with nearest neighbor distance, suggesting that eviction by dominant crayfish may enforce spacing. Social
status appears to significantly impact crayfish spatial distribution and shelter acquisition such that more dominant crayfish
exhibit increased control over space and shelter. Finally, this study suggests the possibility that stable crayfish dominance
hierarchies exist in nature. 相似文献
3.
The locomotor activity patterns and agonistic encounters of cultured juvenile (IX–XIII stage) American lobsters, Homarus americanus (Milne-Edwards) held in 8 experimental environments were investigated to examine their relative contribution to aggressive level. Three variables: (1) lobsters individually or communally maintained, (2) shelters present or absent, and (3) open or closed seawater system were tested in a set of factorial experiments. Locomotor activity of lobsters held in a 12 h: 12 h light: dark regime was recorded for individually separated lobsters for the first 5 days and for communally held lobsters for the next 5 days of a 10-day experimental period. All lobsters maintained individually had similar levels of activity. When the same individuals were communally maintained, there appeared to be social inhibition of activity. In addition, communally held lobsters without shelter were twice as active as those provided with shelter. The activity levels of groups of communally held lobsters with shelter progressively decreased over the experimental period. All lobsters became somewhat entrained to the light: dark cycle and were nocturnally active. However, the degree of entrainment was strongly influenced (P<0.001) by the presence or absence of shelter and other lobsters. Individually maintained lobsters all showed good entrainment, although those provided with shelter were slightly better entrained. The presence of conspecifics desynchronized activity patterns when shelter was not provided. Aggressive level, as measured by the frequency of agonistic encounters per 15-min observation period and the number and types of displays per encounter, decreased over an 8-day period for groups of 3 lobsters in all experimental environments. Lobsters maintained in a closed system initially showed higher frequencies of agonistic encounters than those held in an open system. The observed decrease in aggressive level with time primarily resulted from decreased activity levels. When two lobsters met, the probability of an agonistic encounter was about 0.8 throughout the experimental period, but decreasing activity levels resulted in progressively fewer encounters. The results suggest several approaches for limiting aggression among communally maintained lobsters in culture systems by environmental manipulation. 相似文献
4.
Male Iberian rock lizards may reduce the costs of fighting by scent matching of the resource holders
Animals should adopt strategies to minimize the costs of intraspecific aggressive interactions. For example, individuals should
be able to identify resource holders in advance and avoid fighting with them because residents are generally more likely than
intruders escalate aggression. It has been suggested that scent marks function mainly to allow competitor assessment by conveying
the costs of entering a scent-marked area. Individuals may identify territory owners by comparing the scent of substrate marks
with the scent of any conspecific they encounter nearby, assessing whether these two scents match or not, a mechanism known
as scent matching. Here, we examined the response of male Iberolacerta cyreni lizards to areas scent-marked by other males and the potential role of scent matching in agonistic interactions. We designed
a laboratory experiment where we allowed a male to explore the scent-marked substrate of another male, and then we immediately
staged agonistic encounters in a nearby clean neutral area with either the male that had produced the scent marks (matching
treatment) or with a different non-matching individual male. The higher chemosensory exploratory rates of substrate scent
marks in comparison to clean substrates suggested that males detected and spent more time exploring scent marks to obtain
information on the donor male. Moreover, this information was later used to decide the fighting strategy. Intruding males
delayed time until the first agonistic interaction, reduced the intensity of fights and the number of aggressive interactions,
and won less interactions with males which scent matched that of scent marks (because they would be considered as the territory
owners) than with other non-matching individuals. Our results show that male I. cyreni lizards use scent matching as a mechanism to assess the ownership status of other males, which could contribute to modulate
intrasexual aggression, reducing costs of agonistic interactions. 相似文献
5.
Crayfish are excellent model organisms to study the proximate mechanisms underlying the maintenance of dominance hierarchies
in invertebrates. Our aim here was to investigate whether Procambarus clarkii males use social eavesdropping to discriminate dominant from subordinate crayfish. To this end, we conducted an experiment
composed of a “passive” and an “active” phase. In the passive phase, “focal” individuals were allowed (treatment 1) or not
(treatment 2) to see and smell two size-matched crayfish fighting while, in the subsequent active phase, they were allowed
to freely interact with the fighting dyad. None of the recorded variables showed any significant difference between the two
treatments, but, invariably, focal individuals were able to promptly discriminate dominant from subordinate crayfish. This
study provides evidence that male crayfish recognize the social status of a conspecific without the need of direct or indirect
experience with it and avoid dominants—and thus dangerous opponents—by means of a badge of status. A form of “winner and loser
effects” could also contribute to the structuring of dominance/subordinate relationships. The implication of these results
in understanding the maintenance of dominance hierarchies in invertebrates are discussed and compared with findings previously
achieved in the context of mate choice by P. clarkii females, who do appear to use eavesdropping to identify dominants and subordinates. 相似文献
6.
Ecological Impact of Introduced Crayfish on Benthic Fishes in a British Lowland River 总被引:5,自引:0,他引:5
Pacifastacus leniusculus (Dana), a native crayfish of western North America, was introduced into the U.K. in 1976. Our study examined some interactions between P. leniusculus and benthic fish in a British lowland river, the River Great Ouse. In a river survey an inverse correlation was found between the abundance of crayfish and the two dominant benthic fishes, bullhead (Cottus gobio L.) and stone loach ( Noemacheilus barbatulus [L.]) in six riffles. The benthic fishes were least abundant in the riffle nearest the original site of crayfish introduction and gradually increased in abundance both up and down river as crayfish abundance decreased. The hypotheses that crayfish compete with bullheads and stone loach for shelter and prey on fish were tested by laboratory experiments in an outdoor artificial stream (6 × 2 m) with recirculating water and 12 artificial shelters on the bottom. In competition experiments 12 fish of one species were alternatively kept alone and with 12 crayfish for 3-day cycles lasting a total of 12 days. The results showed that crayfish out-competed both fish species for shelter. Predation was measured by keeping 24 fish of each species alone and with 36 crayfish for 10 days respectively in the artificial stream. The mortalities of both fish species were significantly higher when crayfish were present. The loss of fish could be partly due to predation because crayfish guts contained the remains of some lost fish and they were observed preying on both fishes in a tank. In the river crayfish lived at high densities reaching ≥ to 20 m−2 in riffles, and they continued to disperse. This may lead to a great reduction in benthic fish abundance if not local extinctions. 相似文献
7.
Contests often occur between members of the same sex when they compete for access to mates, but inter-sexual contests may
occur over access to other essential resources such as food or shelter. Despite the possibility that such contests are common,
most studies focus on male fighting, and very few have analysed fights between males and females. Because males and females
differ physically and physiologically, fighting ability or resource-holding potential (RHP) may also be subject to inter-sexual
variation. In this study, we investigate size-controlled inter-sexual contests over the ownership of empty gastropod shells
in the hermit crab Pagurus bernhardus. During these fights, there are two roles, attacker and defender, and we use a fully orthogonal experimental design to compare
the performance of males and females in each role, when fighting either a male or female opponent. Although females fight
more intensely, male attackers have an advantage when compared to females playing the attacker role, as they are more likely
to evict the defender from its shell and thus win the resource. Further, in the defender role, male defenders are subject
to shorter attacks than female defenders. The differences in agonistic performance could not be attributed to differences
in perceived resource value between the sexes or to differences in body or weapon size. There are clear differences in the
agonistic behaviour of males and females, and this possibility should be incorporated into models of contest behaviour. In
particular, evolutionarily stable strategies may be expected to vary with sex ratios. 相似文献
8.
Alejandra Valero Robyn Hudson Edgar Ávila Luna Constantino Macías Garcia 《Behavioral ecology and sociobiology》2005,59(2):262-269
When approached by males, females of the Amarillo fish (Girardinichthys multiradiatus) perform a behaviour called vibration or they are aggressively challenged. We quantified vibration and assessed whether it compromises the rate of feeding attempts in dyads kept in outdoor enclosures. Male approaches resulted in female vibration and in a reduced feeding rate. Vibration was not evoked by female–female aggression, which was frequent and always ended in the subordinate fleeing from the dominant female. Using a closed respirometer we found that vibration is costly; oxygen consumption of females was greater in the presence of a male (which evoked vibration) than in the presence of a non-familiar female (when no vibration occurred). By recording interactions of females confined in aquaria in the presence and in the absence of males, we confirmed that escaping is the only available response to deal with female aggression. Females kept without males participated in frequent aggressive (even lethal) interactions that did not abate while the subordinate female was in sight of the dominant, and which caused premature births and injuries. Yet in the alternative treatment aggression ceased when a male approached, prompting vibration in both females. Thus, in the Amarillo, in as much as it evokes energetically costly female vibrations, male courtship is an expression of sexual conflict. However, in the absence of males, frequent female aggression potentially annuls the benefits of not vibrating. We propose that a complete appraisal of the consequences of sexual conflict must include an assessment of the costs imposed by intra-sexual interactions. 相似文献
9.
The establishment of dominance hierarchies through aggressive interactions is very common in insect societies. In many cases,
it is also mediated through pheromone emissions that enable individuals to evaluate the reproductive quality and level of
aggressiveness of the dominant individual, thereby reducing the number and intensity of costly fights. Here, we studied these
processes in the primitively eusocial bee Bombus terrestris, using a paired bee system. Specifically, we investigated the behavioral, reproductive, and pheromonal correlates of dominance
establishment. Workers were shown to establish dominance hierarchies using overt aggression within 3–4 days. Thereafter, the
aggression drastically decreased, and dominance was maintained mostly by ritualized agonistic behavior. The behaviorally dominant
bee lost the ester compounds that workers produce in their Dufour's gland (the so-called “sterility signal”) concomitantly
with the development of her ovaries. The other bee announced as subordinate by continuously producing high amounts of those
esters. The hypothesis that sterility signaling serves as an appeasement signal to pacify the dominant bees is supported by
the negative correlation found between the proportion of these esters and the level of aggression that the subordinate received
from the dominant worker. Physical interactions, and presumably also the ensuing overt aggression between the bees, were essential
for the above pheromonal change to take place and enabled the dominant workers to develop their ovaries and to lay eggs. The
subordinate bee’s signaling of non-reproductive status may minimize energy expenditure in costly fights and help stabilize
the reproductive division of labor among workers. 相似文献
10.
Jo McEvoy Geoffrey M. While David L. Sinn Erik Wapstra 《Behavioral ecology and sociobiology》2013,67(1):79-90
Competition between males is a key component of the agonistic intrasexual interactions that influence resource acquisition, social system dynamics, and ultimately reproductive success. Sexual selection theory predicts that traits that enhance success in intrasexual competition (particularly male–male competition) should be favored. In vertebrates, this often includes body size and aggression, with larger and/or more aggressive males outcompeting smaller or less aggressive conspecifics. The majority of studies consider aggression as a flexible trait which responds to local social or environmental conditions. However, aggression frequently shows considerable within-individual consistency (i.e., individuals have identifiable aggressive behavioral types). Little is known about how such consistency in aggression may influence competition outcomes. We integrated a detailed field study with a laboratory experiment to examine how a male’s aggressive phenotype and his size influence competitive interactions in Egernia whitii, a social lizard species which exhibits strong competition over resources (limited permanent shelter sites and basking sites). Individual aggression and size did not predict competition outcome in the laboratory nor did they predict home range size, overlap, or reproductive success in the field. However, winners of laboratory trial contests maintained consistent aggressive phenotypes while consistency in aggression was lost in losers. We suggest that aggression may be important in other functional contexts, such as parental care, and that alternative traits, such as fighting experience, may be important in determining competition outcome in this species. 相似文献
11.
G. W. Uetz William J. McClintock Douglas Miller Elizabeth I. Smith Kristina K. Cook 《Behavioral ecology and sociobiology》1996,38(4):253-257
Males of the brush-legged wolf spider Schizocosa ocreata (Hentz) have conspicuously decorated forelegs used in courtship and agonistic displays. Approximately one in five juvenile
males has a missing or regenerating foreleg, and regeneration of a leg lost during development usually results in the absence
of a decorative tuft on that leg. The subsequent asymmetry in this male secondary character significantly decreases success
in both courtship of females and male-male agonistic interactions. Experimental removal of tufts from one leg of previously
successful symmetric males produces similar results. As a test for concomitant behavioral effects, female spiders were shown
video images of a courting male with symmetric tufts and the same video image altered to have asymmetric tufts. Female receptivity
to the asymmetric video image was lower. In contrast to fluctuating asymmetry resulting from developmental instability, leg
tuft asymmetry in S. ocreata most likely arises from a single event during ontogeny – possibly leg loss from an aggressive or predator encounter – and
may serve as a quality indicator in female mate choice.
Received: 27 July 1995/ Accepted after revision: 19 November 1995 相似文献
12.
The influence of predation risk and food deprivation on the behavior and activity of juvenile American lobsters, Homarus americanus Milne Edwards, was examined in single and paired individuals in laboratory experiments performed during 1988 and in the winter
of 1991/92. In the presence of a predator (the tautog Tautoga onitis Linnaeus) restrained behind a barrier, single lobsters significantly reduced the time spent feeding at night, consumed fewer
mussels, and quickly brought them back to shelter. Single lobsters did not forage during the day in any treatment. If deprived
of food for 60 h, they consumed more mussels and spent more time walking than recently fed (12-h food-deprived) lobsters.
Paired lobsters did forage during the day in the presence of a predator. The smaller lobsters (subdominant) in the pairs foraged
for a longer time in the presence than in the absence of a predator and significantly longer than single individuals. Shelter
occupancy was significantly shorter in single, recently fed lobsters in the presence of a predator compared to time spent
sheltering in its absence. Among food-deprived lobsters, paired individuals spent a significantly shorter time within the
shelter than single lobsters in the absence of a predator. Larger (dominant) lobsters, however, spent more time than subdominant
lobsters within the shelter during all periods of the day. Without a predator, paired lobsters spent significantly more time
than single ones in shelter-related activities. Under predation risk, subdominant lobsters concentrated shelter-building time
during the day and built a higher percent of alternative shelters than either single or dominant lobsters. In the absence
of a predator, paired lobsters walked in the open area for a significantly longer time than single ones in the absence of
a predator. This apparently was associated with fighting between dominant and subdominant lobsters and the attempts of the
larger lobster to drive the smaller one from its shelter. During the day, lobsters fought for a significantly longer time
in the presence than in the absence of a predator. When the tautog was not constrained, mortality rate was similar in both
single and paired lobsters. Mortality rate among subdominant lobsters, however, was seven times higher than among dominant
lobsters. We suggest that the risk of predation interferes with the ability of single juvenile lobsters to acquire and consume
food. They appear to trade off energetic consideration against risk of predation when foraging away from the shelter. The
introduction of a conspecific competitor to the system may further increase risk (of the subdominant) to the predator. Intraspecific
interactions tend to increase the risk of predation to smaller lobsters but increase the survival rate among larger lobsters.
Received: 6 February 1995 / Accepted: 2 September 1997 相似文献
13.
The small cichlid fish Neolamprologus multifasciatus is endemic to Lake Tanganyika and is unique among fish because it lives in complex social groups with several reproductive
males and females, all of which participate in defending their territory against neighbors and intruders. Individuals use
empty snail shells for breeding and shelter. Previous parentage analysis using microsatellites suggested occasional exchange
of individuals between groups. In field experiments, we found that females showed a higher tendency than males to migrate
into territories already occupied by a resident pair. The phenomenon and causes of female-biased immigration were further
investigated in aquarium experiments: Nine of 15 females, but only 2 of 15 equally sized males, settled in territories of
established pairs. Territorial males exhibited more aggression toward strange males (potential reproductive competitors) than
toward strange females (potential additional mates); their females were more aggressive toward strange females (probably competitors
for shells) than toward strange males. Apparently, a conflict exists between the sexes regarding the immigration of additional
females. This conflict seems to be the selective basis for observed active male interference in aggressive disputes between
females in the territory. Interfemale tolerance in a group was greater in the male’s presence than in his absence.
Received: 1 February 2000 / Received in revised form: 2 May 2000 / Accepted: 5 May 2000 相似文献
14.
Francesca Gherardi 《Behavioral ecology and sociobiology》2006,59(4):500-510
A study was conducted to determine whether asymmetries in both resource-holding potential (RHP) and resource value (RV) influence
dominance and fighting behavior in the hermit crab Pagurus longicarpus. A total of 120 groups of three crabs were observed for 10 min in four experiments that tested all diverse combinations of
equal/different RHP (i.e. ‘body size’) and equal/different RV (i.e. ‘shell size’ and ‘shell quality’). In a fifth experiment,
dominant and subordinate individuals of the same size category (26 groups) were forced to enter shells of opposite quality
than those previously occupied, and then the behavior of the reconstituted original groups was observed for additional 10 min.
As expected, crabs in lower quality shells were more willing to initiate and to escalate fights. However, their attacks were
directed to any crab of the group, independently of the defender's shell quality, and the fight duration did not vary with
the different value of the resources at stake. This may indicate that P. longicarpus is unable to assess the quality of the shells available in its social environment but bases its tactical decisions during
fights solely on its own resource. This suggestion was confirmed by the change in the fighting behavior of crabs whose shell
quality was experimentally altered. This manipulation induced an overall increase in the intensity of aggression, drastic
modification of crab behavior, and inversion of the hierarchy even though these crabs have had previous experiences of wins/losses
and were familiar to the other members of the group. In this species, large crab size and/or the occupancy of adequate (and
oversized) shells appeared to be the most likely determinant of contest resolution. Individuals seemed to retain a memory
of the previously held resource and behaved accordingly. 相似文献
15.
Animals often prefer areas containing physical structure, and population density often increases with structural complexity, presumably because physical complexity in habitats may offer protection from predators and aggressive competitors. Consequently, increased habitat complexity often results in reduced territory size, lower aggression levels and reduced resource monopolisation by dominants. If behavioural plasticity is limited at early life stages, increased habitat complexity may reduce the relative fitness of aggressive, dominant strategies. Here we tested this hypothesis in an experiment on newly emerged brown trout (Salmo trutta) fry. We show, for the first time, that increased habitat complexity reduces the fitness (i.e. growth rate) of aggressive dominant individuals in relation to subordinates, and that this relation is reversed in simple habitats. Variation in environmental complexity may thus induce fluctuating selective pressures, maintaining behavioural variation in natural populations and allowing subordinate and dominant strategies to coexist. 相似文献
16.
Determinants of social dominance and inheritance of agonistic behavior in an island population of silvereyes,Zosterops lateralis 总被引:1,自引:0,他引:1
Jiro Kikkawa James N. M. Smith Robert Prys-Jones Paul Fisk Carla Catterall 《Behavioral ecology and sociobiology》1986,19(3):165-169
Summary We examined components of agonistic behavior and dominance in parents and offspring of silvereyes on Heron Island, Great Barrier Reef, to discover their determinants. The data were collected over four years on 1,235 juveniles and their parents. Of four behavioral characters used to compare juveniles and their parents, bill clattering was seen significantly more among young from female parents that exhibited bill clattering. The total absence of submissive behavior and the total absence of aggressive behavior were shown more often than not by young from dominant male parents and subordinate female parents, respectively. Young fledging early in the breeding season tended to be more dominant than those fledging late in the season. The number of brood-mates or the local nest density did not affect the dominance of young. Dominance status appears to be little affected by the performance of parents. 相似文献
17.
Summary. In amphibians and fishes, evidence is increasing that chemical cues from injured conspecifics can play a role in the chemical
labelling and learned recognition of unfamiliar predators. In this laboratory study, we tested the prediction that prior chemical
exposure to a non-native predator feeding on conspecific tadpoles will subsequently allow tadpoles of the common toad (Bufo bufo) to recognize the chemical cues specifically released by this starved predator. Furthermore, we investigated the vulnerability
of this chemically-mediated process to herbicide contamination. With these aims in view, groups of tadpoles were kept either
unexposed or exposed for ten days to chemical cues from Turkish crayfish (Astacus leptodactylus) previously fed on tadpoles, both in uncontaminated water and in the presence of four sublethal concentrations of amitrole
(0.01, 0.1, 1 and 10 mg.l−1). We then assessed the effects of the six conditioning treatments on general activity and behavioural response to chemical
cues from starved crayfish. Larval treatments did not affect the general activity of the tadpoles. By contrast, the treatments
had significant effects on the behavioural response to the test solution prepared form starved crayfish. The only tadpoles
to show an antipredator behavioural response to the chemical stimulation from starved crayfish belonged to the groups derived
from chemical exposure to tadpole-fed crayfish in uncontaminated water and in contaminated water with the lowest concentration
of amitrole (0.01 mg.l−1). Conversely, this chemical stimulation produced no behavioural change in the control group or in the groups derived from
exposure to tadpole-fed crayfish in contaminated water containing 0.1, 1 and 10 mg.l−1 of amitrole. This study demonstrates that chemical cues released during the predator’s feeding activity can subsequently
be used by common toad tadpoles in the recognition of an unfamiliar predator. In addition, our results show that the presence
of sublethal amitrole concentrations can impair this recognition process. Such a pesticide effect might be especially detrimental
for amphibian populations threatened by invasive predators. 相似文献
18.
Natalie M. Sopinka Julie R. Marentette Sigal Balshine 《Behavioral ecology and sociobiology》2010,64(12):1947-1958
There is increasing concern for the disruptive effects seen in aquatic species exposed to environmental contaminants. However,
few studies have investigated the impact of such contaminants on the behavior of individuals living in exposed waters. Contaminant
exposure can affect animal populations by disrupting behaviors including feeding, locomotion, and mating. In this study, we
examined how living in an ecosystem polluted by combinations of polycyclic aromatic hydrocarbons, polychlorinated biphenyls,
and heavy metals (arsenic, cadmium, iron, lead, zinc) impacts contest behavior in the round goby (Neogobius melanostomus). Fish collected from heavily contaminated and cleaner sites in Lake Ontario were subjected to a resource contest to determine
the effect of these contaminants on aggression and the establishment of dominance hierarchies, which in turn influence access
to food, shelter, and mating opportunities. Dominance establishment (a clear resource winner) was less obvious among fish
from the contaminated site compared to the more stable hierarchies that formed between pairs of fish from the clean site.
Pairs of fish from the contaminated site performed more assessment displays compared to fish from clean sites. These results
suggest that the costs of living in an environment under exposure can shape behavioral repertoires. The altered conflict resolution
strategies of contaminated fish may reflect impaired cognitive function, sensory perception, and/or higher metabolic load
associated with aggression. This study provides support for the utilization of quantifiable behavioral differences as ecologically
relevant measures of contaminant exposure. 相似文献
19.
The costs and benefits of territory sharing for the Caribbean coral reef fish,Scarus iserti 总被引:1,自引:0,他引:1
Kenneth E. Clifton 《Behavioral ecology and sociobiology》1990,26(2):139-147
Summary Along the Caribbean coast of Panama, groups of unrelated female striped parrotfish, Scarus iserti, co-defend a common feeding territory. Field manipulations of group size and composition were performed to examine the benefits and costs accrued by dominant fish within these shared territories. Dominant fish benefit from the presence of relatively large subordinates because they share in the defense of the territory. Removals of these fish caused increases in defense time and decreases in feeding time for dominant group members. Dominants benefit from the presence of small subordinates because they increase the foraging efficiency of dominants. Removals of smaller subordinates caused reductions in the feeding time of dominant fish, although no changes in defense time occurred. Concurrently, dominant fish reduce costs of resource depletion by displacing subordinate group members from good food patches. Dominance interactions within a group reduce the amount of time subordinates spend feeding (subordinate individuals fed at higher rates following the removal of a dominant) and limit a subordinate's access to high quality resources. This combination of benefits and reduced costs ultimately contributes to the economic defensibility of a striped parrotfish territory and has led to the evolution of group territorial behavior in the absence of kin selection and cooperative parental care. 相似文献
20.
Food distribution is hypothesized to be important in determining the nature of female relationships within social groups of
primates. When food limits female reproductive success, spatially clumped foods are expected to produce strong, linear dominance
hierarchies within groups, whereas more spatially dispersed foods are expected to produce weaker or non-existent dominance
hierarchies. The association between food distribution and competitive relationships presumably occurs because clumped foods
are usurpable but dispersed foods are not. We examined the spatial distribution of food patches (trees) and patch size relative
to feeding behavior and agonistic interactions in vervets and patas monkeys, two closely related and sympatric species that
nonetheless differ in the strength of the female dominance hierarchy. Food patches of both patas monkeys and vervets were
small in size and randomly distributed in Acacia drepanolobium habitat. In contrast, in A. xanthophloea woodland, the habitat type that was exclusively used by vervets, food patches were larger and more spatially clumped. These
similarities and differences between and within species were correlated with similarities and differences in the strength
and linearity of their dominance hierarchies. Patas monkeys and vervets in A. drepanolobium habitat had dominance hierarchies that were weakly defined because there were relatively few agonistic interactions between
females. By contrast, in A. xanthophloea habitat, vervets had a stronger, linear dominance hierarchy characterized by a higher rate of agonistic interactions over
food. The covariation of agonistic interactions with patch size is discussed in relation to depletion time, another characteristic
that may covary with food distribution, and resource renewal rate, an important determinant of agonistic interactions in insectivorous
birds, fishes, insects, and mammals.
Received: 18 February 2000 / Revised: 5 September 2000 / Accepted: 26 September 2000 相似文献