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1.
Scott Nunes Peter A. Zugger Anne L. Engh Kurt O. Reinhart Kay E. Holekamp 《Behavioral ecology and sociobiology》1997,40(3):199-207
We examined the effects of food provisioning on the natal dispersal behavior of Belding's ground squirrels (Spermophilus beldingi). We provided extra food to adult and yearling females in their maternal territories during pregnancy and lactation, and
to offspring of these females in their natal areas for 6 weeks after weaning. We used unprovisioned young of unprovisioned
mothers as controls. Provisioning influenced the probability of dispersal from the natal area by female but not male S. beldingi. All surviving male S.␣beldingi dispersed by 55 weeks of age, regardless of whether they and their mothers received extra food. By contrast, we observed
a significant trend, beginning 3 weeks after weaning and continuing through the yearling year, for a greater proportion of
provisioned than control female S. beldingi to emigrate from the natal area. Competition for food did not appear to influence natal dispersal of females. However, overall
population density, density of females weaning litters, and rates of aggression and vigilance among these females, were higher
in provisioned than control areas, suggesting that competition for non-food resources was unusually intense in provisioned
areas. We propose that juvenile female, but not juvenile male, S. beldingi may emigrate from the natal site to increase access to areas with low densities of conspecifics. Together with findings of
earlier workers, our results suggest that spatial and temporal distributions of environmental resources are important influences
on the dispersal behavior of female ground squirrels.
Received: 28 February 1996 / Accepted after revision: 16 October 1996 相似文献
2.
Social monogamy and extra-pair fertilization in an Australian lizard, Tiliqua rugosa 总被引:3,自引:0,他引:3
C. Michael Bull Steven J. B. Cooper Ben C. Baghurst 《Behavioral ecology and sociobiology》1998,44(1):63-72
This study investigates social monogamy in the Australian sleepy lizard, Tiliqua rugosa. At a 70-ha site near Mount Mary, South Australia, we radio tracked 55 adult female and 39 adult male lizards during their
spring activity periods. Each lizard was observed in 1–5 years. Females were observed with a single male partner on an average
of 10.8 days per year, although in 17.3% of cases, females were observed on 2 or fewer days with a male. The most intense
pairing period each year was 15 September–15 November when females were with male partners on an average of 36% of observation
days. Partnerships lasted an average of 43.3 days each year. After mating in early November, the pairs separated. Observations
of females pairing with other males were rare. Most males (82%) were also consistently monogamous, although 7 were observed
pairing with 2 females within one season. To investigate paternity, we allowed 21 gravid females to give birth to 42 offspring
in the laboratory. We determined genotypes at five polymorphic microsatellite DNA loci for the females, their male partners
and their offspring. Four litters (19%) and 6 of the offspring from those litters (14.3%) showed evidence of extra-pair fertilization
(EPF). Although the sample sizes are small, females of polygynous males were more likely to experience EPF.
Received: 22 February 1998 / Accepted after revision: 23 May 1998 相似文献
3.
Neil J. Buckley 《Behavioral ecology and sociobiology》1997,41(4):267-279
In field tests of the information-center hypothesis (ICH) in south Texas with black vultures (Coragyps atratus) and turkey vultures (Cathartes aura), large carcasses were provided and kept under continuous observation. The use vultures made of these bait sites and their
patterns of arrival were recorded to evaluate predictions derived from the ICH. Turkey vultures discovered most bait sites
(30 of 31) first, but frequently were displaced from the food by later-arriving black vultures. This competitive exclusion
by black vultures limited subsequent feeding opportunities for turkey vultures sufficiently that few (27%) returned on subsequent
days to bait sites they had previously visited. I found no evidence that those turkey vultures that did return to bait sites
acted as leaders for groups of naive birds and led them to bait sites – knowledgeable and naive turkey vultures did not arrive
at bait sites together, and groups arriving at bait sites were not larger on subsequent days than on the first days carcasses
were available. In contrast, a significantly larger percentage (47%) of knowledgeable black vultures returned to bait sites
they had visited on previous days, and the first groups of black vultures arriving at bait sites on subsequent days were significantly
larger than the equivalent groups on first days. Nine flocks of black vultures that arrived on subsequent days at bait sites
before sunrise (which suggests the birds had commuted directly from a roost) contained knowledgeable birds, and two of these
flocks contained both knowledgeable and naive individuals. Overall, 10 of 54 naive tagged black vultures (18.5%) arrived at
bait sites under circumstances that suggested they had followed conspecifics to the food from a roost. However, most black
vultures apparently found carcasses through independent search or by using local enhancement. Therefore, I conclude that while
following from roosts to food sites is a strategy used by black vultures, at this study site it is one they use relatively
infrequently.
Received: 20 February 1997 / Accepted after revision: 28 June 1997 相似文献
4.
Friederike Range 《Behavioral ecology and sociobiology》2006,59(4):511-520
Sooty mangabeys are terrestrial monkeys exhibiting female philopatry and male dispersal. Studies in captivity as well as in the wild have found that adult females form linear dominance hierarchies. However, while captive studies found no evidence for a matrilineal social system, a previous study in Taï National Park, Ivory Coast, suggested that relatedness could influence both dominance rank and affiliation pattern among adult females. Here I test whether the dominance rank, coalitionary behavior, and affiliative behavior of juveniles in a group of free-ranging mangabeys in the Taï National Park are in accordance with a matrilineal, individual, or age-related dominance system. I found that juvenile females' dominance ranks remained stable over time and were highly correlated with the dominance ranks of their mothers, whereas juvenile males' dominance ranks were initially correlated with the ranks of their mothers, but showed greater instability with increasing age. Moreover, coalitions occurred mainly between juveniles and animals that were close in rank, including their mothers and siblings. Finally, juvenile females associated and groomed preferentially with close-ranking juvenile and adult females. Juvenile males showed similar preferences in affiliation with adult females, but when associating with juvenile males, they preferred peers. The observed social behavior of free-ranging juvenile sooty mangabeys resembled the social behavior described for juveniles of many matrilineal primate species. 相似文献
5.
Jill M. Goldstein Glen E. Woolfenden Jack P. Hailman 《Behavioral ecology and sociobiology》1998,44(1):15-22
Prebreeders of the Florida scrub-jay (Aphelocoma coerulescens) are less likely to be found on their natal territories with a same-sex stepparent than with parents or an opposite-sex stepparent.
We tested two models that had been proposed to account for this sexual asymmetry. The dominance hypothesis states that stepparents
perceive same-sex prebreeders as competitors, primarily for a mate, so behave aggressively toward them. The pair-formation
hypothesis states that prebreeders remain home to pair eventually with the opposite-sex stepparent. Predictions from these
two models were tested by analyses from a quarter-century of records on a study population at Archbold Biological Station
and by new behavioral field observations at the Station. Results clearly rejected the latter and strongly supported the former
hypothesis. No prediction from the pair-formation hypothesis was confirmed: no pairing by a prebreeder of either sex has ever
occurred with a stepparent; remaining home was equally frequent in age-one males with stepmothers and genetic mothers, and
in females with stepfathers and genetic fathers; and the same results were found in age-two prebreeders. By contrast, the
data strongly supported the dominance hypothesis. Field data showed higher aggression rates by stepfathers to male prebreeders
and stepmothers to female prebreeders than by parents to their same-sex genetic offspring. Fewer age-one males remained home
with a stepfather than with the genetic father, and the same was found for age-one females with a stepmother and genetic mother;
at age two, the effect occurred only in female prebreeders. The two hypotheses make different predictions about prebreeders
with two stepparents versus with both parents, thus providing a critical test. The dominance hypothesis correctly predicted
decreased duration at home by age-one males and females; data for age-two females were in the direction of predicted difference
but not significant; and, as in other tests, no effect was found for age-two males. We propose that age-two male prebreeders
remain home despite elevated aggression from stepfathers because these prebreeders retain the possibility of budding from
or inheriting the natal territory.
Received: 16 July 1997 / Accepted after revision: 26 June 1998 相似文献
6.
Studies of the otariids (fur seals and sea lions), a highly sexually dimorphic group, have provided conflicting evidence of
differential maternal expenditure in male and female offspring and, thus, suggestions that they conform to predictions of
investment theory are equivocal. Since the mid-1970s, a diversity of research on Antarctic fur seals (Arctocephalus gazella) including studies of their reproductive ecology, lactation energetics, and foraging behaviour have been conducted at Bird
Island, South Georgia that have resulted in one of the more complete and diverse data sets for any species of otariid. These
long-term data were reviewed to determine whether there was any evidence to support that differential maternal expenditure
occurred in Antarctic fur seals. Most of the data examined were collected during five consecutive austral summers from 1988
through 1992 and included years in which local food resources were abundant and scarce. We were unable to detect differences
in the sex ratios of pups at birth or sex-biased differences in growth rates estimated from serial data, the number of foraging
trips made, the duration of attendance ashore, diving behaviour, suckling behaviour, or milk consumption in any year and in
the duration of foraging trips or age at weaning in 2 of 3 years. In addition, we found no evidence of greater reproductive
costs between mothers with sons or daughters relative to their reproductive performance the following year. In contrast, sex-biased
differences were only found in the duration of foraging trips in 1990, the age at weaning in 1988, and consistently in growth
rates estimated from cross-sectional data. We suggest that differential maternal expenditure does not occur in Antarctic fur
seals because male pups probably do not gain greater benefit from additional maternal expenditure than female pups. After
weaning, males experience a period of rapid juvenile growth over 3–4 years during which time body mass nearly trebles. This
growth will almost certainly be dependent upon available food resources then rather than on any maternal expenditure received
over the first 4 months of life and, thus, the assumptions of the Trivers and Willard hypothesis are probably invalid for
Antarctic fur seals.
Received: 10 July 1996 / Accepted after revision: 3 March 1997 相似文献
7.
Xavier Lambin 《Behavioral ecology and sociobiology》1997,40(6):363-372
Numerous accounts of partial or complete breeding dispersal by adult females reported in the literature on microtines have
been interpreted as maternal bequeathal. However, for most species, no causal relationship between a female's movements between
successive litters and the settlement of her offspring in the natal range has been demonstrated. I tested predictions from
the bequeathal hypothesis using data from an intensive study of Townsend's voles where genetical relationship had been determined
by marking most pups in the maternal nest before weaning. After correcting statistically for temporal changes in the distance
moved between successive litters I rejected the following predictions: (1) that females with one or several daughters of reproductive
age should be more likely to disperse or disperse farther between successive births than females without such daughters; (2)
that mothers should be more likely to bequeath their range to their daughters in spring when the latter would gain most from
having ready access to a breeding range; (3) that daughters benefit from their mother abandoning the natal range through an
increase in their probability of recruitment; and (4) that daughters actually use the home range vacated by their mother.
I critically reassess the empirical studies quoted as evidence that breeding dispersal is a form of parental investment in
microtines and other mammals. Most empirical studies cited in support of the bequeathal hypothesis often only contain anecdotal
reports of movements by breeding females or do not mention it as one of its possible adaptive functions. Some studies contain
evidence only consistent with the bequeathal hypothesis whereas others are incompatible with this explanation. Documented
evidence of bequeathal comes exclusively from species which rely on a semi-permanent resource such as a midden, mound or burrow.
I conclude that there is no indication from Townsend's voles or any other microtines that females abandon their breeding range
to their female offspring as a form of parental investment.
Received: 27 February 1996 / Accepted after revision: 1 March 1997 相似文献
8.
We examined patterns of concurrent multiple mating in a live-bearing poeciliid fish, the sailfin molly (Poecilia latipinna). We tested whether the probability of multiple paternity was related to female body size or fertility and whether the rate
of multiple paternity varied among four populations that differed in their distributions of female body size and fertility.
We analyzed data on mother and offspring genotypes for three polymorphic allozymes by three techniques, including a maximum-likelihood
estimator that accounts for sampling error in both parental and offspring allele frequencies. The estimated rate of multiple
paternity varied between 0.09 and 0.85, and the rate in one population varied seasonally between 0.33 (spring) and 0.85 (autumn).
The variation in these rates was not associated with variation in body-size distributions among populations but was closely
associated with variation in size-specific fertility: populations with greater variation in female fertility had higher multiple-paternity
rates. Within two populations, logistic regression revealed that individual females of larger body size and greater size-specific
fertility were more likely to carry multiply sired broods. This result is consistent with observations made in one of the
populations 5 years earlier. In general, the results strongly suggest that the mating system varies markedly among conspecific
populations of sailfin mollies and that larger, more fertile females are the objects of intermale competition.
Received: 6 May 1996 / Accepted in revised form: 5 December 1996 相似文献
9.
Jay D. Evans 《Behavioral ecology and sociobiology》1998,44(1):35-42
Most social groups have the potential for reproductive conflict among group members. Within insect societies, reproduction
can be divided among multiple fertile individuals, leading to potential conflicts between these individuals over the parentage
of sexual offspring. Colonies of the facultatively polygynous ant Myrmicatahoensis contain from one to several mated queens. In this species, female sexuals were produced almost exclusively by one queen.
The parentage of male sexuals was more complex. In accordance with predictions based on worker sex-allocation preferences,
male-producing colonies tended to have low levels of genetic relatedness (i.e., high queen numbers). Correspondingly, males
were often reared from the eggs of two or more queens in the nest. Further, over half of the males produced appeared to be
the progeny of fertile workers, not of queens. Overall investment ratios were substantially more male biased than those predicted
by genetic relatedness, suggesting hidden costs associated with the production of female sexuals. These costs are likely to
include local resource competition among females, most notably when these individuals are adopted by their maternal nest.
Received: 3 March 1998 / Accepted after revision: 20 June 1998 相似文献
10.
A. D. Tucker H. I. McCallum C. J. Limpus K. R. McDonald 《Behavioral ecology and sociobiology》1998,44(2):85-90
We compared natal dispersals of freshwater crocodiles (Crocodylus johnstoni) against the prediction of male dispersal bias for a polygynous mating system. The crocodiles inhabited a linear series of
pools and we calculated the net distances from natal pools to recapture locations some 12–18 years later, at maturity. Philopatry
was assessed in terms of adult social distances. A female social distance was 0.46 pools and a male social distance was 1.0
pool. By these criteria, both sexes showed low levels of philopatry (7–12%). However, individuals of both sexes dispersed
from the natal site long before they were sexually mature. Divergence in dispersal patterns by sex occurred after the maturity
threshold, as males dispersed two to three times farther than females. Intrasexual competition by males is resolved by a size-based
hierarchy. The displacement of small males from local mating access is a probable cause of the longer dispersals undertaken
by males. Competition, rather than inbreeding avoidance, is driving dispersal in this population of freshwater crocodiles.
Received: 8 May 1998 / Accepted after revision: 26 June 1998 相似文献
11.
Brood sex ratio is dependent on female mating status in polygynous great reed warblers 总被引:2,自引:0,他引:2
Isao Nishiumi 《Behavioral ecology and sociobiology》1998,44(1):9-14
Females capable of adjusting the sex ratio of their offspring should be more fit than females lacking such an ability. In
polygynous birds where breeding success in males is more strongly influenced by body size and/or attractiveness than in females,
females might produce more sons when predicting good conditions or when mating with attractive males. Polygynous great reed
warbler, Acrocephalusarundinaceus, males direct most of their feeding effort to the primary (first-hatching) nest and in these nests increase their feeding
effort in relation to the brood sex ratio (proportion of sons). Therefore, with the expectation of well-nourished sons, we
would predict that females which start breeding first within harems might produce more sons than those which start breeding
later, and in anticipation of sons with good genes, that females mated to polygynous males might produce more sons than females
mated to monogamous males. I took blood samples from hatchlings and determined the sex using DNA markers. The sex ratio of
primary (monogamous and polygynous primary) broods is more male-biased (mean 0.58 males, n = 50) than that of secondary (polygynous secondary and tertiary) broods (mean 0.46, n = 25). Moreover, in the secondary broods with the largest clutch (five eggs), in which offspring are most likely to suffer
food shortage, the sex ratio was distinctively female biased (mean 0.33, n = 10). In the primary broods, sex ratio was correlated to harem size. The results suggest that great reed warbler females
modify the brood sex ratio to produce both well-nourished sons and sons with good genes, but the former effect is probably
stronger than the latter factor.
Received: 11 March 1998 / Accepted after revision: 23 May 1998 相似文献
12.
A molecular genetic analysis of social structure, dispersal, and interpack relationships of the African wild dog (Lycaon pictus ) 总被引:7,自引:0,他引:7
Derek J. Girman M. G. L. Mills Eli Geffen Robert K. Wayne 《Behavioral ecology and sociobiology》1997,40(3):187-198
The African wild dog is a highly social, pack-living predator of the African woodland and savannah. The archetypal wild dog
pack consists of a single dominant breeding pair, their offspring, and non-breeding adults who are either offspring or siblings
of one of the breeding pair. Non-breeding adults cooperate in hunting, provisioning and the protection of young. From these
observations follows the prediction that the genetic structure of wild dogs packs should resemble that of a multigenerational
family, with all same-sexed adults and offspring within a pack related as sibs or half-sibs. Additionally, a higher kinship
between females from neighboring packs should be evident if females tend to have small dispersal distances relative to males.
We test these predictions through analysis of mitochondrial DNA control region sequences and 14 microsatellite loci in nine
wild dog packs from Kruger National Park, Republic of South Africa. We show that as predicted, African wild dog packs generally
consist of an unrelated alpha male and female, subdominant close relatives, and offspring of the breeding pair. Sub-dominant
wild dogs occasionally reproduce but their offspring rarely survive to 1 year of age. Relatedness influences the timing and
location of dispersal events as dispersal events frequently coincide with a change in pack dominance hierarchy and dispersers
often move to areas with a high proportion of close relatives.
Received: 22 February 1996 / Accepted after revision: 16 November 1996 相似文献
13.
Coalitionary mate guarding by male chimpanzees at Ngogo, Kibale National Park, Uganda 总被引:13,自引:0,他引:13
David P. Watts 《Behavioral ecology and sociobiology》1998,44(1):43-55
Cooperative mate guarding by males is unusual in mammals and birds, largely because fertilizations are non-shareable. Chimpanzees
live in fission-fusion communities that have cores of philopatric males who cooperate in inter-group aggression and in defending
access to the females in their community. Male contest mating competition is restrained within communities, but single high-ranking
males sometimes try to mate guard estrous females. Data from an unusually large chimpanzee commmunity at Ngogo, Kibale National
Park, Uganda, that contains more males than any previously studied community show new variation in chimpanzee mate-guarding
behavior. Contrary to expectation given the large number of males, mate guarding was as common as, or more common than, at
other sites, and males other than the alpha male guarded more often. More strikingly, pairs or trios of top-ranking males
sometimes engaged in cooperative aggression to prevent estrous females from mating with other males, but tolerated each other's
mating activities. Both single males and coalitions mostly guarded periovulatory females. Mate-guarding coalitions were previously
unknown in chimpanzees. Coalitions occurred in large mating parties, seemingly because these often contained too many males
for single males to maintain exclusive access to estrous females. Coalition members gained higher shares of copulations than
they could have expected from solo mate guarding, and suffered lower per capita costs of guarding (as inferred from aggression
rates). Two males who most often participated in coalitions formed two-male coalitions at about the point where the number
of males present made it unlikely that either could get 50% or more of total copulations on his own, and formed trios when
this value dropped below 33%. Kin selection could be a factor in cooperation among male chimpanzees, but coalition members
were not necessarily close relatives and the apparent structure of payoffs fit that of mutualism. Furthermore, reliance of
male chimpanzees on support from allies to maintain high rank could have led to trading of mating exclusivity for support
against mating competitors.
Received: 28 May 1997 / Accepted after revision: 16 May 1998 相似文献
14.
Arjan M. Boonman Martijn Boonman Frank Bretschneider Wim A. van de Grind 《Behavioral ecology and sociobiology》1998,44(2):99-107
Daubenton's bat, a trawling vespertilionid bat species, hunts for insects that fly close to, or rest on, the water surface.
During summer, many ponds at which Daubenton's bats hunt become gradually covered with duckweed. The purpose of this study
was to investigate the effects of duckweed cover on the hunting behaviour of Daubenton's bats and on the ultrasound-reflecting
properties of the water surface. Our study revealed the following. (1) Daubenton's bat avoids water surfaces covered with
duckweed. (2) Prey abundance was related to the number of foraging Daubenton's bats but was independent of duckweed cover.
(3) When mealworms were presented among standardized amounts of duckweed to naturally foraging Daubenton's bats, they caught
significantly less mealworms when the duckweed cover was increased. (4) Measurements with ultrasonic signals show that a water
surface covered with duckweed returns a much stronger background echo at small angles (i.e. parallel to the water surface)
compared to an uncovered water surface. It seems likely that a cover of duckweed on the water surface interferes with prey
detection by masking the echoes returning from prey. (5) It was relatively difficult for the bats to discriminate small patches
of duckweed from mealworms. The proposed discrimination mechanism for this trawling bat species suggests that single duckweed
patches can also be mistaken for natural prey by Daubenton's bats.
Received: 4 January 1998 / Accepted after revision: 19 July 1998 相似文献
15.
We examined adult-juvenile conflict in the guanaco (Lama guanicoe). During spring, territorial males become increasingly aggressive toward all juveniles born the previous year and begin expelling them from family groups. In an apparent effort to reduce aggression, juveniles display submissive crouches when being observed, approached, or attacked by the territorial male. Therefore, we assessed the influence of juvenile submissive behavior on the timing of dispersal and also examined if dispersal time was related to survival and reproductive performance as adults. We also evaluated hypotheses regarding the evolution of juvenile mammalian dispersal in the context of if and how each may favor the forced dispersal of juvenile guanacos by territorial males. Juveniles generally dispersed in late spring and early summer, and a nearly equal proportion of females (n=46; 48%) and males (n=49; 52%) dispersed. More-submissive animals generally dispersed later than less-submissive animals. Juvenile sex and dispersal time were not related to survival. In contrast, juvenile sex and dispersal time were related to reproductive performance. The probability of reproducing was highest when juveniles dispersed early and decreased with increasing time in family groups prior to dispersal. The largest proportion of juveniles was forced to disperse during a 2-week interval following the peak of the breeding season. Competition for food resources is likely very intense at this juncture and territorial males may force older juveniles to disperse in order to divert food resources to younger neonates. Additionally, juveniles may be forced to disperse after territorial males mate their mothers to prevent lost mating opportunities, because females leave territories when their offspring disperse and possibly prior to mating with males. We conclude that the forced dispersal of juvenile guanacos by territorial males is ultimately driven by competition for food resources on territories. The timing of dispersal, however, may be tempered by the chronology of matings between territorial males and particular adult females, and/or genetic relatedness between territorial males and juveniles. 相似文献
16.
Corey R. Freeman-Gallant 《Behavioral ecology and sociobiology》1997,40(6):395-400
Empirical relationships between parentage and male parental care are commonly interpreted in the context of life-history
models that consider increased offspring survivorship as the only benefit of paternal effort. However, indirect benefits associated
with male care can also influence a male's response to cuckoldry: if females allocate paternity according to their prior experience
with male parental care, it may pay for males to provision extra-pair young in early broods. Here, I assess the relationship
between first-brood parentage and paternal care in a population of Savannah sparrows (Passerculussandwichensis) where a male's fertilization success in the second brood appears to be influenced by his prior parental performance. Based
on the multi-locus DNA fingerprinting of 17 first broods, male feeding effort was influenced by parentage (percent of brood
resulting from within-pair fertilizations) but not by brood size, male mating status (monogamous versus polygynous), timing
of breeding (hatching date), structural size (wing length) or condition (mass). Males provided more care to broods that contained
few within-pair young. This result supports the idea that males provision young to increase their future mating success, but
alternative hypotheses involving male quality and timing of breeding cannot be excluded.
Received: 13 August 1996 / Accepted after revision: 22 February 1997 相似文献
17.
Growth rate is a life-history trait often linked to various fitness components, including survival, age of first reproduction, and fecundity. Here we present an analysis of growth-rate variability in a wild population of savannah baboons (Papio cynocephalus). We found that relative juvenile size was a stable individual trait during the juvenile period: individuals generally remained consistently large-for-age or small-for-age throughout development. Resource availability, which varied greatly in the study population (between completely wild-foraging and partially food-enhanced social groups), had major effects on growth. Sexual maturity was accelerated for animals in the food-enhanced foraging condition, and the extent and ontogeny of sexual dimorphism differed with resource availability. Maternal characteristics also had significant effects on growth. Under both foraging conditions, females of high dominance rank and multiparous females had relatively large-for-age juveniles. Large relative juvenile size predicted earlier age of sexual maturation for both males and females in the wild-feeding condition. This confirmed that maternal effects were pervasive and contributed to differences among individuals in fitness components.Communicated by J. Setchell 相似文献
18.
A. Koenig 《Behavioral ecology and sociobiology》2000,48(2):93-109
Van Schaik’s socioecological model predicts interrelations among food distribution, competitive regimes, and female social
relationships. To test the internal consistency of the model, feeding competition was examined in three differently sized
groups of a forest-dwelling population of Hanuman langurs (Semnopithecus entellus). The nutritional condition of females was used as a direct indicator of feeding competition and related to the seasonal
variation in resource distribution and abundance. Female dominance hierarchies were characterized by displacements. Dominance
hierarchies were significantly linear and relatively stable, but less so with increasing group size. Physical condition correlated
with dominance rank and high-ranking females were in the best condition, indicating within-group contest competition. The
strength of this relationship became less pronounced with increasing group size. The females of the medium-sized group were
in the best physical condition indicating between-group contest plus within-group scramble competition. Closer examination
revealed variable costs and benefits of group foraging with a predominance of within-group scramble competition when food
was more abundant. The results support some basic predictions of the model. Limiting food abundance was bound to ubiquitous
within-group scramble competition. The use of clumped resources translated into differences in net energy gain based on dominance.
In contrast to the predictions, group-size-related costs and benefits were related to food abundance instead of food distribution.
As predicted, within-group contest competition was linked to a linear dominance hierarchy. The absence of nepotism and coalitions
in Hanuman langurs may be attributed to dominance hierarchies that are unstable through time, probably minimizing fitness
gain via kin support.
Received: 25 May 1999 / Received in revised form: 18 February 2000 / Accepted: 25 February 2000 相似文献
19.
Altered responses to female odors in parasitized male mice: neuromodulatory mechanisms and relations to female choice 总被引:5,自引:0,他引:5
M. Kavaliers D. D. Colwell K.-P. Ossenkopp T. S. Perrot-Sinal 《Behavioral ecology and sociobiology》1997,40(6):373-384
There is accumulating evidence that females may preferentially select parasite-free or -resistant males. Minimal attention
has, however, been paid to the mate preferences and responses of the parasitized male hosts themselves. Here, we considered
the effects of parasitic infection on male host mate responses, the neuromodulatory correlates of these responses, and the
relations of these responses to female mate choice. Using an odor “preference” test, we examined the effects of different
stages of an acute, sub-clinical infection with the naturally occurring, enteric, single host, protozoan parasite, Eimeria vermiformis, on the responses of male mice, Mus musculus domesticus, to the odors of estrous females along with the responses of uninfected females to the parasitized males. At 4 days post-infection
(non-infective, pre-patent stage) E. vermiformis-infected male mice showed a significantly decreased preference for the odors of estrous females, whereas at 10 days post-infection
(infective, patent stage) infected males showed a significantly increased preference for the odors of estrous females. Parasitized
males displayed no significant changes in their responses to the odors of non-estrous females, supporting effects on the reproductively
related responses of the host. In parallel, estrous females displayed a reduced interest in the odors of infected males. Least
interest was expressed in the odors of the patent, infective males, consistent with the avoidance of contagion. Using selective
opioid peptide receptor agonists and antagonists we found evidence that enhanced kappa opioid peptide (e.g., dynorphin) activity
was related to the decreased sexual interest of the pre-infective males, while augmented delta opioid peptide (e.g., enkephalin)
activity was associated with the enhanced responses of the infective males to females. We further showed that acute kappa
opiate administration reduced the responses of uninfected males to females and that uninfected females displayed modified
responses to the odors of uninfected males subject to acute modifications of opioid activity. We suggest that these differential
shifts in endogenous opioid activity in the parasitized males are associated with and, or related to alterations in neuro-immune
and endocrine functions. These findings show that parasitic infection can have, depending on the stage of infection and associated
neuromodulatory changes, either significant facilitatory or inhibitory effects on male host preferences for and responses
to females.
Received: 22 April 1996 / Accepted after revision: 15 March 1997 相似文献
20.
On the evolutionary stability of female infanticide 总被引:3,自引:0,他引:3
Territoriality among female rodents may have evolved as an adaptation to intraspecific competition for resources or, alternatively,
to defend pups against infanticide. In order to evaluate the latter, we analyse the conditions that allow an infanticidal
strategy to invade a population of non-infanticidal females, and the circumstances under which infanticide may become an evolutionarily
stable strategy (ESS). Our game theoretical analyses indicate that infanticide has to be associated with some direct (cannibalism)
or indirect (reduced competition) resource benefits in order to invade a non-infanticidal population. We also expect that
females will primarily kill litters of nearby neighbors, thereby removing the closest competitors while keeping costs at a
low level. However, once established in a population, infanticide may be an ESS, even if females do not gain any resource
benefits. This is theoretically possible if a female through infanticide can reduce the possibility that other, potentially
infanticidal, females establish and/or stay close to her nest. While behavioral data indicate that these special circumstances
sometimes occur, they may be too specific to apply generally to small rodents. Therefore, we expect that the evolutionary
stability of infanticide often requires resource benefits, and that female infanticide in small rodents may, in fact, be a
consequence rather than a cause of territoriality.
Received: 27 June 1996 / Accepted after revision: 28 December 1996 相似文献