共查询到20条相似文献,搜索用时 15 毫秒
1.
Juliana Valencia Elena Solís Gabriele Sorci Carlos de la Cruz 《Behavioral ecology and sociobiology》2006,60(3):399-404
In cooperatively breeding species, helpers may contribute to the success of the brood by increasing the number of independent offspring, but also, they may affect offspring condition and, hence, their survival and recruitment into the breeding population. This second type of benefits is rarely included in theoretical models or assessed in field studies. Immune response is a good proxy of individual quality and fitness, and there is good evidence that the performance of the immune system of chicks during the nestling phase is related to their chances of survival and future reproduction. However, no study has so far explored whether helpers at the nest might contribute to enhance immune functioning of nestlings in species with a cooperative breeding system. Here we investigate this issue in the azure-winged magpie (Cyanopica cyanus) and found for the first time a positive correlation between the number of helpers at nest and the cell-mediated immune response of nestlings. This effect was not explained by a general improvement of body condition of chicks because it was independent of individual variation in body mass or tarsus length. Our results suggest that helping can have subtle effects on the quality of offspring that may influence their survival and future reproduction. 相似文献
2.
Density and extra-pair fertilizations in birds: a comparative analysis 总被引:18,自引:0,他引:18
Møller and Birkhead (1992, 1993) reported that extra-pair copulations (EPCs) occur more frequently in colonial than dispersed nesting birds. We comprehensively reviewed published data to investigate how breeding density affects extra-pair fertilizations (EPFs). Within species EPFs appeared to increase with density: two of three studies on colonial breeders and six of eight on dispersed nesters showed increases in EPFs with increasing density. However, comparisons among species (n?=?72) revealed no evidence that EPF frequencies correlated with (1) nesting dispersion, (2) local breeding density, or (3) breeding synchrony, even when each of these variables in turn was held constant and phylogenetic relationships were taken into account via contrast analyses. Methodological and biological reasons for the disparity between observational studies of EPCs and molecular genetic analyses of EPFs are discussed. 相似文献
3.
Reproductive success in a low skew, communal breeding mammal: the banded mongoose, Mungos mungo 总被引:1,自引:1,他引:0
Jason S. Gilchrist 《Behavioral ecology and sociobiology》2006,60(6):854-863
In most cooperatively breeding species, reproduction is monopolised by a subset of group members. However, in some species
most or all individuals breed. The factors that affect reproductive success in such species are vital to understanding why
multiple females breed. A key issue is whether or not the presence of other breeders is costly to an individual’s reproductive
success. This study examines the factors that affect the post-parturition component of reproductive success in groups of communal-breeding
banded mongoose (Mungos mungo), where up to ten females breed together. Per-litter reproductive success was low (only 18% of pups survived from birth to
independence). Whilst singular breeding was wholly unsuccessful, there were costs associated with breeding in the presence
of increasing numbers of other females and in large groups. Synchronisation of parturition increased litter success, probably
because it minimises the opportunity for infanticide or decreases competitive asymmetry between pups born to different females.
There was no evidence of inbreeding depression, and reproductive success was generally higher in litters where females only
had access to related males within their group. I conclude that communal breeding in female banded mongooses represents a
compromise between the benefits of group-living and communal pup care on the one hand, and competition between females to
maximise their personal reproductive success on the other. Such conflicts are likely to occur in most communal breeding species.
Whilst communal breeding systems are generally considered egalitarian, negative effects of co-breeders on individual reproductive
success is still an issue. 相似文献
4.
Stephan J. Schoech Ronald L. Mumme John C. Wingfield 《Behavioral ecology and sociobiology》1996,39(2):77-90
To determine whether fundamental differences exist in the reproductive physiology of breeder and nonbreeder Florida scrub-jays
(Aphelocoma coerulescens), we compared plasma levels of testosterone (T) and luteinizing hormone (LH) in males, and estradiol (E2) and LH in females. Although male breeders had higher overall T and larger testes, nonbreeders’ T paralleled that of breeders,
and their testes were more than an order of magnitude larger than regressed testes. Breeder and nonbreeder males had equivalent
baseline LH, and equivalent changes in LH following a gonadotropin-releasing hormone (cGnRH-I) challenge. The T, LH and GnRH
challenge data indicate that nonbreeder males have functional hypothalamo-pituitary-gonadal (HPG) axes. We found no hormonal
evidence of inbreeding suppression in males: nonbreeders that did not live with their mothers and those that did had similar
T. Male nonbreeders that were exposed to E2-implanted females had higher T than did controls, suggesting that the lack of within-pair stimulation is a key factor in
whether an individual delays breeding. Female nonbreeders had E2 titres equal to or higher than breeders and neither basal LH nor LH following GnRH challenge differed by breeding status.
Nonbreeders’ ovarian follicles were smaller than breeders’, but were larger than they would be during the non-breeding season.
These data suggest that nonbreeders were primed for breeding and were simply waiting for an opportunity or a required stimulus.
Female nonbreeders that lived in a territory with an unrelated male breeder had significantly higher E2 than those that remained with their fathers. Similarly, nonbreeders that were captured away from their home territories had
elevated E2. However, nonbreeders that lived with their fathers had E2 that was equivalent to breeding females, suggesting that inbreeding avoidance may not be the primary factor leading to delayed
breeding in females.
Received: 13 June 1995 /Accepted after revision: 27 April 1996 相似文献
5.
Satoshi Awata Hiroyuki Munehara Masanori Kohda 《Behavioral ecology and sociobiology》2005,58(5):506-516
It is suggested that some fish of the genus Julidochromis, substrate-brooding Tanganyikan cichlids with biparental care, breed cooperatively with helpers. We studied the social system of J. ornatus in the wild and analysed genetic parentage using microsatellites. Within the studied population three patterns of social system were identified: monogamous pairs (61%, 44 of 72 groups), pairs with helpers (29%, 21), and polygamous harems with helpers (controlled by either a large female or large male owner; 10%, 7). In cooperatively breeding groups, the number of helpers at each nest ranged from 1 to 6 (median 1), and male helpers were more numerous than female helpers. In both sexes, the body size was different among individuals of different social status (harem owner > breeder > helper). Helpers and harem owners of both sexes exhibited brood defence although its frequency was low. The molecular analysis revealed that (1) the helpers were mostly unrelated to dominant breeders, (2) many helpers of both sexes contributed genetically to the next generations, (3) male helpers had high siring success (41% of young in total), and (4) large young unrelated to group members were detected at 30% of observed nests, which may be due to breeder (or helper) replacements and immigration of young. We discuss the implications of these results for understanding the complex social system of this species, especially the low reproductive skew in comparison with other cooperatively breeding cichlids. 相似文献
6.
Malaria and risk of predation: a comparative study of birds 总被引:5,自引:0,他引:5
Predators have been hypothesized to prey on individuals in a poor state of health, although this hypothesis has only rarely been examined. We used extensive data on prey abundance and availability from two long-term studies of the European Sparrowhawk (Accipiter nisus) and the Eurasian Goshawk (Accipiter gentilis) to quantify the relationship between predation risk of different prey species and infection with malaria and other protozoan blood parasites. Using a total of 31 745 prey individuals of 65 species of birds from 1709 nests during 1977-1997 for the Sparrowhawk and a total of 21 818 prey individuals of 76 species of birds from 1480 nests for the Goshawk during 1977-2004, we show that prey species with a high prevalence of blood parasites had higher risks of predation than species with a low prevalence. That was also the case when a number of confounding variables of prey species, such as body mass, breeding sociality, sexual dichromatism, and similarity among species in risk of predation due to common descent, were controlled in comparative analyses of standardized linear contrasts. Prevalence of the genera Haemoproteus, Leucocytozoon, Plasmodium, and Trypanosoma were correlated with each other, and we partitioned out the independent effects of different protozoan genera on predation risk in comparative analyses. Prevalence of Haemoproteus, Leucocytozoon, and Plasmodium accounted for interspecific variation in predation risk for the two raptors. These findings suggest that predation is an important factor affecting parasite-host dynamics because predators tend to prey on hosts that are more likely to be infected, thereby reducing the transmission success of parasites. Furthermore, this study demonstrates that protozoan infections are a common cause of death for hosts mediated by increased risk of predation. 相似文献
7.
Behavioral and demographic changes following the loss of the breeding female in cooperatively breeding marmosets 总被引:3,自引:0,他引:3
C. Lazaro-Perea C. S. S. Castro R. Harrison A. Araujo M. F. Arruda C. T. Snowdon 《Behavioral ecology and sociobiology》2000,48(2):137-146
Recent models of the evolution and dynamics of family structure in cooperatively breeding vertebrates predict that the opening
of breeding vacancies in cooperatively breeding groups will result in (1) dispersal movements to fill the reproductive position,
and (2) within-group conflict over access to reproduction. We describe the behavioral and demographic changes that followed
the creation of breeding vacancies in three wild groups of cooperatively breeding common marmosets (Callithrix jacchus). Replacement of the breeding female was rapid when no adult females remained in the group, but did not occur for several
months when other adult females were present. Aggression of adult animals towards same-sex potential immigrants was associated
with a period of reduced affiliation, increased intragroup agonism, no intragroup sexual behavior, and frequent extragroup
copulations. This ended with the fissioning of groups along sexual lines. After replacement, multiple males copulated with
multiple females and vice versa, with no increases in sexually related aggression. Female-female conflict was resolved through
infanticide. The lack of direct conflict between males is consistent with cooperative polyandry. After a breeding vacancy
appeared, marmoset groups showed conflict of interests among group members similar to those shown by cooperatively breeding
birds, but they used different behavioral mechanisms to resolve those conflicts. Our data provide important evidence from
a cooperatively breeding mammal to support Emlen’s model for the evolution of vertebrate families, but they suggest that species-specific
inter- and intrasexual competitive strategies should be considered before the model can be applied to other cooperatively
breeding vertebrates.
Received: 23 November 1999 / Received in revised form: 28 March 2000 / Accepted: 1 April 2000 相似文献
8.
Karen J. Nutt 《Behavioral ecology and sociobiology》2007,61(11):1651-1663
Current mating system theory predicts that the number of females breeding in a group will depend on the number of females
in the group and the accessibility of unrelated males, whereas the number of males breeding in a group will depend on the
ability of males to control access to reproductive females. By combining information on group composition with genetic data,
I determined whether breeding patterns in a rock-dwelling rodent, Ctenodactylus gundi, were concordant with these expectations. C. gundi breeding patterns varied from facultative monogamy to uni-male polygyny to multi-male polygyny. The number of reproductive
individuals of each sex in a group increased with group size. Whereas communal breeding among related females tended to increase
female reproductive success, males breeding in the same group were unrelated to other group members and seemed to compete
over access to matings. While some males were assigned offspring from neighboring social groups, most group-living males successfully
monopolized the reproduction of females within their group. There was no evidence that females had multiply sired litters,
although some bred with alternative males in separate breeding attempts. Although numerous individuals were not assigned as
parents or offspring, genetic information enabled me to determine that most unassigned individuals were philopatric group
members, whereas only a few were unrelated immigrants into their current social group. Together, these results provide evidence
that C. gundi social groups represent fairly distinct reproductive units whose breeding patterns are dependent on group size and composition
in accordance with theoretical predictions.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
Family insurance: kin selection and cooperative breeding in a solitary primate (Microcebus murinus) 总被引:1,自引:0,他引:1
Lactation imposes substantial physiological costs on mothers and should therefore not be directed towards foreign offspring. Such allonursing, however, is common in mammal species that share roosts. Hypotheses to explain allonursing among such plural breeders include misdirected parental care, milk evacuation, brood parasitism, reciprocity, and kin selection. The necessary behavioral data, in combination with data on kinship and kin recognition, have rarely been available to distinguish among these explanations, however. In this study, we provide evidence for cooperative nursing and adoption by plural-breeding females in a nocturnal primate, the gray mouse lemur (Microcebus murinus), in which females forage solitarily during the night, but form day-time sleeping groups with one to two other females. We observed 34 resident females in an 8 ha study area in Kirindy Forest, Madagascar, over three consecutive annual breeding seasons and determined genetic relationships among all members of this population. Five sleeping groups of adult females were filmed inside their roosts during one breeding season after females gave birth. The composition of groups changed substantially across years, but they always consisted of close maternal relatives. All females within a group gave birth to one to three infants. They regularly transferred only their own offspring among roosting sites, demonstrating an ability to discriminate between their own and other’s offspring, but they regularly groomed and nursed related offspring other than their own and adopted related dependent young after their mother’s death. Kin selection may therefore be the main selective force behind cooperative breeding among these closely related females with a high mortality risk, providing each of them with family insurance. 相似文献
10.
Walter D. Koenig Eric L. Walters Joseph Haydock 《Behavioral ecology and sociobiology》2009,63(11):1659-1665
In cooperatively breeding acorn woodpeckers (Melanerpes formicivorus), helper males have a large positive effect on fledging success in good acorn crop years but only a small positive effect
in poor acorn crop years, while helper females exhibit the opposite pattern. Based on these findings, we tested the “concealed
helper effects” hypothesis, which proposes that laying females reduce investment in eggs (with respect to their size, number,
or quality) in a way that confounds helper effects and results in an absence of a relationship between helpers and breeding
success. Results generally failed to support the hypothesis. Mean egg size was positively related to temperatures during the
10 days prior to egg-laying and negatively related to the food supply as indexed by the prior fall’s acorn crop, but there
were no significant differences vis-à-vis helpers except for interactions with the acorn crop that only partly corresponded
to those predicted. With respect to clutch size, females laid larger clutches when assisted by female helpers, opposite the
pattern predicted. Although our results suggest that egg size is adjusted to particular ecological circumstances, we conclude
that neither egg nor clutch size is adjusted in a way that confounds the apparent effects of helpers, as proposed by the concealed
helper effects hypothesis. 相似文献
11.
Parasites are ubiquitous in populations of free-ranging animals and impact host fitness, but virtually nothing is known about the factors that influence patterns of disease risk across species and the effectiveness of behavioral defenses to reduce this risk. We investigated the correlates of malaria infection (prevalence) in Neotropical primates using data from the literature, focusing on host traits involving group size, body mass, and sleeping behavior. Malaria is spread to these monkeys through anopheline mosquitoes that search for hosts at night using olfactory cues. In comparative tests that used two different phylogenetic trees, we confirmed that malaria prevalence increases with group size in Neotropical primates, as suggested by a previous non-phylogenetic analysis. These results are consistent with the hypothesis that larger groups experience increased risk of attack by mosquitoes, and counter to the hypothesis that primates benefit from the encounter-dilution effect of avoiding actively-seeking insects by living in larger groups. In contrast to non-phylogenetic tests, body mass was significant in fewer phylogeny-based analyses, and primarily when group size was included as a covariate. We also found statistical support for the hypothesis that sleeping in closed microhabitats, such as tree holes or tangles of vegetation, reduces the risk of malaria infection by containing the host cues used by mosquitoes to locate hosts. Due to the small number of evolutionary transitions in sleeping behavior in this group of primates, however, this result is considered preliminary until repeated with a larger sample size. In summary, risk of infection with malaria and other vector-borne diseases are likely to act as a cost of living in groups, rather than a benefit, and sleeping site selection may provide benefits by reducing rates of attack by malaria vectors.Electronic Supplementary Material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
12.
村级养殖种植园区碳素物质流分析——以北京市平谷区西柏店村为例 总被引:1,自引:0,他引:1
将西柏店村畜禽养殖规模折合为1.5万头猪场当量污染负荷,并将整个园区生产工艺分为养殖、废弃物处理和种植3个阶段,不考虑隐藏流的情况下,以1年为系统边界,通过数据调查、已有资料研究和小区种植试验,采用物质流分析方法分析了西柏店村养殖种植园区在整个生产工艺的碳素流动,以期为村级养殖种植园区大力发展低碳经济提供新的方法和视角,为村级区域循环经济及可持续发展提供减少环境压力解决方案的科学依据。通过园区养殖种植过程的C素分析表明,养殖阶段年输入C素总量为112.52×10^4 kg,其中猪身总固碳量为40.04×10^4 kg,粪碳和尿碳总量为49.29×10^4 kg,以CO2形式代谢排出的C为23.19×10^4 kg。废弃物处理阶段输入的碳主要为粪碳和尿碳,其总量为49.29×10^4 kg,其中9.79×10^4 kg尿碳直接进入种植阶段,39.50×10^4 kg粪碳进入沼气站处理,沼气转化出的碳为11.02×10^4 kg,其中CH4为8.43×10^4 kg,CO2为2.59×10^4 kg,养殖污水中通过CH4排放再加上其他途径释放的碳约有23.66×10^4 kg,占粪碳量的59.89%。进入种植阶段的碳素主要为尿碳、沼渣和沼液的碳素,合计为14.61×10^4 kg,假设该村43 hm^2耕地能全部施用沼肥,不计其他作物种植,1季玉米种植土壤可库存有机碳为60.50×10^4 kg,为进入种植阶段碳素14.61×10^4 kg的4倍,还可增加植物有机碳27.31×10^4 kg。由C素流动分析可知,西柏店村具有可容纳该村养殖废弃物的环境容量,有较好实现养殖废弃物循环利用的条件,但需大力加强畜禽废弃物的管理和处理,提高园区养殖废弃物循环利用效率。 相似文献
13.
The number of males in primate social groups: a comparative test of the socioecological model 总被引:2,自引:2,他引:0
Charles L. Nunn 《Behavioral ecology and sociobiology》1999,46(1):1-13
As applied to polygynous mammals, the socioecological model assumes that environmental risks and resources determine the
spatial and temporal distribution of females, which then sets male strategies for monopolizing fertile matings. The effects
of female spatial distribution (i.e., female number) and temporal overlap (female mating synchrony) have been examined in
comparative studies of primates, but the relative influence of these two factors on male monopolization potential (the number
of males) remains unclear. One particular problem is that female synchrony is more difficult to estimate than female number.
This paper uses multivariate statistical methods and three independent estimates of female synchrony to assess the roles of
spatial and temporal effects in the context of a phylogenetically corrected dataset. These analyses are based on sensitivity
analyses involving a total of four phylogenies, with two sets of branch length estimates for each tree, and one nonphylogenetic
analysis in which species values are used (because male behavior may represent a facultative response to the distribution
of females). The results show: (1) that breeding seasonality predicts male number (statistically significant in six out of
nine sensitivity tests); (2) that expected female overlap, after controlling for female group size using residuals, also accounts
for the number of males in primate groups (significant in eight out of nine tests), and (3) that actual estimates of female
mating synchrony predict male number, again after correcting for female group size (significant in five out of nine tests).
Nonsignificant results are in the predicted direction, and female group size is significant in all statistical tests. These
analyses therefore demonstrate an independent influence of female temporal overlap on male monopolization strategies in mammalian
social systems.
Received: 24 July 1998 / Received in revised form: 5 February 1999 / Accepted: 7 February 1999 相似文献
14.
Phosphorus (P) sediment sorption is regarded as the most important buffering process against P increases in overlying water. In this study, two shallow eutrophic sediments (Mei and Hua) with distinct compositions were selected to assess effects of pH (from 6 to 9) and ionic strength (IS) (0, 0.001, 0.01 and 0.1 M KCl) on P sorption. In Mei sediments, the P sorption decreased as pH increased (6.97–9.13), but it increased as IS increased over the pH range in question. These results could be attributed to the negatively charged surface of Mei sediments, as indicated by the salt titration curve, and the high cation exchange capacity (CEC). P sorption in Hua sediments was facilitated by a pH increase (6.12–7.49), but it was hindered by an IS increase. A reasonable explanation for this phenomenon is that calcium phosphate precipitates at high pHs and that Cl? exchanges with P because the surface is weakly charged (small CEC). These results indicate that the sediment P sorption may have trends opposite to one another in relation to the salt change (e.g. drought and rainy season) in the lake water between the two sediments. These data provide additional support to explain P concentration variations in lakes. 相似文献
15.
Joseph J. Nocera Philip D. Taylor Laurene M. Ratcliffe 《Behavioral ecology and sociobiology》2008,62(11):1769-1777
Migrating animals face numerous mortality risks, such as novel predators with which they may not be accustomed. Most animals
can recognize predators innately; however, additional predator information can be collected to enhance familiarity. Because
migrating birds rarely participate in mobs, they may seek alternative information sources such as cues provided by other birds
that can provide information on predator location, identity, and degree of threat. We predicted that Nearctic–Neotropical
migrants (hereafter, “migrants”) would react to vocal antipredator cues (e.g., mob-calls) of species residing in areas through
which they migrate. To test this, we conducted experiments in Belize during spring migration, using playbacks of mob-calls
of black-capped chickadees (Poecile atricapillus) and blue-gray tanagers (Thraupis episcopus); tanagers are familiar to all birds in Belize; chickadees are novel to residents but familiar to migrants. This also allowed
us to assess response to novel and out-of-context antipredator signals. Resident birds did not respond to novel chickadee
mob-calls, but did respond to familiar tanager calls. Birds overwintering south of our study area, which were migrating during
our study, responded most strongly to chickadee playbacks. Conversely, individuals of species that include our study area
in their winter range did not respond to either playback. This is the first evidence that birds react to vocal antipredator
cues during migration, which may be a strategy used by migrants to learn about predators. Although residents failed to recognize
a foreign cue, migrating birds responded most strongly to the out-of-context chickadee cue, associated with breeding grounds
>2,000 km northward.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
Nepal formally embarked on decentralized participatory conservation programmes in 1990. To assess who participates in and benefits from such programmes, stratified random questionnaire surveys of 234 households and interviews with 29 user group chairs were conducted in the buffer zones of two protected areas of the Nepalese Terai: Bardia National Park and Suklaphanta Wildlife Reserve. The Poisson regression shows that gender, education, household affluence, and conservation attitudes were significant predictors of people's participation in decentralized conservation programmes, while family size, ethnicity and resource dependency were not. The benefits of participation outweighed the costs based on respondents' estimates. The performance of grassroots organizations and levels of participation were correlated. Nepal's decentralized participatory conservation has achieved efficiency, relative equity and effectiveness to some extent. Yet the central government should devolve more power to local communities to sustain the achievements as well as to provide more equitable benefits to residents to ensure the effectiveness and sustainability of conservation programmes. 相似文献
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19.
Cypermethrin and chlorpyrifos pesticide- (5, 15 and 30 ppm) induced effects on growth, metabolic and antioxidative behaviour of Azolla pinnata were analysed after 96 h of treatment. Growth of A. pinnata was increased by 72–76% over the initial mass under control condition. Further, the growth was decreased by 26 and 30% following treatment with 5 ppm of cypermethrin and chlorpyrifos, respectively, compared to control. Whereas, 30 ppm of pesticide treatment caused substantial decrease in biomass accumulation, even less than the initial mass. The Chlorophyll a content was declined at higher concentrations of chlorpyrifos, while carotenoids content increased significantly in the presence of both the pesticides. Photosynthetic rate showed declining trend with rising concentration of pesticides, while an increasing trend was noticed in the case of respiratory O2 consumption. The oxidative biomarkers malondialdehyde, superoxide radicals and hydrogen peroxide increased with increasing concentration of both the pesticides. The activity of enzymatic antioxidants enzyme superoxide dismutase, glutathione-S-transferase and ascorbate peroxidase (APX) was enhanced with increasing concentrations of both the pesticides; however, a declining trend was noticed in the case of APX at 30 ppm chlorpyrifos treatment. The study concludes that chlorpyrifos appeared to be more toxic than cypermethrin; however, both the pesticides significantly reduced the growth performance. 相似文献
20.
Marine Biology - During the breeding season 1996/97 we compared the foraging and diving behaviour of adult Magellanic penguins (Spheniscus magellanicus), growth rates of their chicks and their... 相似文献