共查询到20条相似文献,搜索用时 31 毫秒
1.
Carola Borries Volker Sommer Arun Srivastava 《International journal of primatology》1994,15(3):421-443
We studied grooming among adults of a one-male multifemale troop of free-ranging Hanuman langurs (Presbytis entellus)living near Jodhpur, India, for 9 years. The 11–13 females devoted about 6% of their day to allogrooming. Adult males, whose
tenures averaged 2.2 years, were transient figures in the troop's history, as reflected by their rather peripheral role in
the grooming network. Females groomed males 4–40 times more frequently (1006 episodes) than vice versa- (176 episodes). Adult
females received 97% of all grooming from other adult females (6655 episodes). Although females exhibited an age- inversed
dominance hierarchy, they did not compete for grooming access to particular troop mates. Dyads of all possible rank differences
occurred as frequently as expected: 51% of grooming was directed up the hierarchy and 49% down it. Young, high- ranking individuals
gave and received significantly more grooming than the oldest, low- ranking females did. The pattern seemed to be influenced
by kin selection because of the presumably high degree of female relatedness. They invested most in troopmates with the highest
reproductive value, i.e., the youngest individuals. This trend was coupled with a preference of closest kin (mothers and daughters).
Reciprocity was the outstanding feature since all adult females groomed and were groomed by all others. Such a tight social
net might establish the necessary cohesion during frequent territorial disputes with neighboring troops. 相似文献
2.
《新西兰生态学杂志》2011,30(2):273-278
The Wellington tree weta, Hemideina crassidens, is a harem-polygynous nocturnal insect whose males defend and mate groups of females residing in cavities in trees. In this study I examined sexual differences in gallery use (number of galleries occupied per unit time), distance travelled per night and activity patterns after sunset. In addition, I investigated how gallery size affected each of these variables. On average, males and females did not differ in the number of galleries visited per night, or in the distance they travelled per night; however, adult males were more likely to be seen earlier in the night than later. Although males and females did not differ in their gallery use or distance travelled, adult males occupied a significantly greater number of galleries and travelled greater distances per night at sites with small galleries than did males at sites with large galleries. These results suggest that habitat structure of a forest patch influences intrasexual tree weta behaviour. 相似文献
3.
Sommer S 《Animal behaviour》2000,59(6):1087-1094
Sex-specific predation on adult individuals is often predicted by different behaviour in males and females resulting from different reproductive strategies and social systems. High predation pressure and the need for biparental care are considered a possible ecological basis for the evolution of monogamy, the most puzzling social system in mammals. In species where adults and offspring are vulnerable to the same predators, males and females may protect their offspring to different extents because of conflicting demands of investment in current and future offspring. I present the first empirical data on age- and sex-specific predation pressure by top predators on a monogamous rodent and the sex-specific behavioural responses of the prey species to different rates of predation. During an annual predation peak, only offspring and adult males were killed but no females. Whereas males and females travelled similar distances at night before the period of high predation on offspring, males moved further during this period. At the same time, males and females increased their distance from their offspring but males stayed closer to them than females. As a consequence, the distance between the members of the pair increased during the predation peak. The males' behaviour could lead to their encountering predators more frequently which would reduce survival prospects. The different behaviour of males and females provides empirical evidence that males invest in the welfare of current offspring at the cost of higher predation risk whereas females protect their residual reproductive value. Copyright 2000 The Association for the Study of Animal Behaviour. 相似文献
4.
The technique of mark-release-recapture was used to study survival before and after sexual maturity in adults of the damselfly Pyrrhosoma nymphula (Sulzer). Fewer females were recaptured upon return to water to breed despite no differences in dispersal or daily survival rate between the sexes over the immature period. Because females took longer to mature than males, their poorer recapture rate was attributed to greater overall mortality during their longer maturation phase. Survivorship curves for tenerals marked at emergence suggested that overall survival of immature adults was similar to, if not better than, that of mature adults. The reasons for this are discussed.
Jolly's model was used to estimate daily survival rates for mature adults. The assumptions of the model were tested rigorously. Estimates for females were statistically less reliable than those for males. Mean reproductive spans for males and females were 6.8 and 6.6 days, respectively, giving mean total adult lifespans of 19.4 days and 21.6 days for individuals surviving the maturation period.
Because neither sex visited the breeding site every day, sampling exclusively at water resulted in underestimation of mean reproductive spans for both sexes. Female reproductive spans were underestimated to a greater extent; because females remain away from water longer between visits, there is a greater chance that they will die before being recaptured.
Mean reproductive spans were also underestimated when only a sub-section of the habitat was sampled. Females were significantly more mobile than males and this increased the likelihood that they would move out of the study area, resulting in more severe underestimation. The importance of obtaining accurate estimates of mature lifespan for females is discussed. 相似文献
Jolly's model was used to estimate daily survival rates for mature adults. The assumptions of the model were tested rigorously. Estimates for females were statistically less reliable than those for males. Mean reproductive spans for males and females were 6.8 and 6.6 days, respectively, giving mean total adult lifespans of 19.4 days and 21.6 days for individuals surviving the maturation period.
Because neither sex visited the breeding site every day, sampling exclusively at water resulted in underestimation of mean reproductive spans for both sexes. Female reproductive spans were underestimated to a greater extent; because females remain away from water longer between visits, there is a greater chance that they will die before being recaptured.
Mean reproductive spans were also underestimated when only a sub-section of the habitat was sampled. Females were significantly more mobile than males and this increased the likelihood that they would move out of the study area, resulting in more severe underestimation. The importance of obtaining accurate estimates of mature lifespan for females is discussed. 相似文献
5.
Variation in Helper Type Affects Group Stability and Reproductive Decisions in a Cooperative Breeder
Recent studies have shown that differences in life history may lead to consistent inter‐individual variation in behavioural traits, so‐called behavioural syndromes, animal personalities or temperaments. Consistencies of behaviours and behavioural syndromes have mainly been studied in non‐cooperative species. Insights on the evolution of cooperation could be gained from studying individual differences in life histories and behavioural traits. Kin selection theory predicts that if an individual’s reproductive ability is low, it had to aim at gaining inclusive fitness benefits by helping others. We tested this prediction in the cooperatively breeding cichlid Neolamprologus pulcher, by assessing reproductive parameters of adults that had been tested earlier for aggressiveness and for their propensity to assist breeders when they had been young (‘juveniles’). We found that juvenile aggression levels predicted the acceptance of a subordinate in the group when adult. Males which were aggressive as juveniles were significantly more likely to tolerate a subordinate in the group when compared with males which were peaceful as juveniles, whereas females which were more aggressive as juveniles tended to expel subordinates more often. Females produced significantly smaller clutches when paired to males which had helped more as a juvenile, despite the fact that adult males hardly provided direct brood care. There was no evidence that females with a high propensity to help when young, produced smaller clutches or eggs when adult, but they took longer to lay their first clutch when compared with females with a low propensity to help when young. These results suggest that variation in behavioural types might explain variation in cooperation, the extent of group‐living and reproductive decisions. 相似文献
6.
A. Koenig 《American journal of primatology》1995,35(4):311-317
Data from published sources about size and composition of wild common marmoset groups (Callithrix jacchus) were analyzed to see if the number of juveniles in a group is closely related to the number of other group members. Mean group size was 8.7 members including 4.4 adults (1.8 females, 2.5 males), 2.9 subadults, and 1.4 juveniles. The number of juveniles was significantly positively correlated to the number of adult males. Groups with one or two adult males had significantly fewer juveniles (mean: 1:1 juveniles) than groups containing more than two adult males (mean: 2.0 juveniles). Apart from a different number of subadults, results showed obvious similarities between common marmosets and tamarins of the genus Saguinus in size and composition of subgroups of adults as well as the key role of adult males in mediating the reproductive success of a breeding female. Common marmoset females seem to gain direct fitness benefits in increased reproductive success from the presence of a larger number of adult males. Whether or not other group members get fitness benefits depends on the reproductive strategy of adult males (monogamy vs. polyandry), their kinship, and on the genetic relationship of nonbreeders to the offspring of the breeding female. © 1995 Wiley-Liss, Inc. 相似文献
7.
Some aspects of sociosexual behavior and the age at which maturing females experienced their first evident pregnancy and at
which maturing males caused their first evident pregnancy were recorded in Saguinus fuscicolliscohabiting from 6 months of age with either an adult or a maturing sex partner. The following pair combinations and trios
were studied: young male -young female, young male-adult female, adult male-young female, and adult male-young male-young
female. The most frequent type of social interaction between young animals was rough and tumble play, while huddling was the
most frequent interaction between young animals and their adult partners. Grooming and sexual interactions were very infrequent
and there were no differences in the frequencies of these interactions among subject groups. Maturing females cohabiting with
an adult male conceived significantly earlier than maturing females cohabiting with a male of their own age. Maturing males
cohabiting with adult females sired offspring at a significantly earlier age than males cohabiting with a female of their
own age. Some possible behavioral and physiological processes involved in the causation of early reproductive success in young
tamarins cohabiting with adults are discussed.
Saguinus fuscicollis fuscicollis andSaguinus fuscicollis illigeri. 相似文献
8.
Field studies of the social organization of yellow-bellied marmots (Marmota flaviventris) in the vicinity of Gothic, Colorado, were initiated in 1962. Data collected during the subsequent 14 years are sufficient to analyse the behaviours that correlate with the time yearling male and yearling female marmots leave their natal home sites. Dispersal of yearling male yellow-bellied marmots was delayed when there were many yearling males in a harem, when yearling males were underweight, and when the rates of amicable interactions between yearling males and adults were high. Dispersal of yearling females was delayed when adults behaved amicably toward them and when the rates of adult aggression were low. Dispersal of yearling females was independent of the number of females in a harem. These observations are in accord with a model of dispersal that relates sexual differences in dispersal to maternal reproductive tactics, and to responses of yearlings that would maximize their own fitness. 相似文献
9.
Entomopathogenic nematodes are lethal insect parasites that reproduce exclusively inside their hosts in nature. Infection decisions made by the free-living infective-stage juveniles have an impact on reproductive success, but it is likely that mating decisions are made by adults while inside their host. We investigated sexual communication between male and female adult stages of Steinernema carpocapsae (Rhabditida: Steinernematidae) to assess whether mating is chemically mediated during the adult stage or results from incidental encounters between adults inside the insect host. To assess chemical communication, we measured the behavioral response of adult male S. carpocapsae to several different potential sources of chemical information. Male S. carpocapsae responded to virgin females only and were not influenced by mated conspecific females, conspecific males, or heterospecific females. These results show that species-specific communication takes place between adult entomopathogenic nematodes within the host cadaver just prior to mating. 相似文献
10.
1. Intraspecific variation in diet can be an important component of a species niche breadth. We tested the hypothesis that sex differences in seasonal foraging behaviour and energy storage of sexually size dimorphic grey seals Halichoerus grypus (Fabrisius 1971) are reflected in differences in the diet and niche breadth. Diet composition was estimated for 496 adult (226 males, 270 females) and 91 juvenile (46 males/45 females; all 6 months old) grey seals sampled between 1993 and 2000 using quantitative fatty acid signature analysis. Niche breadth and overlap were estimated using the Shannon-Weaver diversity index (H') and the Morisita-Horn index (C(H)), respectively. 2. Sand lance Ammodytes dubius (Reinhardt 1837) and redfish Sebastes sp. (Cuvier 1829) accounted for a high proportion of the diet in both sexes and age groups. However, the diets of adult males were significantly more diverse across all seasons (H': males 0.36 +/- 0.007 vs. females 0.28 +/- 0.007) and less energy dense in spring (male 5.3 +/- 0.07 kJ g(-1) vs. females 5.6 +/- 0.09 kJ g(-1)) than those of adult females. 3. Season and sex explained most of the observed variation in adult diets, but there were significant sex-season interactions. These differences were most evident during the post-breeding (spring) foraging period when energy acquisition is important to female recovery of nutrient stores needed to support pregnancy. Females selected fewer and higher quality prey species in spring than males. 4. There were no sex differences in the diets of juvenile grey seals. Although many of the species overlapped with those eaten by adults, juvenile niche breadth (H': 0.41 +/- 0.014, n = 91) was significantly broader than that of adults (H': 0.30 +/- 0.011, n = 115). Juvenile diets were also of lower energy density (5.3 +/- 0.04 kJ g(-1)) than those of adults (5.6 +/- 0.09 kJ g(-1)), suggesting less selectivity in these young and relatively na?ve predators. 5. Sex-specific seasonal changes in diet correspond to seasonal changes in diving behaviour and rate of body energy accumulation of adult males and females. Sex-specific reproductive requirements appear to be a primary factor generating the intraspecific variation in the seasonal foraging ecology of this large marine carnivore. However, sex differences in the breadth and energy content of diets also suggest the influence of body-size dimorphism as a factor shaping the diet of this species. 相似文献
11.
In four large aviaries, we studied social assortment and reproductive behaviour of female brown-headed cowbirds housed with males differing in age class and in corresponding levels of intrasexual interaction. Juvenile and adult females resided with either (1) adult males, (2) juvenile males, (3) adult and juvenile males, or (4) no males. We observed social behaviour of males and females from September 1999 through to the 2000 breeding season. Throughout the year, males in the different conditions showed different levels of social interaction, with adult males being most engaged in male-male interactions and juvenile males being least engaged in male-male interactions. Females in the four conditions differed in their associations with males and with other females. In conditions with adult males, females spent more time near males, approached males more often, and associated with females less. During the breeding season, females in conditions with more adult males copulated more and produced more fertile and viable eggs. In the condition where females were housed with juvenile males, they copulated less, laid fewer eggs and destroyed more of their eggs. Results indicate that throughout the year, females are sensitive to male age and behaviour in their social group, and that this sensitivity can have reproductive consequences. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved. 相似文献
12.
A comparison of the mating behavior of adolescent and adult female rhesus macaques (Macaca mulatta) 总被引:2,自引:0,他引:2
This study compares adult and adolescent female rhesus macaques with regard to (1) characteristics of their copulatory partners,
(2) their proceptive behaviors, and (3) adult male behaviors toward them during estrus. We conducted focal follows of 24 adolescent
and 65 adult free-ranging estrous female rhesus macaques on Cayo Santiago during two mating seasons. Compared to adult females,
adolescents presented sexually to males at higher rates; copulated more frequently with rankless young male, and extra-group
males; and, in one of two mating seasons, were ignored more frequently by males to whom they presented sexually. Adolescents
tended to copulate with ranked, resident males at higher frequencies on days when the operational sex ratio (adult males:estrous
adult females) was high. Males directed “muzzle-up” signals to adolescents at lower rates than to adults in one of two mating
seasons, although this effect vanished when males who might have fathered adolescent females were excluded from analysis.
Adolescents did not differ consistently from adults in strength of the correlation between proximity maintenance (dyadic Hinde's
Index) and copulation rate, or in approach rate to males. Adolescent females, relative to adult females, presented sexually
more to rankless young males, but did not present more to ranked, resident males. Both proximate (e.g. endocrine) and ultimate
(e.g. differential fecundity; female-female mate competition) explanations may account for the reported differences between
adult and adolescent female rhesus macaque sexuality. 相似文献
13.
B L Pope 《American journal of physical anthropology》1966,24(3):361-369
Howler monkeys, Alouatta caraya, were collected in family groups from islands in the Rio Parana in northern Argentina. The body weights, lens weights, dental age and reproductive status of 261 individuals illustrated sexually dimorphic body weights after a period of accommodation as young adults, a large proportion of older females (even though there are more young adult males than females) and a higher percentage of pregnancies among these older females. Seventeen families, representing the entire social system of one island, showed that about three quarters were adult (equally divided between the sexes but with fewer older males than females) and the remaining quarter were immature (with an equal sex ratio). Half of the adult females were either pregnant or suckling young. The mean family size is seven which includes peripheral males. Group size and composition as well as adult to immature proportions compared closely with data on A. caraya in the Chaco of Argentina and the 1951 census of A. palliata on Barro Colorado Island. It can be said that when these two species of Alouatta occur in small size families, they have in common: a high proportion of adults to immature, a low proportion of infants, and can have either an equal sex ratio (A. caraya) or preponderance of females (A. palliata). 相似文献
14.
Arun B. Venkataraman 《Ethology : formerly Zeitschrift fur Tierpsychologie》1998,104(8):671-684
Two free-ranging packs of dholes (Asiatic wild dog, Cuon alpinus) were monitored for a period of 6 yr (Sep. 1990-Sep. 1996) in the Mudumalai sanctuary, southern India. Demographic data on age structure, litter-size, sex ratio and age and sex specific dispersal were collected. Behavioural data on social interactions and reproductive behaviour among pack members were obtained to determine the frequencies of dominant and subordinate behaviours shown by male and female pack members and a measure of each male's reproductive access to females. Behaviours displayed by pack members at dens were recorded to determine whether any age- or sex-specific role specialization existed during pup care. Tenures for dominant males and females within the pack were calculated to ascertain the rate of breeding vacancies occurring within packs. Approximate levels of genetic relatedness within packs were determined by studying pedigrees. In most years one study pack had a male-biased adult sex ratio. This was caused by almost two-fold higher dispersal of adult females over adult males. A considerable variance existed in the percentage of sub-adults dispersing from the two packs. Differences existed in the frequencies of dominant and subordinate behaviours shown by males. For males, dominance ranks and ranks based on submissive behaviours were not correlated with frequencies of reproductive behaviours. Subordinate males also displayed reproductive behaviours. In packs, dominant males had lower tenures than dominant females indicating that among males breeding vacancies arose more quickly. The litter size was found to be negatively correlated with the age of the breeding female. There were no significant differences across individuals of varying age or sex classes in the display of pup care behaviours. Significant differences did exist among individual adults. Genetic relatedness among packs tended to vary temporally as a consequence of possible mating by subordinate animals and immigration of new males into the pack. In conclusion, it appears that males delay dispersal and cooperate within their natal packs because of the variety of reproductive strategies they could pursue within. A combination of ecological constraints and the difficulties of achieving breeding status within non-natal packs may make early dispersal and independent breeding less beneficial. 相似文献
15.
Johanna Kiss Zoltán Németh András Kosztolányi Zoltán Barta 《Ecological Entomology》2020,45(6):1504-1508
1. Biparental care is stabilised if parents perform different tasks during care. Specialised parental roles may require different time and energy budgets that in turn are expected to influence the activity and space use of sexes. 2. Here we investigate movement patterns of the biparental Lethrus apterus beetle using a grid of pitfall traps in their natural habitat. 3. Sexes of the burrow building L. apterus perform different roles during caregiving, as females collect most of the leaves, which serve as food for the offspring while paired males stay mostly in the burrow. We hypothesised that sex differences in mate search and parental activities are reflected in movement patterns. 4. We found that females frequently travelled short distances, whereas males were detected less often but when detected, they travelled significantly longer distances than females. 5. Our results are consistent with the notion that efficient parental food provisioning requires more localised movement and activity patterns. Furthermore, the long distance movements of some males may indicate active mate searching behaviour. 相似文献
16.
This research presents male-female differences in stress response evidenced in human remains from the Medieval site of Kulubnarti
in Sudanese Nubia. This analysis is unique in that a direct comparison of subadult males and females is rarely possible using
archaeological remains. Rather, such analyses invariably rely on evidence of subadult differences retained in adult (sexable)
skeletons. In the case of Kulubnarti, natural mummification has made it possible to measure sex-specific differences among
subadults as well as adults following five avenues of investigation: 1) mortality, 2) growth and development, 3) enamel hypoplasia,
4) cribra orbitalia, and 5) cortical bone maintenance.
A comparison of mean life expectancy (eox) values for males and females aged 10–55+ years revealed a consistent pattern of
greater female survivorship, particularly in childhood (age 10 category) where female life expectancy exceeds that of males
by 19%. Measures of growth and development, enamel hypoplasia, cribra orbitalia, and cortical bone loss were subsequently
used to test a hypothesis of greater female resiliency based on the mortality data.
Male-female differences in skeletal maturation are pronounced with male skeletal ages averaging a significant 2.9 years below
their dental age. Females show no significant differences with an average skeletal age 0.75 years ahead of dental age. Males
begin hypoplasia formation one year earlier than females and, prior to age four, average 18% more hypoplasias (p<0.05). Also,
by age 8, males have on average more than twice the frequency of cribra orbitalia (p<0.05).
In contrast to their consistent pattern of reduced childhood stress, adult females lose significantly more cortical bone than
their male counterparts and have less cortical bone across the adult age range. Nevertheless, females outnumber males of all
ages with a sex-ratio below but parallel to that observed in modern populations. The rapid age-related reduction in males
relative to females, even in old age, suggests a continuing female resiliency in spite of their greater rate of osteopenia
and may reflect a reproductive advantage to the population through heightened female survival and adaptability. 相似文献
17.
J. S. Shellman-Reeve 《Proceedings. Biological sciences / The Royal Society》1999,266(1415):137
In species where parental investment is extensive for both sexes, both males and females are predicted to exhibit choosiness when seeking their lifetime partners. Evidence is presented that both courting males and females are choosy in the wood-dwelling, biparental termite Zootermopsis nevadensis. There are, however, sex differences both in the method of mate rejection and in the mate-choice criteria. In particular, females are more likely than males to invite an extra suitor into the nest, whereas males are more likely than females to leave their nest and partner and seek a replacement elsewhere. Correlational analyses of adults show that head width is a mate-choice criterion used by females, whereas body mass and fat mass are used by males. Among males and females that sought replacement mates, those that had been rejected previously were more likely to end up paired with an adult that also had been rejected, compared with adults that had not been rejected. Additional findings reveal a rich repertoire of courting behaviours characterized by extensive intra- and intersexual conflict, including mate rejection, intrasexual combat, and even intrapair aggression. 相似文献
18.
George S Lewbel 《Journal of experimental marine biology and ecology》1978,33(2):133-151
The amphipod Caprella gorgonia Laubitz & Lewbel is an obligate commensal on gorgonian octocorals. Its primary host is Lophogorgia chilensis (Verrill), found below 20 m.C. gorgonia breeds throughout the year, with wide fluctuations in abundance. Mating and oviposition follow molting. Sex reversal does not occur; two distinct sexes are present from the first instar after emergence from the brood pouch.Young males and females grow at approximately the same rate, but males are larger by a relatively constant increment. Males continue to grow at their original rate to a maximum size (about twice that of females). The growth rate of females is not limited by the onset of reproduction and brooding, but rather by an approach to maximum size when the rate is greatly reduced. Fecundity of females is not affected by size.The population sex ratio is about 1:3 (males:females), and about 1:4 among adults. The secondary sex ratio is 1:1. The post-emergence sex ratio bias is a result of heavier mortality among males. Sex ratios drop from 50% at emergence to 25% as females approach maximum size, then rise to 100% in larger size classes.Differential predation on males did not appear to be a source of any sex ratio bias. Adult males possess a “poison spine”, a puncturing weapon on the large second gnathopod, which functions in mating-related intraspecific combat with other males. Intraspecific male aggression during mating is a major cause of sex ratio bias. In the laboratory, increased density in breeding groups may affect mortality due to male aggression. In nature, adult sex ratios are negatively correlated with population density. The reproductive capacity of the population is not limited by a shortage of adult males, despite the low adult sex ratio. 相似文献
19.
2008年6月份至2009年5月份对吐鲁番沙虎的巢域进行调查:2008年6月份至2008年8月份为繁殖季节(RS),2008年9月份至2009年5月份(冬眠期除外)为非繁殖季节(NRS)。利用截趾标志重捕法研究吐鲁番沙虎的巢域,共标记283只吐鲁番沙虎,累计繁殖季节24只,非繁殖季节43只重捕超过3次(其中13只个体在繁殖季节和非繁殖季节均够3次以上捕捉次数,为重复个体),可以用于计算个体巢域面积数据。利用软件MapGis计算最小凸多边形法(MCP)巢域面积,并分析性别、体型大小、季节等因素对巢域的影响。结果表明:吐鲁番沙虎非繁殖季节雄性、雌性与幼体各组间的巢域面积差异均显著,繁殖季节巢域面积差异不显著;雌雄个体不同季节或全年合并比较巢域面积差异性均不显著;非繁殖季节面积与吻肛长(SVL)显著相关、全年成体组的巢域面积与吻肛长显著相关;成体巢域面积季节差异显著(U=41,P=0.046),幼体则没有季节差异(U=159,P=0.537)。因而,吐鲁番沙虎的巢域大小受性别因素影响不大,体型大小对巢域面积有显著影响,由于繁殖、食物资源等的季节变化是影响吐鲁番沙虎巢域最重要的因素。 相似文献
20.
Bengt Karlsson 《Evolution; international journal of organic evolution》1995,49(5):955-961
A cross-taxonomic comparison of resources allocated to reproductive reserves at adult eclosion reveals that females belonging to polyandrous species receive more ejaculate material and allocate proportionally less of their total reserves to potential reproduction compared to females belonging to monandrous species. These results suggest that adult females of polyandrous species have a higher expected nutrient income and are consistent with the idea that females can benefit from male nutrient donations transferred during mating. Males show the opposite pattern: males of polyandrous species allocate proportionally more to reproduction. This is expected since males in polyandrous species have both proportionally heavier ejaculates and have a higher ejaculative production capacity than do males in monandrous species. Interestingly, adults of the genus Heliconius which can obtain nutrients crucial to reproduction by pollen feeding do not seem to follow these patterns as strong as only nectar-feeding butterflies. Instead, the association between degree of polyandry and resources allocated to reproduction is relaxed. 相似文献