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1.
Correlates of extra-pair fertilization success in hooded warblers 总被引:13,自引:0,他引:13
Bridget J. M. Stutchbury W. H. Piper D. L. Neudorf S. A. Tarof Judith M. Rhymer G. Fuller R. C. Fleischer 《Behavioral ecology and sociobiology》1997,40(2):119-126
We examined correlates of extra-pair fertilization (EPF) success in the hooded warbler (Wilsonia citrina), a species where females pursue extra-pair matings. The good genes hypothesis predicts that females choose extra-pair mates
with morphological or behavioral traits that reflect differences in male genetic quality. EPFs were common, as 35.3% (42/119)
of broods contained extra-pair young (EPY) and 26.7% (95/356) of nestlings were the result of EPFs. There was a strong skew
in male EPF success which increased the variance in annual male mating success 2–3 fold. However, male morphology did not
predict EPF success, as extra-pair males were not older or larger than the males they cuckolded. Likewise, there were no significant
correlations between the proportion of extra-pair young in a brood and male size or age. The good genes hypothesis predicts
that high-quality males will be consistently preferred as genetic mates, but the number of young sired by a male with his
social mate was not consistent from one year to the next. There was a significant negative correlation between female age
and proportion of EPY produced, which could result if older females obtain higher-quality social mates. We found no strong
evidence that females choose extra-pair mates for good genes, but females may use behavioral rather than morphological cues
to assess relative male quality.
Received: 31 May 1996 / Accepted after revision: 17 October 1996 相似文献
2.
Sexual cohabitation as mate-guarding in the leaf-curling spider Phonognatha graeffei Keyserling (Araneoidea, Araneae) 总被引:1,自引:1,他引:1
The leaf-curling spider Phonognatha graeffei incorporates a twisted leaf into the central hub of its orb-web that is used as a retreat. This species is unusual among orb-weaving
spiders because males cohabit in the leaf retreat with both immature and mature females, mating with the former shortly after
the female molts. Cohabitation appears to be a form of mate-guarding because cohabiting males respond agonistically to rival
males that venture onto the web, and their behaviour depends upon the reproductive status of the female; males defending immature
females are more aggressive than those defending virgin, adult females. Males copulate with previously mated females for significantly
longer than with virgin females. Females may cannibalise cohabiting males, which occurs independently of whether the female
has been deprived of food. Females that cannibalise a single male do not have a higher fecundity than non-cannibalistic females.
Received: 2 February 1996 / Accepted after revision: 27 October 1996 相似文献
3.
Patrick J. Weatherhead 《Behavioral ecology and sociobiology》1997,40(3):151-158
Using data from a 6-year paternity study of red-winged blackbirds, I tested the hypotheses that increased nesting synchrony
should either promote extra-pair mating by increasing the advantage of extra-pair mating to females, or decrease extra-pair
mating by constraining males from seeking extra-pair copulations. Contrary to these hypotheses, the occurrence of extra-pair
paternity did not vary with nesting synchrony over the breeding season, or vary with the number of synchronous nests within
territories or within marshes, or with nesting order on territories. However, for nearly all nests with extra-pair young,
there were fewer females synchronous with that nest on the cuckolder's territory than on the territory of the cuckolded male.
This “advantage” of a synchrony difference was less pronounced for older males that cuckolded younger males, particularly
when the two males were not neighbors. Collectively, these results suggest that breeding synchrony affects extra-pair mating
by affecting mate guarding, but that breeding synchrony alone can not be used to predict which females are more likely to
engage in extra-pair mating, nor with which extra-pair males they will mate. Understanding why extra-pair mating by older
males is less affected by breeding synchrony may explain much about both the proximate and ultimate causes of extra-pair mating
in red-winged blackbirds.
Received: 7 June 1996 / Accepted after revision: 25 November 1996 相似文献
4.
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
5.
P. Jivoff 《Behavioral ecology and sociobiology》1997,40(3):175-185
In many species, post-copulatory mate guarding prevents other males from mating with the guarded female. In crabs, males
stay with their mates to protect the female from predators because, in some species, mating occurs when she is soft and vulnerable
after molting. I tested the relative roles of sperm competition and predation on the duration of the post-copulatory association
in the blue crab, Callinectes sapidus. Unpaired females suffered greater predation mortality than paired females and males stayed with the female longer in the
presence of predators than in their absence, suggesting that the post-copulatory association protects females during their
vulnerable period. However, the association may also occur in blue crabs because of sperm competition since spermathecal contents
of females in the field indicate that 12.4% mated twice. Females experimentally mated with two males contained both males
ejaculates and each ejaculate had access to the unfertilized eggs, suggesting that the size of a male's ejaculate influences
his fertilization rate in a multiply-mated female. Males stayed longest in response to a high risk of sperm competition. Longer
post-copulatory associations allowed the first male's ejaculate to harden into a type of sperm plug, which limited the size
of a second inseminator's ejaculate in a non-virgin female as compared with a virgin. Males passed larger ejaculates in the
presence of rivals and when previous ejaculates were in the female spermathecae, another response to sperm competition. Larger
ejaculates may need longer post-copulatory associations before a more effective sperm plug forms. Large males stayed with
the female longer, which is consistent with their ability to pass larger ejaculates than small males and suggests that there
may be costs to minimizing the duration of the post-copulatory association. In the field, associations last long enough to
protect the female during her vulnerable phase and may ensure that the guarding male fertilizes the most eggs in the female,
even if she remates. Thus, the post-copulatory association protects female blue crabs from additional inseminators as well
as from predators.
Received: 23 January 1996 / Accepted after revision: 9 November 1996 相似文献
6.
R. Terry Bowyer Janet L. Rachlow Kelley M. Stewart Victor Van Ballenberghe 《Behavioral ecology and sociobiology》2011,65(12):2251-2260
Evidence of female fomentation of male–male aggression as a mechanism of mate choice is rare, especially in mammals. Female
choice of mates in polygynous species may be masked by intense male competition or by males attempting to restrict female
choice. We studied protest moans of female Alaskan moose Alces alces gigas in interior Alaska, USA, from 1987 to 1990, to determine if moans incited male–male aggression. Alaskan moose exhibit a mating
system in which one dominant male (the harem master) herds, defends, courts, and attempts to mate with females in his harem.
Protest moans were given by females only in response to courtship. We hypothesized that if protest moans were related to females
reducing harassment and exercising mate choice, females should give protest moans more frequently when courted by small males
and less often when courted by large males, and that rates of male–male aggression would be elevated following protest moans.
Harems were composed of one large male, with a mean of 4.4 females (median = 3 females); 10% of 132 harems included ≥10 females.
The temporal pattern of protest moans from late August through November was associated with, but tended to lag behind, mating
behavior. The rate of protest moans given by females decreased with increasing size of males courting them. Male–male aggression
was significantly less during periods without protest moans than during periods in which protest moans occurred. These results
indicate that female moose gave protest moans to reduce harassment by smaller males, and assure a mating opportunity with
the most dominant male. Such a subtle mechanism of indirect mate choice by females may occur in other vertebrates in which
choice is limited by a mating system in which male–male combat and male dominance over females reduces opportunities for female
choice. The importance of female choice may be undervalued in studies of sexual selection in mammals. 相似文献
7.
Association patterns of sailfin mollies (Poecilia latipinna): alternative hypotheses 总被引:3,自引:0,他引:3
Caitlin Gabor 《Behavioral ecology and sociobiology》1999,46(5):333-340
Individuals may associate with each other due to a variety of selective forces, such as intra- and intersexual selection,
and conspecific recognition. Previous studies have concluded that mate choice governs association behavior in polygynous species
of fish. I examined whether mate choice underlies the preference for larger individuals by examining preference for association
(time spent in proximity to a fish) not only between opposite-sex individuals but also between same-sex individuals of the
live-bearing sailfin molly (Poecilia latipinna). Males and females from three size classes were tested with a large and a small object fish of the same and opposite sex.
Females preferred to associate with larger over smaller males. Males also preferred to associate with larger over smaller
females, as expected. The same female and male test fish also preferred to associate with larger over smaller fish of the
same sex. Moreover, females demonstrated no significant difference in their strength of preference (large–small) when offered
males or females. The same held true for males. When males and females were subsequently tested with one large male and one
large female, females tended to prefer large males while males showed no significant preference for association based on sex.
In another experiment, females were tested with a large female and a small male, and significantly preferred the former. These
findings suggest that association patterns may have arisen under a variety of conditions, such as predation pressures, shoaling
behavior, and associative preference behavior. The assumption that association behavior is a uniformly sufficient predictor
of mate choice in fish needs to be re-examined for P. latipinna and other species.
Received: 6 November 1998 / Received in revised form: 12 May 1999 / Accepted: 12 May 1999 相似文献
8.
We estimated the cost to females of the lekking butterfly Coenonympha pamphilus of visiting males on leks instead of taking off and soliciting courtship from males passing them outside leks, as occurs
in the non-lekking congener C. tullia. We followed released virgin females of C. pamphilus in the field until they mated. We estimated the time they lost by remaining perched and not approaching males that passed
them, and observed how often and at what distance virgin females were passed by males in the field. We then calculated how
much faster these females would have been detected if they had taken off and approached these males, using probabilities of
detection as a function of passing distance derived from field observations on C. tullia females. C. pamphilus females on average lost 201 min by not approaching males on their way to leks. To estimate what this time loss meant in terms
of fitness, we measured how the age at mating affected fecundity. Using field measures of fecundity and mortality, the time
loss translated into an average 2.8% reduction in fecundity as a best estimate, and an average 1.3% reduction in fecundity
as a lower estimate. This fitness cost is larger than has been reported earlier for a lekking bird, but is probably too small
to eliminate the possibility of indirect benefits of mating with males on leks.
Received: 15 August 1996 / Accepted after revision: 24 January 1997 相似文献
9.
D. A. Westcott 《Behavioral ecology and sociobiology》1997,40(4):235-242
Interactions between males on leks may play an influential role in lek formation and the regulation of lek size. In this
paper I present the results of a playback experiment that simulated de novo settlement at sites adjacent to currently existing display territories of the ochre-bellied flycatcher, Mionectes oleagineus. In the study population, males displayed both solitarily and at small leks. A large proportion of males held no display
territory at all. A stranger's song was played to both solitary and lekking males from 10 m outside their territorial boundaries.
In separate playbacks, lekking males were also played neighbour's song. Both lekking and solitary territorial males reacted
to the playback by decreasing their song rate, approaching the playback speaker and, on occasion, attacking the model. Solitarily
displaying males responded more aggressively to playback of stranger's song than did lek males. Lek males were able to distinguish
between their neighbour's and a stranger's song and did so irrespective of whether it was played from the neighbour's territory
or from outside the lek. In addition to distinguishing between neighbours and strangers, lek males modified their responses
to these different playbacks depending on where the playback originated. These results suggest that male-male interactions
can be influential in structuring leks. In M. oleagineus, interactions between males are aggressive and act to limit rather than augment lek size.
Received: 6 March 1996 / Accepted after revision: 9 December 1996 相似文献
10.
Sexual conflict in the snake den 总被引:3,自引:0,他引:3
Red-sided garter snakes (Thamnophis sirtalis parietalis) court and mate in spring, soon after they emerge from large communal overwintering dens in south-central Manitoba. Because
of a massive bias in the operational sex ratio, every female attracts intense courtship from dozens to hundreds of males.
We suggest that this courtship constitutes significant ”harassment,” because it delays the females’ dispersal from the den
and hence increases their vulnerability to predation. Small females may face the greatest costs, because they are less able
to escape from amorous males (who court all females, even juvenile animals). Our measurements show that males are stronger
and faster than females. Experimental trials confirm that the locomotor ability of females (especially small females) is greatly
reduced by the weight of a courting male. Arena trials show that intense courtship stimulates females to attempt to escape.
Remarkably, some females that are too small to produce offspring may nonetheless copulate. This precocious sexual receptivity
may benefit juvenile females because copulation renders them unattractive to males, and thus allows them to escape more easily
from the den. Female ”tactics” to escape male harassment may explain other puzzling aspects of garter snake biology including
size-assortative mating, temporal patterns in dispersal from the den, avoidance of communal dens by young-of-the-year snakes,
and female mimicry. Hence, sexual conflict may have influenced important features of the mating system and behavioral ecology
of these animals.
Received: 8 May 2000 / Revised: 28 July 2000 / Accepted: 30 July 2000 相似文献
11.
Quality-indicating sexually selected traits may have their honesty maintained by their costs or by an inherent “revealing”
nature. Long tails in birds are usually considered to be costly “handicaps”, but may have additional potential as revealing
indicators through the incidence of breakage. Magpies Pica pica with unbroken and less abraded tails paired earlier, but did not nest or fledge young earlier than pairs with tails in poorer
condition. Pairs mated assortatively by tail quality, and magpies with very broken tails remained unmated. Pairs in which
both members had almost undamaged tails fledged more offspring than pairs with poorer tails. Tail quality did not correlate
with the extent of any habitat type in the territory. Tail damage thus honestly indicated a magpie's reproductive potential,
and the data are consistent with its having a role in mate choice, as a revealing element of tail morphology.
Received: 28 March 1996 / Accepted after revision: 9 December 1996 相似文献
12.
Female mallard mating preferences for multiple male ornaments 总被引:3,自引:1,他引:3
K. E. Omland 《Behavioral ecology and sociobiology》1996,39(6):353-360
Mating preferences were studied in captive wild-stock female mallards. Independent observers scored ornament brightness for
the bill and eight plumage areas of male mallards on a scale of 1 to 6. Ornament scores were generally positively correlated
with each other as indicated by univariate correlations and principal component analysis. Males with higher bill scores were
significantly more likely to obtain pairings. None of eight individual plumage ornaments were significant predictors of pairing
success, but males with higher average plumage scores had significantly higher pairing success. Males that completed the molt
first were also significantly more likely to be paired. Thus females may have paid some attention to plumage brightness. Stepwise
multiple regression produced a model that included only bill and molt, both of which contributed a similar degree (r
2 = 0.39); plumage ornaments and size measurements did not enter the model. These results are interpreted in light of hypotheses
for the evolution of multiple ornaments, and phylogenetic plumage patterns in dabbling ducks.
Received: 18 December 1995 / Accepted after revision: 22 September 1996 相似文献
13.
Ornamentation predicts reproductive success in female pipefish 总被引:5,自引:0,他引:5
Anders Berglund Gunilla Rosenqvist Patricia Bernet 《Behavioral ecology and sociobiology》1997,40(3):145-150
In the sex-role reversed pipefish Syngnathus typhle females compete for access to males and males are choosy. Females develop a temporary ornament when competing over mates
with other females and when performing nuptial dances with males. This ornament is an amplification of the normal striped
pattern in these fishes. We here show experimentally that (1) the contrast of this normal pattern forecasts the extent to
which the ornament is shown, (2) contrast and ornamentation honestly signal female quality (egg numbers), (3) contrast and
ornamentation accurately predict female mating success, (4) contrast is a phenotypically plastic trait specifically exaggerated
under situations of female – female competition, and (5) neither contrast nor ornament are energetically expensive to the
females (i.e., they are independent of short-term nutritional status). Hence, as predicted in sex-role reversed species, ornament
design is constrained by costs to female fecundity: an energetically demanding ornament would impair on a female's ability
to produce eggs. The type of ornament described here is the expected one, costly for reasons other than being energetically
expensive to produce.
Received: 4 April 1996 / Accepted after revision: 27 October 1996 相似文献
14.
Control of reproduction in social insect colonies: individual and collective relatedness preferences in the paper wasp, Polistes annularis 总被引:1,自引:0,他引:1
David C. Queller J. M. Peters Carlos R. Solís Joan E. Strassmann 《Behavioral ecology and sociobiology》1997,40(1):3-16
Social insect colonies often have one or a few queens. How these queens maintain their reproductive monopoly, when other
colony members could gain by sharing in the reproduction, is not generally known. DNA microsatellite genotyping is used to
determine reproductive interests of various classes of colony members in the paper wasp, Polistes annularis. The relatedness estimates show that the best outcome for most individuals is to be the reproductive egg-layer. For workers,
this depends on the sex of offspring: they should prefer to lay their own male eggs, but are indifferent if the queen lays
the female eggs. The next-best choice is usually to support the current queen. As a rule, subordinates and workers should
prefer the current queen to reproduce over other candidates (though subordinates have no strong preference for the queen over
other subordinates, and workers may prefer other workers as a source of male eggs). This result supports the theory that reproductive
monopoly stems from the collective preferences of non-reproductives, who suppress each other in favor of the queen. However,
we reject the general hypothesis of collective worker control in this species because its predictions about who should succeed
after the death of the present queen are not upheld. The first successor is a subordinate foundress even though workers should
generally prefer a worker successor. If all foundresses have died, an older worker succeeds as queen, in spite of a collective
worker preference for a young worker. The results support the previous suggestion that age serves as a conventional cue serving
to reduce conflict over queen succession.
Received: 3 May 1996 / Accepted after revision: 22 September 1996 相似文献
15.
Reproductive dominance and differential ovicide in the communally breeding burying beetle Nicrophorus tomentosus 总被引:4,自引:0,他引:4
Michelle Pellissier Scott 《Behavioral ecology and sociobiology》1997,40(5):313-320
Communal breeding can be characterized by the division of reproduction among cooperating individuals and, if the distribution
of reproduction is inequitable, by the mechanisms for achieving skewed reproductive success. The burying beetle (Nicrophorus tomentosus) is a facultative communal breeder. Unrelated adults, especially females, provide extensive parental care to broods of mixed
parentage. The frequency and degree of reproductive skew between two females were examined experimentally. On medium-size
carcasses, the proportion of eggs attributed to each female was not significantly different from random in 42% of the broods,
skewed in 42% and not shared in 16%. Although reproduction was usually skewed in favor of the larger female, the relative
sizes of the two females did not predict the degree of skew. On large carcasses, the proportion of eggs attributed to each
female was not different from random in 87% of the broods and weakly skewed in 13%. Several mechanisms for biasing reproductive
success were investigated. Females increase the proportion of their offspring in the brood by committing differential ovicide.
Secondly, burying and preparing a carcass cooperatively stimulates ovarian development of the larger female and slows it for
the smaller female, reducing or delaying oviposition by the subordinate. Thirdly, larger females are more likely to be dominant
and are more fecund than smaller females.
Received: 20 July 1996 / Accepted after revision: 30 November 1996 相似文献
16.
Russell C. Titus C. Ray Chandler Ellen D. Ketterson Val Nolan Jr. 《Behavioral ecology and sociobiology》1997,41(3):165-169
Frequency of singing by birds may vary with reproductive stage in ways that reflect variation in the functions of song in
intersexual and intrasexual communication. In dark-eyed juncos (Junco hyemalis) high-amplitude song is produced only by males. To investigate the function of this song, we tested whether fertility of
females affected singing by their mates or by neighboring males. Using focal observations, song censuses, and radiotracking
data, we determined whether song production varied between and among periods when females were fertile and non-fertile. Our
findings show that males do not increase song production when their mates are fertile, nor do they increase song production
when neighboring females are fertile. These results suggest that male juncos do not signal their intent to defend territories
(or mates) more when females are fertile and that they do not use song to advertise to specific potential participants in
extra-pair fertilizations.
Received: 13 February 1997 / Accepted after revison: 2 May 1997 相似文献
17.
Relatedness, polyandry and extra-group paternity in the cooperatively-breeding white-browed scrubwren (Sericornis frontalis ) 总被引:3,自引:0,他引:3
Linda A. Whittingham Peter O. Dunn Robert D. Magrath 《Behavioral ecology and sociobiology》1997,40(4):261-270
We used DNA fingerprinting to examine the genetic parentage and mating system of the cooperatively breeding white-browed
scrubwren, Sericornis frontalis, in Canberra, Australia. Our analyses revealed a remarkable variety of mating tactics and social organization. Scrubwrens
bred in pairs or multi-male groups that consisted of a female and two or more males. Females were always unrelated to the
pair male or alpha (dominant) male. Among multi-male groups we found three different mating tactics. Firstly, when alpha and
beta (subordinate) males were unrelated, they usually shared paternity in the brood. This resulted in both males gaining reproductive
benefits directly. Secondly, when beta males were not related to the female but were related to the alpha males, beta males
sired offspring in some broods. In this situation, beta males gained reproductive benefits both directly and potentially indirectly
(through the related alpha male). Thirdly, when beta males were related to the female or both the female and alpha male, they
remained on their natal territory and did not sire any offspring. Thus beta males gained only indirect reproductive benefits.
Overall, when group members were related closely, the dominant male monopolized reproductive success, whereas when the members
were not related closely the two males shared paternity equally. This positive association between monopolization of reproduction
and relatedness is predicted by models of reproductive skew, but has not been reported previously within a single population
of birds. Other cooperatively breeding birds with both closely related and unrelated helpers may show a similar variety of
mating tactics. Finally, we found that extra-group paternity was more common in pairs (24% of young) than in multi-male groups
(6%), and we discuss three possible reasons for this difference.
Received: 21 May 1996 / Accepted after revision: 14 December 1996 相似文献
18.
Carola Borries 《Behavioral ecology and sociobiology》1997,41(3):139-150
In the seasonally breeding langur (Presbytis entellus) population of Ramnagar, South Nepal, where multimale groups prevail, 25 attacks on 11 infants (including one actual killing)
by seven adult males were witnessed in five groups by six observers between 1990 and 1996. Circumstantial evidence also indicates
three additional attempts at infanticide and in seven additional cases infanticide was presumed or likely. Infanticide presumably
accounted for 30.8–62.5% of infant mortality in the first 2 years of life. Most attackers (91.4%) were residents of the infants'
group and had immigrated after the infants had been born (75.0%) or conceived (25.0%). Thus, they were not related to the
victims. The interbirth interval was shortened if an infant died either prior to September of its 1st year of life (mean = 1.2
years), or its 2nd year (mean = 2.0) and even its 3rd year (mean = 2.4). All attackers remained in the group at least until
the next mating season; high-ranking males maintained their dominance rank and lower-ranking males rose in rank. Since rank
and mating success were correlated and rank and reproductive success might be correlated, all attackers had a good chance
of siring the next infant of the victims' mothers and could thus have benefited by their action. Infanticide seems to be a
male reproductive strategy at Ramnagar. Infanticide has never before been reported among seasonally breeding langurs living
at such low densities. This is also the first detailed report of infanticide as a male reproductive strategy in a seasonally
breeding primate population.
Received: 19 December 1996 / Accepted after revision: 7 June 1997 相似文献
19.
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
20.
Differential interests between the sexes regarding the number of copulations can result in sexual harassment. Hence, females
may have less time available for foraging. Male sexual harassment often leads to fitness reduction in females. We used the
mating complex of the bisexual fish Poecilia mexicana and the co-occurring all-female Poecilia formosa to study sexual harassment and its incurred cost on female feeding efficiency. P. formosa is a sperm-dependent parthenogen that requires mating with host males to induce embryogenesis, but the male genes are not
used. We therefore predicted P. mexicana males to prefer conspecific females. Hence, costs of male sexual harassment should not occur in unisexuals. While P. formosa are at a disadvantage compared to P. mexicana females due to male mate choice (leading to sperm limitation), this could be traded-off by suffering less from sexual harassment.
In our experiment, we found males to direct significantly more pre-copulatory mating behaviour towards conspecific females,
whereas actual mating attempts did not differ between species. Contrary to our prediction, both types of females started feeding
later and spent less time feeding in the presence of a male partner compared to the time spent feeding with another female,
suggesting that females of both species suffer from male harassment. The focal females' feeding time declined with increasing
body size of the female competitor, and the same pattern was found when a male was present. We discuss that—besides sexual
harassment—other factors such as food competition and female mate choice may affect female feeding efficiency. 相似文献