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11.
Independence, not conflict, characterizes dart-shooting and sperm exchange in a hermaphroditic snail
Although the sexes are united in hermaphrodites, conflict can still occur because the male and female functions have separate
interests. We examined the evidence for conflict in the mating system of the terrestrial snail Cantareus aspersus (formerly Helix aspersa) where sharp, calcareous darts are ‘shot’ during courtship. We predicted that the use of the dart would either reflect or
create conflict and this would be evident in either the courtship behavior or the transference of sperm. Previous studies
demonstrated that the dart functions after sperm transfer to increase sperm survival. Using detailed observations of mating
snails, we examined the factors that determine dart shooting order, the behavioral responses after being hit by a dart, the
accuracy of dart shooting, and the allocation of sperm resources. We found that each dart was shot independently, and each
animal appeared to be interested only in getting off the best possible shot, probably one that penetrates deeply near the
genital pore. There is no evidence of mating conflict. Every snail transfers sperm to its partner, and the size of the donation
does not depend on the success or failure of either snail’s dart shot. Although the receipt of a dart does not appear to cause
harm, it may produce indirect costs due to the partial loss of control over fertilization. We conclude that mating in C. aspersus is a partnership in which independent actors demonstrate unconditional reciprocity during courtship and sperm transfer. 相似文献
12.
Kensuke Nakata 《Behavioral ecology and sociobiology》1998,43(4-5):223-227
To optimally allocate resources between workers, reproductive females, and males, ant workers have to be able to identify
the sex of larvae and raise them differently. The ability of workers to discriminate between the sexes in the brood was tested
in colonies of queenless ponerine ants, Diacamma sp., from Japan. The ratio of male eggs in the egg pile was increased experimentally. This manipulation resulted in a corresponding
increase in the ratio of adult males, suggesting that Diacamma workers do not raise the sexes differently.
Received: 4 November 1997 / Accepted after revision: 14 March 1998 相似文献
13.
Clint D. Kelly 《Behavioral ecology and sociobiology》2008,62(6):855-871
A long-standing hypothesis in behavioural ecology posits that males with greater resource-holding potential (RHP) control
resource sites deemed more valuable by sexually-receptive females and, thereby, males controlling such sites accrue greater
reproductive success (RS). This hypothesis has historically been investigated using three separate but non-mutually exclusive
relationships (male RHP vs. resource value, resource value vs. male RS and male RHP vs. RS). The relationships between these
three variables are predicted to be strongly positive, however, due to measurement error and biological noise, perfect correlations
(r = 1.0) are rare in biology even for well-established relationships. Moreover, the inaccurate identification of either the
male trait(s) important to RHP or the resource characteristic sought by females will weaken the observed strength of the relationships.
Here, I use meta-analysis to quantitatively describe the general pattern of these relationships in animals. I predict that
the relationships between male RHP, resource-value and RS should be significantly positive (male RHP and resource-value should
explain a large amount of the variation in male RS). My meta-analysis supports this hypothesis; however, in the best case
scenario only ca. 20% of the variation in the response variable was explained. I conclude by identifying areas in which we
need to improve our investigations of resource-defence animals and recommending approaches to meet these needs.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
G. W. Uetz William J. McClintock Douglas Miller Elizabeth I. Smith Kristina K. Cook 《Behavioral ecology and sociobiology》1996,38(4):253-257
Males of the brush-legged wolf spider Schizocosa ocreata (Hentz) have conspicuously decorated forelegs used in courtship and agonistic displays. Approximately one in five juvenile
males has a missing or regenerating foreleg, and regeneration of a leg lost during development usually results in the absence
of a decorative tuft on that leg. The subsequent asymmetry in this male secondary character significantly decreases success
in both courtship of females and male-male agonistic interactions. Experimental removal of tufts from one leg of previously
successful symmetric males produces similar results. As a test for concomitant behavioral effects, female spiders were shown
video images of a courting male with symmetric tufts and the same video image altered to have asymmetric tufts. Female receptivity
to the asymmetric video image was lower. In contrast to fluctuating asymmetry resulting from developmental instability, leg
tuft asymmetry in S. ocreata most likely arises from a single event during ontogeny – possibly leg loss from an aggressive or predator encounter – and
may serve as a quality indicator in female mate choice.
Received: 27 July 1995/ Accepted after revision: 19 November 1995 相似文献
15.
José P. Veiga 《Behavioral ecology and sociobiology》1996,39(5):345-352
In many bird species the cryptic winter plumage is due to the presence of light feather tips that conceal conspicuous colorations.
The gradual abrasion of these tips that makes sexual traits visible has been interpreted as a strategy to improve mating success
(here referred as the permanent exhibition hypothesis). However, under some circumstances, the maintenance of a full plumage
that facultatively enables the bird to exhibit or cover aggression-inducing traits has proved to be advantageous (the coverable
badge hypothesis). In a population of house sparrows where black throat patches (here called badges) are used in intrasexual
competition, the degree of abrasion of dull feather tips that conceal bright colour early in the breeding season correlated
neither with badge size nor with traits indicating morphology and body condition. These results are only in accordance with
predictions of the coverable badge hypothesis. In 1992 experimental clipping of badge feather tips, which forced permanent
exposure of badges, negatively affected birds with the largest badges in terms of nest acquisition, but an opposite trend
was indicated for birds with the smallest badges. In 1993, when more novel birds in the study area were competing for nesting
sites than in 1992, only badge size, but not the experimental manipulation, affected nesting success. These results suggest
that the loss of the ability to conceal badges was disadvantageous, and more so if most competing individuals had already
been resident in the colony in previous years and the larger their badges were. There is a striking contrast between the results
reported for this study population, where badges mainly signal fighting ability, and those reported for another house sparrow
population, where badges are mainly used in mate choice. In this last population, tip abrasion is advantageous for dominant
individuals showing the largest badges. This suggests that the trade-off between conserving versus wearing off the feathers
that conceal ornaments could have different optimal resolutions depending on the relative importance of inter and intrasexual
selection on indicator traits.
Received: 29 September 1995/Accepted after revision: 14 July 1996 相似文献
16.
Several sexual selection theories assume certain benefits of female mate preference. The direct benefit, i.e., the direct contribution from males to their offspring and females, has been well tested empirically. However, the indirect benefit, i.e., the male's genetic contribution to their offspring, has been poorly demonstrated. Female preference for males' carotenoid-based coloration is known in some animals. Since animals must acquire carotenoids through foods, it is often hypothesized that the brightness of the carotenoid-based coloration is a reliable indicator of the male's foraging ability. Hence, females' indirect benefits, such as greater foraging ability in their offspring, through mate preference for the carotenoid-based coloration are assumed. However, the heritability of the foraging ability for foods that serve as carotenoid resources has not been tested. In this study, a maze experiment was performed in guppies (Poecilia reticulata) to examine the heritability of the foraging ability for algae, carotenoid resources in nature. The latency for completing algal-foraging tasks in this experiment showed high individual variation. Heritable estimates of the foraging ability were substantial (h
2 = 0.57 – 0.66) and significant, suggesting a genetic contribution to the foraging ability from fathers to their offspring. This result may support the hypothesis that indirect benefits influence the evolution of female choice. 相似文献
17.
Bo Terning Hansen Lars Erik Johannessen Tore Slagsvold 《Behavioral ecology and sociobiology》2007,61(8):1203-1209
Imprinting plays a key role in the development of species recognition, with young imprinting upon the morphological characters
of their parents. However, the potential role that cultural transmission might play in species recognition remains largely
uninvestigated. Great tits (Parus major) and blue tits (Cyanistes caeruleus) do not normally perceive each other as sexual competitors or potential partners. However, after reciprocal interspecific
cross-fostering, both species may perceive individuals of the foster species as potential rivals or mates. Although the experience
of being raised by heterospecifics clearly has affected the species recognition of cross-fostered birds, some of them breed
naturally with conspecifics. The offspring of such cross-fostered birds (OCF) are hence raised by parents that look like ordinary
conspecifics but display deviant species recognition as compared to controls in terms of aggressive response towards rivals.
Comparing the aggressive behavior of OCF, cross-fostered birds and controls towards territorial intruders may thus help tease
apart the influence of morphological vs behavioral cues of parents in the development of offspring species recognition. To
this end, we compared birds from all three treatments with respect to their aggressive response to territorial intruders of
both species during the breeding season. OCF and controls did not differ in their pattern of response towards heterospecific
and conspecific stimuli. Compared to cross-fostered birds, OCF and controls showed less aggression towards heterospecific
intruders, while the response towards conspecific intruders did not differ between treatments. These results demonstrate that
both tit species imprint on the morphological characters of their parents, but that parental behavior is not important for
the development of species recognition in terms of aggressive response towards territorial intruders. 相似文献
18.
Peter D. Dijkstra Renske Hekman Rüdiger W. Schulz Ton G. G. Groothuis 《Behavioral ecology and sociobiology》2007,61(4):599-609
The nature of the costs maintaining honesty of sexual signalling in inter- and intrasexual interactions remains a contentious
issue. For carotenoid-based colour ornaments, it has been hypothesized that the honesty of the signal is enforced when carotenoid
allocation to colour expression is traded off against carotenoid availability for immunocompetence. In addition, honesty is
enforced if androgens required for colour expression are immunosuppressive. We tested whether there is a trade-off between
colour expression and immunocompetence in a lek-breeding haplochromine cichlid fish, Pundamilia nyererei, from Lake Victoria with a carotenoid-based nuptial dress. First, we showed that expression of red nuptial colouration and
social rank in a group were positively correlated. We then successfully manipulated the level of colour advertisement by socially
stimulating individually housed males with a rival male: Stimulated males developed larger areas of red nuptial colouration
and had higher levels of circulating 11-ketotestosterone (11-KT) than non-stimulated males. We subsequently tested the humoral
immune response to a novel antigen (sheep red blood cells). There was no overall significant effect of social stimulation
on antibody production, but in the stimulated males, the degree of red colouration and the antibody response were negatively
correlated. This significant interaction between colour and treatment thus shows that the negative correlation between colouration
and antibody production is dependent on the (manipulated) social environment. This study provides correlational and experimental
evidence for a trade-off between expression of a sexual trait and one component of immune function in fish. We found no evidence
for a direct effect of 11-KT on antibody production, and we discuss alternative mechanisms that could mediate the trade-off. 相似文献
19.
José Martín Emilio Civantos Luisa Amo Pilar López 《Behavioral ecology and sociobiology》2007,62(2):173-179
Evidence for parasite-mediated sexual selection has been found in many species that use visual ornaments to attract females.
However, in many animals, variation in female responses to scents of parasitized males suggests that parasitic infections
might also affect information conveyed by pheromones (i.e., chemical ornaments). Thus, pheromones might also function in parasite-mediated
sexual selection. We show here that female lizards Psammodromus algirus responded differently to femoral gland secretions of males according to the parasite load and health of these males. Scents
of healthier males elicited more tongue flicks (a chemosensory behavior) by females, suggesting that these scents were more
attractive. Chemical analyses showed that parasite load and the T-cell-mediated immune response were related to the variability
in the proportions of some lipids in secretions of males. Further trials testing the chemosensory responses of females to
chemical standards indicated that females actually discriminated the chemicals related to males’ health from other chemicals
found in secretions. We suggest that these chemical ornaments may provide reliable information on the health and degree of
parasitic infection of a male. 相似文献
20.
Sexual selection and cuckoldry in a monogamous songbird: implications for sexual selection theory 总被引:11,自引:0,他引:11
Geoffrey E. Hill Robert Montgomerie Christina Roeder Peter Boag 《Behavioral ecology and sociobiology》1994,35(3):193-199
Sexual selection is generally assumed to be weaker in monogamous than in polygynous animals. Recently, though, extra-pair fertilizations have been hailed as an important force in generating variance in reproductive success among males in socially monogamous species, thereby increasing the intensity of sexual selection. To see if extra-pair copulations contribute to variance in male reproductive success in the house finch (Carpodacus mexicanus), we used DNA fingerprinting to determine the paternity of chicks from 35 nests. This species is a socially monogamous passerine in which plumage brightness serves as a sexually selected indicator of male quality. Out of 119, nestlings 10 (8.3%) were fathered by a male other than the attending male, but cuckoldry occurred randomly with respect to the plumage colouration, size, or age of the attending male. Thus extra-pair fertilizations do not generate variance in male reproductive success with respect to plumage colour. On the other hand, a strongly male-biased sex ratio and asynchronous breeding by females may generate substantial variance in male reproductive success and could explain the evolution of ornamental colouration. 相似文献