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41.
Mark R. Forbes Dean G. McCurdy Keiko Lui Selma I. Mautner J. Sherman Boates 《Behavioral ecology and sociobiology》2006,60(1):87-95
Potential rates of reproduction (PRR) differ between the sexes of many animal species. Adult sex ratios together with PRR
are expected to determine the operational sex ratio (OSR) defined as the ratio of fertilizable females to sexually active
males at any given time. OSR is expected to determine the degree to which one sex competes for another—the limiting sex. We
explored the potential for mate limitation in an intertidal amphipod, Corophium volutator (Pallas). Males have higher PRR than females, but males may be limiting because of extreme female-biased sex ratios observed
in this species. Consistent with this idea, late season females were less likely to be ovigerous and had smaller size-specific
clutches, both of which were associated with seasonal declines in availability of males of reproductive size. Seasonal changes
in ovigery could not be explained by seasonal changes across sites in other factors (e.g., female body size or phenology of
breeding). Smaller females were less likely to become ovigerous later in the season at three of four sites. Seasonal reductions
in clutch size also occurred among small females expected to be reproducing for their first time. In complimentary laboratory
experiments, reduced likelihood of ovigery and reduced fecundity occurred when the number of receptive females was increased
relative to availability of a reproductively active male. Our results suggest male mate limitation can occur seasonally in
this species and that male limitation is regionally widespread and may affect recruitment. 相似文献
42.
In temperate-zone birds, testosterone (T) influences male behavior during the breeding season. The elevation of plasma levels of T to a breeding baseline is necessary for basic reproductive behaviors, but it is still unclear whether variation in T levels above this critical threshold influences the intensity of these behaviors. Such a relationship between T and sexually selected traits is a critical assumption of the immunocompetence handicap hypothesis. We here experimentally elevated T levels in blue-tit males above the natural mean (T-males) during the period of nest building and egg laying, without manipulating hormone levels during chick feeding. T-males neither interacted more often with other males, nor did they respond more aggressively to a dummy intruder, compared to males with control implants. T-males did not guard their social mates more closely, but they were more likely to interact with potential extra-pair mates. Females mated to T-males did not change their behavior during egg laying and the treatment did not significantly affect male and female feeding rates. Despite this, nests of T-males produced larger and heavier fledglings in one study year. Our observations suggest that T levels above the natural mean during the mating period do not increase aggressive or territorial behavior in male blue tits. However, if females perceived T-males as high-quality mating partners, superior offspring development in nests of T-males might be caused by higher maternal investment. Hence, male behaviors involved in mate attraction may have been influenced by T levels above the natural mean.Communicated by R. Gibson 相似文献
43.
U. M. Savalli 《Behavioral ecology and sociobiology》1994,35(4):227-234
Recent investigations of male ornaments in sexual selection have used experimental manipulation of tail length in three widowbird species, but only for one of these have correlates of male reproductive success been reported. I examined correlates of male attractiveness to nesting females over two breeding seasons for the polygynous yellow-shouldered widowbird, Euplectes macrourus, in order to discover which cues females may be using to select mates. The black, long-tailed ( 10 cm) males defend large territories and build nest frames, or cock's nests, which females then line and use for nesting. I examined various aspects of male morphology, five behavioral displays, territory characteristics, and the number of cock's nests that males built. Few correlates of mating success were found. The best predictor was the number of cock's nests that a male builds, though one courtship display also correlated with male mating success in 1 year, as did average grass height. Tail length did not correlate with male mating success. A partial correlation analysis confirmed that cock's nests and, in 1 year, grass height, were the primary contributers to male success. Females may choose where to nest primarily on the availability of suitable nesting sites. Long tails may be used by females seeking extra-pair copulations or in male-male competition for territories. 相似文献
44.
Strike-induced chemosensory searching by a teiid lizard,the golden tegu (Tupinambis nigropunctatus) 总被引:1,自引:0,他引:1
William E. Cooper Jr. 《Chemoecology》1993,4(2):79-85
Summary Strike-induced chemosensory searching (SICS) is experimentally demonstrated in a teiid lizard,Tupinambis nigropunctatus. SICS consists of a concurrent post-strike elevation in tongue-flick rate (PETF) and searching movements after voluntary release or escape of bitten prey or removal of prey from the predator's mouth. The results are consistent with previous data showing that PETF and/or SICS occur in all families of scleroglossan lizards and snakes and all families of actively foraging lizards yet studied. The relatively short duration of SICS (2 min) in a lizard having lingual and vomeronasal structure highly specialized for chemosensory sampling and analysis suggests that phylogenetic and ecological factors may be more important than morphology in determining the duration. The greatest known durations occur only in the presumably monophyletic clade containing varanoid lizards and snakes, all of which have highly developed chemical sampling and chemoreceptor apparatus, but in addition feed on prey that has a high probability of being relocated by prolonged scent-trailing. Because only active foragers move through the habitat while tongue-flicking and exhibit lingually mediated prey chemical discrimination, only active foragers may be expected to use SICS. SICS would appear to be useless to an ambush forager and might disrupt its defensive crypticity, rendering it more detectable to predators and prey. Therefore, it may be predicted that SICS is adaptively adjusted to foraging mode. 相似文献
45.
We removed the mates of ten male black-capped chickadees (Pares atricapillus) during the nest-building period to determine the effect of female presence on dawn singing. During the first dawn chorus following mate removal, males sang significantly longer, increased movement within their territory, and increased the percentage of their territory covered while singing. After the female was returned, these parameters returned to the pre-removal values. Males did not alter the frequency range or modal frequency of their songs when the mate was removed, nor did they change the degree of frequency shifting in the fee-bee song. We conclude that dawn singing in the black-capped chickadee acts, in part, as an intersexual signal, and that the behavior of frequency shifting in the song may be directed more toward rival males than females.
Correspondence to: K. Otter 相似文献
46.
Variation in reproductive potential usually occurs among individuals of both sexes; for example, some individuals may carry
more gametes or be able to continue to generate more gametes in their reproductive life than others. Therefore, to maximize
their reproductive success, both sexes are expected to show adaptations for mate choice. However, most authors concentrated
on how females choose their mates with the belief that females invest more in reproduction than males, and males are generally
eager to pair with any female. In this paper, we report our work on a polygamous moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), with special emphasis on male pre- and in-copulation mate choice in relation to the reproductive
quality and re-copulation potential of females. We show that in E. kuehniella, younger and heavier females have significantly higher reproductive value than older and lighter ones, and male sperm supply
significantly decreases over successive copulations. Males exercise pre-copulation mate choice by selecting females with higher
reproductive potential for copulation and in-copulation mate choice by allocating more sperm to females with higher reproductive
potential. However, high-quality females are more likely to re-copulate than low-quality ones, and allocation of more sperm
to females by males does not increase female reproductive outputs. It is suggested that the allocation of more sperm to high-quality
females functions to increase sperm competitiveness against rivals. 相似文献
47.
Male seahorses (genus Hippocampus) provide all post-fertilization parental care, yet despite high levels of paternal investment, these species have long been
thought to have conventional sex roles, with female mate choice and male–male competition. Recent studies of the pot-bellied
seahorse (Hippocampus abdominalis) have shown that sex-role reversal occurs in high-density female-biased populations, indicating that male mating preferences
may lead to sexual selection on females in this species. Egg size, egg number, and offspring size all correlate positively
with female body size in Hippocampus, and by choosing large mating partners, male seahorses may increase their reproductive success. While male brood size is
also positively correlated with body size, small H. abdominalis males can carry exceptionally large broods, suggesting that the fecundity benefits of female preference for large partners
may be limited. We investigated the importance of body size in reproductive decisions of H. abdominalis, presenting focal individuals of both sexes with potential mating partners of different sizes. Mating preferences were quantified
in terms of time spent courting each potential partner. Male seahorses were highly active throughout the mate-choice trials
and showed a clear behavioral preference for large partners, while females showed significantly lower levels of activity and
equivocal mating preferences. The strong male preferences for large females demonstrated here suggest that sexual selection
may act strongly on female body size in wild populations of H. abdominalis, consistent with predictions on the importance of female body size for reproductive output in this species.
An erratum to this article can be found at 相似文献
48.
S. D. Goldsworthy D. J. Boness R. C. Fleischer 《Behavioral ecology and sociobiology》1999,45(3-4):253-267
When closely related species breed in sympatry, and where hybrids have lower fitness, reinforcement theory predicts that
selection should favour mechanisms that reduce the probability of interspecific matings. If this situation arises among species
that exhibit resource defence polygyny where males and females of different species reside in the same territories, there
may be some conflict between mate choice based on territory-holding ability (sexual selection) and mate choice for correct
species. We investigated this in a population of fur seals where three species are sympatric and where some females breed
in the territories of heterospecific males, and where interspecific matings and hybrid pups are observed. The territorial
status of males and the birthing sites of females were determined during daily observations, as were the movements of males
and females, the location of matings and mating partners. DNA extracted from skin samples was used to determine paternities
using DNA fingerprinting and the mtDNA genotype of individuals. Individuals were also classed on the basis of species-typical
phenotype. We found that extra-territory inseminations (ETIs) were significantly more prevalent (67%) when territorial males
and resident females were of different phenotype than when of similar phenotype (27%), but mtDNA genotype had no effect on
the rate of ETIs. ETIs were probably by males with the same phenotype, as pups born to these females in the following season
had the same phenotype as their mothers, suggesting they were not hybrids. These results suggest that within the resource
defence polygynous mating system of these sympatric fur seals, female mate choice is more influenced by male phenotype than
genotype. Contrary to our predictions, our study indicates that potential conflict between mate choice based on sexual selection
and species recognition is unlikely, because females have some capacity to discriminate between males both within and between
species on phenotypic traits additional to those under sexual selection. Although at least 25% of the pups born in this study
were hybrid, this study can only support reinforcement theory if hybrids have reduced fitness. The fitness of hybrids among
the species studied is currently unknown.
Received: 19 January 1998 / Accepted after revision: 12 September 1998 相似文献
49.
Males of five species of three tribes in the longhorned beetle subfamily Cerambycinae produce volatile pheromones that share a structural motif (hydroxyl or carbonyl groups at carbons two and three in straight-chains of six, eight, or ten carbons). Pheromone gland pores are present on the prothoraces of males, but are absent in females, suggesting that male-specific gland pores could provide a convenient morphological indication that a species uses volatile pheromones. In this article, we assess the taxonomic distribution of gland pores within the Cerambycinae by examining males and females of 65 species in 24 tribes using scanning electron microscopy. Gland pores were present in males and absent in females of 49 species, but absent in both sexes of the remaining 16 species. Pores were confined to indentations in the cuticle. Among the species that had male-specific gland pores were four species already known to produce volatile compounds consistent with the structural motif. These findings support the initial assumption that gland pores are associated with the production of pheromones by males. There were apparently no taxonomic patterns in the presence of gland pores. These findings suggest that volatile pheromones play an important role in reproduction for many species of the Cerambycinae, and that the trait is evolutionarily labile. 相似文献
50.
S. Sommer 《Behavioral ecology and sociobiology》2005,58(2):181-189
A growing number of studies indicate that females can increase the viability of their offspring by gaining direct benefits such as parental care or genetic advantages through selective mating with certain males. Among the best candidates for the genetic basis of mate choice in vertebrates are the genes of the major histocompatibility complex (MHC) because these highly polymorphic genes may increase offspring viability and provide direct cues for mate choice. A free-ranging, pair-living rodent was used as an example to investigate MHC-dependent mate choice in an obligate monogamous species, the Malagasy giant jumping rat Hypogeomys antimena. Two possible mechanisms of mate choice were tested. First, mate choice may occur to increase the heterozygosity of MHC genes in the progeny and, second, mates might choose each other according to the degree of dissimilarity of their functional MHC DRB (exon 2) proteins in order to maximise the allelic divergence in their offspring. Analyses of 65 Hypogeomys couples failed to confirm associations of mating patterns with the MHC genotype to increase heterozygosity or MHC allelic divergence in the progeny. Also, no evidence for mechanisms to increase the allelic divergence was found in sex-specific analyses where a male or female, respectively, migrated to and was accepted by a territory and burrow holder of the opposite sex. However, the frequency distribution of 0, 1 or 2 new alleles potentially available for the progeny differed significantly when a new male was chosen by a territory-holding female. In contrast to current models, genetically similar instead of dissimilar mates seem to be the preferred choice. This is the first study investigating the role of the MHC in mate selection in an obligate monogamous rodent.Communicated by G. Wilkinson 相似文献