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1.
Jean-Christophe Aymes Maider Larrieu Cédric Tentelier Jacques Labonne 《Die Naturwissenschaften》2010,97(4):435-439
Egg cannibalism is a common behavior among fish taxa and is largely studied in species with parental care. Heterocannibalism
and filial cannibalism have both been reported in salmonids, a group with no extended parental care, but the topic remained
somewhat under-documented, especially in brown trout (Salmo trutta). In the present study, 83 spawning events were recorded finely with high-resolution video in three natural populations.
Redd covering dynamics by females and the timing of cannibalism showed that eggs were vulnerable mainly during the first 120 s
after spawning. Cannibalism occurred in 25% of spawnings and was principally perpetrated by peripherals but the sires also
cannibalized their brood, especially after multiple mating. The probability of cannibalism increased with operational sex
ratio but did not correlate with the date in spawning season. Occurrence of cannibalism also differed between populations.
Our results suggest that such behavior is frequent and may reduce the fitness of parents. Its evolutionary implications for
population ecology should be considered, since it appeared to be controlled by environmental and spatial factors. 相似文献
2.
Parental care is an energetically demanding activity that ensures genes are efficiently passed from one generation to the next. According to evolutionary theory, the greatest energetic investment should be directed towards offspring that are most closely related to the parent. Male fathead minnows, Pimephales promelas, provide this parental investment to developing embryos but not newly hatched larvae. Therefore, selection should favour recognition of embryonic kin to ensure energetic expenditure is optimally invested. In this study, adult male fathead minnows were tested using behavioural assays, with egg cannibalism as an endpoint, to determine whether adult males could discriminate between related and unrelated embryos. Egg cannibalism was highest when adult male fathead minnows were presented with unrelated eggs and lowest when presented with eggs fertilized by the test subject (related eggs). The degree of cannibalism was also a function of breeding status. Unrelated males in breeding condition showed an intermediate response between the low cannibalism demonstrated by related males and the high cannibalism demonstrated by unrelated males in a nonbreeding condition. These results suggest that although male fathead minnows can discriminate between unrelated and related embryos, at least some component of parental investment is a simple function of breeding status. 相似文献
3.
We investigated the mating patterns in 22 breeding pairs of wild American goldfinches (Carduelis tristis) with respect to their body size, condition, and carotenoid-based, yellow plumage colour. Using reflectance spectrometry, we objectively quantified plumage colours across the bird-visible wavelengths, revealing a unexpected UV peak in the reflectance spectrum from yellow feathers. We summarized our colour measurements using a principal components analysis to create a single variable, carotenoid PC1, that represents the intensity of this carotenoid-based yellow colour, a measure of phenotypic quality in this species. We found no evidence of assortative mating with respect to measures of body size or condition but there was positive assortative mating by carotenoid PC1, such that the yellow plumage colours of males and females were significantly correlated within pairs. We argue that the yellow carotenoid coloration of goldfinches may be important in mutual mate choice and, thus, that sexual selection in this species may act upon female ornamentation, as well as the more obvious plumage signals of males. Because assortative mating results in an increase in genetic variance, we suggest that this might be a mechanism that maintains variance in ornamental traits in spite of the variance-eroding effects of sexual selection. 相似文献
4.
Providing parental care is potentially costly. Costs can arise through elevated energy expenditure or from an increased risk of mortality. A cost of parental care can also occur because a parent is compromised in their ability to forage. We used pumpkinseed Lepomis gibbosus, a fish with an alternative male mating strategy, to test whether parental males differed in their feeding in comparison with females and cuckolder males. To address this question, we examined the stomach contents of female, cuckolder male, and parental male pumpkinseed during the breeding season over an entire diel cycle. We showed that parental males had a lower total weight of food in their stomachs in comparison with females, while cuckolder males did not. Parental males also had a lower weight and number of chironomids in their stomachs. The temporal pattern of feeding of parental males diverged from that of females, and they had a lower probability of pupal chironomids in their stomachs, which implies spatial segregation in foraging. Parental males had a greater probability of conspecific eggs in their stomachs than females, while the probability of egg cannibalism did not differ between cuckolder males and females. Overall, these finding meet predictions in accordance with an assumption that parental care and territoriality can compromise feeding. 相似文献
5.
6.
Bercovitch FB Widdig A Trefilov A Kessler MJ Berard JD Schmidtke J Nürnberg P Krawczak M 《Die Naturwissenschaften》2003,90(7):309-312
In many mammalian species, male reproductive success appears to climb sharply at young adulthood, form a brief plateau during prime ages, and decline among older animals, a pattern often attributed to reduced physical condition with ageing. However, solid evidence to either substantiate or refute this profile among nonhuman primates is lacking. Here, we combine a decade of genetic analysis of paternity among free-ranging rhesus macaques, Macaca mulatta, with information about body condition in order to evaluate how changes in morphology might govern age-specific reproduction among males. We show that age-specific reproductive success traverses the same life history profile as found in other mammals, but reductions in reproductive output with advanced age were associated with reduced chances of survivorship rather than accompanied by diminished body condition. We demonstrate that variance in male age at onset of reproduction is three times greater than variance in female age at onset of reproduction. We provide the first evidence from primates that age-specific reproductive output among males is not a consequence of age-related changes in body condition, but reflects social and demographic factors. 相似文献
7.
We analyzed the relationships among spleen size, body condition (measured as kidney fat), and larval counts of the nematode
Elaphostrongylus cervi in red deer (Cervus elaphus). The aim was to investigate the interaction between host body condition and intensity of infection with parasites. As red
deer are highly polygynous, we also tested whether these relationships varied with sex and age of the hosts. Kidney fat and
spleen size were positively correlated in subadults (2–3 years old) and adults (>3 years old), but not in calves (<1 year
old) or yearlings (1–2 years old). Spleen size was negatively associated with nematode load in subadult females and in adult
males. These two age classes are potentially the most nutritionally stressed, as subadult hinds are still growing and often
engaging in rearing their first calf, and adult stags were sampled just after the rut, which is recognized as a substantial
energy drain in this age–sex class, as they compete to hold females during the mating season. Body condition related negatively
to parasite count only in adult males. In the context of red deer life history, these findings suggest that spleen size is
dependent on body condition and that it could be affected by variation in resource partitioning among immune defense, growth,
and reproductive effort in red deer. For the first time in a wild mammal, the spleen mass is shown to be positively related
to body condition and negatively related to parasite infection. We conclude that elucidating whether spleen mass reflects
immune defense investment or a measure of general body condition should contribute to understanding topical issues in mammal
ecology. 相似文献
8.
Microplitis croceipes (Hymenoptera: Braconidae) is a larval parasitoid of Helicoverpa/Heliothis spp. In the course of mass rearing of M. croceipes, we found that females oviposited in the conspecific adults in rearing cages. When 20 pairs of inexperienced females and
males or of experienced females and males were reared in a cage, the males lived for 14–15 days and the females for 18–20 days
on average. At their death, 37–42% of the males and 50–57% of the females contained conspecific eggs or first instar larvae
in their abdominal cavity. When two of inexperienced females met on a host-infested leaf of soybean, they attempted to sting
each other. Of the attacked females, 30% contained a conspecific egg laid in their abdomen. In abdominal cavity of the adults
parasitized by a conspecific female, the majority of the parasitoid eggs laid disappeared within 1 day after oviposition.
Only 10–30% of the parasitoid eggs laid in conspecific adults hatched 3–4 days after oviposition, but those larvae never molted
to second instar. When the adults were stung by one or two conspecific females, their subsequent longevity was significantly
shorter than that for the control adults. Oviposition in conspecific adults may be prevalent in other parasitic wasps that
quickly oviposit without intensive host examination, and have cuticle and size of abdomen to be stung by conspeicifcs. 相似文献
9.
Unpublished field observations in Leucauge argyra, a tropical orb weaver spider, suggest the occurrence of conspicuous mating plugs that could reduce or prevent remating attempts.
Otherwise, the sexual behavior of this species remains unknown. The aims of this study were to describe the courtship behavior
and copulation in L. argyra and investigate mating plug formation in this species. Fourteen virgin females and 12 plugged females were exposed to up
to three males and checked for mating plug formation. Of the 12 virgins that copulated, nine produced plugs (five immediately
after copulation), and the five plugged females that copulated produced another mating plug immediately after copulation.
We did not detect the transfer of any male substance during copulation but observed a whitish liquid emerging from female
genital ducts. Plug formation was positively associated with male twanging during courtship. One virgin and four plugged females
cannibalized males. In seven trials with virgins and in three trials with plugged females, the male’s palp adhered to a substance
that emerged from female genital ducts and spread on her genital plate. The male had to struggle energetically to free his
glued palp; two of these males were cannibalized while trying to release their palps. Females seem to determine copulation
duration by altering the timing of mating plug formation and through sexual cannibalism. This is the first case reported of
a mating plug as a sticky trap for males. 相似文献
10.
Increased egg estradiol concentration feminizes digit ratios of male pheasants (<Emphasis Type="Italic">Phasianus colchicus</Emphasis>) 总被引:1,自引:0,他引:1
The length ratio between individual digits differs between males and females in humans, other mammals, lizards, and one bird
species. Sexual dimorphism in digit ratios and variation among individuals of the same sex may depend on differential exposure
to androgens and estrogens during embryonic life. Organizational effects of sex hormones could cause the observed correlations
between digit ratios and diverse phenotypic traits in humans. However, no study has investigated experimentally the effect
of prenatal estrogens on digit ratios. We analyzed the effect of estradiol injection in ring-necked pheasant (Phasianus colchicus) eggs on digit ratios. Males from control eggs had higher ratios between the second or third and the fourth digit of the
right foot compared to females. Estradiol-treated eggs produced males with lower (feminized) right foot second to fourth digit
ratio. Thus, we provided the first experimental evidence that prenatal exposure to physiologically high estrogen levels affects
bird digit ratios. 相似文献
11.
Sneaking tactic, a male alternative reproductive tactic involving sperm competition, is generally adopted by small individuals
because of its inconspicuousness. However, large size has an advantage when competition occurs between sneakers for fertilization
of eggs. Here, we suggest that both large- and small-size advantages of sneaker males are present within the same species.
Large sneaker males of the dusky frillgoby Bathygobius fuscus showed a high success rate in intruding into spawning nests because of their advantage in competition among sneaker males
in keeping a suitable position to sneak, whereas small sneakers had few chances to sneak. However, small sneaker males were
able to stay in the nests longer than large sneaker males when they succeeded in sneak intrusion. This suggests the possibility
of an increase in their paternity. The findings of these size-specific behavioural advantages may be important in considering
the evolution of size-related reproductive traits. 相似文献
12.
Leclaire S White J Arnoux E Faivre B Vetter N Hatch SA Danchin E 《Die Naturwissenschaften》2011,98(9):773-782
Carotenoid pigments are important for immunity and as antioxidants, and carotenoid-based colors are believed to provide honest
signals of individual quality. Other colorless but more efficient antioxidants such as vitamins A and E may protect carotenoids
from bleaching. Carotenoid-based colors have thus recently been suggested to reflect the concentration of such colorless antioxidants,
but this has rarely been tested. Furthermore, although evidence is accruing for multiple genetic criteria for mate choice,
carotenoid-based colors have rarely been shown to reflect both phenotypic and genetic quality. In this study, we investigated
whether gape, tongue, eye-ring, and bill coloration of chick-rearing black-legged kittiwakes Rissa tridactyla reflected circulating levels of carotenoids and vitamins A and E. We further investigated whether integument coloration reflected
phenotypic (body condition and fledging success) and genetic quality (heterozygosity). We found that the coloration of fleshy
integuments was correlated with carotenoid and vitamin A levels and fledging success but only in males. Furthermore, the coloration
of tongue and eye-ring was correlated with heterozygosity in both males and females. Integument colors might therefore be
reliable signals of individual quality used by birds to adjust their parental care during the chick-rearing period. 相似文献
13.
In several animal species, females discriminate against previous mates in subsequent mating decisions, increasing the potential
for multiple paternity. In spiders, female choice may take the form of selective sexual cannibalism, which has been shown
to bias paternity in favor of particular males. If cannibalistic attacks function to restrict a male's paternity, females
may have little interest to remate with males having survived such an attack. We therefore studied the possibility of female
discrimination against previous mates in sexually cannibalistic Argiope bruennichi, where females almost always attack their mate at the onset of copulation. We compared mating latency and copulation duration
of males having experienced a previous copulation either with the same or with a different female, but found no evidence for
discrimination against previous mates. However, males copulated significantly shorter when inserting into a used, compared
to a previously unused, genital pore of the female. 相似文献
14.
Panayiotis Pafilis Shai Meiri Johannes Foufopoulos Efstratios Valakos 《Die Naturwissenschaften》2009,96(9):1107-1113
Resource availability, competition, and predation commonly drive body size evolution. We assess the impact of high food availability
and the consequent increased intraspecific competition, as expressed by tail injuries and cannibalism, on body size in Skyros
wall lizards (Podarcis gaigeae). Lizard populations on islets surrounding Skyros (Aegean Sea) all have fewer predators and competitors than on Skyros but
differ in the numbers of nesting seabirds. We predicted the following: (1) the presence of breeding seabirds (providing nutrients)
will increase lizard population densities; (2) dense lizard populations will experience stronger intraspecific competition;
and (3) such aggression, will be associated with larger average body size. We found a positive correlation between seabird
and lizard densities. Cannibalism and tail injuries were considerably higher in dense populations. Increases in cannibalism
and tail loss were associated with large body sizes. Adult cannibalism on juveniles may select for rapid growth, fuelled by
high food abundance, setting thus the stage for the evolution of gigantism. 相似文献
15.
The bumblebee Bombus terrestris is not only an effective pollinator, but also a potential invasive alien species outside its native range. Recently, nearly
30% of queens of the Japanese native species Bombus hypocrita sapporoensis and B. hypocrita hypocrita were estimated to copulate with B. terrestris males in the field, suggesting that indigenous bumblebees could be genetically deteriorated through hybrid production with
the introduced species. In this study, we evaluated hybrid production between the introduced B. terrestris and the indigenous B. hypocrita sapporoensis under laboratory conditions. The hatching rate of eggs derived from interspecific matings was 0% and 8.6% depending on the
direction of the cross, which was significantly lower than that from intraspecific matings of B. terrestris (76.9%) and B. hypocrita sapporoensis (78.9%). Genetic studies using microsatellite markers revealed that both haploid and diploid individuals were present in
the egg stage, whereas all hatched larvae were haploid. In addition, histological studies revealed that eggs derived from
interspecific matings terminated development 2 days after oviposition. These results strongly suggested that eggs derived
from interspecific matings are inviable due to post-mating isolation mechanisms. Mass release of exotic pollinators could
cause serious population declines of native bumblebee species. 相似文献
16.
Clotilde Biard Nicolas Saulnier Maria Gaillard Jérôme Moreau 《Die Naturwissenschaften》2010,97(11):987-995
In the study of parasite-mediated sexual selection, there has been controversial evidence for the prediction that brighter
males should have fewer parasites. Most of these studies have focused on one parasite species. Our aim was to investigate
the expression of carotenoid-based coloured signals in relation to patterns of multiple parasite infections, to determine
whether colour reflects parasite load of all parasite species, or whether different relationships might be found when looking
at each parasite species independently. We investigated the relationship between bill colour, body mass and plasma carotenoids
and parasite load (feather chewing lice, blood parasite Plasmodium sp., intestinal parasites cestodes and coccidia) in the blackbird (Turdus merula). Bill colour on its own appeared to be a poor predictor of parasite load when investigating its relationships with individual
parasite species. Variation in parasite intensities at the community level was summarised using principal component analysis
to derive synthetic indexes of relative parasite species abundance and absolute parasite load. The relative abundance of parasite
species was strongly related to bill colour, plasma carotenoid levels and body mass: birds with relatively more cestodes and
chewing lice and relatively less Plasmodium and coccidia had a more colourful bill, circulated more carotenoids and were heavier. These results suggest that bill colour
more accurately reflects the relative intensities of parasite infection, rather than one-by-one relationships with parasites
or absolute parasite burden. Investigating patterns of multiple parasite infection would thus improve our understanding of
the information conveyed by coloured signals on parasite load. 相似文献
17.
The migration strategies of birds may vary strongly between species and also between age and/or sex groups. We studied the autumn migration and body condition of molecularly sexed Reed Warblers Acrocephalus scirpaceus and Sedge Warblers Acrocephalus schoenobaenus (211 and 208 ind., respectively) at a stopover site on Lake Druzno, Northern Poland, in 2008. Immature male Reed Warblers were caught significantly later than females (median dates 9 days later), but in the Sedge Warbler, both sexes of immatures migrated at about the same time. Adult males and females of both species did not differ in their time of migration. Adult and immature males of both species were larger (wing length and body mass) than females. In both species, fat reserves were similar in both sexes of both age classes. Adults of both sexes of Reed and Sedge Warbler were generally caught earlier than immatures. In both species, the body mass and fat reserves of immatures were generally less than in adults. The autumn protogyny of immature Reed Warblers may allow smaller females to limit competition with bigger males during migration and at the wintering grounds. In the Sedge Warbler, which tends to match its migration to peak of occurrence of superabundant food at stopover sites, both sexes gain an advantage from migrating at the same time. Since part of the measured wing length variation in both species was explained by sex differences, temporal trends in wing length recorded at stopover sites should be interpreted with caution. 相似文献
18.
Reversed sex change by widowed males in polygynous and protogynous fishes: female removal experiments in the field 总被引:1,自引:0,他引:1
Sex change, either protogyny (female to male) or protandry (male to female), is well known among fishes, but evidence of bidirectional
sex change or reversed sex change in natural populations is still very limited. This is the first report on female removal
experiments for polygnous and protogynous fish species to induce reversed sex change in the widowed males in the field. We
removed all of the females and juveniles from the territories of dominant males in the cleaner wrasse Labroides dimidiatus (Labridae) and the rusty angelfish Centropyge ferrugata (Pomacanthidae) on the coral reefs of Okinawa. In both species, if new females or juveniles did not immigrate into the territories
of the widowed males, some of them emigrated to form male–male pairs. When a male–male pair formed, the smaller, subordinate
partner began to perform female sexual behaviours (n = 4 in L. dimidiatus; n = 2 in C. ferrugata) and, finally, released eggs (n = 1, respectively). Thus, the reversed sex change occurred in the widowed males according to the change of their social status.
These results suggest that such female removal experiments will contribute to the discovery of reversed sex change in the
field also in other polygnous and protogynous species. 相似文献
19.
Carotenoid pigments cannot be synthesized by vertebrates but must be ingested through the diet. As they seem to be a limited
resource, carotenoid-based ornaments are particularly interesting as possible honest signals of individual quality, in particular
of foraging efficiency and nutritional status. Some studies have demonstrated the condition dependence of carotenoid-based
plumage in birds. However, many other carotenoid-pigmented bare parts (i.e. skin, caruncles, bills, cere, and tarsi) are present
in birds but, in comparison with plumage, little is known about these traits as indicators of individual quality. Here, we
show that the eye ring pigmentation and bill redness of the red-legged partridge (Alectoris rufa) are positively associated to body condition and recent changes in body mass. Also, we found a negative relationship between
these two traits and heterophil-to-lymphocyte ratio, an indicator of physiological stress (the relationship with bill redness
being significant only for males). In an experiment, we found that after a period of reduction in food intake (with the consequent
loss of body mass), food-restricted birds showed lower eye ring pigmentation than ad-libitum-fed birds. Therefore, different
ornaments seem to reflect changes in body condition but at different speeds or intensities (eye ring, a fleshy ornament, appears
to respond more rapidly to changes in the nutritional status than a keratinized structure as the bill). These results indicate
that carotenoid-based ornaments are condition-dependent traits in the red-legged partridge, being therefore susceptible to
be employed as honest signals of quality in sexual selection. 相似文献
20.
A male gift to its partner? Cyanogenic glycosides in the spermatophore of longwing butterflies (<Emphasis Type="Italic">Heliconius</Emphasis>) 总被引:1,自引:0,他引:1
Males of several insect species transfer nuptial gifts to females during mating, typically in the form of a protein-rich spermatophore.
In chemically defended species, males could potentially enhance such a gift with chemicals that help protect the female, her
eggs, or both. This was shown for lepidopteran species that accumulate pyrrolizidine alkaloids. Most Heliconius butterflies are presumably protected from predators by virtue of de novo synthesized and/or sequestered cyanogenic glycosides.
Males of Heliconius species are known to transfer nutritional gifts to the females but whether defensive chemicals could also be transferred
is not known. To ascertain whether transfer of cyanogens occurs, we dissected freshly mated females from nine different Heliconius species and analyzed spermatophores for cyanogenic glycosides. We found cyanogens in the spermatophores of all nine species.
This is the first time cyanogenic glycosides are reported in the spermatophores of arthropods. We discuss the implications
of these findings for Heliconius biology and for other cyanogenic insects as well. We suggest that chemically defended species commonly lace their nuptial
gifts with defensive chemicals to improve gift quality. 相似文献