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Kyle M. Benowitz Allen J. Moore 《Biological journal of the Linnean Society. Linnean Society of London》2016,119(4):1082-1088
Parenting strategies can be flexible within a species and may have varying fitness effects. Understanding this flexibility and its fitness consequences is important for understanding why parenting strategies evolve. In the present study, we investigate the fitness consequences of flexible parenting in the burying beetle Nicrophorus orbicollis, a species known for its advanced provisioning behaviour of regurgitated vertebrate carrion to offspring by both sexes. We show that, even when a parent is freely allowed to abandon the carcass at any point in time, biparental post‐hatching care is the most common pattern of care adopted in N. orbicollis. Furthermore, two parents together raised more offspring than single parents of either sex, showing that the presence of the male can directly influence parental fitness even in the absence of competitors. This contrasts with studies in other species of burying beetle, where biparental families do not differ in offspring number. This may explain why biparental care is more common in N. orbicollis than in other burying beetles. We suggest how the fitness benefits of two parents may play a role in the evolution and maintenance of flexible biparental care in N. orbicollis. 相似文献
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- In this study, evidence is provided of social immunity in the offspring of a sub‐social species, the burying beetle, Nicrophorus vespilloides.
- Nicrophorus vespilloides is a carrion breeder and, in a similar fashion to the adult beetles, the offspring produce exudates that exhibit lytic activity, which are used to coat the breeding resource. This strategy defends against the microbial community.
- The lytic activity in larval exudates declines as the brood develops, perhaps being most beneficial at the start of the breeding bout.
- Changing levels of parental care through widowing/orphaning affects lytic activity in the larval exudates, with levels decreasing in the absence of both parents.
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The behavioural mechanisms and patterns of protandrous sex change in bluebanded gobies Lythrypnus dalli were investigated and compared to the well-described behaviour patterns of protogynous sex change. To do this, unisex groups of males and females were established; behavioural and anatomical changes were recorded over a 42 day period as social status and sexual phenotype were determined. In all cases, social status, rather than the expression of a particular behaviour, accurately predicted final sexual phenotype. Rates of submissive behaviour, but not aggressive behaviour, were predictive of each discrete status class. Multiple individuals changed sex simultaneously if their sexual phenotype and social status were discordant, a novel finding suggesting that once a social hierarchy is established, individuals determined their sexual phenotype, regardless of initial sex, based on a simple operational principle: if subordinate express female, if dominant or not subordinate express male. This work demonstrates that similar mechanisms underlie sex change in both directions in L. dalli and potentially other sex changing species. 相似文献
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Variation in gene expression leads to phenotypic diversity and plays a central role in caste differentiation of eusocial insect species. In social Hymenoptera, females with the same genetic background can develop into queens or workers, which are characterized by divergent morphologies, behaviours and lifespan. Moreover, many social insects exhibit behaviourally distinct worker castes, such as brood‐tenders and foragers. Researchers have just started to explore which genes are differentially expressed to achieve this remarkable phenotypic plasticity. Although the queen is normally the only reproductive individual in the nest, following her removal, young brood‐tending workers often develop ovaries and start to reproduce. Here, we make use of this ability in the ant Temnothorax longispinosus and compare gene expression patterns in the queens and three worker castes along a reproductive gradient. We found the largest expression differences between the queen and the worker castes (~2500 genes) and the smallest differences between infertile brood‐tenders and foragers (~300 genes). The expression profile of fertile workers is more worker‐like, but to a certain extent intermediate between the queen and the infertile worker castes. In contrast to the queen, a high number of differentially expressed genes in the worker castes are of unknown function, pointing to the derived status of hymenopteran workers within insects. 相似文献
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1. The density‐dependent prophylaxis hypothesis predicts that individuals in high‐density populations will invest more resources in immune defence than individuals at lower densities. 2. However, recent work suggests that this prediction may not apply to all situations; solitarious species may paradoxically have higher scores than crowded counterparts in certain immune assays. 3. To investigate the relationship between a key immune parameter and field population densities, the total haemocyte counts (THCs) of Australian plague locusts (Chortoicetes terminifera) from three population densities in Western Australia were compared. 4. THCs were negatively correlated with field population densities, and locusts removed from a marching band and kept in isolation had increased THCs relative to group‐housed controls. 5. These results demonstrate that immune investment can inversely relate to population density in field conditions. 6. We suggest that isolated locusts increase their haemocyte densities relative to crowded conspecifics in response to potentially greater exposure to parasitoids and nematodes. 相似文献
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Johnson SE 《American journal of physical anthropology》2003,120(1):83-98
The social environment is a key feature influencing primate life histories. Chacma baboons (Papio hamadryas ursinus) are a female-bonded species with a strict linear dominance hierarchy. In this species, the allocation of energy to competing demands of growth and reproduction is hypothesized to vary as a function of competitive ability, which in turn increases with social rank. Since growth rate is a major component of life history models, measures of age-specific growth were used to analyze variation in life history traits across social ranks. Weights of 42 immature baboons were obtained without sedation or baiting from a troop of well-habituated chacma baboons in the Okavango Delta, Botswana. Using demographic and weight data from this wild population, five main findings emerged: 1) Weight for age and growth rate of infant and juvenile females are positively associated with maternal rank. 2) Male growth is not influenced by maternal rank. 3) Female growth shows smaller variation across feeding conditions than male growth. 4) Low-ranking adult females continue investment in offspring through prolonged lactation until they reach a weight comparable to that of high-ranking infants. 5) The benefit of rank to reproductive success shown in this study is 0.83 additional offspring. Reproductive span determined predominantly by age at maturation contributes 27-38% to the difference in expected number of offspring by rank, vs. 62-73% due to reproductive rate. These findings have major implications for understanding the role of social environment in phenotypic plasticity of life history traits, and in the evolution of primate life histories. 相似文献
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P. E. Hopwood A. J. Moore T. Tregenza N. J. Royle 《Journal of evolutionary biology》2015,28(7):1394-1402
Male parents spend less time caring than females in many species with biparental care. The traditional explanation for this pattern is that males have lower confidence of parentage, so they desert earlier in favour of pursuing other mating opportunities. However, one recent alternative hypothesis is that prolonged male parental care might also evolve if staying to care actively improves paternity. If this is the case, an increase in reproductive competition should be associated with increased paternal care. To test this prediction, we manipulated the level of reproductive competition experienced by burying beetles, Nicrophorus vespilloides (Herbst, 1783). We found that caregiving males stayed for longer and mated more frequently with their partner when reproductive competition was greater. Reproductive productivity did not increase when males extended care. Our findings provide support for the increased paternity hypothesis. Extended duration of parental care may be a male tactic both protecting investment (in the current brood) and maximizing paternity (in subsequent brood(s) via female stored sperm) even if this fails to maximize current reproductive productivity and creates conflict of interest with their mate via costs associated with increased mating frequency. 相似文献
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Population divergence in antipredator defence and behaviour occurs rapidly and repeatedly. Genetic differences, phenotypic plasticity or parental effects may all contribute to divergence, but the relative importance of each of these mechanisms remains unknown. We exposed juveniles to parents and predators to measure how induced changes contribute to shoaling behaviour differences between two threespine stickleback species (benthics and limnetics: Gasterosteus spp). We found that limnetics increased shoaling in response to predator attacks, whereas benthics did not alter their behaviour. Care by limnetic fathers led to increased shoaling in both limnetic and benthic offspring. Shoaling helps limnetics avoid trout and avian predation; our results suggest that this adaptive behaviour is the result of a combination of paternal effects, predator-induced plasticity and genetic differences between species. These results suggest that plasticity substantially contributes to the rapid divergence in shoaling behaviour across the post-Pleistocene radiation of sticklebacks. 相似文献
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We examined the selective consequences of variation in behaviour and endocrine physiology in two female throat-colour morphs of the lizard, Uta stansburiana in the wild. Female morphs differed in home-range distribution patterns and corticosterone levels in relation to the density and frequency of their female neighbours. Levels of plasma corticosterone of yellow-throated females increased with increased density of both morphs. In contrast, orange-throated females had reduced levels of corticosterone in response to increased density of orange females. Additionally, females with lower corticosterone survived poorly, suggesting that social interactions and high local densities of orange females may be potentially costly for orange females. These results are consistent with decreased fitness effects and suppression of immune function previously reported for orange female morphs surrounded by more orange neighbours. These correlations, in conjunction with previous work in this system, indicate that corticosterone is likely to be an important physiological mechanism regulating female fitness in nature. 相似文献
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Hexameric storage proteins are widespread in insects and provide a source of amino acids when demand is high and intake is
limited, such as during metamorphosis. We investigated the occurrence of storage protein levels in alates and in colony founding
pairs in a dry-wood nesting species and two soil-nesting species of termites. Females and males contained similar quantities
of storage protein at the time of the mating flight. Alates of soil-nesting species contained much higher levels of storage
protein than the wood nesting species. After eggs hatched, protein stores plummeted in both sexes of both ecological types.
Greater storage by alates of soil-nesting species is correlated with lack of access food during founding and the larger number
of workers produced in their first broods.
Received 3 June 2007; revised 3 and 21 August 2007; accepted 23 August 2007. 相似文献
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Laura R. Stein Alison M. Bell 《Evolution; international journal of organic evolution》2019,73(5):1037-1044
Phenotypic plasticity might influence evolutionary processes such as adaptive radiations. Plasticity in parental care might be especially effective in facilitating adaptive radiations if it allows populations to persist in novel environments. Here, we test the hypothesis that behavioral plasticity by parents in response to predation risk facilitated the adaptive radiation of three‐spine sticklebacks. We compared the behavior of fathers across multiple ancestral (marine) and derived (freshwater) stickleback populations that differ in time since establishment. We measured behavioral plasticity in fathers in response to a predator found only in freshwater environments, simulating conditions marine males experience when colonizing freshwater. The antipredator behavior of males from newly established freshwater populations was intermediate between marine populations and well‐established freshwater populations. In contrast to our predictions, on average, there was greater behavioral plasticity in derived freshwater populations than in ancestral marine populations. However, we found greater individual variation in behavioral reaction norms in marine populations compared to well‐established freshwater populations, with newly established freshwater populations intermediate. This suggests that standing variation in behavioral reaction norms within ancestral populations might provide different evolutionary trajectories, and illustrates how plasticity can contribute to adaptive radiations. 相似文献
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SUSANNE SHULTZ ROBIN I. M. DUNBAR 《Biological journal of the Linnean Society. Linnean Society of London》2010,100(1):111-123
In birds, large brains are associated with a series of population‐level phenomena, including invasion success, species richness, and resilience to population decline. Thus, they appear to open up adaptive opportunities through flexibility in foraging and anti‐predator behaviour. The evolutionary pathway leading to large brain size has received less attention than behavioural and ecological correlates. Using a comparative approach, we show that, independent of previously recognized associations with developmental constraints, relative brain size in birds is strongly related to biparental care, pair‐bonding, and stable social relationships. We also demonstrate correlated evolution between large relative brain size and altricial development, and that the evolution of both traits is contingent on biparental care. Thus, biparental care facilitates altricial development, which permits the evolution of large relative brain size. Finally, we show that large relative brain size is associated with pair‐bond strength, itself a likely consequence of cooperation and negotiation between partners under high levels of parental investment. These analyses provide an evolutionary model for the evolution of and prevalence of biparental care, altricial development, and pair‐bonding in birds. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 111–123. 相似文献
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Abstract. To determine whether increased water motion affects patterns of regeneration in the subtidal burrowing brittlestar Hemipholis elongata (phylum Echinodermata), individuals were subjected to laboratory-controlled turbulence conditions. Half of each replicate aquarium experienced oscillatory (wave-like) turbulence while the other half had no turbulence. Individual brittlestars from which arm-tips had been removed were allowed to burrow and to regenerate. Regenerated arm-tip length and weight were tested for differences between organisms in calm and turbulent conditions. Regenerated arm-tip length differed significantly between control and treatment, but arm-tip dry weight and skeleton/tissue ratio of regenerated arm-tips did not. To quantify plasticity in the skeleton, 15 morphological measurements made on the proximal face of vertebral ossicles (using scanning electron microscopy) were integrated as an index of overall ossicle size. We found a significant difference in the overall size index of the vertebral ossicles between treatments, but could not determine which of the measurements contributed most to the difference. The results indicate that regeneration in H. elongata is a complex process that can be modified by environmental conditions. 相似文献
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Abstract. In this study, we investigated a functional trade-off between trunk attachment and trunk-spine development in the acanthocephalan Corynosoma cetaceum . The worms live attached to the stomach and upper intestine of their cetacean definitive hosts, using the proboscis and spiny foretrunk as the main holdfast; the spiny hindtrunk can also attach by bending ventrally. When the hindtrunk bends, ventral compression generates an anterior fold (AF) and a posterior fold (PF). A morphological analysis based on 7,823 individuals collected from 10 franciscana dolphins, Pontoporia blainvillei , revealed that spines were smaller and more variable in size and occurrence in the folds than on neighboring areas; the growth of fold spines seemed to be inhibited to various degrees. Spines were more reduced in the AF than in the PF, and spines of both folds were more reduced in females than in males. Patterns of reduction appeared to be directly related to the intensity of fold compression associated with hindtrunk bending. Fold compression could induce plastic inhibition of spine growth, and/or could make fold spines maladaptive, spines being reduced by natural selection. Apparently, fold spines neither contact the substrate, nor are they exposed to the environment when the hindtrunk attaches. Therefore, fold spines could have reduced, or lost, their primary function, at least in the definitive host. The reduction and variability of spines in C. cetaceum seem to be unique among Corynosoma species. 相似文献
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The evolution of sociality in insects holds a central place in evolutionary theory. By examining the phylogenetic patterns of solitary and social behavior and how they correlate with ecological variables, we may identify factors important in the evolution of sociality. In this study, we investigated historical and biogeographical patterns of sociality in a socially polymorphic bee species (one that demonstrates both social and solitary nesting behavior). This unique system allows for a more powerful examination of evolutionary transitions in sociality than interspecific studies of obligately social and solitary species. We conducted a phylogenetic analysis among populations of the halictine bee Halictus rubicundus and then identified relationships among mitochondrial DNA sequence data, sociality, environmental conditions at the nesting site, and geographic location of populations of this species. Within North America, populations of H. rubicundus expressing social and solitary behavior belong to different genetic lineages. Sociality is also correlated with at least one environmental variable used in this study. Taken together, the results support the predictions for genetic control of sociality, but they are still consistent with social behavior at some level being determined by the environmental conditions at the nesting site. 相似文献