共查询到20条相似文献，搜索用时 15 毫秒
1.
M. D. E. Fellowes A. R. Kraaijeveld H. C. J. Godfray 《Evolution; international journal of organic evolution》1999,53(4):1302-1305
Replicate lines of Drosophila melanogaster have been selected for increased resistance against one of two species of parasitoid wasp, Asobara tabida and Leptopilina boulardi. In both cases, it has been shown that an improved ability to mount an immunological defense against the parasitoid's egg is associated with reduced survival when the larvae are reared under conditions of low resource availability and thus high competition. We show here that in both sets of selected lines, lower competitive ability is associated with reduced rates of larval feeding, as measured by the frequency of retractions of the cephalopharyngeal skeleton. This suggests that the same or similar physiological processes are involved in the trade-off between competition and resistance against either parasitoid and shows how the interaction between adaptations for competition and natural enemy resistance may be mediated. 相似文献
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MATHILDE POYET SEBASTIEN HAVARD GENEVIEVE PREVOST OLIVIER CHABRERIE GERALDINE DOURY PATRICIA GIBERT PATRICE ESLIN 《Physiological Entomology》2013,38(1):45-53
Unlike other Drosophila species, the invasive Drosophila suzukii Matsumura (Diptera: Drosophilidae) shows a remarkable pest status. Among the physiological traits that may explain the high level of resistance to parasitoids of Drosophila larvae, the haemocyte load is shown repeatedly to play an important role. To determine whether haemocyte load can explain immunity resistance of D. suzukii to parasitoids, the haemocytes of parasitized and healthy larvae are quantified in two Japanese and three French populations of D. suzukii. Parasitization tests are conducted with two larval parasitoids: the paleartic Leptopilina heterotoma Thomson (Hymenoptera: Figitidae) and the Asian Asobara japonica Belokobylskij (Hymenoptera: Braconidae). Based on morphological and functional criteria, D. suzukii has classes of haemocytes similar to those described in Drosophila melanogaster. However, healthy larvae of the five populations tested possess particularly large numbers of haemocytes compared with D. melanogaster. Haemocyte load is also higher in larvae from the French populations than in the Japanese strains. The ability of D. suzukii larvae to encapsulate eggs of L. heterotoma is associated with a particularly high load of circulating haemocytes. However, it is notable that A. japonica induces a strong depression of the haemocyte population in this resistant host associated with an inability to encapsulate parasitoid eggs. The results show that the cellular immune system plays a major role in the failure of larval parasitoids to develop in most instances in larvae of D. suzukii, possibly contributing to the success of this species as an invader. 相似文献
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M. D. E. Fellowes A. R. Kraaijeveld H. C. J. Godfray 《Evolution; international journal of organic evolution》1999,53(3):966-972
An increase in resistance to one natural enemy may result in no correlated change, a positive correlated change, or a negative correlated change in the ability of the host or prey to resist other natural enemies. The type of specificity is important in understanding the evolutionary response to natural enemies and was studied here in a Drosophila-paxasitoid system. Drosophila melanogaster lines selected for increased larval resistance to the endoparasitoid wasps Asobara tabida or Leptopilina boulardi were exposed to attack by A. tabida, L. boulardi and Leptopilina heterotoma at 15°C, 20°C, and 25°C. In general, encapsulation ability increased with temperature, with the exception of the lines selected against L. boulardi, which showed the opposite trend. Lines selected against L. boulardi showed large increases in resistance against all three parasitoid species, and showed similar levels of defense against A. tabida to the lines selected against that parasitoid. In contrast, lines selected against A. tabida showed a large increase in resistance to A. tabida and generally to L. heterotoma, but displayed only a small change in their ability to survive attack by L. boulardi. Such asymmetries in correlated responses to selection for increased resistance to natural enemies may influence host-parasitoid community structure. 相似文献
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Life history variation can be genetically based, or it may be due to environmental effects on the phenotype. In this paper we examine life history variation in relation to differences in habitat in the parasitoid Asobara tabida. Differences in the spatial distribution of host patches, the length of the season, host suitability, and competition between parasitoids all contribute to the selection for differences in life history between strains from northern and southern Europe. Strains were compared with respect to the allocation between reproduction and survival in experimental environments that varied with regard to the availability of food or to the number of hosts offered per day. Upon emergence parasitoids originating from southern Europe have higher egg loads and smaller fat reserves than parasitoids originating from northern Europe. Parasitoids from both southern and northern Europe show plasticity in allocation: food shortage causes a decrease in egg production, and rich breeding opportunities an increase in egg production. This plasticity is greater in the northern strain. Fat reserves play a central role in the physiology of this allocation. Fat can be used for both reproduction and survival. There is no oosorption, so once fat is allocated to reproduction it can no longer be used for survival. Differences in plasticity in allocation can therefore be considered as differences in the timing of egg production. 相似文献
6.
A trade‐off between reproduction and somatic maintenance and hence survival is fundamental to life‐history theory. We investigated the relationship between female fecundity and longevity in Homo sapiens using data from 153 countries located all over the world. The raw correlation between life span and fecundity was highly significant with a negative trend. After longevity and fecundity estimates were controlled for by confounding factors such as historical (i.e. human ethnic groups), religious, geographical, socio‐economical and parasitological components, we still observed a negative relationship between the mean female fecundity and the mean longevity in a country. These findings support the hypothesis for the existence of a trade‐off between these two key life‐history traits in humans, as also reported by a recent single longitudinal study in England. 相似文献
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Vavre F Dedeine F Quillon M Fouillet P Fleury F Bouletreau M 《Evolution; international journal of organic evolution》2001,55(8):1710-1714
Wolbachia-induced cytoplasmic incompatibility (CI) can have two consequences in haplodiploid insects: fertilized eggs either die (female mortality, FM) or they develop into haploid males (male development, MD). Origin of this diversity remains poorly understood, but current hypotheses invoke variation in damage suffered by paternal chromosomes in incompatible eggs, thus intermediate CI types should be expected. Here, we show the existence of such a particular CI type. In the parasitoid wasp Leptopilina heterotoma, we compared CI effects in crosses involving lines derived from a single inbred line with various Wolbachia infection statuses (natural tri-infection, mono-infection, or no infection). Tri-infected males induce a FM CI type when crossed with either uninfected or mono-infected females. Crossing mono-infected males with uninfected females results in almost complete CI with both reduced offspring production, indicating partial mortality of fertilized eggs, and increased number of sons, showing haploid male development of others. Mono-infected males thus induce an intermediate Cl type when mated with uninfected females. The first evidence of this expected particular CI type demonstrates that no discontinuity separates MD and FM CI types, which appear to be end points of a phenotypic continuum. Second, different CI types can occur within a given species and even within offspring of a single pair. Third, phenotypic expression of the particular CI type induced by a given Wolbachia variant depends on other bacterial variants that co-infect the same tissues. These results support the idea that haplodiploids should be helpful in clarifying evolutionary pathways of insect-Wolbachia associations. 相似文献
8.
Stella F. Uiterwaal Ian T. Lagerstrom Thomas M. Luhring Miranda E. Salsbery John P. DeLong 《Ecology and evolution》2020,10(3):1368-1377
The effects of climate change—such as increased temperature variability and novel predators—rarely happen in isolation, but it is unclear how organisms cope with multiple stressors simultaneously. To explore this, we grew replicate Paramecium caudatum populations in either constant or variable temperatures and exposed half to predation. We then fit thermal performance curves (TPCs) of intrinsic growth rate (rmax) for each replicate population (N = 12) across seven temperatures (10°C–38°C). TPCs of P. caudatum exposed to both temperature variability and predation responded only to one or the other (but not both), resulting in unpredictable outcomes. These changes in TPCs were accompanied by changes in cell morphology. Although cell volume was conserved across treatments, cells became narrower in response to temperature variability and rounder in response to predation. Our findings suggest that predation and temperature variability produce conflicting pressures on both thermal performance and cell morphology. Lastly, we found a strong correlation between changes in cell morphology and TPC parameters in response to predation, suggesting that responses to opposing selective pressures could be constrained by trade‐offs. Our results shed new light on how environmental and ecological pressures interact to elicit changes in characteristics at both the individual and population levels. We further suggest that morphological responses to interactive environmental forces may modulate population‐level responses, making prediction of long‐term responses to environmental change challenging. 相似文献
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Yongjie Liu Zhixia Ying Shichang Wang Jinbao Liao Hui Lu Liang Ma Zhenqing Li 《Ecology and evolution》2017,7(16):6284-6291
Masting is defined as the intermittent highly variable production of seed in a plant population. According to reproductive modes, that is, sexual and asexual reproduction, masting species can be separated into three groups, that is, (1) species, for example, bamboo, flower only once before they die; (2) species, for example, Fagus, reproduce sexually; and (3) species, for example, Stipa tenacissima, reproduce both sexually and asexually. Several theories have been proposed to explore the underlying mechanisms of masting. However, to our knowledge, no theory has been found to explain the mechanism of masting species that reproduce both sexually and asexually. Here we refine the Resource Budget Model by considering a trade‐off between sexual and asexual reproduction. Besides the depletion efficient (i.e., the ratio of the cost of seed setting and the cost of flowering), other factors, such as the annual remaining resource (i.e., the rest of the resource from the photosynthetic activity after allocating to growth and maintenance), the trade‐off between sexual and asexual reproduction, and the reproductive thresholds, also affect masting. Moreover, two potential reproductive strategies are found to explain the mechanisms: (1) When the annual remaining resource is relatively low, plants reproduce asexually and a part of the resource is accumulated as the cost of asexual reproduction is less than the annual remaining resource. Plants flower and set fruits once the accumulated resource exceeds the threshold of sexual reproduction; (2) when the annual remaining resource is relatively high, and the accumulated resource surpasses the threshold of sexual reproduction, masting occurs. Remarkably, under certain depletion efficient, more investigation in sexual reproduction will lead plants to reproduce periodically. Additionally, plants investigate less resource to reproduce periodically when depletion efficient keeps increasing as plants can reproduce efficiently. Overall, our study provides new insights into the interpretation of masting, especially for species that reproduce both sexually and asexually. 相似文献
10.
M. Lin M. Chevalier S. Lek L. Zhang R. E. Gozlan J. Liu T. Zhang S. Ye W. Li Z. Li 《Journal of fish biology》2014,85(2):343-354
This study tested whether eutrophication could influence life‐history traits of a cyprinid, Chanodichthys erythropterus, in 10 Chinese lakes. Using the von Bertalanffy growth model, the asymptotic length (L∞) and the growth performance index (IGRO) were significantly affected by eutrophication. The gonado‐somatic index (IG) and relative fecundity (FR) were significantly lower in mesotrophic lakes than in eutrophic and hypertrophic lakes. These results indicate that increasing eutrophication affects the life‐history tactics of a freshwater fish. 相似文献
11.
Classical models of the evolution of virulence predict that multiple infections should select for elevated virulence, if increased competitiveness arises from faster growth. However, diverse modes of parasite competition (resource-based, antagonism, immunity manipulation) can lead to adaptations with different implications for virulence. Using an experimental evolution approach we investigated the hypothesis that selection in mixed-strain infections will lead to increased antagonism that trades off against investment in virulence. Selection in mixed infections led to improved suppression of competitors in the bacterial insect pathogen Bacillus thuringiensis. Increased antagonism was associated with decreased virulence in three out of four selected lines. Moreover, mixed infections were less virulent than single-strain infections, and between-strain competition tended to decrease pathogen growth in vivo and in vitro. Spiteful interactions among these bacteria may be favoured because of the high metabolic costs of virulence factors and the high risk of mixed infections. 相似文献
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Xiaofang Wang Zhong Wei Mei Li Xueqi Wang Anqi Shan Xinlan Mei Alexandre Jousset Qirong Shen Yangchun Xu Ville‐Petri Friman 《Evolution; international journal of organic evolution》2017,71(3):733-746
Parasites and competitors are important for regulating pathogen densities and subsequent disease dynamics. It is, however, unclear to what extent this is driven by ecological and evolutionary processes. Here, we used experimental evolution to study the eco‐evolutionary feedbacks among Ralstonia solanacearum bacterial pathogen, Ralstonia‐specific phage parasite, and Bacillus amyloliquefaciens competitor bacterium in the laboratory and plant rhizosphere. We found that while the phage had a small effect on pathogen densities on its own, it considerably increased the R. solanacearum sensitivity to antibiotics produced by B. amyloliquefaciens. Instead of density effects, this synergy was due to phage‐driven increase in phage resistance that led to trade‐off with the resistance to B. amyloliquefaciens antibiotics. While no evidence was found for pathogen resistance evolution to B. amyloliquefaciens antibiotics, the fitness cost of adaptation (reduced growth) was highest when the pathogen had evolved in the presence of both parasite and competitor. Qualitatively similar patterns were found between laboratory and greenhouse experiments even though the evolution of phage resistance was considerably attenuated in the tomato rhizosphere. These results suggest that evolutionary trade‐offs can impose strong constraints on disease dynamics and that combining phages and antibiotic‐producing bacteria could be an efficient way to control agricultural pathogens. 相似文献
13.
Geoff A. Parker Catherine M. Lessells Leigh W. Simmons 《Evolution; international journal of organic evolution》2013,67(1):95-109
Reproductive males face a trade‐off between expenditure on precopulatory male–male competition—increasing the number of females that they secure as mates—and sperm competition—increasing their fertilization success with those females. Previous sperm allocation models have focused on scramble competition in which males compete by searching for mates and the number of matings rises linearly with precopulatory expenditure. However, recent studies have emphasized contest competition involving precopulatory expenditure on armaments, where winning contests may be highly dependent on marginal increases in relative armament level. Here, we develop a general model of sperm allocation that allows us to examine the effect of all forms of precopulatory competition on sperm allocation patterns. The model predicts that sperm allocation decreases if either the “mate‐competition loading,”a, or the number of males competing for each mating, M, increases. Other predictions remain unchanged from previous models: (i) expenditure per ejaculate should increase and then decrease, and (ii) total postcopulatory expenditure should increase, as the level of sperm competition increases. A negative correlation between a and M is biologically plausible, and may buffer deviations from the previous models. There is some support for our predictions from comparative analyses across dung beetle species and frog populations. 相似文献
14.
1. Generalist koinobiont parasitoids often exhibit high flexibility in their development; their larvae shorten or prolong the developmental period depending on the host quality at parasitisation. However, flexibility of the growth rate of parasitoid larvae has rarely been investigated so far. 2. This study investigated how the koinobiont parasitoid wasps Asobara japonica and Leptopilina ryukyuensis regulate their larval growth when they parasitise host Drosophila larvae with varying larval periods. 3. In both parasitoid species, the preimaginal period was longer when they parasitised 1‐day‐old larvae of Drosophila rufa than when they parasitised older larvae of D. rufa or when they parasitised larvae of Drosophila simulans, a species with a shorter larval period than D. rufa. After host pupariation, A. japonica accelerated its growth, thereby showing a biphasic growth curve. On the other hand, L. ryukyuensis did not accelerate its growth after host pupariation. 4. Growth retardation of parasitoid larvae in 1‐day‐old D. rufa larvae would contribute to avoiding excess growth before host pupariation, because the excess growth of parasitoid larvae would have negative effects on host growth. The growth rate acceleration of A. japonica after host pupariation suggests that they enhance resource utilisation in a host that has reached maximum body mass. It remains uncertain as to why L. ryukuensis does not show clear accelerated growth after host pupariation. Nonetheless, these results suggest that parasitoid larvae have the ability to detect the developmental stage of hosts in a species‐specific manner. 相似文献
15.
Heat‐shock proteins (Hsps) and their cognates are primary mitigators of cell stress. With increasingly severe impacts of climate change and other human modifications of the biosphere, the ability of the heat‐shock system to affect evolutionary fitness in environments outside the laboratory and to evolve in response is topic of growing importance. Since the last major reviews, several advances have occurred. First, demonstrations of the heat‐shock response outside the laboratory now include many additional taxa and environments. Many of these demonstrations are only correlative, however. More importantly, technical advances in “omic” quantification of nucleic acids and proteins, genomewide association analysis, and manipulation of genes and their expression have enabled the field to move beyond correlation. Several consequent advances are already evident: The pathway from heat‐shock gene expression to stress tolerance in nature can be extremely complex, mediated through multiple biological processes and systems, and even multiple species. The underlying genes are more numerous, diverse and variable than previously appreciated, especially with respect to their regulatory variation and epigenetic changes. The impacts and limitations (e.g., due to trade‐offs) of natural selection on these genes have become more obvious and better established. At last, as evolutionary capacitors, Hsps may have distinctive impacts on the evolution of other genes and ecological consequences. 相似文献
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Joanna Sudyka 《BioEssays : news and reviews in molecular, cellular and developmental biology》2019,41(11)
Reproduction, a basic property of biological life, entails costs for an organism, ultimately detectable as reduction in survival prospects. Telomeres are an excellent candidate biomarker for explaining these reproductive costs, because their shortening correlates with increased mortality risk. For similar reasons, telomeres are perceived as biomarkers of individual “quality.” The relationship between reproduction and telomere dynamics is reviewed, emphasizing that cost and quality perspectives, commonly presented in isolation, should be integrated. While a majority of correlative studies have confirmed the relationship between telomere dynamics and various reproductive outputs, only limited experimental support exists showing that reproduction causes telomeres to shorten. A shift of focus to experimental manipulations of reproductive effort/telomere dynamics is crucial. However, the observation of survival reduction in response to these manipulations is essential for establishing telomeres as genuine biomarkers, allowing to unravel trade‐offs related to reproduction. 相似文献
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The Beta species complex shows a gradient of life histories from pronounced semelparity (big‐bang reproduction) to pronounced iteroparity (repeated reproduction). Models assume a trade‐off between investment in reproduction and survival. Reproductive effort is thought to increase with decreasing life span, and to be invariable in semelparous plants and susceptible to environmental conditions in iteroparous plants. These assumptions and hypotheses were verified by a greenhouse experiment testing six different life cycles at three contrasting nutrient levels. This study suggests that reproductive effort is negatively correlated with mean life span along the life‐cycle gradient. Unlike semelparous beets, reproductive effort in iteroparous beets is extremely sensitive to nutrient level. Phenotypic correlation between allocation to reproduction and allocation to survival generally appeared significantly negative in the longest‐lived iteroparous beets, nonsignificant in intermediate life histories and obviously positive in semelparous beets (no trade‐off control). 相似文献
18.
In seasonal environments with limited time and energy resources, double‐brooded birds face trade‐offs in the timing of their two reproductive attempts and in the effort allocated to the first and the second broods. In the Barn Swallow Hirundo rustica a long care period for the first brood enhances the survival of first‐brood chicks, but also delays the start of the second brood, which in turn reduces the survival prospects of second‐brood chicks. Probably as a response to this trade‐off, double‐brooded Barn Swallows reduce the period of post‐fledging care for first‐brood fledglings. By radiotracking whole families, we investigated the determinants of this behaviour and its consequences for the survival of the first‐brood fledglings. The end of the females’ investment in post‐fledging care of the first brood was related to the beginning of egg synthesis for the second clutch. With the start of egg synthesis, females significantly reduced provisioning rates to the first‐brood fledglings to less than one‐fifth of the previous rates, while the proportion of time they spent foraging remained high. Assuming that the females’ foraging success was constant, we conclude that their energy income was allocated to egg production rather than fledgling provision. Males did not compensate for the females’ reduced feeding rates. Thus the start of egg production for the second clutch had a marked effect on the quantity of food received by first‐brood fledglings. In parallel with the changes in parental behaviour and provisioning rates, we observed a marked drop in the daily survival rate of first‐brood chicks. These results support the hypothesis that females face a strong trade‐off in the allocation of energy to subsequent broods. Energy allocation to a second clutch involves a cost in terms of reduced provisioning, and as a result the survival of first‐brood chicks is compromised. This is probably outweighed by the improved success of an early second brood. 相似文献
19.
Akhmetzhanov AR Grognard F Mailleret L 《Evolution; international journal of organic evolution》2011,65(11):3113-3125
The interplay between individual adaptive life histories and populations dynamics is an important issue in ecology. In this context, we considered a seasonal consumer-resource model with nonoverlapping generations. We focused on the consumers decision-making process through which they maximize their reproductive output via a differential investment into foraging for resources or reproducing. Our model takes a semi-discrete form, and is composed of a continuous time within-season part, similar to a dynamic model of energy allocation, and of a discrete time part, depicting the between seasons reproduction and mortality processes. We showed that the optimal foraging-reproduction strategies of the consumers may be \"determinate\" or \"indeterminate\" depending on the season length. More surprisingly, it depended on the consumers population density as well, with large densities promoting indeterminacy. A bifurcation analysis showed that the long-term dynamics produced by this model were quite rich, ranging from both populations' extinction, coexistence at some season-to-season equilibrium or on (quasi)-periodic motions, to initial condition-dependent dynamics. Interestingly, we observed that any long-term sustainable situation corresponds to indeterminate consumers' strategies. Finally, a comparison with a model involving typical nonoptimal consumers highlighted the stabilizing effects of the optimal life histories of the consumers. 相似文献
20.
Michael A. Quance Michael Travisano 《Evolution; international journal of organic evolution》2009,63(6):1406-1416
Resistance to predation, herbivory, or disease often comes at a cost such that resistant genotypes are competitively inferior to their sensitive counterparts in the absence of predators, herbivores, or pathogens. The effects of this trade‐off on natural populations depend on its sensitivity to environmental changes. We used Escherichia coli and bacteriophage T4 as a model predator/prey system to study the effects of temperature on the cost of resistance. An array of independent T4‐resistant mutants, derived from a single ancestral strain of E. coli B, had a mean reduction in competitive fitness that depended strongly on environmental temperature; the cost of resistance generally increased with temperature. Genetic variance for fitness among phage‐resistant mutants also depended on temperature; however, genetic variance increased at high and low thermal extremes. These results suggest that temperature is likely to be an important determinant of the consequences of predation in natural communities. We also discuss the underlying mechanistic basis for the cost of resistance in this system and its interaction with temperature. 相似文献