Journal of Evolutionary Biology最新文献

As organisms age, the fitness of the offspring they produce can decline, which is often attributed to parental senescence. However, few studies have tested for effects of parental age on offspring fitness in wild populations or in short-lived vertebrates, and only recently have studies begun to examine such effects in male and female offspring independently. Here, we use five generations of mark-recapture and genetic parentage data from an island population of a short-lived lizard, the brown anole (Anolis sagrei), to test for effects of maternal and paternal age on the survival to adulthood, first-year reproductive success, longevity, and lifetime fitness of their offspring. When comparing parents of different ages within the same offspring cohort, survival to adulthood increased with paternal age in sons, but we found no effects of maternal or paternal age on any component of fitness in daughters and no evidence that parental age effects differed based on the sex of the parent or the offspring. When considering repeated measures of individual parents sampled at multiple ages, we found that first-year reproductive success of sons decreased with paternal age, but longevity of sons increased with maternal age. However, when pooling sons and daughters, we found no overall effects of parental age on any component of offspring fitness, and little evidence that parental age effects differed between sons and daughters. Our study adds to the growing literature suggesting that negative effects of parental age on offspring fitness may not be as prevalent as once thought, particularly in wild populations.

In cannibalistic interactions, the same chemical cue may signal either threat or hunting opportunity, depending on the receiver's perspective. In this study, we conducted a series of behavioral experiments to assess how varying concentrations of kairomones and alarm cues from injured conspecifics influence predation pressure that cannibalistic dragonfly larvae Brachytron pratense exert on heterospecific prey (Daphnia magna). Exposure to all chemical cue treatments increased larval mobility, but the response was non-linear: at low concentrations of conspecific cues, larvae displayed increased activity within refuges, leading to reduced hunting efficiency and prey consumption-suggesting a self-defensive behavioral response. In contrast, higher cue concentrations prompted more exploratory movement outside refuges without a corresponding increase in heterospecific prey capture. These findings suggest that B. pratense modulates foraging strategy in response to conspecific chemical cues, prioritizing cannibalistic interactions over heterospecific predation. This shift leads to density-dependent, nonlinear predation pressure and highlights the overlooked indirect effects of predator cannibalism on predator-prey interaction dynamics.

Host-parasite relationships are often shaped by coevolutionary arms races. While abiotic influences on these dynamics are well documented, a combined analysis of abiotic and biotic factors is essential for understanding coevolution, particularly under climate change. In this study, we analysed the interactions of the obligate social parasite Temnothorax americanus, a dulotic ant, and its primary host, the ant T. longispinosus, focusing on behavioural and cuticular hydrocarbon (CHC) traits that govern parasite invasion and host defence. We studied the link between these traits and local climate as well as parasite prevalence. Our results revealed that behavioural interactions were more strongly associated with climate than parasite prevalence. Hosts from warmer, drier regions exhibited reduced aggression during parasite encounters, opting to pick up the brood and flee, while parasites from these regions exhibited greater aggression and activity. CHCs mediating enemy recognition in these ants were linked to local climate and parasite prevalence in both species. As all colonies were maintained under standardized conditions for a year, we attribute the observed phenotypic traits to evolutionary adaptation rather than phenotypic plasticity. Our findings suggest that both abiotic and biotic factors play critical roles in shaping co-evolving traits, sometimes leading to unexpected patterns that would potentially be overlooked when considering only a single factor. These insights provide a framework for understanding how climate influences coevolution of interacting species.

Honest signals have long posed a challenge for evolutionary biologists to explain. Here, we propose a general Darwinian theory of signalling, signalling trade-off theory, to explain both honest and dishonest signalling based on recent theoretical and empirical developments. The leading explanation for honest signalling has been the handicap principle (HP), which argues that signals are honest because they are costly. We summarize the main reasons why the HP-and the related costly signalling paradigm-can be fully rejected. Instead, we propose an alternative and more general explanation for honest signalling. The acceptance of the erroneous HP was based on misinterpretations of early signalling models. These models contrary to common interpretations, show that signals are honest, not because they are costly (handicaps), but because cheating (deception) is costly. Deception is costly due to differential signalling costs or differential benefits, or more generally differential trade-offs (i.e., an antagonistic constraint between two functions). Trade-offs are the basis evolutionary life-history theory, and we argue that they are also central to explaining signal honesty and deception. Unlike costs, trade-offs can fully represent both aspects of an investment (marginal cost vs. marginal benefit) over different timescales arising in evolutionary analyses. We examine the alternative explanations proposed to explain honest signalling, such as indices and social punishment, and show that these hypotheses require trade-offs, despite being overlooked. We examine more recent theoretical models that demonstrate that signalling trade-offs maintain honesty, even without signalling costs (handicaps) at the evolutionary equilibrium. Moreover, we show that differential trade-offs are both necessary and sufficient to explain honest signals in cases with conflict of interest. Based on these advances, we argue that differential signalling trade-offs provide a general evolutionary explanation for both dishonest and honest signals and also unify earlier alternative proposals about signal honesty. Finally, we demonstrate that short-term investments under trade-offs at the proximate level (once considered handicap mechanisms) can result in long-term fitness benefits, which thus integrates proximate and evolutionary explanations for signal honesty. We also address how results from sexual selection studies (e.g., terminal investment) are consistent with our theory.

The current economics of scientific publishing reveal a profound imbalance: academia pays prices far exceeding the actual costs of publication. Rather than supporting research, much of this expenditure sustains the profits of a few dominant commercial publishers. Transitioning to responsible publishing is a collective challenge that requires raising awareness among scientists about the problem and the solutions available. We present DAFNEE, a database of academia-friendly journals in ecology, evolutionary biology and archaeology (https://dafnee.isem-evolution.fr/). DAFNEE includes information on over 600 journals (co)run by academic or non-profit institutions, aiming at helping to keep publishing funds within the academic community. The database details these journal's business models, article processing charges, citation rates and partnerships. We show that DAFNEE journals compare favourably to non-DAFNEE ones in terms of editorial and financial policy, while offering similar citation rates. Finally, we offer several recommendations aimed at encouraging authors, reviewers, and evaluators to adopt more responsible publishing practices.

When altricial birds hatch, they are unable to regulate their own temperature, but by the time they fledge they are thermally independent. Early-life conditions have been shown to be an important factor contributing to fitness. However, it is currently unknown to what extent body temperature during endothermy development is driven by genetic variation or by the early environment. We use thermal images of cross-fostered house sparrows (Passer domesticus) throughout the nestling period to separate genetic and environmental drivers of body temperature. We estimated negligible heritability of body temperature at all ages. We further found that there are effects from the natal environment that carry over into the late nestling stage. A correlation between the early- and mid-nestling periods was explained by the natal environment, and during this period body temperature and growth followed independent developmental trajectories. Furthermore, higher body temperature was under viability selection, independent of body mass. We, therefore, demonstrate that the natal environment influences future offspring phenotype via a novel measure; body temperature. Our study provides a novel investigation into the environmental and genetic drivers of body temperature variation in a wild bird, furthering our understanding of how traits evolve.

Species' range shifts are common in nature, often involving the colonization of new habitats. Identifying the evolutionary processes responsible for the colonization of novel environments is then fundamental to understanding the current distribution of organisms and predicting responses to ongoing global change. Leontodon longirostris is a short-lived plant native of the Western Mediterranean Basin that expanded its range through adaptive changes in key phenotypic traits along a south-to-north environmental gradient in the Iberian Peninsula. Here, we provide some insights into the genomic basis of adaptation underlying the colonization of novel environments during range expansion. In particular, we were interested in the role of preexisting genetic diversity to facilitate adaptation, and the identification of genes that have responded to selection in the novel colonized environments. We combined genomic, phenotypic, and environmental information to analyse (i) the prevalence of hard versus soft selective sweeps in ancestral and expanded populations, and (ii) the association of 168,733 SNPs with phenotypic traits and environmental variables. Our results suggest that adaptation during range expansion primarily occurred through selection on standing genetic variation already present in the ancestral populations. We also identified a small set of candidate genes involved in signalling pathways that may underlie changes in life-history traits related to colonization. Although functional validation is still needed, these findings highlight the potential role of regulatory networks in facilitating adaptation during range expansion.

In several insect models, high-fat diets and high-sugar diets have detrimental effects, but it is largely unknown if multigenerational exposure can curb this metabolic distress through adaptation. Our study aimed to investigate how high-fat and high-sugar diets affect the fitness of the common house fly Musca domestica, and if multigenerational experimental evolution with diet-induced selection pressure leads to compensatory metabolic changes. House fly larvae were reared on a high-fat, high-sugar, or control diet for 51 consecutive generations whereupon we measured larval, pupal, and adult life-history traits. To test direct effects of the diets on life-history traits, we switched the 50th generation of control diet flies onto the experimental diets. Initial exposure to the high-fat diet caused a significant decrease in pupal viability, larval dry weight, and adult-weight-to-length ratio, whereas relative larval fat content significantly increased. The high-sugar diet solely increased adult weight-to-length ratio. When comparing the effects of initial exposure to the effects after 51 generations of experimental evolution, the high-fat diet flies exhibited the same detrimental effects as previously observed. Additionally, after 51 generations, the high-fat-diet and high-sugar-diet flies experienced a drastic decrease in female fecundity. Direct comparison of the single-generational exposed and the multigenerational evolved lines confirmed that the diet-induced adverse metabolic effects expanded across generations. Our results suggest that house flies do not adapt to unbalanced diets and instead experience additional reproductive disruptions when selected on these diets for multiple generations.

Conspicuous sexual signals are frequently under selection from conflicting sources, such as natural versus sexual selection and precopulatory versus postcopulatory sexual selection, which may act in the same or different directions. The Pacific field cricket (Teleogryllus oceanicus) is undergoing rapid evolutionary trait loss: mutations that render males obligately silent (the "flatwing phenotype") have become established on several islands of Hawai'i. Females strongly discriminate against silent males, yet flatwings do gain matings. In this study, we take advantage of this natural system to understand how investment in ejaculate quality under high and low perceived sperm competition risk (manipulated using acoustic cues) differs between wild type males and flatwings, which obligately adopt alternative reproductive tactics (ARTs). We replicated our study in two islands with different flatwing frequencies because female mating rate and therefore sperm competition risk is likely higher in O'ahu than Kaua'i. We measured testes mass and gene expression for three seminal fluid proteins (SFPs) that affect paternity success, sperm viability, and female propensity to remate. Compared to Kaua'i males, O'ahu males showed higher residual testes mass and expression of ToSfp011, which increases male sperm viability and paternity success, and reduces mate searching behaviour by females. We found no effect of immediate sperm competition risk or wing morph on any of the SFPs or testes mass. Differential SFP expression and residual testes mass in Hawaiian populations that likely differ in mating rate are compatible with the predictions of sperm competition theory.

Terrestrial animal species often employ both walking and flying as modes of locomotion. Although flight facilitates more efficient long-distance travel compared to ambulation, it imposes more stringent constraints on body mass. Consequently, birds frequently demonstrate an interspecific trade-off between their flight and walking capabilities. Despite this, the relationship between these two modes of transportation has not been explored in insects, which represent the Earth's most speciose group and possess both flight and walking abilities. This study investigated the relationship between walking and flight activities in the red flour beetle (Tribolium castaneum), a facultatively flying and walking insect. We utilized previously established strains selected for either high (H) or low (L) walking activity. We then compared flight activity and lipid content, which functions as metabolic fuel for flight, between the H and L strains. Our findings indicate that H-beetles exhibited significantly greater flight activity than L-beetles, demonstrating a positive correlation between walking and flying activity in T. castaneum. This suggests that, contrary to observations in birds, small insects such as T. castaneum do not incur a trade-off between walking and flight. Furthermore, L-beetles exhibited significantly higher proportion of body lipid mass, suggesting that individuals with reduced locomotor activity tend to accumulate more fat, irrespective of their primary mode of movement.