Expansion of anthropogenic noise and night lighting across our planet
is of increasing conservation concern
. Despite growing knowledge of physiological and behavioural responses to these stimuli ...from single-species and local-scale studies, whether these pollutants affect fitness is less clear, as is how and why species vary in their sensitivity to these anthropic stressors. Here we leverage a large citizen science dataset paired with high-resolution noise and light data from across the contiguous United States to assess how these stimuli affect reproductive success in 142 bird species. We find responses to both sensory pollutants linked to the functional traits and habitat affiliations of species. For example, overall nest success was negatively correlated with noise among birds in closed environments. Species-specific changes in reproductive timing and hatching success in response to noise exposure were explained by vocalization frequency, nesting location and diet. Additionally, increased light-gathering ability of species' eyes was associated with stronger advancements in reproductive timing in response to light exposure, potentially creating phenological mismatches
. Unexpectedly, better light-gathering ability was linked to reduced clutch failure and increased overall nest success in response to light exposure, raising important questions about how responses to sensory pollutants counteract or exacerbate responses to other aspects of global change, such as climate warming. These findings demonstrate that anthropogenic noise and light can substantially affect breeding bird phenology and fitness, and underscore the need to consider sensory pollutants alongside traditional dimensions of the environment that typically inform biodiversity conservation.
Flowering plants possess an unrivaled diversity of mechanisms for achieving sexual and asexual reproduction, often simultaneously. The commonest type of asexual reproduction is clonal growth ...(vegetative propagation) in which parental genotypes (genets) produce vegetative modules (ramets) that are capable of independent growth, reproduction, and often dispersal. Clonal growth leads to an expansion in the size of genets and increased fitness because large floral displays increase fertility and opportunities for outcrossing. Moreover, the clonal dispersal of vegetative propagules can assist “mate finding,” particularly in aquatic plants. However, there are ecological circumstances in which functional antagonism between sexual and asexual reproductive modes can negatively affect the fitness of clonal plants. Populations of heterostylous and dioecious species have a small number of mating groups (two or three), which should occur at equal frequency in equilibrium populations. Extensive clonal growth and vegetative dispersal can disrupt the functioning of these sexual polymorphisms, resulting in biased morph ratios and populations with a single mating group, with consequences for fertility and mating. In populations in which clonal propagation predominates, mutations reducing fertility may lead to sexual dysfunction and even the loss of sex. Recent evidence suggests that somatic mutations can play a significant role in influencing fitness in clonal plants and may also help explain the occurrence of genetic diversity in sterile clonal populations. Highly polymorphic genetic markers offer outstanding opportunities for gaining novel insights into functional interactions between sexual and clonal reproduction in flowering plants.
Sexual reproduction and clonality in eukaryotes are mostly seen as exclusive, the latter being rather exceptional. This view might be biased by focusing almost exclusively on metazoans. We analyze ...and discuss reproduction in the context of extant eukaryotic diversity, paying special attention to protists. We present results of phylogenetically extended searches for homologs of two proteins functioning in cell and nuclear fusion, respectively (HAP2 and GEX1), providing indirect evidence for these processes in several eukaryotic lineages where sex has not been observed yet. We argue that (i) the debate on the relative significance of sex and clonality in eukaryotes is confounded by not appropriately distinguishing multicellular and unicellular organisms; (ii) eukaryotic sex is extremely widespread and already present in the last eukaryotic common ancestor; and (iii) the general mode of existence of eukaryotes is best described by clonally propagating cell lines with episodic sex triggered by external or internal clues. However, important questions concern the relative longevity of true clonal species (i.e., species not able to return to sexual procreation anymore). Long-lived clonal species seem strikingly rare. We analyze their properties in the light of meiotic sex development from existing prokaryotic repair mechanisms. Based on these considerations, we speculate that eukaryotic sex likely developed as a cellular survival strategy, possibly in the context of internal reactive oxygen species stress generated by a (proto) mitochondrion. Thus, in the context of the symbiogenic model of eukaryotic origin, sex might directly result from the very evolutionary mode by which eukaryotic cells arose.
Transition from sexual reproduction to parthenogenesis constitutes a major life‐history change with deep evolutionary consequences for sex‐related traits, which are expected to decay. The pea aphid ...Acyrthosiphon pisum shows intraspecific reproductive polymorphism, with cold‐resistant cyclically parthenogenetic (CP) lineages that alternate sexual and asexual generations and cold‐sensitive obligately parthenogenetic (OP) lineages that produce only asexual females but still males. Here, the genotyping of 219 pea aphid lineages collected in cold‐winter and mild‐winter regions revealed contrasting population structures. Samples from cold‐winter regions consisted mostly of distinct multilocus genotypes (MLGs) usually represented by a single sample (101 different MLGs for 111 samples) and were all phenotyped as CP. In contrast, fewer MLGs were found in mild‐winter regions (28 MLGs for 108 samples), all but one being OP. Since the males produced by OP lineages are unlikely to pass on their genes (sexual females being rare in mild‐winter regions), we tested the hypothesis that their traits could degenerate due to lack of selection by comparing male production and male reproductive success between OP and CP lineages. Male production was indeed reduced in OP lineages, but a less clear pattern was observed for male reproductive success: females mated with OP males laid fewer eggs (fertilized or not) but OP and CP males fertilized the same proportion of eggs. These differences may stem from the type of selective forces: male production may be counter‐selected whereas male performances may evolve under the slower process of relaxed selection. The overall effective reproductive capacity of OP males could result from recent sex loss in OP lineages or underestimated reproductive opportunities.
For more than a century, the medical profession has made enormous efforts to understand and treat women's reproductive bodies. But only recently have researchers begun to ask basic questions about ...how men's health matters for reproductive outcomes, from miscarriage to childhood illness. What explains this gap in knowledge, and what are its consequences? Rene Almeling examines the production, circulation, and reception of biomedical knowledge about men's reproductive health. From a failed nineteenth-century effort to launch a medical specialty called andrology to the contemporary science of paternal effects, there has been a lack of attention to the importance of men's age, health, and exposures. Analyzing historical documents, media messages, and qualitative interviews, GUYnecology demonstrates how this non-knowledge shapes reproductive politics today.
Reproductive isolation is a prerequisite for speciation. Failure of communication between female tissues of the pistil and paternal pollen tubes imposes hybridization barriers in flowering plants.
...LURE1 (AtLURE1) peptides and their male receptor PRK6 aid attraction of the growing pollen tube to the ovule. Here, we report that the knockout of the entire
gene family did not affect fertility, indicating that AtLURE1-PRK6-mediated signaling is not required for successful fertilization within one
species. AtLURE1s instead function as pollen tube emergence accelerators that favor conspecific pollen over pollen from other species and thus promote reproductive isolation. We also identified maternal peptides XIUQIU1 to -4, which attract pollen tubes regardless of species. Cooperation between ovule attraction and pollen tube growth acceleration favors conspecific fertilization and promotes reproductive isolation.
The reasons that clonal plants shift between sexual and clonal reproduction have persisted as a knowledge gap in ecological literature. We hypothesized that clonal plants' shifts between sexual and ...clonal reproduction in different environments are driven by the relative costs of sexual and clonal reproduction. Moreover, we hypothesized plants prioritize sexual reproduction over clonal reproduction. To test these hypotheses, we determined the costs of sexual and clonal reproduction, and proportions of sexual and clonal reproduction of Caragana stenophylla along a climatic aridity gradient (semi-arid, arid, very arid and intensively arid zones) in the Inner Mongolia Steppe using several complementary field experiments.
The cost of sexual reproduction increased while the cost of clonal reproduction decreased as climatic drought stress increased from the semi-arid to the intensively arid zones. The changes in the costs of these reproductive modes drove a shift in the reproductive mode of C. stenophylla from more sexual reproduction in the semi-arid zone to more clonal propagation in the intensively arid zone. However, because of the evolutionary advantages of sexual reproduction, sexual reproduction still held priority over clonal production in C. stenophylla, with the priority of sexual reproduction gradually increasing from the semi-arid to the intensively arid zones.
Our study suggested that sexual reproduction has relatively high priority in propagation of C. stenophylla. However, if the costs of sexual reproduction are too high, C. stenophylla likely chooses clonal reproduction, and the ratio between sexual and clonal reproduction could be mediated by reproductive cost. These reproductive strategies reflect optimal resource utilization, and allow the persistence of both reproductive modes across stressful conditions depending on their evolutionary advantages.
Asexual and sexual reproduction are the most important biological events in the life cycle of phytopathogenic and toxigenic Fusarium and are responsible for disease epidemics. However, the signaling ...molecules which induce the asexual reproduction of Fusarium are unknown. Herein we describe the structure elucidation, including the absolute configuration, of Fusarium asexual reproduction inducer (FARI), a new sesquiterpene derivative, by spectroscopic analysis, total synthesis, and conidium‐inducing assays of synthetic isomers. We have also uncovered the universality of FARI among Fusarium species. Moreover, a mechanism‐of‐action study suggested that the Gpmk1 and LaeA signaling pathways are required for conidium formation induced by FARI; conversely, the Mgv1 of mitogen‐activated protein kinase is not involved in conidium formation. FARI exhibited conidium‐inducing activity at an extremely low dose and high stereoselectivity, which may suggest the presence of a stereospecific target.
A way to fight blight in sight: Fusarium asexual reproduction inducer (FARI), a newly discovered sesquiterpene derivative, induced the formation of conidia (see micrographs) in notorious Fusarium graminearum at an extremely low dose. The universality of FARI among Fusarium species was uncovered. Furthermore, a mechanism‐of‐action study revealed that Gpmk1 and LaeA signaling pathways are required for conidium formation induced by FARI.
Sexual reproduction can lead to major conflicts between sexes and within genomes. Here we report an extreme case of such conflicts in the little fire ant Wasmannia auropunctata. We found that sterile ...workers are produced by normal sexual reproduction, whereas daughter queens are invariably clonally produced. Because males usually develop from unfertilized maternal eggs in ants and other haplodiploid species, they normally achieve direct fitness only through diploid female offspring. Hence, although the clonal production of queens increases the queen's relatedness to reproductive daughters, it potentially reduces male reproductive success to zero. In an apparent response to this conflict between sexes, genetic analyses reveal that males reproduce clonally, most likely by eliminating the maternal half of the genome in diploid eggs. As a result, all sons have nuclear genomes identical to those of their father. The obligate clonal production of males and queens from individuals of the same sex effectively results in a complete separation of the male and female gene pools. These findings show that the haplodiploid sex-determination system provides grounds for the evolution of extraordinary genetic systems and new types of sexual conflict.
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