Female Fitness Research Articles

Selection of Floral Traits by Pollinators and Seed Predators during Sequential Life History Stages.

AbstractOrganismal traits often influence fitness via interactions with multiple species. That selection is not necessarily predictable from pairwise interactions, such as when interactions occur during different life cycle stages. Theoretically, directional selection during two sequential episodes (e.g., pollination and seed survival) can generate quadratic or correlational selection for a set of traits that passes both selective filters. We compared strength of selection during pollination versus seed predation in the field and tested whether interactions with multiple species give rise to nonlinear selection on floral traits. We planted common gardens with seeds of two species of Ipomopsis and hybrids at sites where pollination was primarily by hummingbirds or also included hawk moths. We examined selection on six floral traits, including corolla width, sepal width, color, nectar, and two scent compounds. Female fitness (seeds) was broken down into fitness during (1) pollination (seeds initiated) and (2) seed predation (proportion of seeds escaping fly predation). All traits showed evidence of selection. Directional and quadratic selection were stronger during seed initiation than during seed predation. Correlational selection occurred mostly during seed initiation rather than arising from combining species interactions at two points in the life cycle. These results underscore how multispecies interactions can combine to exert selection on trait combinations.

Effects of Training Loads on Stress Tolerance and Mucosal Immunity in High-Intensity Functional Fitness Athletes

ABSTRACT Purpose: This study aimed to analyze the effects of training load on stress tolerance (ST) and secretory immunoglobulin A (SIgA) in male and female high-intensity functional fitness (HIFF) athletes during two different 10 and consecutive weekly training volume loads [higher (week 1) and lower volume (week 2)]. Methods: 14 athletes [7 males: 29.3 (±5.8) years; 86.3 (±8.2) kg and 176.8 (±3.8) cm and 7 females: 32.7 (±4.4) years; 60.0 (±6.7) kg and 162.5 (±5.9) cm] participated. The ST, assessed by Daily Analysis of Life Demand in Athletes questionnaire (DALDA) and Saliva sampling were performed in four time-points (pre (T1) and post (T2) week 1; pre (T3) and post (T4) week 2). Results: Female athletes showed a decrease in ST (symptoms of stress) from 15 T1 to T3 [F(3,36) = 7.184, p˂ 0.001, ηp2 = 0.374], without difference in male athletes (p > .05). There is a significant difference of SIgA concentration [F(3.36) = 3.551; p = .024; ηp2 = 0.228], with a significant decrease in female athletes group in T2 compared to T1 (p = .013) and T4 (p = .023). In addition, the different training volume loads did not impact mucosal immunity in male athletes (p > .05). Conclusion: The current findings suggest that higher HIFF volume results in decreased ST and SIgA concentration in female 20 athletes and a subsequent decrease in training volume loads contributed to restoring these variables.

Godman‐Salvin Prize

Godman‐Salvin Prize

The Age of Fitness: How the Body Came to Symbolize Success and Achievement

In the wake of several books published over the last decade on the history of United States fitness, historian Jürgen Martschukat offers an international examination of the subject by considering German and American fitness cultures in the late twentieth and early twenty-first centuries. Originally published in German in 2019, Martschukat's volume synthesizes a broad array of primary and secondary literature in chapters that, while not organized strictly chronologically, provide a multilayered narrative and advance critical perspectives on several themes in contemporary Western fitness. Chapters such as “Working,” “Having Sex,” and “Fighting” follow introductory sections that establish context for recent historical dynamics. Translated by Alex Skinner, the book is written in a clear and authoritative style that allows Martschukat's interpretative stance to reach a wide academic audience.Comparative material on German history and culture comes as a welcome supplement to more well-covered American narratives. For Martschukat, what unites the story of fit bodies across contemporary Western societies is neoliberalism and the biopolitics of capitalist market forces. Evolving from eighteenth- and nineteenth-century concepts of liberalism and Darwinian competition, today's obsessions with working on oneself allow advocates to express their value as productive members of society. Civic recognition follows those who “can credibly show that they invest in themselves, work on themselves, and know how to tap their own potential” (17) as opposed to others who cannot meet these modern demands.Martschukat's overtly negative take on fitness culture distinguishes his study from other recent monographs. Unfortunately, this creates opportunities for ideological heavy-handedness and overgeneralization that too often disrupt his argument. Turn-of-the-twentieth-century fitness and the media empire of Bernarr Macfadden is an example of neoliberal white male supremacy until in subsequent paragraphs it is not, and the accomplishments of women and minority groups are briefly addressed. In another chapter, Martschukat breezes from an early 1980s report in Der Spiegel on corporate workout programs to United States’ welfare reform in 1996, all examples of “mak[ing] citizens responsible for themselves as market actors, rather than protecting them from market risks through social safeguards” (63). Such forceful narration may convince readers already committed to Martschukat's brand of political engagement, but too many are left wondering whether his ideological boogeyman hunting actually explains change over time. He seems to realize this by the middle of the book, offering up a compelling chapter that links Viagra to historic and contemporary fitness culture, but he excuses himself in conclusion that “race as a category has received less attention so far in this chapter” (103). Perhaps Skinner's translation is partly to blame for the book's often jarring and obtrusive identity-based posturing, but Martschukat cannot escape entirely for failing to produce a more elegant, or at least more consistent, historical treatise.Unsurprisingly, therefore, the book's final chapter on the Western physical hero repeats familiar tropes about the late twentieth century and the “backlash” of muscular Americanism associated with the era of President Ronald Reagan. Meanwhile, examples that could complicate this interpretation are passed over. For example, Jane Fonda and the explosion of female fitness in the 1980s is given one sentence. In the end, The Age of Fitness too often substitutes academic synthesis and critical consensus for historical precision in the manner of an exciting online read but one that ultimately fails as an honest study of its subject matter. Readers expecting a carefully nuanced overview and argument are better served elsewhere.

The genetic basis of variation in sexual aggression: Evolution versus social plasticity.

Male sexual aggression towards females is a form of sexual conflict that can result in increased fitness for males through forced copulations (FCs) or coercive matings at the cost of female lifetime fitness. We used male fruit flies (Drosophila melanogaster) as a model system to uncover the genomic contributions to variation in FC, both due to standing variation in a wild population, and due to plastic changes associated with variation in social experience. We used RNAseq to analyse whole-transcriptome differential expression (DE) in male head tissue associated with evolved changes in FC from lineages previously selected for high and low FC rate and in male flies with varying FC rates due to social experience. We identified hundreds of genes associated with evolved and plastic variation in FC, however only a small proportion (27 genes) showed consistent DE due to both modes of variation. We confirmed this trend of low concordance in gene expression effects across broader sets of genes significant in either the evolved or plastic analyses using multivariate approaches. The gene ontology terms neuropeptide hormone activity and serotonin receptor activity were significantly enriched in the set of significant genes. Of seven genes chosen for RNAi knockdown validation tests, knockdown of four genes showed the expected effect on FC behaviours. Taken together, our results provide important information about the apparently independent genetic architectures that underlie natural variation in sexual aggression due to evolution and plasticity.

Predictors of individual performance and evolutionary potential of life-history traits in a hematophagous ectoparasite.

Little is known about the intraspecific variation of parasite life‐history traits and how this variation may affect parasite fitness and evolution. We investigated how life‐history traits predict success of individual tree‐hole ticks Ixodes arboricola and estimated their evolutionary potential, as well as genetic correlations within stages and phenotypic correlations within and across stages. Ticks were followed individually over two generations while allowed to feed on great tits Parus major. After accounting for host and tick maternal effects, we found that short feeding times and high engorgement weights strongly increased molting success. Molting time was also positively correlated with feeding success in adults. In larvae and nymphs, we found negative phenotypic correlations between engorgement weight and both feeding and molting time, the latter supported by a negative genetic correlation. We found sex‐related differences in feeding time (longer in male nymphs) and molting time (longer in male larvae but shorter in male nymphs). Also, time since the last feeding event (set experimentally) reduced larval and nymphal fitness, whereas it increased adult female fitness. Furthermore, we found significant heritability and evolvability, that is, the potential to respond to selection, for engorgement weight and molting time across all stages but no significant heritability for feeding time. Our findings suggest that variation in tick fitness is shaped by consistent individual differences in tick quality, for which engorgement weight is a good proxy, rather than by life‐history trade‐offs.

Investigating the interaction between inter-locus and intra-locus sexual conflict using hemiclonal analysis in Drosophila melanogaster

BackgroundDivergence in the evolutionary interests of males and females leads to sexual conflict. Traditionally, sexual conflict has been classified into two types: inter-locus sexual conflict (IeSC) and intra-locus sexual conflict (IaSC). IeSC is modeled as a conflict over outcomes of intersexual reproductive interactions mediated by loci that are sex-limited in their effects. IaSC is thought to be a product of selection acting in opposite directions in males and females on traits with a common underlying genetic basis. While in their canonical formalisms IaSC and IeSC are mutually exclusive, there is growing support for the idea that the two may interact. Empirical evidence for such interactions, however, is limited.ResultsHere, we investigated the interaction between IeSC and IaSC in Drosophila melanogaster. Using hemiclonal analysis, we sampled 39 hemigenomes from a laboratory-adapted population of D. melanogaster. We measured the contribution of each hemigenome to adult male and female fitness at three different intensities of IeSC, obtained by varying the operational sex ratio. Subsequently, we estimated the intensity of IaSC at each sex ratio by calculating the intersexual genetic correlation (rw,g,mf) for fitness and the proportion of sexually antagonistic fitness-variation. We found that the intersexual genetic correlation for fitness was positive at all three sex ratios. Additionally, at male biased and equal sex ratios the rw,g,mf was higher, and the proportion of sexually antagonistic fitness variation lower, relative to the female biased sex ratio, although this trend was not statistically significant.ConclusionOur results indicate a statistically non-significant trend suggesting that increasing the strength of IeSC ameliorates IaSC in the population.

Ewe are what ewe wear: bigger horns, better ewes and the potential consequence of trophy hunting on female fitness in bighorn sheep.

In polygynous species, secondary sexual traits such as weapons or elaborate ornaments have evolved through intrasexual competition for mates. In some species, these traits are present in both sexes but are underdeveloped in the sex facing lower intrasexual competition for mates. It is often assumed that these underdeveloped sexually selected traits are a vestige of strong sexual selection on the other sex. Here, we challenge this assumption and investigate whether the expression of secondary sexual traits is associated with fitness in female bighorn sheep. Analyses of 45 years of data revealed that female horn length at 2 years, while accounting for mass and environmental variables, is associated with younger age at primiparity, younger age of first offspring weaned, greater reproductive lifespan and higher lifetime reproductive success. There was no association between horn length and fecundity. These findings highlight a potential conservation issue. In this population, trophy hunting selects against males with fast-growing horns. Intersexual genetic correlations imply that intense selective hunting of large-horned males before they can reproduce can decrease female horn size. Therefore, intense trophy hunting of males based on horn size could reduce female reproductive performance through the associations identified here, and ultimately reduce population growth and viability.

Quantifying male harm and its divergence.

Male harm arises when traits that increase reproductive success in competition with other males also harm females as a side effect. The extent of harm depends on male and female phenotypes, both of which can diverge between populations. Within a population, harm is inferred when increased exposure to males reduces female fitness, but studies of the divergence of male harm rarely manipulate male exposure. Here, we quantify male harm and compare its magnitude between two lab populations of Drosophila serrata that were derived from a common ancestor 7 years earlier and subsequently held under conditions that minimized environmental differences. We manipulated female exposure to males in a factorial design involving all four combinations of males and females from these populations, providing insight into divergence in both sexes. Our results reveal substantial harm to females and provide stronger evidence of divergence in males than in females. Using these and other published data, we discuss conceptual issues surrounding the quantification and comparison of harm that arise because it involves a comparison of multiple quantities (e.g., female fitness under varying male exposure), and we demonstrate the increased insight that is gained by manipulating male exposure to quantify these quantities.

Effects of Female and Male Density on their Mating Performance and Female Post-Mating Reproductive Fitness in Plagiodera versicolora (Laicharting) (Coleoptera: Chrysomelidae)

In insects, mating performance and female post-mating reproductive fitness is closely related to female and male density. In nature, females and males of the willow leaf beetle, Plagiodera versicolora (Laicharting), exhibit the phenomenon of swarming damage. This study investigated the effects of female and male density on their mating performance and on female post-mating fecundity, egg hatching rates, and egg-laying patterns. Female and male density had a significant positive effect on the time from pairing to successful mating and on female fecundity, the duration of the egg-laying period, and the number of egg clutches, but it had a significant negative effect on the egg hatching rate. Female and male density had no significant effect on female post-mating longevity and the number of eggs per clutch. Our study shows that variation in female fecundity and egg-laying patterns is an adaptive strategy for P. versicolora at relatively high population densities. This strategy helps to expand the distribution of offspring and lower the competition for food resources among offspring, which, in turn, helps to maintain or increase population abundance.

The evolution of sex peptide: sexual conflict, cooperation, and coevolution.

ABSTRACTA central paradigm in evolutionary biology is that the fundamental divergence in the fitness interests of the sexes (‘sexual conflict’) can lead to both the evolution of sex‐specific traits that reduce fitness for individuals of the opposite sex, and sexually antagonistic coevolution between the sexes. However, clear examples of traits that evolved in this way – where a single trait in one sex demonstrably depresses the fitness of members of the opposite sex, resulting in antagonistic coevolution – are rare. The Drosophila seminal protein ‘sex peptide’ (SP) is perhaps the most widely cited example of a trait that appears to harm females while benefitting males. Transferred in the ejaculate by males during mating, SP triggers profound and wide‐ranging changes in female behaviour and physiology. Early studies reported that the transfer of SP enhances male fitness while depressing female fitness, providing the foundations for the widespread view that SP has evolved to manipulate females for male benefit. Here, we argue that this view is (i) a simplification of a wider body of contradictory empirical research, (ii) narrow with respect to theory describing the origin and maintenance of sexually selected traits, and (iii) hard to reconcile with what we know of the evolutionary history of SP's effects on females. We begin by charting the history of thought regarding SP, both at proximate (its production, function, and mechanism of action) and ultimate (its fitness consequences and evolutionary history) levels, reviewing how studies of SP were central to the development of the field of sexual conflict. We describe a prevailing paradigm for SP's evolution: that SP originated and continues to evolve to manipulate females for male benefit. In contrast to this view, we argue on three grounds that the weight of evidence does not support the view that receipt of SP decreases female fitness: (i) results from studies of SP's impact on female fitness are mixed and more often neutral or positive, with fitness costs emerging only under nutritional extremes; (ii) whether costs from SP are appreciable in wild‐living populations remains untested; and (iii) recently described confounds in genetic manipulations of SP raise the possibility that measures of the costs and benefits of SP have been distorted. Beyond SP's fitness effects, comparative and genetic data are also difficult to square with the idea that females suffer fitness costs from SP. Instead, these data – from functional and evolutionary genetics and the neural circuitry of female responses to SP – suggest an evolutionary history involving the evolution of a dedicated SP‐sensing apparatus in the female reproductive tract that is likely to have evolved because it benefits females, rather than harms them. We end by exploring theory and evidence that SP benefits females by functioning as a signal of male quality or of sperm receipt and storage (or both). The expanded view of the evolution of SP that we outline recognises the context‐dependent and fluctuating roles played by both cooperative and antagonistic selection in the origin and maintenance of reproductive traits.

Effects of an App-Based Physical Exercise Program on Selected Parameters of Physical Fitness of Females in Retirement: A Randomized Controlled Trial.

Modern technologies enable new options in the delivery of physical exercise programs. Specially designed app-based programs can be used to help older people in particular to integrate physical exercise into their daily lives. This study examines the influence of an app-based physical exercise program on selected parameters of physical fitness, such as muscular strength, balance, and flexibility. The women (n = 110) were on average 65.3 (± 1.5) years old and, compared to age-specific norm values, healthy. The 14-week intervention consisted of an app-based, unsupervised physical exercise program, in which the exercise frequency and duration of sessions were self-selected. The physical exercise program consisted of simple, functional exercises such as arm circles, squats, lateral raises. The participants were provided with an elastic resistance band and an exercise ball allowing them to increase exercise intensity if needed. Participants were randomly assigned to intervention group (IG) and control group (CG). 71% of the IG used the physical exercise program at least 1.2 times per week, whereas 25% of the IG showed usage rates above four times per week. Significant effects were found in the domains of muscular strength and flexibility. While IG could maintain their performance in isometric muscular strength tests and increased their flexibility, CG faced a decrease in those parameters. Thus, this app-based physical exercise program had positively influenced muscular strength and flexibility in women over 60 years of age.

Spatial bet hedging, thermal trade-offs and glyphosate: crickets integrate multivariate information during oviposition

Animals are increasingly exposed to thermal and chemical stressors across spatially heterogeneous landscapes, and adaptive reproductive decisions may mitigate the effects of multiple stressors. Yet, the combined effects of temperature and glyphosate (a broad-spectrum herbicide that is potentially the most commonly used pesticide worldwide) on maternal decision making and terrestrial embryos are unknown. Here, we integrate the effects of temperature, glyphosate (alone and in its commercial formulation, Roundup®) and spatial heterogeneity on oviposition (egg-laying) behaviour, which affects the fitness of females and their offspring. We used the variable field cricket, Gryllus lineaticeps , to test several hypotheses explaining oviposition site selection, specifically the roles of embryo survival, offspring phenotype and maternal survival in oviposition decisions. Temperature (but not glyphosate) affected oviposition and offspring success, with higher performance at intermediate temperatures and lower performance at the extremes, and oviposition increased with the availability of oviposition sites, particularly at warmer temperatures. Environmental context influenced support for oviposition site selection hypotheses. For example, spatial bet hedging (putatively related to maternal survival) was temperature sensitive and it modulated support for the ‘offspring phenotype’ and ‘embryo survival’ hypotheses. Specifically, an increased availability of oviposition sites prompted females to oviposit at warmer temperatures, thereby favouring offspring phenotype (increased developmental rate) at an expense to embryo survival (reduced hatching success). In summary, the interconnectedness of spatial and thermal heterogeneity (but not a common pesticide) played large roles in decision making that affects transgenerational fitness. • We tested hypotheses for oviposition (egg laying) site selection in G. lineaticeps. • We examined effects of temperature, glyphosate and spatial heterogeneity. • More numerous and warmer sites favoured developmental rate, not embryo survival. • Temperature influenced spatial bet hedging during egg laying. • Regardless of temperature, glyphosate did not affect egg laying or embryos.

The effects of prey lipid on female mating and reproduction of a wolf spider.

As predators, the macronutrients spiders extract from their prey play important roles in their mating and reproduction. Previous studies of macronutrients on spider mating and reproduction focus on protein, the potential impact of prey lipid content on spider mating and reproduction remains largely unexplored. Here, we tested the influence of prey varying in lipid content on female mating, sexual cannibalism, reproduction, and offspring fitness in the wolf spider Pardosa pseudoannulata. We acquired 2 groups of fruit fly Drosophila melanogaster that differed significantly in lipid but not protein content by supplementing cultural media with a high or low dose of sucrose on which the fruit flies were reared (HL: high lipid and LL: low lipid). Subadult (i.e., 1 molt before adult) female spiders that fed HL flies matured with significantly higher lipid content than those fed LL flies. We found that the mated females fed with HL flies significantly shortened pre-oviposition time and resulted in a significantly higher fecundity. However, there was no significant difference in female spiders varying in lipid content on other behaviors and traits, including the latency to courtship, courtship duration, mating, copulation duration, sexual cannibalism, offspring body size, and survival. Hence, our results suggest that the lipid content of prey may be a limiting factor for female reproduction, but not for other behavioral traits in the wolf spiders P. pseudoannulata.

Mapping sex differences in the effects of protein and carbohydrates on lifespan and reproduction in Drosophila melanogaster: is measuring nutrient intake essential?

Understanding how diet affects reproduction and survival is a central aim in evolutionary biology. Although this relationship is likely to differ between the sexes, we lack data relating diet to male reproductive traits. One exception to this general pattern is Drosophila melanogaster, where male dietary intake was quantified using the CApillary FEeder (CAFE) method. However, CAFE feeding reduces D. melanogaster survival and reproduction, so may distort diet-fitness outcomes. Here, we use the Geometric Framework of Nutrition to create nutrient landscapes that map sex-specific relationships between protein, carbohydrate, lifespan and reproduction in D. melanogaster. Rather than creating landscapes with consumption data, we map traits onto the nutrient composition of forty agar-based diets, generating broad coverage of nutrient space. We find that male and female lifespan was maximised on low protein, high carbohydrate blends (~ 1P:15.9C). This nutrient ratio also maximised male reproductive rates, but females required more protein to maximise daily fecundity (1P:1.22C). These results are consistent with CAFE assay outcomes. However, the approach employed here improved female fitness relative to CAFE assays, while effects of agar versus CAFE feeding on male fitness traits depended on the nutrient composition of experimental diets. We suggest that informative nutrient landscapes can be made without measuring individual nutrient intake and that in many cases, this may be preferable to using the CAFE approach. The most appropriate method will depend on the question and species being studied, but the approach adopted here has the advantage of creating nutritional landscapes when dietary intake is hard to quantify.

Ecological Constraints on Sexual Selection in a Human-Modified Landscape

Anthropogenic activities are changing the sensory landscape, interfering with transmission and reception of sexual signals. These changes are leading to alterations in mating behaviour with consequences to fitness. In systems where mate-finding involves long-distance signalling by one sex and approach by the other sex, the spatial distribution of signallers can have implications for male and female fitness. Spatial distribution of signallers is typically determined by an interplay of multiple factors, both ecological and evolutionary, including male competition, female choice and resources, such as calling and oviposition sites. We investigated the possible influence of resource distribution (signalling sites) on the strength and direction of sexual selection acting on false-leaf katydid Onomarchus uninotatus males, signalling in a human-modified landscape in the Western Ghats, India, a biodiversity hotspot. The landscape has changed from evergreen forests to plantations owing to human settlements. We first determined the spatial distribution of calling males and of available calling sites, which are trees of the genus Artocarpus, in the landscape. Using the information on male spacing, call transmission and hearing thresholds, the perceptual spaces of male signals were computed to understand the acoustic environment of calling males and females. It was found that both calling males and females could hear calls of males from neighbouring trees with a probability of 0.76 and 0.59, respectively. Although calling males were found to be spaced apart more than predicted by chance, significant overlap was seen in their acoustic ranges. Clustering of males enables females to easily sample multiple males, facilitating mate choice, but is detrimental to males as it increases competition for females. Using simulations, we determined the optimal spatial distributions of O. uninotatus males for female choice, and for reduction of male competition, given the signalling site distribution. The observed distribution of signallers was then compared with the hypothetical optimal distributions to examine the drivers of signaller spacing. Spacing of calling males in the field was found to be not optimal for either males or females. Resource distribution was found to limit the effectiveness of sexual selection drivers in pushing male spacing toward fitness optima of males or females.

Effects of multiple feedings on sensitized rabbits on the fitness of Phlebotomus papatasi (Diptera: Psychodidae)

In the present study, we evaluated the effects of antibodies anti-sandfly saliva on the fecundity of Phlebotomus papatasi, vector of zoonotic cutaneous leishmaniasis in the Old World. Rabbits were repeatedly exposed to sandfly bites. Immune sera showed increased levels of anti-sandfly saliva antibody compared to the pre-exposition period. The analysis of biological parameters revealed no decline on the feeding success of females P. papatasi fed on rabbits repeatedly exposed to sandfly bites. Our results showed that anti-sandfly saliva antibodies of rabbits are not detrimental to the fitness of females P. papatasi. Thus, rabbits did not acquire resistance to sandflies following repeated exposures, and that contribute in maintaining a high density of P. papatasi. To control sandfly infestations and Leishmania transmission, more studies are needed for a better understanding of the mechanisms governing the resistance of hosts to bites of sandflies.

Changes in Florets’ Vertical Direction within Inflorescence Affects Pollinator Behavior, and Fitness in Trifolium repens

Ecological interactions between flowers and pollinators greatly affect the reproductive success. To facilitate these interactions, many flowers are known to display their attractive qualities, such as scent emission, flower rewards and floral vertical direction, in a rhythmic fashion. However, less is known about how plants regulate the relationship between these flower traits to adapt to pollinator visiting behavior and increase reproduction success. Here we investigated the adaptive significance of the flower bending from erect to downward in Trifolium repens. We observed the flowering dynamic characteristics (changes of vertical direction of florets, flowering number, pollen grain numbers, pollen viability and stigma receptivity over time after blossom) and the factors affecting the rate of flower bending in T. repens. Then we altered the vertical direction of florets in inflorescence of different types (upright and downward), and compared the pollinator behaviors and female reproductive success. Our results showed that florets opened sequentially in inflorescence, and then bend downwards slowly after flowering. The bending speed of florets was mainly influenced by pollination, and bending angle increased with the prolongation of flowering time, while the pollen germination rate, stigma receptivity and nectar secretion has a rhythm of “low-high-low” during the whole period with the time going. The visiting frequency of all the four species of pollinators on upward flowers was significantly higher than that of downward flowers, and they especially prefer to visit flowers with a bending angle of 30°–60°, when the flowers was exactly of the highest flower rewards (nectar secretion and number of pollen grains), stigma receptivity and pollen germination rate. The seed set ratio and fruit set ratio of upward flowers were significantly higher than downward flowers, but significantly lower than unmanipulated flowers. Our results indicated that the T. repens could increase female and male fitness by accurate pollination. The most suitable flower angle saves pollinators’ visiting energy and enables them to obtain the highest nectar rewards. This coordination between plants and pollinators maximizes the interests of them, which is a crucial factor in initiating specialized plant-pollinator relationships.

The handsome liar: Male spiders offering worthless gifts can benefit increasing mating duration

AbstractFemales of nuptial gift‐giving species are known to mate with several males, so that they secure multiple ejaculates and food via nuptial gifts. However, gifts may decrease females’ reproductive success, for instance, if they received non‐nutritive gifts (worthless). The gift‐giving mating system of the spider Paratrechalea ornata creates a scenario in which females may receive either a nutritive prey or a worthless inedible item wrapped in silk. The worthless gift tactic is expected to be less successful as females should prefer to mate and to mate for longer with males offering nutritive gifts. However, at the moment, the scarce information suggests that both mating tactics may have similar reproductive success. By exposing females to a double mating experimental design, we examined whether mating access and duration correlate with the gift type (nutritive‐worthless), mating order (first‐second), and male size, and additionally explored possible effects on female fitness (e.g., fecundity). We found that the females accepted to mate with courting males independently of gift type, mating order, or size. But, mating duration was positively correlated with male size, and longer when males offered worthless gifts. Furthermore, females’ fecundity increased with mating duration and female size. This demonstrated that males offering worthless gifts might enhance their reproductive success by transferring more sperm than those offering nutritive gifts. Thus, either due to female choice or male effort, male size might be a more relevant feature for reproductive success than gift type, which can explain the high frequencies of worthless gifts in the field.

Single-nucleus transcriptomes reveal evolutionary and functional properties of cell types in the Drosophila accessory gland.

Many traits responsible for male reproduction evolve quickly, including gene expression phenotypes in germline and somatic male reproductive tissues. Rapid male evolution in polyandrous species is thought to be driven by competition among males for fertilizations and conflicts between male and female fitness interests that manifest in postcopulatory phenotypes. In Drosophila, seminal fluid proteins secreted by three major cell types of the male accessory gland and ejaculatory duct are required for female sperm storage and use, and influence female postcopulatory traits. Recent work has shown that these cell types have overlapping but distinct effects on female postcopulatory biology, yet relatively little is known about their evolutionary properties. Here, we use single-nucleus RNA-Seq of the accessory gland and ejaculatory duct from Drosophila melanogaster and two closely related species to comprehensively describe the cell diversity of these tissues and their transcriptome evolution for the first time. We find that seminal fluid transcripts are strongly partitioned across the major cell types, and expression of many other genes additionally defines each cell type. We also report previously undocumented diversity in main cells. Transcriptome divergence was found to be heterogeneous across cell types and lineages, revealing a complex evolutionary process. Furthermore, protein adaptation varied across cell types, with potential consequences for our understanding of selection on male postcopulatory traits.