Sexual Traits Research Articles

Floral and reproductive traits are an independent dimension within the plant economic spectrum of temperate central Europe.

Major dimensions of plant ecological strategies have been widely studied bringing forward the concept of 'economic spectra' of plants. Sexual reproductive traits, 'floral traits', have been largely neglected in this context, despite their strong link to fitness. Here, we aimed at integrating floral traits into the dimensionality of plant form and function so far dominated by vegetative traits. We used principal component analyses and constructed trait networks to assess the correlation structure of leaf, belowground, plant size-related, and floral traits. We studied forbs within two independent datasets; one compiled from central European trait databases and one sampled in the Austrian Alps. Floral traits defined the second dimension of trait variability within both datasets, while plant size determined the first dimension. Floral traits were largely independent from the leaf economic spectrum. Flower size, however, positively scaled with plant size and leaf size. Mating system was the most well-connected trait across modules of plant tissue/organ types. The independence of floral traits was consistent also after accounting for phylogenetic relationships between species. Floral traits explained a unique part of the variation in plant form and function and thus, likely play a distinctive ecological role within the whole plant economic spectrum.

Nutrient-dependent allometric plasticity in a male-diphenic mite.

Male secondary sexual traits often scale allometrically with body size. These allometries can be variable within species and may shift depending on environmental conditions, such as food quality. Such allometric plasticity has been hypothesized to initiate local adaptation and evolutionary diversification of scaling relationships, but is under‐recorded, and its eco‐evolutionary effects are not well understood. Here, we tested for allometric plasticity in the bulb mite (Rhizoglyphus robini), in which large males tend to develop as armed adult fighters with thickened third legs, while small males become adult scramblers without thickened legs. We first examined the ontogenetic timing for size‐ and growth‐dependent male morph determination, using experimentally amplified fluctuations in growth rate throughout juvenile development. Having established that somatic growth and body size determine male morph expression immediately before metamorphosis, we examined whether the relationship between adult male morph and size at metamorphosis shifts with food quality. We found that the threshold body size for male morph expression shifts toward lower values with deteriorating food quality, confirming food‐dependent allometric plasticity. Such allometric plasticity may allow populations to track prevailing nutritional conditions, potentially facilitating rapid evolution of allometric scaling relationships.

Genetic Basis of Sexual Maturation Heterosis: Insights From Ovary lncRNA and mRNA Repertoire in Chicken.

Sexual maturation is fundamental to the reproduction and production performance, heterosis of which has been widely used in animal crossbreeding. However, the underlying mechanism have long remained elusive, despite its profound biological and agricultural significance. In the current study, the reciprocal crossing between White Leghorns and Beijing You chickens were performed to measure the sexual maturation heterosis, and the ovary lncRNAs and mRNAs of purebreds and crossbreeds were profiled to illustrate molecular mechanism of heterosis. Heterosis larger than 20% was found for pubic space and oviduct length, whereas age at first egg showed negative heterosis in both crossbreeds. We identified 1170 known lncRNAs and 1994 putative lncRNAs in chicken ovary using a stringent pipeline. Gene expression pattern showed that nonadditivity was predominant, and the proportion of nonadditive lncRNAs and genes was similar between two crossbreeds, ranging from 44.24% to 49.15%. A total of 200 lncRNAs and 682 genes were shared by two crossbreeds, respectively. GO and KEGG analysis showed that the common genes were significantly enriched in the cell cycle, animal organ development, gonad development, ECM-receptor interaction, calcium signaling pathway and GnRH signaling pathway. Weighted gene co-expression network analysis (WGCNA) identified that 7 out of 20 co-expressed lncRNA-mRNA modules significantly correlated with oviduct length and pubic space. Interestingly, genes harbored in seven modules were also enriched in the similar biological process and pathways, in which nonadditive lncRNAs, such as MSTRG.17017.1 and MSTRG.6475.20, were strongly associated with nonadditive genes, such as CACNA1C and TGFB1 to affect gonad development and GnRH signaling pathway, respectively. Moreover, the results of real-time quantitative PCR (RT-qPCR) correlated well with the transcriptome data. Integrated with positive heterosis of serum GnRH and melatonin content detected in crossbreeds, we speculated that nonadditive genes involved in the GnRH signaling pathway elevated the gonad development, leading to the sexual maturation heterosis. We characterized a systematic landscape of ovary lncRNAs and mRNAs related to sexual maturation heterosis in chicken. The quantitative exploration of hybrid transcriptome changes lays foundation for genetic improvement of sexual maturation traits and provides insights into endocrine control of sexual maturation.

Experimental manipulation of sexual traits in barn swallow populations-No evidence for divergent sexual selection.

Safran et al. (2016a) manipulated two sexual traits (ventral plumage coloration and tail streamer length) in male barn swallows (Hirundo rustica) and reported divergent effects on paternity change between two study populations, in Colorado and Israel. They concluded that geographical variation in the two phenotypic traits is maintained by divergent sexual selection. However, the response variable they used, the longitudinal change in paternity from a pre‐treatment clutch to a post‐treatment clutch, does not reflect an unbiased effect of the treatment. Here, I show that the magnitude of the change in paternity is influenced by variation in the initial paternity score among the treatment groups, which is presumably due to stochastic variation from low sample sizes in the treatment groups. When the bias was accounted for in re‐analyses of the Israeli dataset, the statistical significance of one of two treatment effects disappeared. Similar re‐analyses of the American population were not possible due to inaccessibility of raw data for individual clutches, but an assessment of the mean scores indicates that the two significant treatment effects in this population were similarly biased in their initial paternity scores. The conclusion of divergent sexual selection on male phenotypic traits between the two populations does not seem to be supported.

Low Prolactin Levels Identify HSDD and a Low Inhibition Profile in Women with Sexual Symptoms

ABSTRACT Introduction Data on the role of prolactin (PRL) in the physiologic range in the female sexual response are scanty. Objective We aimed at investigating the association between PRL levels and sexual function, and specifically, with the desire domain as assessed by the Female Sexual Function Index. We also explored the presence of a cut-off level of PRL able to identify women with a diagnosis of Hypoactive Sexual Desire Disorder (HSDD). Methods N=234 pre- and post-menopausal women (mean age 45.2+-12.4 years) consulting for female sexual dysfunction (FSD), and sexually active in the previous 4 weeks, were retrospectively analysed. A clinical, biochemical and pharmacological evaluation was performed. All patients completed the FSFI, the Female Sexual Distress Scale-Revised (FSDS-R), the Middlesex Hospital Questionnaire (MHQ) for the screening of psychopathological symptoms and the Sexual excitation/sexual inhibition scale (SIS/SES). Biochemical assessment included PRL (by luminescent oxygen channeling immunoassay). Results Only few patients (n=9) had hyperPRL (PRL> 483.0 mU/L) and showed a significantly higher MHQ total score (p=0.043), lower Total (p=0.037), Desire (p=0.002), Arousal (p=0.024) and Satisfaction (p=0.026) FSFI scores and a higher FSDS-R score (p=0.006) compared with women with normoPRL women. At univariate linear regression analysis, we did not find a significant correlation between FSFI total score and PRL levels. Hypothesizing the non-linearity of the association between these 2 variables, we tested different fitting models and found that the quadratic relationship was the best fitting (R2=0.11).When stratifying normoPRL women into tertiles (T1: PRL < 163.55 mU/L; T2= PRL > 163.55 and < 262.0 mU/L; T3: PRL > 262.0 and < 483.0 mU/L), a significant difference emerged in FSFI Desire (p=0.001), Arousal (p=0.033) and Satisfaction (p=0.019) among the 4 groups; however, only the difference in Desire was confirmed (p=0.034) in a multivariate model. A post-hoc analysis showed that only women in the T3 PRL tertile had significantly higher scores in FSFI Desire (p=0.011) and Satisfaction (0.045) vs. women with hyperPRL.After excluding hyperPRL women, we compared PRL between women with (n=35) and without HSDD (n=190) and observed that those with HSDD showed significantly lower PRL levels (p=0.002). ROC curve analysis for PRL levels showed an accuracy of 0.615 +- 0.022, p = 0.040, in predicting HSDD, and when a threshold of PRL<190 mU/L was chosen, sensitivity and specificity for HSDD were both 64.7%. Finally, we compared women with PRL levels > and < 190 mU/L. At multivariate analysis, women with PRL <190 mU/L showed a significantly lower cortisol (p=0.017) and SIS1 score (p=0.049), a scale of sexual inhibition, than women with PRL >190 mU/L (bit still in the normal range). Conclusions FSD women with hyperPRL showed a worse sexual function than those with normal PRL levels. However, when stratifying normoPRL women based on PRL tertiles, those included in the highest group had the best FSFI profile. Measuring PRL level in women with FSD is important, not only in order to ascertain the presence of a hyperPRL condition, but also to potentially predict the presence of HSDD or of a lower sexual inhibitory trait. Disclosure No

DMRT Transcription Factors in the Control of Nervous System Sexual Differentiation.

Sexual phenotypic differences in the nervous system are one of the most prevalent features across the animal kingdom. The molecular mechanisms responsible for sexual dimorphism throughout metazoan nervous systems are extremely diverse, ranging from intrinsic cell autonomous mechanisms to gonad-dependent endocrine control of sexual traits, or even extrinsic environmental cues. In recent years, the DMRT ancient family of transcription factors has emerged as being central in the development of sex-specific differentiation in all animals in which they have been studied. In this review, we provide an overview of the function of Dmrt genes in nervous system sexual regulation from an evolutionary perspective.

Environment and mate attractiveness in a wild insect.

The role of female choice in sexual selection is well established, including the recognition that females choose their mates based on multiple cues. These cues may include intrinsic aspects of a male's phenotype as well as aspects of the environment associated with the male. The role of the spatial location of a potential mate has been well studied in territorial vertebrates. However, despite their role as laboratory models for studies of sexual selection, the potential for insects to choose their mates on the basis of location has scarcely been studied. We studied a natural population of individually tagged crickets (Gryllus campestris) in a meadow in Northern Spain. Adults typically move between burrows every few days, allowing us to examine how pairing success of males can be predicted by the burrow they occupy, independent of their own characteristics. We observed the entirety of ten independent breeding seasons to provide replication and to determine whether the relative importance of these factors is stable across years. We find that both male ID and the ID his burrow affect the likelihood that he is paired with a female, but the burrow has a consistently greater influence. Furthermore, the two factors interact: the relative attractiveness of an individual male depends on which burrow he occupies. Our finding demonstrates a close interaction between naturally and sexually selected traits. It also demonstrates that mate choice studies may benefit from considering not only obvious secondary sexual traits, but also more cryptic traits such as microhabitat choice.

The vocalization of the red junglefowl is a signal of body size and individual health.

Bird songs are considered a sexually selected trait that can reflect the individual health of males as well as the vitality of potential mates and their competitors. Vocalization features should, therefore, be related to parasite load and body condition. Here, we performed a thorough acoustic analysis of the display calls of 9-month-old sub-adults and 18-month-old adults of pasture-raised red junglefowls Gallus gallus. We investigated whether the calls of pasture-raised red junglefowls can indicate body size and body condition, in addition to the influence of parasitic infection intensity on the expression of sexual traits. We found that frequency-related syllable parameters were significantly positively correlated with wing length in adults, whereas body weight was independent of both the frequency and temporal parameters of calls. In addition, we correlated parasitic load with the expression of sexually selected traits and discovered a positive association between the intensity of parasite infection and wing length in sub-adults, independent of vocal parameters. Overall, the results suggest that the vocalization of red junglefowls may convey reliable body size information, which will facilitate further studies of different vocal parameters in the transmission of bird vocalizations.

Evolutionary interactions between thermal ecology and sexual selection

Thermal ecology and mate competition are both pervasive features of ecological adaptation. A surge of recent work has uncovered the diversity of ways in which temperature affects mating interactions and sexual selection. However, the potential for thermal biology and reproductive ecology to evolve together as organisms adapt to their thermal environment has been underappreciated. Here, we develop a series of hypotheses regarding (1) not only how thermal ecology affects mating system dynamics, but also how mating dynamics can generate selection on thermal traits; and (2) how the thermal consequences of mate competition favour the reciprocal co-adaptation of thermal biology and sexual traits. We discuss our hypotheses in the context of both pre-copulatory and post-copulatory processes. We also call for future work integrating experimental and phylogenetic comparative approaches to understand evolutionary feedbacks between thermal ecology and sexual selection. Overall, studying reciprocal feedbacks between thermal ecology and sexual selection may be necessary to understand how organisms have adapted to the environments of the past and could persist in the environments of the future.

The Great Porn Experiment V2.0: Sexual Arousal Reduces the Salience of Familiar Women When Heterosexual Men Judge Their Attractiveness

Pornography has become widely accessible in recent years due to its integration with the Internet, generating social scientific and moralistic debate on potential “media effects,” given correlations between consumption and various sexual traits and behaviors. One popular public debate (Wilson, 2012) claimed that exposure to Internet pornography has addictive qualities that could impact men’s sexual relationships, underpinned by the “Coolidge effect,” where males are sexually motivated by the presence of novel mates. As claims about Internet and sexual addictions are scientifically controversial, we provide a direct experimental test of his proposal. Adapting a paradigm used to examine “Coolidge-like” effects in men, we examined the extent to which exposure to images of pornographic actresses altered men’s attractiveness ratings of (1) familiar faces/bodies on second viewing and (2) familiar versus novel women’s faces/bodies. Independent of slideshow content (pornographic versus clothed versions of same actress), heterosexual men were less attracted to familiar bodies, and homosexual men were less attracted to familiar women (faces and bodies), suggesting that mere visual exposure to attractive women moderated men’s preferences. However, consistent with one of our preregistered predictions, heterosexual but not homosexual men’s preferences for familiar versus novel women were moderated by slideshow content such that familiar women were less salient on the attractiveness dimension compared to novel women when sexual arousal was greater (pornographic versus clothed slideshows). In sum, our findings demonstrate that visual exposure/sexual arousal moderates attractiveness perceptions, albeit that much greater nuance is required considering earlier claims.

PEREMPUAN DALAM VIDEO GIM : Representasi Perempuan Dalam Dead or Alive 6

In media industry, women are often represented as an object which cannot be separated from their sexual attractiveness. This kind of female sexualization also presents in various video games, such as Dead or Alive 6. Through this study, researcher tries to understand how female characters are represented in Dead or Alive 6 using Roland Barthes’s semiotic analysis. As for the result, four picked characters, Kasumi, Honoka, Marie Rose, and Momiji represent signs of sexualization such as their fashion, innocence, legal character but looks like an underage, or a paradox between sacredness and taboo. The sexualization of characters in Dead or Alive 6 turns the sexual traits of legal female characters as its selling point. Dead or Alive 6 sexualizes its female characters as part of its selling value by selling various expensive downloadable contents (DLC) in form of maid, bikini, or any other sexy costumes that has nothing to do with characters’ ability. The “water mode” and “soft mode” also can be considered as sexual exploitation towards the female characters as its selling point. It can be read that the game takes advantage from the players’ sexual fantasy as a goldmine.

Resource-dependent investment in male sexual traits in a viviparous fish.

Exaggerated and conspicuous sexually selected traits are often costly to produce and maintain. Costly traits are expected to show resource-dependent expression, since limited resources prevent animals from investing maximally in multiple traits simultaneously. However, there may be critical periods during an individual's life where the expression of traits is altered if resources are limited. Moreover, costly sexual traits may arise from sexual selection acting both before (pre-copulatory) and after mating (post-copulatory). Gaining a robust understanding of resource-dependent trait expression therefore requires an approach that examines both episodes of sexual selection after resource limitation during different times in an individual's life. Yet few studies have taken such an approach. Here, we examine how resource restriction influences a set of pre- and post-copulatory traits in male pygmy halfbeaks (Dermogenys collettei), which invest in sexual ornaments and routinely engage in male-male contests and sperm competition. Critically, we examined responses in males when resources were restricted during development and after reaching sexual maturity. Both pre- and post-copulatory traits are resource-dependent in male halfbeaks. Body size, beak size, courtship behavior, and testes size were reduced by diet restriction, while, unexpectedly, the restricted-diet group had a larger area of red color on the beak and fins after diet treatment. These patterns were generally consistent when resources were restricted during development and after reaching sexual maturity. The study reinforces the role of resource acquisition in maintaining variation among sexual traits.

Sex and male breeding state predict intraspecific trait variation in mouth-brooding fishes.

Sex‐specific reproductive roles contribute to sexual dimorphic morphological trait variations. In uniparental mouth‐brooding fishes, the mouth performs a reproductive function in addition to its key roles in feeding and respiration, resulting in the potential for sex‐specific functional performance trade‐offs. Trait differences related to parental care may occur when the individual matures or be restricted to periods when the parent is mouth‐brooding. This study explored sexual dimorphism and morphological trait adaptations related to feeding, breeding, respiration and locomotion performance in two paternal mouth‐brooding freshwater fishes (Glossamia aprion and Neoarius graeffei). Eight morphological traits were evaluated for sexual dimorphism (non‐brooder males vs. females) and male breeding state differences (brooders vs. non‐brooders). Male breeding state was a significant predictor of trait variation in both species. Brooders differed in buccal volume and in several feeding and locomotory traits compared to non‐brooder males. Non‐brooder males had bigger buccal volumes and relative eye diameters (G. aprion) and larger relative gape sizes (N. graeffei) compared to females, a potential response to both mouth‐brooding and feeding requirements. Although there were clear trait differences between brooder and non‐brooder males, further research is required to confirm whether individuals return to their former morphology once mouth‐brooding has ceased or if trait differences are maintained post‐brooding. This study highlights the importance of considering the potential impacts of intraspecific trait variation on the performance of critical life functions, such as feeding, respiration and locomotion across the life history.

Genital Cutting as Gender Oppression: Time to Revisit the WHO Paradigm

The World Health Organization (WHO) condemns all medically unnecessary female genital cutting (FGC) that is primarily associated with people of color and the Global South, claiming that such FGC violates the human right to bodily integrity regardless of harm-level, degree of medicalization, or consent. However, the WHO does not condemn medically unnecessary FGC that is primarily associated with Western culture, such as elective labiaplasty or genital piercing, even when performed by non-medical practitioners (e.g., body artists) or on adolescent girls. Nor does it campaign against any form of medically unnecessary intersex genital cutting (IGC) or male genital cutting (MGC), including forms that are non-consensual or comparably harmful to some types of FGC. These and other apparent inconsistencies risk undermining the perceived authority of the WHO to pronounce on human rights. This paper considers whether the WHO could justify its selective condemnation of non-Western-associated FGC by appealing to the distinctive role of such practices in upholding patriarchal gender systems and furthering sex-based discrimination against women and girls. The paper argues that such a justification would not succeed. To the contrary, dismantling patriarchal power structures and reducing sex-based discrimination in FGC-practicing societies requires principled opposition to medically unnecessary, non-consensual genital cutting of all vulnerable persons, including insufficiently autonomous children, irrespective of their sex traits or socially assigned gender. This conclusion is based, in part, on an assessment of the overlapping and often mutually reinforcing roles of different types of child genital cutting—FGC, MGC, and IGC—in reproducing oppressive gender systems. These systems, in turn, tend to subordinate women and girls as well as non-dominant males and sexual and gender minorities. The selective efforts of the WHO to eliminate only non-Western-associated FGC exposes the organization to credible accusations of racism and cultural imperialism and paradoxically undermines its own stated goals: namely, securing the long-term interests and equal rights of women and girls in FGC-practicing societies.

Concentrations of Boar Taint Compounds Are Weakly Associated with Sexual Behavior of Young Boars.

Simple SummaryBoar taint is an off-odor and off-flavor affecting pork meat caused by the accumulation of three main compounds in the adipose tissue of uncastrated male pigs: androstenone, skatole, and indole. Boar taint occurrence is associated with sexual maturity onset; thus, strategies for reducing boar taint compound concentrations might lead to impaired male sexual behavior. This study investigated the relationships between boar taint compound concentrations and sexual behavior traits (sexual arousal, salivation, mounting performance, interest in the dummy sow, penis unsheathing, and overall libido) scored during training with the dummy sow in 391 young boars. Overall, our results suggest that a weak relationship between boar taint compounds and sexual behavior traits exists. The maximization of libido performances was observed at high levels of androstenone, intermediate or low levels of skatole, and intermediate to high levels of indole, but the relationship between BT compounds and sexual behavior appears to be weak.Strategies to control boar taint (BT) in meat relies on the reduction of skatole, indole, and androstenone concentration. This might have unfavorable effects on the libido of breeding boars. The association between BT compound concentration in backfat and libido was investigated in 391 commercial breeding boars. Six sexual behavior traits (SBT; sexual arousal, salivation, mounting performance, interest in the dummy sow, penis unsheathing, and overall libido score) were scored during the training of the boars with the dummy sow. Variation in SBT was analyzed by proportional-odds cumulative logistic models. Overall, indole, skatole, and androstenone concentrations were weakly associated with libido. Farm of origin, age at training or body weight, and BT compound levels were poor predictors of boar performance (the area under the ROC curve ranged from 0.60 to 0.69). This indicates that BT compound concentrations were weakly associated with libido, even though the probability of observing good SBT scores increased with high levels of androstenone, intermediate or low levels of skatole, and intermediate to high levels of indole. Hence, practices aiming at reducing androstenone, and controlling the concentrations of skatole and indole to intermediate levels are not expected to impair the libido of young boars.

Characterization of the Interrenal Gland and Sexual Traits Development in cyp17a2-Deficient Zebrafish.

Unlike the Cytochrome P450, family 17, subfamily A, member 1 (Cyp17a1), which possesses both 17α-hydroxylase and 17,20-lyase activities involved in the steroidogenic pathway that produces androgens and estrogens, Cytochrome P450, family 17, subfamily A, polypeptide 2 (Cyp17a2) possesses only 17α-hydroxylase activity and is known essential for the synthesis of cortisol. Besides with expressed in testes and ovaries, where the cyp17a1 is mainly expressed, cyp17a2 is also expressed in the interrenal gland in fish. Until now, the roles of cyp17a2 in fish, especially in sexual traits development and hypothalamic-pituitary-interrenal (HPI) axis, are poorly studied. To investigate the roles of Cyp17a2 in teleosts, the cyp17a2-null zebrafish was generated and analyzed by us. The significantly decreased cortisol concentration was observed both in the cyp17a2-deficient males and females at adult stage. The interrenal gland enlargement, increased pituitary proopiomelanocortin a (pomca) expression, decreased locomotion activity and response to light-stimulated stress were observed in cyp17a2-deficient fish. Intriguingly, the cyp17a2-deficient males were fertile and with normal breeding tubercles on the pectoral fin, but females were infertile, deficient in genital papilla and with decreased gonadosomatic index (GSI). The increased progesterone (P4), 17α,20β-dihydroxy-4-pregnen-3-one (DHP) and 11-ketotestosterone (11-KT) in the cyp17a2-deficient males and females were observed. The increased concentration of testosterone (T) and estradiol (E2) was observed in cyp17a2-/- females and cyp17a2-/- males, respectively. By examining the ovaries development of cyp17a2-deficient fish at 3 months postfertilization (mpf), we observed that the oocytes were over-activated. Taken together, our findings demonstrate that Cyp17a2 is indispensable for production and physiology of cortisol, and cyp17a2-deficiency resulted in diminished cortisol but accumulated P4 and DHP, which may result in the over-activated oocytes in cyp17a2-deficient females.

Ancillary polymorphic floral traits between two morphs adaptive to hawkmoth pollination in distylous plant Tirpitzia sinensis (Linaceae)

BackgroundFloral morphs are characterized differentiations in reciprocal positions of sexual organs and ancillary floral traits in heterostylous plants. However, it remains unclear how differential floral morphs ensure reproductive success between morphs using the same pollinator.ResultsMeasurements of floral traits in white-flowered Tirpitzia sinensis with long corolla tubes indicated that it is typically distylous, long-styled (L-) morph producing more but smaller pollen grains per flower than short-styled (S-) morph. Both morphs secreted more nectar volume at night than in the day and the sugar composition was rich in sucrose, potentially adaptive to pollination by hawkmoths (Macroglossum spp.) which were active at dusk. A bumblebee species functioned as the nectar robber in both morphs and a honeybee as the pollen feeder in the S-morph. The L-morph secreted more nectar volume but relatively lower sucrose/hexose ratio than the S-morph. Floral visitation rate by hawkmoths was higher but its pollination efficiency was lower in the S-morph than the L-morph. Hand pollination treatments indicated self-incompatibility in T. sinensis and seed set of open-pollinated flowers did not differ between morphs.ConclusionsOur findings suggest that the two morphs differ with respect to traits relevant to pollination. The L-morph, with its exserted stigma, has more pollen grains per anther and a greater volume of nectar, which may prolong the foraging time and increase the pollination efficiency of hawkmoths. The S-morph has a higher sucrose/hexose ratio in its nectar which can be more attractive to hawkmoths and increase the visit rates. Ancillary polymorphic floral traits between two morphs are adaptive to hawkmoth and ensure reproductive success in distylous plant T. sinensis.

Tusk anomalies in narwhals (Monodon monoceros) from Greenland

The elongated, spiraled tusk of male narwhals (Monodon monoceros) grows continuously throughout the life of the whale and is most likely a secondary sexual trait used in male–male hierarchical competition and possibly in female mate choice. Sex determination in narwhals is typically based on the presence (male) or absence (female) of an erupted tusk, but anomalies such as females with tusks, tuskless males or double-tusked whales occur, although infrequently. In this study, we collected reproductive data and recorded the presence or absence of a tusk in narwhals from the Inuit hunt in Greenland (1993 and 2010–19) with the purpose of estimating the frequency of tusk anomalies. We found that of the 173 whales, 2.9% displayed tusk anomalies. Tusked females constituted 1.5% of sampled females, tuskless males 2.8% of sampled males and double-tusked males 0.9% of sampled males. Biological information on a tusked female, a tuskless male and a double-tusked male was collected and is presented here. The tusked female was sexually mature, and 18 ovarian scars (indicating pregnancies) documented a long reproductive lifespan. The complete female tusk was estimated to be between 146 and 151 cm in length. The tuskless male was sexually maturing, as indicated by body dimensions, and the double-tusked male was sexually immature, with the two tusks measuring <90 cm in length. Although narwhals exhibit extremely low levels of genetic diversity, tusk anomalies persist in the populations, perhaps facilitated by the reproductive ability of whales with tusk anomalies.

Personality, sperm traits and a test for their combined dependence on male condition in guppies.

There is evidence that animal personality can affect sexual selection, with studies reporting that male behavioural types are associated with success during pre- and post-copulatory sexual selection. Given these links between personality and sexual traits, and the accumulating evidence that their expression can depend on an individual's dietary status (i.e. condition), a novel prediction is that changes in a male's diet should alter both the average expression of personality and sexual traits, and their covariance. We tested these predictions using the guppy Poecilia reticulata, a species previously shown to exhibit strong condition dependence in ejaculate traits and a positive correlation between sperm production and individual variation in boldness. Contrary to expectation, we found that dietary restriction—when administered in mature adult males—did not affect the expression of either behavioural (boldness and activity) or ejaculate traits, although we did find that males subjected to dietary stress exhibited a positive association between sperm velocity and boldness that was not apparent in the unrestricted diet group. This latter finding points to possible context-dependent patterns of covariance between sexually selected traits and personalities, which may have implications for patterns of selection and evolutionary processes under fluctuating environmental conditions.

Contamination effects on sexual selection in wild dung beetles.

Sexual selection influences the expression of secondary sexual traits, which are costly to produce and maintain and are thus considered honest indicators of individual condition. Therefore, sexual selection could select for high-quality individuals able to respond to stressful conditions, with impacts on population-level fitness. We sampled dung beetles from 19 pastures and investigated if contamination by herbicides and veterinary drugs modifies male investment in sexually selected traits and has associated population-level effects. We measured horn size, condition dependence (i.e. size-corrected body mass) and allometry, besides abundance and sexual size dimorphism in three species: Copris incertus, Euoniticellus intermedius and Digitonthophagus gazella. In contrary to our expectations, horn size was independent of contamination and individual condition. However, strong positive allometric relationships were reduced by herbicide contamination for C. incertus and D. gazella and were increased by ivermectin for C. incertus, revealing differential investment in horn production according to body size in contaminated habitats. At the population level, large-horned C. incertus males were more abundant in contaminated pastures, potentially revealing a case of evolutionary rescue by sexual selection or a plastic response to higher population densities. Finally, chemical compounds affected the sexual size dimorphism of all three species, with potential effects on female fecundity or intrasexual selection. Together, our findings indicate that contamination interferes with sexual selection processes in the wild, opening new questions regarding the role of sexual selection in favouring species persistence in contaminated environments.