An MD-2-related lipid-recognition protein is required for insect reproduction and integument development

The myeloid differentiation factor 2 (MD-2)-related lipid-recognition protein is involved in immune responses through recognizing bacteria lipopolysaccharide in mammals, arthropods and plants. However, the physiological roles of MD-2 in other biological processes are largely unknown. Here, we identified three homologue MD-2 genes ( NlML1 , NlML2 and NlML3 ) by searching the genome and transcriptome databases of the brown planthopper Nilaparvata lugens , a hemipteran insect species. Temporospatial analysis showed that the NlML1 gene was highly expressed in the fat body but much less so in the other tissues, while the NlML2 and NlML3 genes were highly expressed in the testis or digestive tract. RNA interference-mediated depletion of the NlML1 gene significantly downregulated the transcription of numerous integument protein genes. The NlML1 knockdown led to moulting failure and mortality at the nymph–adult transition phase, impaired egg laying and hatching, and reduced 20-hydroxyecdysone (20E) production in the nymphs. 20E could rescue the deficient moulting phenotypes derived from ds NlML1 RNAi. These novel findings indicate that NlML1 is required for nymphal moulting and female reproductive success as it plays an important role in regulating 20E synthesis, lipid and chitin metabolisms in N. lugens , thus contributing to our understanding of developmental and reproductive mechanisms in insects.

Structural anther mimics improve reproductive success through dishonest signalling that enhances both attraction and the morphological fit of pollinators with flowers

Numerous studies have identified traits associated with pollen mimicry, however, the processes underlying floral deception remains poorly documented for these structures. We studied the importance of attraction and mechanical fit of anther mimics in Tritonia laxifolia (Iridaceae) and their relative contributions to reproductive success. To determine anther mimics role in pollinator attraction, we offered bees binary preferences to flowers painted with UV absorbent and reflecting paint. We also conducted preference experiments between flowers with excised anther mimics and unmanipulated controls, from which mechanical fit was assessed using single visits. Anther mimics effects on female reproductive success was determined using similar treatments, but on rooted plants. Bees preferred UV absorbent over UV reflecting anther mimics. Preference for flowers with and without the three-dimensional structures was equal. Single visits resulted in more pollen deposition on unmanipulated controls over flowers with their anther mimics excised, which was directly linked to pollen-collecting behaviour. Controls with unmanipulated anther mimics experienced more seed set than those with their anther mimics excised. This study provides insights into pollinator-mediated selection on deceptive floral signals and shows that three-dimensional anther mimics increases reproductive success through both attraction, and pollen collecting behaviours that improve the fit between flowers and pollinators.

The effect of reproductive state on activity budget, feeding behavior, and urinary C-peptide levels in wild female Assamese macaques

The source of maternal energy supporting reproduction (i.e., stored or incoming) is an important factor determining different breeding strategies (capital, income or mixed) in female mammals. Key periods of energy storage and allocation might induce behavioral and physiological shifts in females, and investigating their distribution throughout reproduction helps in determining vulnerable phases shaping female reproductive success. Here, we examined the effects of reproductive state on activity budget, feeding behavior, and urinary C-peptide (uCP) levels, a physiological marker of energy balance, in 43 wild female Assamese macaques (Macaca assamensis). Over a 13-month study period, we collected 96,266 instantaneous records of activity and 905 urine samples. We found that early lactating females and non-gestating–non-lactating females follow an energy-saving strategy consisting of resting more at the expense of feeding and consuming mostly fruits which contributed to enhancing their energy intake and feeding efficiency. We found an opposite pattern in gestating and late lactating females who feed more at the expense of resting and consume mostly seeds, providing a fiber-rich diet. Storing food into cheek pouches increased throughout gestation while it decreased all along with lactation. Lastly, we found the highest uCP levels during late gestation. Our results reflect different feeding adaptations in response to the energetic costs of reproduction and suggest a critical role of fat accumulation before conception and metabolizing fat during gestation and lactation. Overall, our study provides an integrative picture of the energetics of reproduction in a seasonal species and contributes to our understanding of the diversity of behavioral and physiological adaptations shaping female reproductive success. Significance statement To offset their substantial energetic investment in reproduction, mammalian females may modify their behavior and the way they extract energy from their environment. In addition, as a result of heightened energy expenditure, female reproduction might trigger physiological shifts. To date, most studies investigated the energetic costs of female reproduction using either a behavioral or a physiological approach. To arrive at a more comprehensive picture, we combined behavioral data with a physiological marker of energy balance, i.e., urinary C-peptide, in a seasonal primate species in its natural habitat. Our results indicate that throughout the reproductive cycle, behavioral and physiological adaptations operate concomitantly, inducing modifications in female activity budget, feeding behavior, and suggesting shifts in fat use. Overall, our results illustrate the relevance of combining data on behavior and hormones to investigate breeding strategies in coping with the energetic costs of reproduction.

Mating system and female reproductive success of the endemic and endangered epiphyte Rhynchostele cervantesii (Orchidaceae) in a cloud forest in Michoacan, Mexico

Background and aims – The Orchidaceae family is vulnerable, because of the destruction of their habitat, as well as the extraction of individuals from natural populations. This is the case of the genus Rhynchostele Rchb.f.; among the actions considered important for appropriate conservation strategies for this genus is the generation of fundamental knowledge, such as on its reproductive biology. The objective of this work is to understand the mating system and reproductive success of Rhynchostele cervantesii, an endangered epiphytic orchid endemic to Mexico.Material and methods – Manual and open-pollination treatments were conducted during 2014 and 2015 in a cloud forest in Michoacan, Mexico. In each period, 30 to 40 randomly selected inflorescences were subjected to the following treatments: a) spontaneous-self-pollination, b) emasculation, c) self-pollination, d) cross-pollination, and e) open-pollination. The developed fruits were counted and harvested, the viability of the seeds was determined, through the observation and evaluation of embryos using microscopy.Key results – Significant differences were recorded between the treatments in both 2014 and 2015, with higher fruit production in cross-pollination than in self-pollination and natural-pollination. There were significant differences in seed viability, with higher values for seeds from open-pollination and cross-pollination and lower values for seeds from self-pollination.Conclusions – Rhynchostele cervantesii is a species that requires pollinators for sexual reproduction because there is no fruit production with spontaneous-self-pollination. Under pollen limitation, the fruit set of natural pollination was a lot lower than in cross-pollination although fruits were the same quality. R. cervantesii had a mixed mating system with a tendency to exogamy, presenting high values of female reproductive success compared to other tropical epiphytic orchid species reported in the literature.

Infant Survival Among Free-Living Bonnet Macaques (Macaca radiata) in South India

Female reproductive success depends to a large extent on infants’ ability to survive to maturity. While most studies of female reproductive success have focused on the effects of individuals’ sociodemographic factors (e.g., age/parity, dominance rank) on offspring survival among wild primates living in less disturbed habitats, little research has focused on offspring survival in urban or periurban animals. Here we investigated sociodemographic and anthropogenic determinants of infant survival (up to 1 yr of age) in free-ranging bonnet macaques (Macaca radiata) living in a periurban environment in Southern India. We conducted the study from November 2016 to May 2018, on two groups of bonnet macaques at the Thenmala tourist site in the state of Kerala. Fifty infants were born across two birth seasons. Of these infants, 29.2% died or disappeared in 2017 and 26.9% died or disappeared in 2018. We found that infant survival was strongly influenced by the mother’s parity: infants of experienced mothers had a better chance of survival than those of first-time mothers. We also found that male infants were more likely to die than female infants. However, we found no effects of mothers’ dominance rank, or of frequency of mothers’ interactions with humans and time spent foraging on anthropogenic food, on infant survival. Our results, consistent with findings from other wild primate species, show that even in challenging human-impacted environments, experienced bonnet macaque mothers have greater success than inexperienced ones.

In nomen omen: the effect of flower distance on female reproductive success of the lax-flowered orchid Anacamptis laxiflora (Orchidaceae)

Aims In multiflowered species, the architecture of inflorescences is of primary importance in shaping plant attractiveness. The aim of this study was to disentangle the role of inflorescence traits in plant female reproductive success and pollination patterns along the inflorescence in the lax-flowered orchid Anacamptis laxiflora, a terrestrial species exploiting a deceptive pollination strategy. We also evaluated whether the relationship between inflorescence traits and female reproductive success was modified by the height of surrounding vegetation and/or by population density. Methods We delimited experimental plots in a natural population of A. laxiflora. We tallied the individuals within each plot and categorized low-density plots and high-density plots; then, in part of the plots we manually removed surrounding grass thus producing an equal number of plots with high grass and low grass. Within these plots, we recorded inflorescence traits and female reproductive success (i.e. the number of fruit and their position along the inflorescence). We analyzed these data using Generalized Linear Mixed-Effects Models (GLMMs) and calculated selection gradients. Important Findings We found that all the investigated inflorescence traits influenced female reproductive success. In particular, our GLMMs showed that “average flower distance” was the best predictor for shaping reproductive success patterns. We detected significant positive selection on the investigated inflorescence traits, but these selective trends were strictly linked to both the height of the surrounding vegetation and the population density, suggesting a significant influence of local environmental context in shaping selective patterns. Female reproductive success was not linked to the position of flowers along the inflorescence, suggesting that pollinators visit flowers randomly along the inflorescence without a detectable preference for a specific part. This study highlights the importance of inflorescence traits in shaping female reproductive success of multiflowered deceptive orchids, and confirms a primary role for the environmental context in modifying pollinator-mediated selection patterns.

Motherly love curbs harm: maternal effects can modulate sexual conflict

Strong sexual selection frequently favours males that increase their reproductive success by harming females, with potentially negative consequences for the growth of populations. Understanding what factors may resolve this reproductive “tragedy of the commons” is a key question in evolutionary biology. Studies addressing the evolution of sexual conflict have so far considered direct effects on male and female reproductive success along with indirect genetic benefits (e.g. good genes) to females. Here, we model the evolution of male harm while incorporating male-induced maternal effects on offspring quality. We show that maternal effects can partially align male and female evolutionary interests, fostering cooperation between the sexes and significantly reducing optimal levels of male harm. This finding fits broadly with available evidence across the tree of life, opening a novel avenue to understand the evolution of sexual conflict.

Author Correction: Food-provisioning negatively affects calf survival and female reproductive success in bottlenose dolphins

An amendment to this paper has been published and can be accessed via a link at the top of the paper.