Probability Of Mating Research Articles

Mathematical Modeling of Mating Probability and Fertile Egg Production in Helminth Parasites.

In this work, we obtained a general formulation for the mating probability and fertile egg production in helminth parasites, focusing on the reproductive behavior of polygamous parasites and its implications for transmission dynamics. By exploring various reproductive variables in parasites with density-dependent fecundity, such as helminth parasites, we departed from the traditional assumptions of Poisson and negative binomial distributions to adopt an arbitrary distribution model. Our analysis considered critical factors such as mating probability, fertile egg production, and the distribution of female and male parasites among hosts, whether they are distributed together or separately. We show that the distribution of parasites within hosts significantly influences transmission dynamics, with implications for parasite persistence and, therefore, with implications in parasite control. Using statistical models and empirical data from Monte Carlo simulations, we provide insights into the complex interplay of reproductive variables in helminth parasites, enhancing our understanding of parasite dynamics and the transmission of parasitic diseases.

Global dynamics of a simple model for wild and sterile mosquitoes.

There are known methods to manage the population dynamics of wild and sterile mosquitoes by releasing genetically engineered sterile mosquitoes. Even if a two-dimensional system of ordinary differential equations is considered as a simple mathematical model for developing release strategies, fully understanding the global behavior of the solutions is challenging, due to the fact that the probability of mating is ratio-dependent. In this paper, we combine a geometric approach called the time-scale transformation and blow-up technique with the center manifold theorem to provide a complete understanding of dynamical systems near the origin. Then, the global behavior of the solution of the two-dimensional ordinary differential equation system is classified in a two-parameter plane represented by the natural death rate of mosquitoes and the sterile mosquito release rate. We also offer a discussion of the sterile mosquito release strategy. In addition, we obtain a better exposition of the previous results on the existence and local stability of positive equilibria. This paper provides a framework for the mathematical analysis of models with ratio-dependent terms, and we expect that it will theoretically withstand the complexity of improved models.

On the feasibility of malaria hypothesis

In 1954, Allison proposed that hemoglobin S (HbS) gene causes protection against fatal malaria. This would explain the high HbS gene frequency observed in certain regions hyperendemic for malaria, so-called “malaria hypothesis”. This in silico study was conducted to examine the feasibility of the hypothesis under more realistic initial conditions, where a mutant gene with heterozygous advantage against malaria (e.g., HbS) was introduced in a group of Neolithic hunter-gatherers who decided to start agriculture nearby water where malaria killed a proportion of population. The tribe population size, number of children born to each woman in each generation, mortality from malaria and sickle cell disease, the protection factor provided by the gene carriers against malaria, the probability of mating between the members of the parent and offspring populations, population growth, and increased fertility in women heterozygous for HbS, were also considered. For effectively confer protection against malaria within the shortest possible period, the mutation needs to be happened in a small population. For a large population, the process would take around 100 generations (~ 2500 years) or more to provide an effective protection. Even then, the probability that the new gene could survive and propagate to future generations is about 35%. Conventional population genetics equations with differential or difference equations, give totally incorrect estimates of the gene frequency in small populations; discrete mathematics should be used, instead. After introduction of the advantageous mutation, the gene frequency increased until a steady state value. This value is far less than the gene frequency reported in certain tribes of Africa. It seems that the malaria hypothesis, per se, could not explain such a high observed gene frequency, unless HbS is associated with lower mortality from other causes too.

The genomic footprint of social stratification in admixing American populations.

Cultural and socioeconomic differences stratify human societies and shape their genetic structure beyond the sole effect of geography. Despite mating being limited by sociocultural stratification, most demographic models in population genetics often assume random mating. Taking advantage of the correlation between sociocultural stratification and the proportion of genetic ancestry in admixed populations, we sought to infer the former process in the Americas. To this aim, we define a mating model where the individual proportions of the genome inherited from Native American, European, and sub-Saharan African ancestral populations constrain the mating probabilities through ancestry-related assortative mating and sex bias parameters. We simulate a wide range of admixture scenarios under this model. Then, we train a deep neural network and retrieve good performance in predicting mating parameters from genomic data. Our results show how population stratification, shaped by socially constructed racial and gender hierarchies, has constrained the admixture processes in the Americas since the European colonization and the subsequent Atlantic slave trade.

Mating with dead conspecifics in an invasive ladybird is affected by male sexual fasting and time since the female’s death

High promiscuity and low mating partner choosiness in insects can sometimes result in a deviated mating behaviour such as mating with already dead individuals. In this study we investigated the occurrence of necrophilic behaviour in males of the invasive ladybird Harmonia axyridis using two laboratory experiments. For both no-choice and choice experiments, the probability of mating and mating duration were significantly affected by female status (alive, 1-day, 7-day, or 14-day old carcass) and by male mating status (unmated or mated) which was investigated in the no-choice experiment. The presence of chemical cues produced by an alive female did not affect the probability of a male mating with a dead female. In the no-choice experiment, 14-day old female carcasses were significantly less attractive than alive females, and unmated males tended to mate with females of all statuses with significantly higher probability than mated males. In the choice experiment, males showed a significant preference to mate with alive females when compared to 7-day old carcasses but did not distinguish between alive females and 1-day old carcasses. Mating latency (time to the starting of mating) tended to be longer for 14-day old carcasses in the no-choice experiment and was not affected by female status in the choice experiment. Mating duration was negatively affected by age of female carcasses in the no-choice experiment and only 7-day old carcasses were mated for significantly shorter time than alive females in the choice experiment. Mating behaviour was highly consistent for the no-choice and choice experiments. Despite decreasing probability of mating with 7-day and 14-day old carcasses, we observed a surprisingly high frequency of mating with dead conspecifics in the invasive ladybird Harmonia axyridis, which could have serious consequences for transmission of pathogens and affect male fitness even under natural conditions.

Adaptive archive-based multifactorial evolutionary algorithm for constrained multitasking optimization

Evolutionary multitasking has attracted much attention in the field of evolutionary computing. Most of the existing multitasking evolutionary algorithms aim at solving unconstrained multitasking optimization problems. The study on constrained multitasking optimization problems is scarce. However, in practical applications, lots of optimization problems contain constraints. In this paper, an adaptive archive-based multifactorial evolutionary algorithm is proposed to solve constrained multitasking optimization problems. First, an archiving strategy is proposed to store infeasible solutions with better objective function values. With this strategy, useful information on infeasible solutions can be exploited to accelerate the convergence rate. Second, the random mating probability is adjusted through an adaptive strategy to facilitate positive knowledge transfer. Finally, a new mutation strategy is proposed to promote convergence by mutating some random individuals and replacing the individuals with the largest constraint violation. By comparing existing constrained multitasking evolutionary algorithms and some constrained single-task evolutionary algorithms, the results reveal the effectiveness of the proposed algorithm in solving constrained multitasking optimization problems.

Evolutionary competitive multitasking optimization via improved adaptive differential evolution

Competitive multitasking optimization (CMTO) is a special multitasking optimization paradigm that has been recently proposed. In the CMTO problems, the objective values of all tasks are competitive, and the purpose of CMTO is to find an optimal solution for multiple tasks. However, existing algorithms designed for the CMTO problems perform poorly since their resource allocation strategies are prone to incorrect task selection. To remedy this drawback, this paper proposes an improved multitasking adaptive differential evolution, which can be featured as: (i) a success-history based resource allocation strategy is proposed; (ii) an adaptive random mating probability control strategy is devised to adapt to different task combinations; (iii) an adaptive multitasking differential evolution operator is designed to enhance the searchability. To evaluate the performance of the proposed method, three CMTO benchmark test suites and two real-world optimization problems are chosen. Compared with other related methods, the results show that the proposed method achieved better performance empirically.

The effect of sex ratio and group density on the mating success of two lines of Delia platura (Diptera: Anthomyiidae)

Abstract The seedcorn maggot, Delia platura (Meigen) (Diptera: Anthomyiidae), is reported as a polyphagous pest species found in numerous crops, including onion, corn, crucifers, and soy. Two morphologically identical genetic lines of D. platura (H- and N-lines) with distinct distribution ranges were recently discovered. Although many biological traits have been described for D. platura, no study to date has been conducted on the life history strategies and reproductive behaviours of its two lines. Using laboratory-reared colonies, this project investigates the effect of group composition (sex ratio and density) on the mating success and preoviposition period of the two D. platura lines. We found a substantial increase in mating success with increasing proportion of males within mating groups for both lines, whereas we found group density had negligible effects. However, the H-line had a lower average mating probability across treatments compared to the N-line. The preoviposition period decreased as the ratio of males to female increased at low density only for the N-line, and the opposite trend was observed at high density for both lines. These results suggest differences between the mating systems of these two lines, thereby highlighting the need for further research into the factors that influence their respective mating systems.

Reproductive behaviours in male parasitoids: From mating system to pairing pattern

AbstractIt is now acknowledged that mating system is a dynamic characteristic within species or populations. Indeed, behavioural characteristics shaping the mating system can vary at the inter‐individual level, providing raw material for sexual and natural selections, and at the intra‐individual level, because of phenotypic plasticity and ontogeny of individual behaviours. Social environment is an additional source of variation in sexual behaviours. By focusing on males of the parasitoid wasp Venturia canescens, we assessed how sexual behaviours (courtship and mating) vary between and within individuals, considering males' size as inter‐individual source of variation, and age and mating experience as intra‐individual sources of variation. Consequences of the variations in sexual behaviours at the individual level are appraised by quantifying the costs in longevity and offspring production incurred by (repeatedly) mated males. At the population level, we tested the “agility hypothesis” predicting that smaller males win the male–male competition to access females, resulting in a non‐random assortative mating by size and a negative sexual selection on body size. We showed that V. canescens males are polygynous and that mating incurred longevity cost. Old males had a higher probability to court females, but no mating advantage. Smaller males tended to have a higher mating probability, but size was not under sexual selection and there was a random mating pattern according to individual size. Male–male competition intensity did not influence pairing pattern but tended to influence mating dynamic. Overall, our results suggest that sexual behaviours tended to vary at the inter‐ and intra‐individual levels and the effect of social environment remains to be more precisely described. These variations may impact individuals' reproductive success with potential ecological and evolutionary consequences that are discussed.

Predicting the probability of avian reproductive success and its components at a nesting site

Avian reproduction has four prime components: nesting, mating, hatching, and fledging. Predicting the probability of individual components helps in identifying the period of reproduction that would benefit from an increased conservation effort. Identification of biotic, abiotic, and sociological variables of the nesting sites is essential to calculate the component-wise success probabilities. There is no standard methodology to estimate these probability values separately. This study proposes a methodology to estimate the success probability of each component, identifies correlated environmental predictors, and provides a modelling framework to accurately predict the nesting success probabilities using Merops philippinus as a model species. Primary surveillance data and the proposed methodology indicate that the time window between the bird's nesting and mating is most vulnerable to environmental fluctuations. Both biotic and abiotic factors are crucial determinants of nesting success. Sociological factors also play a crucial role in determining the probabilities of these successes. Mating, hatching, and fledging success depend more on biotic factors than abiotic ones. Linear modelling frameworks are helpful in exploring which types of environments are better determinants of the success of a reproductive component. Artificial neural networks are useful in predicting mating, nesting, and overall reproductive success probabilities. Though the models in this study are developed using Merops philippinus data, the proposed methodology and modelling framework is also applicable for other bird species.

Mating and fitness consequences of variation in male allocation in a wind-pollinated plant.

In hermaphrodites, the allocation of resources to each sex function can influence fitness through mating success. A prediction that arises from sex allocation theory is that in wind-pollinated plants, male fitness should increase linearly with investment of resources into male function but there have been few empirical tests of this prediction. In a field experiment, we experimentally manipulated allocation to male function in Ambrosia artemisiifolia (common ragweed) and measured mating success in contrasting phenotypes using genetic markers. We investigated the effects of morphological traits and flowering phenology on male siring success, and on the diversity of mates. Our results provide evidence for a linear relation between allocation to male function, mating, and fitness. We find earlier onset of male flowering time increases reproductive success, whereas later flowering increases the probability of mating with diverse individuals. Our study is among the first empirical tests of the prediction of linear male fitness returns in wind-pollinated plants and emphasizes the importance of a large investment into male function by wind-pollinated plants and mating consequences of temporal variation in sex allocation.

Effect of limited protein consumption during the larval and adult stage on life‐history traits of the Mexican fruit fly

AbstractAnastrepha ludens Loew (Diptera: Tephritidae) is an important mango and citrus pest. The sterile insect technique (SIT) is currently used to control this fly. The SIT involves the release of sterile insects to reduce wild populations through the induction of sterility. Prior to release, insects are mass‐reared on artificial diets. The rearing of A. ludens involves the provision of protein both in the larval and adult stage, thus we studied trade‐offs between larval and adult diets. We compared various yeast concentrations in the larval diet and two formulations in the adult diet, both at small and semi‐mass scale. We determined the quality of the insects at all developmental stages. Low concentrations of torula yeast (TY) (2.9 and 3.6%) produced larvae and pupae of low weight, fewer larvae and pupae, and more males than higher TY concentrations (6.1%), but this was only discernable at a small scale. Adult survival without water and food was significantly lower for non‐irradiated males and females, and irradiated males when reared on 6.1% TY. For mating success, we found that non‐irradiated males reared on 4.8% TY but fed only sugar (S) as adults had lower probability of mating than males fed yeast hydrolysate (YH). For irradiated males, larval diet had no effect on mating competitiveness, only males fed with S + YH in the adult diet had higher mating success than those fed with S only. We propose reducing TY in the larval diet to 5.1%; however, for release colonies S + YH will need to be provided in the adult diet. Knowledge on larval and adult nutritional requirements will aid in our understanding of insect nutritional ecology and will also improve mass‐rearing diets.

Sexually but not parthenogenetically produced females benefit from mating in a stick insect

Abstract In facultatively parthenogenetic populations, the prevalence of sexual reproduction depends on whether females mate and therefore produce sons and daughters or avoid mating and produce daughters only. The relative advantage of mating in such species may depend on a female's own reproductive origin (i.e. development from a fertilised or unfertilised egg) if parthenogenesis reduces heterozygosity similar to sexual inbreeding, or if it inhibits mating, sperm storage or fertilisation. But effects of reproductive origin on development and performance are poorly understood. Using the facultatively parthenogenetic stick insect, Extatosoma tiaratum, we quantified morphology, mating probability, and reproductive success in mated versus unmated females of sexual versus automictic (parthenogenetic) origin. We found strong evidence that increased homozygosity negatively impacted some traits in parthenogenetically produced females: compared to sexually produced females, parthenogenetically produced females were smaller and more prone to deformities in vestigial wings, but not more prone to fluctuating asymmetry in their legs. Parthenogenetically produced females received fewer mating attempts and avoided mating more often than sexually produced females. Yet, contrary to the expectation that sex should rescue parthenogenetic lineages from the detrimental effects of increased homozygosity, parthenogenetically produced females gained no net reproductive benefit from mating, suggesting that physiological constraints limit fitness returns of sexual reproduction for these females. Our findings indicate that advantages of mating in this species depend on female reproductive origin. These results could help to explain spatial distributions of sex in facultatively parthenogenetic animals and evolutionary transitions to obligate asexuality. Read the free Plain Language Summary for this article on the Journal blog.

Carbon emission flow oriented multitasking multi‐objective optimization of electricity‐hydrogen integrated energy system

A grid-connected electricity-hydrogen integrated energy system (EH-IES) is proposed here for the cooperative analysis of electricity, heat, cooling and hydrogen energy flows, where carbon emission flow (CEF) is introduced to allocate the carbon emission. Simultaneously, an improvement multitasking multi-objective optimization (MT-MOO) algorithm is applied to optimize the operation of this EH-IES. The proposed EH-IES optimizes the operational cost, carbon dioxide emission and energy loss while considering the uncertainties of future energy demand, wind and photovoltaic (PV) power outputs. The CEF model is introduced here to allocate the carbon emission among the EH-IES, which can calculate the carbon emission in the energy flow. In order to solve the MOO model, a MT-MOO algorithm is proposed to utilize the implicit information of different optimization tasks. However, there are harmful interactions between the different optimization tasks when the relativity between different optimization tasks is low. Therefore, the paper introduces an online learning random mating probability method which calculates the transformation extent of implicit information online between different optimization tasks. Simulation results show that the proposed EH-IES has good feasibility and efficiency, and the proposed algorithm has better convergence performance than comparing intelligence algorithms.

Hydrocarbon Field (Re-)Development as Markov Decision Process

Summary Hydrocarbon field (re-)development requires that a multitude of decisions are made under uncertainty. These decisions include the type and size of surface facilities, location, configuration, and number of wells but also which data to acquire. Both types of decisions, which development to choose and which data to acquire, are strongly coupled. The aim of appraisal is to maximize value while minimizing data acquisition costs. These decisions have to be done under uncertainty owing to the inherent uncertainty of the subsurface but also of other costs and economic parameters. Conventional value of information (VOI) evaluations can be used to determine how much can be spent to acquire data. However, VOI is very challenging to calculate for complex sequences of decisions with various costs and including the risk attitude of the decision-maker. We are using a partially observable Markov decision process (MDP) to determine the policy for the sequence and type of measurements and decisions to do. A partially observable MDP (POMDP) is characterized by the states (here: description of the system at a certain point in time), actions (here: measurements and development scenario), transition function (probabilities of transitioning from one state to the next), observations (measurements, appraisal activity), and rewards [costs for measurements, expected monetary value (EMV) of development options]. Solving the MDP gives the optimum policy, sequence of the decisions, the probability of maturation (POM) of a project, the EMV, the expected loss, the expected appraisal costs, and the probability of economic success (PES). These key performance indicators can then be used to select in a portfolio of projects the ones generating the highest expected reward for the company. Combining the production forecasts from numerical model ensembles with probabilistic capital and operating expenditures and economic parameters allows for quantitative decision-making under uncertainty.

Polyandrous Mexican Fruit Flies: Second Male Paternity and Biological Attributes of Transgenic Strains.

Simple SummaryThe Mexican fruit fly is an important pest of certain fruits. As part of its control, the Sterile Insect Technique (SIT) is used. This is an environmentally friendly means of control where insects are mass-reared, sterilized, and then released into areas where the pest is found. Sterile insects are dyed with a fluorescent pigment before release, to distinguish them from the wild population. The efficiency of this technique can be diminished if wild females first mate with a sterile male and then with a wild male. For the Mexican fruit fly, several transgenic strains have been developed that express a fluorescent protein marker for field detection, and are also used as reporters in the creation of strains with complex genetic systems. Here, we report on the biological attributes, mating competitiveness, and the proportion of paternity gained by the second male in twice-mated females with males from two transgenic strains. We found that the males expressing green florescence (443-G) had a better overall performance than the males expressing red fluorescence (419-R). We also found that females produced progeny mostly from the second male to mate with her. This could affect release ratios and diminish the efficiency of the SIT if wild females mate first with a sterile male but remate with a wild male, as she will then lay fertile eggs. These findings are helpful towards delimiting which strains can be used in the future, and determining the proportion of sterile to wild individuals that need to be released in affected areas, for the more efficient control of the Mexican fruit fly.Anastrepha ludens (Diptera: Tephritidae), is a damaging agricultural pest. Currently, the Sterile Insect Technique (SIT) is used as part of its control. The SIT consists of the mass-rearing, sterilization, and release of insects in target areas. Sterile males mate with wild females, and prevent them from laying fertile eggs. However, even if females mate with sterile males, they can then remate with a second male. If this second male is wild, then this could reduce the efficiency of the SIT by producing viable offspring. The amount of progeny produced by second males (P2 values) for A. ludens is unknown. Here, we evaluated the biological attributes, mating competitiveness, and the proportion of male paternity gained by the second male, using strains that carry fluorescent marker genes and can be potentially used to develop transgenic sexing strains. Furthermore, the transgenic strains were irradiated, to test their ability to induce sterility in females. We found that the 443-G strain had significantly higher larval survival than the 419-R strain. No significant difference was found between the two strains in their mating probability with wild females. We found P2 values between 67 and 74% for the 419-R and the 443-G strain, respectively. Second male sperm precedence only decreased slightly after 12 days, suggesting that sperm from the first and second male is not mixing with time, but rather the second male’s sperm prevails. Furthermore, sterile 443-G males induced significantly higher sterility in females than sterile males from the 419-R strain. The apparent lower ability of the 443-G strain to inhibit female remating should be further investigated. Knowledge of the pre and postcopulatory performance of transgenic strains will help in understanding their potential for control.

Diversification through gustatory courtship: an X-ray micro-computed tomography study on dwarf spiders

BackgroundSexual selection has been considered to promote diversification and speciation. Sexually dimorphic species have been used to explore the supposed effect, however, with mixed results. In dwarf spiders (Erigoninae), many species are sexually dimorphic—males possess marked prosomal modifications. These male traits vary from moderate elevations to bizarre shapes in various prosomal regions. Previous studies established that male dwarf spiders produce substances in these prosomal modifications that are taken up by the females. These substances can act as nuptial gifts, which increase the mating probability of males and the oviposition rate in females. Therefore, these dimorphic traits have evolved in the context of sexual selection. Here, we explore the evolutionary lability of this gustatory trait complex with the aim of assessing the role of this trait complex in species divergence by investigating (1) if erigonine modified prosomata are inherently linked to nuptial-gift-producing glands, (2) if the evolution of the glands evolution preceded that of the modified prosomal shapes, and by assessing (3) the occurrence of convergent/divergent evolution and cryptic differentiation.ResultsWe reconstructed the position and extent of the glandular tissue along with the muscular anatomy in the anterior part of the prosoma of 76 erigonine spiders and three outgroup species using X-ray micro-computed tomography. In all but one case, modified prosomata are associated with gustatory glands. We incorporated the location of glands and muscles into an existing matrix of somatic and genitalic morphological traits of these taxa and reanalyzed their phylogenetic relationship. Our analysis supports that the possession of glandular equipment is the ancestral state and that the manifold modifications of the prosomal shape have evolved convergently multiple times. We found differences in gland position between species with both modified and unmodified prosomata, and reported on seven cases of gland loss.ConclusionsOur findings suggest that the occurrence of gustatory glands in sexually monomorphic ancestors has set the stage for the evolution of diverse dimorphic external modifications in dwarf spiders. Differences among congeners suggest that the gland position is highly susceptible to evolutionary changes. The multiple incidences might reflect costs of glandular tissue maintenance and nuptial feeding. Our results indicate divergent evolutionary patterns of gustatory-courtship-related traits, and thus a likely facilitating effect of sexual selection on speciation.

Three easy fixes for sire use can enhance genetic progress in community-based breeding programmes.

We analysed options to optimize the use of sires in sheep and goat community-based breeding programmes (CBBP) for three scenarios occurring under field conditions: premature sale of selection candidates, fixed service periods of selected sires and incomplete sire pedigrees. The first scenario was studied by looking at the outcome of combinations of selection pressures in successive selection stages. A compromise of early sale of sire candidates and genetic progress can be obtained by selecting in two stages, such that selection pressure in the first stage is chosen in terms of achieving an acceptable selection potential after the second stage. Simulations showed the dependency of this compromise on selection accuracies and correlation between selection criteria. For a typical sheep CBBP, only 20% of the top three months weighting male lambs need to be retained to achieve 80% of the potential selection differential on six months weight. For the second scenario, two alternatives to fixed service periods were analysed. When across-age BLUP EBVs are not available, individual sires can be programmed to stay in service according to their initial ranking. In typical sheep, CBBPs genetic progress can be increased by about 9% over response to selection with optimum fixed sire service periods. When BLUP EBVs are available, a simulated retrospective analyses of across-age selection of sires in two current sheep CBBPs increased more than twofold the average breeding values actually observed. Thirdly, we studied the benefit of considering possible sires and their mating probabilities when estimating BLUP breeding values instead of setting such sires as unknown. In a current goat CBBP with up to three possible sires included in the pedigree, the accuracy of breeding values nears the accuracy when sires are known and are higher than accuracies when sires are unknown or when possible sires are ignored.

Appearance matters: multiple functional signals of body colours in a weevil

Visual signals in animals are often shaped by sexual selection. For aposematic species, advantages may result from advertising unpalatability to decrease predation and attracting mates to increase reproductive success. On Green Island, Taiwan, most Eupyrgops waltonianus weevils have metallic blue spots on the body; however, some weevils have no conspicuous coloration. The role of coloration in sexual selection and any disadvantages encountered by dull individuals are unknown. To understand whether morphological traits affect mating success in E. waltonianus , we compared different traits between mating and nonmating individuals in the field. A manipulation experiment was also used to test whether coloration affects mating choice and behaviour. The function of colour as an aposematic signal was tested. Results showed that body size and coloration were important indicators of female mating success in field and laboratory experiments, respectively. In the field, males preferred to mate with larger, more conspicuous females, and females preferred to mate with conspicuous males; however, no such preference was shown in the laboratory. Intrasexual competition was stronger in males than in females. Predators avoided colourful weevils. Thus, conspicuous coloration in both sexes is a multifunctional trait and could be an attractive or aposematic signal for different receivers. • The spots on weevils play an important role in survival and reproduction. • Higher spot area ratio was related to a higher mating probability in the field. • Weevils displayed higher levels of male-male than female-female competition. • Weevils' coloration could be attractive or aposematic depending on receiver type.

Disease influences male advertisement and mating outcomes in a critically endangered amphibian

The sublethal effects of infectious disease on reproductive behaviour and mating success are not well understood. Here, we investigated predictors of male mating success in one of Australia's most critically endangered vertebrates: the northern corroboree frog, Pseudophryne pengilleyi. Using a genomic approach to assign parentage, we explored whether infection with the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd), a pathogen responsible for amphibian declines globally, influenced male calling behaviour and mating success. We also explored whether male mating success was predicted by phenotypic traits (age, body size, coloration, call characters) that potentially signal genetic quality, and the soil moisture (water potential) of male-constructed terrestrial nests, which may directly impact offspring survival. We found that Bd significantly influenced male advertisement; Bd-infected males produced calls with significantly higher pulse repetition rates than uninfected males. Older males had a higher probability of mating; however, variation in the number of eggs in a nest was most strongly explained by an interaction between male Bd infection status and call pulse repetition rate. We propose that these relationships may result from either pathogen-mediated changes to host behaviour or host-mediated changes to behaviour (e.g. terminal investment). Regardless of the mechanism, this is the first evidence that male mating success in an amphibian can be influenced by male Bd infection status, highlighting a novel mechanism through which this virulent pathogen can affect amphibian fitness. More broadly, these findings add to a growing body of evidence that pathogens can alter the reproductive biology of their hosts. From a conservation perspective, increased consideration of how sexual selection operates in altered environments has the potential to assist with the management of threatened amphibians worldwide.