Low Mating Research Articles

Roe Deer Reproduction in Western Poland: The Late Autumn Rut Phenomenon

Roe deer (Capreolus capreolus L.) populations in Poland are characterized by low productivity, which is why their reproductive potential was investigated. The presence of corpora lutea (CL) on the ovaries of females hunted in autumn and winter in the years 2015 and 2016 was assessed. Most animals were post-rut and most often had multiple ovulations. However, in early autumn 2015, 60% of the females had no CL. Therefore, they did not participate in mating at the turn of July/August. Those that did ovulate were found to have one CL. In late autumn, 97% of the females were post-rut, mostly with twin ovulations. This confirmed the occurrence of a late autumn rut. This phenomenon had been suggested in studies but not confirmed. In contrast, almost 100% of roe deer ovulated in summer in 2016. It was hypothesized that the reason for the low mating activity of roe deer in the summer of 2015 was heat stress and limited food resources. The summer was exceptionally hot, with many days in July and August when temperatures exceeded 30 °C. The heat combined with low rainfall led to extreme drought. Meanwhile, July and August are the months of mating activity for roe deer. The late autumn rut allowed the roe deer—a monoestrous species—to limit the consequences of a decrease in mating activity or fertility during the hot summer. Global warming may affect roe deer reproduction, so climatic conditions should be considered in population studies, not only in terms of food availability.

Condition‐Dependent Female Aggression and Its Effects on Mating Success and Sexual Cannibalism in Jumping Spiders

ABSTRACTPre‐copulatory sexual cannibalism is an extreme form of aggression toward potential mates. In this study, we examined condition‐dependent female aggression and its effects on mating success and frequency of pre‐copulatory sexual cannibalism in the jumping spider Phidippus audax Hentz 1845. We examined two of the leading hypotheses of why sexual cannibalism may occur, (1) female mate choice and (2) adaptive female foraging. We separated 137 adult virgin female P. audax into three feeding treatments: (1) well‐fed spiders, (2) 14‐day food deprived, and (3) 28‐day food deprived. We recorded weight loss (14‐ and 28‐day treatments) and survival rates. We conducted mating trials to measure the proportion of non‐aggressive and aggressive male and female behaviors, male mating success, and pre‐copulatory sexual cannibalism. Females deprived of food had higher weight loss and lower survival rates than well‐fed females. In addition, food deprived female spiders exhibited higher proportions of aggressive behaviors and pre‐copulatory sexual cannibalism, and lower mating success compared to well‐fed spiders. We found that as male size increased females were less likely to cannibalize males, but we found no effect of male body condition on whether a male mated with or was cannibalized by a female. Our results are consistent with the adaptive foraging hypothesis and corroborates prior research on pre‐copulatory sexual cannibalism.

Effect on the physical field of the die during the backward extrusion process of magnesium alloy wheel

The eccentric placement of billets reduces the service life of the dies, and at the same time causes the scrapping of the wheel blanks. However, for axisymmetric forgings, eccentric placement is unavoidable. In this study, the mutual effects between the billet and the die during backward extrusion of magnesium (Mg) alloy wheels are analyzed by physical and numerical simulations, focusing on the effects on the physical field of the die. There were dangerous points in the design of the combined die structure and the lower mating surface of the female die and the bottom die were prone to stress concentration during the filling process of the Mg wheel, which led to the cracking of the die. The eccentric extrusion of the wheel resulted in a slope in the filling height of the rim, and it had a great effect on the physical field and microstructure distribution at the same time, which in turn affected the physical field distribution of the wheel die, resulting in uneven load distribution at the lower rim of the die and reducing the life of the combined die. The combined die structure optimization solution can process the female die into a curved surface along the fracture surface and at the same time process a hollow circular table to cooperate with the bottom die and the female die.

The Influence of Environmental Factors on Site Selection Augment Breeding Success in Honey Bees: An Insight of Honey Bee Genetic Resource Conservation.

Honey bee reproductive behavior involves a complicated mating system that embodies a number of factors, including environmental and human-induced factors. Controlled breeding in isolated mating stations is a prerequisite to maintain the genetic resources of honey bees through natural mating. The concept of controlled mating is a challenge in most beekeeping operations due to its low mating success rate. Therefore, a detailed investigation into the suitability of isolated mating stations is of interest. Thus, we bred two subspecies of honey bees (Apis cerana koreana and Apis mellifera L.) in isolated mating stations (island) from 2021 to 2023 and in an open breeding station in 2023. Our results demonstrate that the highest percentage of the mating success rate in isolated mating stations was recorded in the Wido Island, which had the highest percentage of bare land, coniferous forests, deciduous forests, fields, and mixed forests. The mating success rate was higher in the summer and spring for A. cerana and A. mellifera, respectively. The mating success rate was higher in open mating compared to controlled mating (Island) and did not vary between pure-breeding and cross-breeding lines. Our findings suggested that mating stations with mixed forest and fields are potential sites for the successful breeding of honey bees.

Estimation of genetic parameters for the implementation of selective breeding in commercial insect production

BackgroundThere is a burgeoning interest in using insects as a sustainable source of food and feed, particularly by capitalising on various waste materials and by-products that are typically considered of low value. Enhancing the commercial production of insects can be achieved through two main approaches: optimising environmental conditions and implementing selective breeding strategies. In order to successfully target desirable traits through selective breeding, having a thorough understanding of the genetic parameters pertaining to those traits is essential. In this study, a full-sib half-sib mating design was used to estimate variance components and heritabilities for larval size and survival at day seven of development, development time and survival from egg to adult, and to estimate correlations between these traits, within an outbred population of house flies (Musca domestica), using high-throughput phenotyping for data collection.ResultsThe results revealed low to intermediate heritabilities and positive genetic correlations between all traits except development time and survival to day seven of development and from egg to adulthood. Surprisingly, larval size at day seven exhibited a comparatively low heritability (0.10) in contrast to development time (0.25), a trait that is believed to have a stronger association with overall fitness. A decline in family numbers resulting from low mating success and high overall mortality reduced the amount of available data which resulted in large standard errors for the estimated parameters. Environmental factors made a substantial contribution to the phenotypic variation, which was overall high for all traits.ConclusionsThere is potential for genetic improvement in all studied traits and estimates of genetic correlations indicate a partly shared genetic architecture among the traits. All estimates have large standard errors. Implementing high-throughput phenotyping is imperative for the estimation of genetic parameters in fast developing insects, and facilitates age synchronisation, which is vital in a breeding population. In spite of endeavours to minimise non-genetic sources of variation, all traits demonstrated substantial influences from environmental components. This emphasises the necessity of thorough attention to the experimental design before breeding is initiated in insect populations.

No fitness effects of same-sex copulations in male red flour beetles.

Same-sex sexual behavior occurs in diverse animal taxa, yet its evolutionary maintenance is poorly understood as such behavior seems to be costly and does not directly increase reproductive success. We used male Tribolium castaneum beetles, which frequently engage in same-sex copulations, to test if same-sex sexual behavior influences future male mating behavior and reproductive success of males. Furthermore, we tested whether same-sex sexual behavior has benefits via indirect sperm translocation. We conducted a series of mating trials demonstrating that males exposed to same-sex behavior did not sire less offspring compared to control males that did not engage in same-sex behavior. This suggests that same-sex copulations did not lead to fitness costs in subsequent mating interactions. In addition, we found no evidence that indirect sperm translocation via an intermediate male occurs in T. castaneum. Taken together, these results imply that same-sex sexual behavior in males is associated with no costs in terms of lower mating rate and reduced siring success and does not seem to entail benefits. Moreover, our data conform to the hypothesis that sexual indiscrimination is prevalent in this species, which may explain the relatively high frequency of same-sex sexual behavior in T. castaneum.

Tympanal ears mediate male-male competition, courtship and mating success in Bicyclus anynana butterflies.

The presence of intra-specific acoustic communication in diurnal butterflies is not well established. Here, we examined the function of the tympanal ear (Vogel's organ, VO) in the seasonally polyphenic butterfly Bicyclus anynana in the context of sexual signalling. We investigated how the VO and the flanking enlarged veins, which are suggested sound resonance chambers, scale with wing size across sexes and seasonal forms, and how disruptions to the VO alter courtship behaviour and mating outcomes. We found that males have VOs similar in size to females despite having smaller wings, and dry season (DS) male cubital and anal veins do not scale with the wing size. This suggests that the VO plays an important role in males and that cubital and anal veins in DS males may be tuned to amplify specific sound frequencies. Behavioural assays performed with deafened and hearing males of different seasonal forms, in pair and triad settings, showed that deafened DS males, but not wet season males, experienced lower mating success relative to their hearing counterparts. Our study documents a novel function for the wing tympanal membrane in mediating courtship and mating outcomes in diurnal butterflies.

Evolution in Islands: contrasting morph frequencies in damselfly populations of the Balearic Islands

Abstract Colour polymorphism is an example of visible phenotypic variability that is often associated with ecological factors and may produce local adaptations. Small populations, particularly in islands, offer opportunities for evolutionary novelties, and are therefore of particular interest to the study of polymorphisms. Here we study the dynamics of female colour morphs in the damselfly Ischnura elegans in the Balearic Islands. We found that insular populations are small, show low density, low mating activity, and low androchrome frequency. Our surveys suggest that male harassment is a powerful force in the dynamics of this female-limited polymorphism, because high male densities result in lower presence of mature females around the water, where copulation takes place. Non-male-like (infuscans) females have higher mating frequency. Androchromes were rare (15%) in all populations, but the frequency of the two non-male like females (infuscans and aurantiaca) was reversed between islands, despite their geographical proximity. We found a possible novel morph, suggesting that insular conditions allow innovations. Fitness differences between the two non-male-like females of I. elegans are still understudied, because most previous research has concentrated on the maintenance of androchromes, and are therefore a priority for future research.

Detrimental impact of a heatwave on male reproductive behaviour and fertility

Understanding how heatwaves impact on different aspects of mating behaviour and fertility is getting increasingly important. In this context, laboratory fertility and mating experiments involving manipulation and exposure of insects to different thermal conditions are common procedures. To conduct such experiments practical methods such as dyes are needed for an easy, non-invasive discrimination of individuals. We report here a study measuring the effect of an extended heat stress applied to males on several parameters of mating behaviour and fertility of laboratory populations of Drosophila subobscura derived from two distinct European locations. We found highly detrimental effects of heatwave on mating behaviour—with longer (courtship and copulation) latencies and lower mating occurrence but no changes in mating duration—and fertility, with reduced fecundity and reproductive success. Furthermore, we also tested the efficacy of food dye as a marker for individual discrimination and mating occurrence. While food dye did not allow to infer the occurrence of a mating based on a transfer of coloration from male to female, it did not affect mating and fertility, attesting its utility has a method for discriminating individuals within mating experiments in the context of thermal studies. Importantly, despite the fact that the heatwave was only applied in males, we observed an impact on behaviour of females that mated with stressed males, by often refusing their nuptial feeding. This opens possibilities for further integrated research on the changes of female and male mating behaviour and fertility under different thermal scenarios.

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.

Why people face difficulties in attracting mates: An investigation of 17 probable predictors of involuntary singlehood

People living in contemporary post-industrial societies frequently find themselves being single without wanting so, and the current research aimed to understand the reasons why. In particular, we aimed to examine the effects of 17 probable predictors of involuntary singlehood on a sample of 1432 Greek-speaking participants. For women, we found that poor flirting capacity, poor sexual functioning, high choosiness, and low agreeableness were associated with higher probability to be involuntarily single than in a relationship or married. Moreover, shyness, agreeableness, sexual functioning, and choosiness had indirect effects. In addition, high choosiness was associated with more years being single. For men, poor flirting capacity, higher neuroticism, lower self-perceived mate value, lower self-esteem, and not having children from previous relationships were associated with higher probability to be involuntarily single than in an intimate relationship or married. Furthermore, conscientiousness, sexual functioning, self-perceived looks, and BMI had indirect effects. Additionally, lower mating effort, low self-perceived mate value, and poor flirting capacity were associated with more years being single.

Effects of Polyploidization on Locomotor and Flight Activity, and Body Size of Males in Japanese Bumblebee, Bombus ignitus

Polyploid animals are seen in the wild in only a few groups such as planaria, weevils, ants, wasps, and bees. The sex of bumblebees is determined by the single-locus complementary sex determination (sl-CSD) system resulting in females emerging from fertilized eggs and males (normal males, haploid) emerging from unfertilized eggs. However, diploid males (polyploids) emerged from fertilized eggs when the sex-determining locus become homozygous caused by inbreeding due to population contraction. To examine the effects of polyploidization on behavioral characteristics in bumblebee males, Bombus ignitus, haploid and diploid males were compared in locomotor activity, ease of staying inside the hive, and flight activity in a laboratory experiment. The results showed that diploid males had higher locomotor activity levels, were less likely to stay inside the hive, and had lower flight activity levels than haploid males. The reduced flight activity levels may lead to lower mating rates in the field. Furthermore, the body size of diploid males was smaller than that of haploid males. Diploid males of bumblebees have a low reproductive and produce diploid sperms to emerge sterile triploids, thus creating a considerable genetic load on the population. The behavioral and morphological characteristics of diploid males may unintentionally serve as a mechanism to prevent the emergence of sterile triploids.

A case study assessing the impact of mating frequency on the reproductive performance of the Hawaiian bobtail squid Euprymna scolopes

BackgroundThe symbiosis between the Hawaiian bobtail squid Euprymna scolopes and bacterium Vibrio fischeri serves as a model for investigating the molecular mechanisms that promote the initial formation of animal-bacterial symbioses. Research with this system frequently depends on freshly hatched E. scolopes, but the husbandry factors that promote hatchling production in a mariculture facility remain underreported. Here we report on the reproductive performance of E. scolopes in response to decreased mating frequency.ResultsOne animal cohort was maintained in a mariculture facility for 107 days, with females assigned to either a control group (mating once every 14 days) or an experimental group (mating once every 21 days). No differences between the groups were observed in survival, the number of egg clutches laid, or hatchling counts. Each group featured multiple females that were hyper-reproductive, i.e., they generated more than 8 egg clutches while in captivity. Examination of the distributions for daily hatchling counts of individual egg clutches revealed significant variation in the hatching patterns among clutches that was independent of mating frequency. Finally, an assessment of hatchling production showed that 93.5% of total hatchlings produced by the cohort were derived from egg clutches laid within the first 70 days.ConclusionsThese results suggest a lower mating frequency does not impede hatchling production. Furthermore, the variation in hatchling production among egg clutches provides new insight into the reproductive performance of E. scolopes as a lab animal for microbiology research.

Toward optimising reproductive output of Eristalis tenax (Diptera: Syrphidae) for commercial mass rearing systems

AbstractDeveloping mass rearing systems for the drone fly, Eristalis tenax, is a crucial step toward its use as a complementary commercial pollinator. To meet the timing of commercial needs for E. tenax, there is significant value to both predicting and managing reproductive output and development within the rearing protocol. To help achieve this, our study focuses on the laboratory manipulation of adult mating and the timing of the development of eggs in E. tenax. To stagger colony cohorts, egg rearing temperatures ranging from 12 to 30°C were found to be suitable for both successful egg development and hatching viability (97 to 28.3 h to first hatch, respectively). The mating window for E. tenax females was established to commence from 2 weeks post eclosion and reached 75 ± 11% mated at 7 weeks. Reproductive output over 12 weeks was assessed in separate cage manipulation trials: (1) varying the sex ratio with 20:40, 30:30 and 40:20 female and male flies respectively per cage and (2) varying the adult density per cage with 15:15, 30:30, 60:60 and 120:120 female and male flies per cage. Female percentage mated and egg cluster size, which averaged 200.6 ± 4.3 eggs per cluster, did not change between treatments in the sex ratio and density trials. Egg cluster output per female was significantly reduced for treatments across both trials, which had more than 30 females in a cage. A stocking rate of 15:15 produced 86% more eggs per female than expected, a percentage well above that of all other treatments. However, the highest stocking density produced the most eggs when assessed at a per cage level. Fly survival was significantly different between the sexes across both trials with males dying earlier in cages stocked with more females than males. Although the fly colonies were held at constant temperatures and light conditions for 6 months, we found evidence of endogenous overwintering behaviours among flies resulting in lower mating rates, egg hatching success and greater longevity among flies studied over winter.

The coevolutionary dynamics of cryptic female choice.

In contrast to sexual selection on traits that affect interactions between the sexes before mating, little theoretical research has focused on the coevolution of postmating traits via cryptic female choice (when females bias fertilization toward specific males). We used simulation models to ask (a) whether and, if so, how nondirectional cryptic female choice (female-by-male interactions in fertilization success) causes deviations from models that focus exclusively on male-mediated postmating processes, and (b) how the risk of sperm competition, the strength of cryptic female choice, and tradeoffs between sperm number and sperm traits interact to influence the coevolutionary dynamics between cryptic female choice and sperm traits. We found that incorporating cryptic female choice can result in males investing much less in their ejaculates than predicted by models with sperm competition only. We also found that cryptic female choice resulted in the evolution of genetic correlations between cryptic female choice and sperm traits, even when the strength of cryptic female choice was weak, and the risk of sperm competition was low. This suggests that cryptic female choice may be important even in systems with low multiple mating. These genetic correlations increased with the risk of sperm competition and as the strength of cryptic female choice increased. When the strength of cryptic female choice and risk of sperm competition was high, extreme codivergence of sperm traits and cryptic female choice preference occurred even when the sperm trait traded off with sperm number. We also found that male traits lagged behind the evolution of female traits; this lag decreased with increasing strength of cryptic female choice and risk of sperm competition. Overall, our results suggest that cryptic female choice deserves more attention theoretically and may be driving trait evolution in ways just beginning to be explored.

How to be a fig nematode

Fig (Moraceae: Ficus) species host vast communities of organisms that are bound together by complicated ecological networks that have influenced community structure and dynamics over evolutionary timescales. Much attention has been paid to the mutualism between figs and their specialized pollinating fig wasps, as well as with often antagonistic non-pollinating fig wasps. Equally ubiquitous to fig systems, but much less understood are the multitude of nematode groups that have independently evolved obligate associations with pollinating fig wasps and proliferate inside fig syconia. In this review we describe what is currently known (and unknown) about these numerous and increasingly studied nematode taxa and how they interact with the fig systems they inhabit. We identify the groups that are currently understood to associate with fig pollinators and outline their known species distributions and evolutionary history, where possible. Special attention is paid to the life history of these nematode groups, especially which features of nematode biology are generalizable across groups and what idiosyncratic peculiarities exist within individual genera. We outline key biological features including host choice, dispersal, disembarkation, diet, mating, and proliferation within figs. We address biological conundrums that have been raised following observational work such as, why do nematodes sometimes infect the wrong host? What adaptations were required for nematodes to successfully adapt and coexist with figs and their pollinators for millions of years? How do nematodes overcome the constraints of low mating group size? Finally, we outline key considerations, gaps in the knowledge, and limitations to expand this field forward towards promising areas of future research. Through better understanding of fig nematodes, we stand to not only know more about Ficus communities, but also more about the evolution and maintenance of interspecific interactions, development, adaptation, and co-evolution in general.

Survive the north: transplantation for conservation of mangrove forests requires consideration of influences of low temperature, mating system and their joint effects on effective size of the reforested populations

Mangrove forests, which occur in the intertidal regions of tropical and sub-tropical zones, have high ecological and economic values. They have rapidly reduced over the past decades due to various reasons. Reforestation is a common strategy for the conservation of mangroves, but information on the renewal capacity and viability of these artificial mangrove populations is still lacking. Here, we estimated the effective population size (NE) of an artificial population of Kandelia obovata (Rhizophoraceae) and explored the effects of intrinsic and extrinsic factors on changes in NE to evaluate population viability and develop appropriate management strategies for mangrove forests. This population consisted of three ecologically and genetically differentiated groups that had experienced a major low-temperature event during the winter of 2015–2016 and varied in cold resistance. We first detected population bottlenecks and estimated contemporary values of NE for different groups using microsatellite data. Next, we performed paternity analyses for seedlings and propagules to explore variations in the reproductive success of individuals within the three groups before and after the low-temperature event. Lastly, we simulated four scenarios to characterize the effects of low temperature, mating system, and variance in reproductive success on changes in NE in a hypothetical metapopulation based on empirical estimates. Our results show that groups with moderate or poor cold resistance experienced local bottlenecks, and shifts in effective breeders occurred following the low-temperature event, which indicates that low temperature has an effect on not only population size but also reproductive success. Furthermore, our simulations revealed that changes in NE are jointly affected by reproductive success, mating system, and environmental conditions. These findings enhance our understanding of the multiple factors that affect NE, and provide key information that will aid the reforestation and management of mangrove forests, especially when they are introduced to high-latitude areas.

Efficient approaches for nuclear transgene stacking in the unicellular green microalga Chlamydomonas reinhardtii

Genetic crossing is routinely applied to alter multigenic traits in the unicellular model green microalga Chlamydomonas reinhardtii (Chlamydomonas). However, efficient antibiotic resistance-based screening for the desired progenies is impossible through the conventional approach when two parental strains are harboring the same antibiotic marker. In this study, we describe a simplified and efficient genetic crossing method for transgene stacking and progeny testing with the desired traits in Chlamydomonas strains harboring the same antibiotic marker. Our hereby-described approach allowed for the successful generation of dual transgene-expressing strains after crossing different mating type transformants harboring the same marker gene. Moreover, we employed a polyethylene glycol (PEG)-mediated protoplast fusion approach as an alternative method to perform transgene stacking in strains harboring the antibiotic markers but with low mating efficiency or mating inability. Using our optimized method, we successfully generated cells expressing several transgenes regardless of their mating efficiency. These methods could be potentially applicable and useful to other unicellular microalgal species.

Are There Edge Effects on the Genetic Diversity of the Trap-Jaw Ant Odontomachus chelifer (Formicidae: Ponerinae) in a Neotropical Savanna Fragment? A First Assessment.

Habitat fragmentation is considered an important threat to biodiversity, increasing species exposure to edge effects. The Brazilian Cerrado savanna is considered a biodiversity hotspot and has been converted to small, isolated fragments due to human activities. Ant communities and colony survivorship are known to be affected by edge effects in Cerrado, but to date there is no information on the genetic diversity of ant colonies at the edge of fragmented areas. Here, we investigate if colony genetic diversity and structure of Odontomachus chelifer (Latreille) ants (Hymenoptera: Formicidae) are subject to edge effects in a Cerrado reserve in southeast Brazil. Using microsatellites, we evaluated the number of breeders (queens and males) and the genetic diversity in O. chelifer colonies located in the interior versus edge of a Cerrado fragment. All O. chelifer nests had multiple queens, which presented a low mating frequency. The number of breeders and most estimates of genetic diversity did not differ between colonies at the edge versus interior of the fragment. Genetic structure was not influenced by nest location as well. However, we detected a small and positive increase in the observed heterozygosity in colonies located at fragment edges. High heterozygosity is thought to be particularly important in fast-changing environments, such as edges, providing an advantage for genetic diversity. Further investigation is needed to assess in greater detail how habitat loss affects O. chelifer biology. Our study is a first step toward elucidating edge effects on genetic diversity of ant colonies, a topic still poorly explored in tropical environments.

Spatial differences in female lobster mating success and population characteristics in southern Massachusetts

The Southern New England stock of American lobster Homarus americanus is currently severely depleted and experiencing recruitment failure, potentially resulting from increased larval or juvenile mortality, decreased larval production, or both. We examined one aspect of larval production, female mating success, in 2 regions of Buzzards Bay, Massachusetts. The inner Bay areas are typically male-dominated, and the deeper regions at the mouth of the Bay have higher proportions of females. These locations were specifically selected to test our primary hypothesis that female-skewed sex ratios would decrease female mating success. Using a non-invasive method to detect ejaculates stored within females’ seminal receptacles, mating success was determined for 3851 females. Contrary to our initial hypothesis, mating success was higher in the outer areas where the sex ratio was female-skewed. We then explored 2 alternative explanations for this spatial pattern in mating success. First, using the ratio of abdominal width to carapace length (ABD:CL) to approximate maturity stage, a large proportion of females from the inner Bay appeared to be immature or primiparous, while females from the outer regions (with a larger ABD:CL ratio) were likely multiparous. Thus, lower mating activity inside Buzzards Bay corresponded with a higher proportion of immature or newly matured females for any given size. Second, low densities of lobsters inside Buzzards Bay may have resulted in a mate-finding Allee effect, leaving some mature females unmated. These 2 alternative explanations for the spatial pattern in mating success are not mutually exclusive; both may be impacting female mating success in the region.