Mating Events Research Articles

Optimising the conservation of genetic diversity of the last remaining population of a critically endangered shrub.

An understanding of genetic diversity and the population genetic processes that impact future population viability is vital for the management and recovery of declining populations of threatened species. Styphelia longissima (Ericaceae) is a critically endangered shrub, restricted to a single fragmented population near Eneabba, 250 km north of Perth, Western Australia. For this population, we sought to characterize population genetic variation and its spatial structure, and aspects of the mating portfolio, from which strategies that optimize the conservation of this diversity are identified. A comprehensive survey was carried out and 220 adults, and 106 seedlings from 14 maternal plants, were genotyped using 13 microsatellite markers. Levels of genetic variation and its spatial structure were assessed, and mating system parameters were estimated. Paternity was assigned to the offspring of a subsection of plants, which allowed for the calculation of realized pollen dispersal. Allelic richness and levels of expected heterozygosity were higher than predicted for a small isolated population. Spatial autocorrelation analysis identified fine-scale genetic structure at a scale of 20 m, but no genetic structure was found at larger scales. Mean outcrossing rate (tm = 0.66) reflects self-compatibility and a mixed-mating system. Multiple paternity was low, where 61 % of maternal siblings shared the same sire. Realized pollen dispersal was highly restricted, with 95 % of outcrossing events occurring at 7 m or less, and a mean pollen dispersal distance of 3.8 m. Nearest-neighbour matings were common (55 % of all outcross events), and 97 % of mating events were between the three nearest-neighbours. This study has provided critical baseline data on genetic diversity, mating system and pollen dispersal for future monitoring of S. longissima. Broadly applicable conservation strategies such as implementing a genetic monitoring plan, diluting spatial genetic structure in the natural population, genetically optimizing ex situ collections and incorporating genetic knowledge into translocations will help to manage the future erosion of the high genetic variation detected.

Effect of advancing age on the reproductive performance of Japanese Thoroughbred broodmares.

ABSTRACTMany studies have reported that advancing age in broodmares has a negative impact on the reproductive performance of horses. However, although the ages at first and last mating vary among broodmares, it is unknown how this variation affects the correlation between age and reproductive performance in mares. Here, in order to examine the effects of the ages at first and last mating, we analyzed all recorded mating events for Thoroughbreds in Japan from 1997 to 2017. We found that the live foal birth rate of mares with a younger age at first mating indeed declined at an earlier age than those with an older age at first mating and that the number of years since the first mating also contributes to the decline in the birth rate. We also found that the live foal birth rate and mean earnings of the produced foals are much higher for mares with an older age at last mating compared with mares with a younger age at last mating. Our results should aid breeders in assessing the value of broodmares and designing breeding strategies.

Size Matters: First record of minimum male size at maturity and mating of free-ranging, endangered Indian Python Python molurus

Indian python Python molurus (Linnaeus, 1758) is one of the world’s giant snakes with maximum lengths measured six to eight meters. Nevertheless, information on the size at maturity of P. molurus is not available. On February 9, 2019, 12:56 pm, one female and two males were observed during the group mating in Moyar River Valley Landscape, Southern India. We report the first observation on smallest male measuring 198 cm total length, 172 cm snoutvent length and weighing 3.3.kg mated with a radio-tagged larger female. At the end of the mating event everted hemi penis were observed in the male pythons. Our observation on the mating and morphology details of P. molurus gives the first glimpse of juvenile the male maturity that representing the youngest known free-ranging matured male of this poorly studied species in its distribution range.

From pollen dispersal to plant diversification: genetic consequences of pollination mode.

Pollinators influence patterns of plant speciation, and one intuitive hypothesis is that pollinators affect rates of plant diversification through their effects on pollen dispersal. By specifying mating events and pollen flow across the landscape, distinct types of pollinators may cause different opportunities for allopatric speciation. This pollen dispersal-dependent speciation hypothesis predicts that pollination mode has effects on the spatial context of mating events that scale up to impact population structure and rates of species formation. Here I consider recent comparative studies, including genetic analyses of plant mating events, population structure and comparative phylogenetic analyses, to examine evidence for this model. These studies suggest that highly mobile pollinators conduct greater gene flow within and among populations, compared to less mobile pollinators. These differences influence patterns of population structure across the landscape. However, the effects of pollination mode on speciation rates is less predictable. In some contexts, the predicted effects of pollen dispersal are outweighed by other factors that govern speciation rates. A multiscale approach to examine effects of pollination mode on plant mating system, population structure and rates of diversification is key to determining the role of pollen dispersal on plant speciation for model clades.

Beaver dams are associated with enhanced amphibian diversity via lengthened hydroperiods and increased representation of slow‐developing species

Abstract Land managers are increasingly using beavers to restore hydrological function, provide wildlife habitat, and mitigate the effects of climate extremes on water balances and ecosystems. Although North American beavers (Castor canadensis) and Eurasian beavers (Castor fiber) both hold great potential for landscape‐scale benefits, more information about the interactions between beavers and wildlife is necessary to maximise the ecological benefits and minimise the social and ecological costs of beaver‐centred management. Beaver dams create large, deep pools with long hydroperiods, which could benefit aquatic and semi‐aquatic species, especially pond‐breeding amphibians, which breed in still and slow‐moving water. We studied the relationship between beaver dams and pond‐breeding amphibians in the southern Washington Cascade Range of the north‐west U.S.A. by surveying 29 beaver‐dammed and 20 undammed lentic sites in three mid‐elevation (560–1,010 m) spatial blocks. We found that mean amphibian species richness was 2.7 times higher in dammed sites than in undammed sites (2.4 vs. 0.9 species). This increase in species richness was driven by increased occupancy of slow‐developing species—red‐legged frogs (Rana aurora) and northwestern salamanders (Ambystoma gracile)—which were also more abundant at sites with dams. These two species were detected almost exclusively in beaver‐dammed sites, suggesting that some amphibians rely heavily on beaver‐dammed sites for successful reproduction in areas such as our study blocks where ponds and wetlands with long hydroperiods are otherwise scarce. Species with highly variable development periods—long‐toed salamanders (Ambystoma macrodactylum) and rough‐skinned newts (Taricha granulosa)—showed nonsignificant trends of higher site occupancy and, in the case of newts, higher number of mating events per hectare in dammed sites compared to undammed sites. Compared to undammed sites, dammed ponds were consistently deeper and had longer hydroperiods, consistent with beavers benefitting slow‐developing amphibians primarily by increasing the quality of lentic breeding habitat. We suggest that slow‐developing amphibians and some variable‐rate developers might benefit greatly from beaver restoration, especially in areas where climate change is predicted to reduce summertime water levels. Beavers could therefore be useful and important components of ecosystem‐based restoration, management, and climate adaption, especially in parts of their native ranges in North America or Eurasia predicted to undergo climatic drying.

Oviposition and refractory periods of the small water strider Microvelia horvathi (Heteroptera: Veliidae) after a single mating event

AbstractMultiple mating can be costly, but also beneficial for females. When the costs outweigh the benefits, mated females can be reluctant to remate for some time. Conversely, females will be likely to remate when they need to replenish sperm and/or receive nutrients contained in the accessory ejaculate substances. Water striders have been commonly used in mating studies as many show a vigorous struggle between the sexes. Generally, water strider females frequently mate with many males and lay many eggs during mating period. However, little is known about their oviposition and refractory periods after an initial mating event. In this study, we revealed that single‐mated females of the small water strider, Microvelia horvathi, could lay eggs for 40 days, reflecting approximately half of their potential oviposition periods. It suggested that M. horvathi females do not need to mate to replenish sperm for some time once they mate. Our results also showed that no female remated after 1 or 3 days of an initial mating event. The proportion of female remating increased with time after the initial mating, however, remating levels reached 26.7% even after 14 days. In this sense, any significant cost of mating outweighs the benefit, which might be one of the factors lowering their remating levels.

Effects of the dominance hierarchy on social interactions, cortisol level, HPG-axis activities and reproductive success in the golden cuttlefish Sepia esculenta

Dominance hierarchies are ubiquitous among group-living animals and markedly affect growth performance, metabolism, agonistic interactions, and stress-related physiology in vertebrates. However, few studies have investigated the effects of dominance hierarchies on the hypothalamic-pituitary-gonadal (HPG) axis and reproduction, especially in cephalopods. In this study, we employed an economically important cephalopod, the golden cuttlefish Sepia esculenta, as the target animal. Adopting the classical paired design, we first identified the formation of a dominance hierarchy and then investigated its effects on social interactions, cortisol level, HPG-axis activities (as indicated by the concentrations of gonadotrophin-releasing hormone (GnRH) and estradiol and the mRNA abundances of gnrh and estrogen receptor (er) genes), and reproductive success (determined by parentage analysis using polymorphic microsatellite loci) during the reproductive period. In general, dominant individuals presented significantly higher frequencies of aggressive behaviors (categorized as attack, chase, displace and threaten behaviors) and reproductive behaviors (designated mating events for males and spawning events for females), lower cortisol concentrations, higher HPG-axis activities, and higher reproductive success than subordinate individuals (all P < 0.05). Strong correlations between the frequencies of reproductive behaviors and reproductive success and among cortisol levels, HPG-axis activities and reproductive success were observed. However, no significant differences between dominant and subordinate individuals in body weight, dorsal mantle length or dorsal mantle width were detected. These results clearly show that dominance hierarchies occur in golden cuttlefish and provide the first evidence that such hierarchies significantly affect stress physiology, HPG-axis activities, and reproductive success in cephalopods. In the aquaculture and artificial reproduction of golden cuttlefish, we suggest that measures be adopted to decrease or eliminate harmful agonistic interactions and the subsequent physiological stress caused by dominance hierarchies to increase the reproductive efficiency.

Functional morphology of the sperm-containing chambers of the sea slug Okenia polycerelloides in the context of sexual selection.

Sea slugs are interesting models to study post-copulatory sexual selection in simultaneous hermaphrodites due to the enormous variation of their reproductive systems. However, the knowledge of the functional morphology of their reproductive system is limited to few species, and it is rarely discussed in the context of sexual selection theory. In this study, we investigated the functional morphology of the sperm-containing chambers (i.e., ampulla, seminal receptacle, and bursa copulatrix) of the reproductive system of Okenia polycerelloides (Ortea & Bouchet, 1983), based on light, confocal, and electron microscopy. Although the morphology of the ampulla is similar to other species, indicating that it is a site for autosperm storage, we found some sperm facing the ampullar epithelium, a feature commonly regarded as characteristic of the seminal receptacle of sea slugs. The seminal receptacle of O. polycerelloides showed secretory activity and contained sperm with distribution and orientation suggestive of stratification of allosperm from distinct mating events, a feature that would affect sperm competition. The bursa copulatrix had epithelial cells with secretory and absorptive characteristics, and contained degraded sperm and yolk granules within its lumen. Comparative analyses of the contents of each organ demonstrated that sperm digestion occurs in the bursa copulatrix and affects sperm heads first, changing their morphology from slender and curved to shorter and ellipsoid before complete lysis. Although digestion and absorption of surplus sperm are currently the main hypothesized functions for the bursa copulatrix, its role in cryptic female choice should not be ruled out. The close structural connection between the seminal receptacle and bursa copulatrix, as well as their muscular walls, would enable control over the fate of the sperm received in each mating event, that is, storage or digestion.

Introduction to “Reproduction: The Female Perspective from an Integrative and Comparative Framework”

SynopsisThis compendium is from a symposium about reproductive biology from the female perspective, but what do we mean by the female perspective? Most obviously, since all of our speakers, and most of our contributors, are female, one meaning is that the female perspective is the view of female scientists. Our diverse contributors are from a spectrum of academic ranks (post-docs to chaired professors) and study a range of animal taxa from insects to mammals. More importantly, we want to examine reproductive biology from the perspective of female organisms themselves. What happens when we examine social behavior, physiology, or ecology strictly from the viewpoint of females? In many cases, the female-centric perspective will alter our prior interpretations. For example, with deoxyribonucleic acid fingerprinting, differences between genetic and behavioral mating-systems became obvious. The scientific community came to realize that assessing parentage is the definitive way to categorize mating systems since using male-mating strategies resulted in flawed conclusions; in fact, the female selection of which sperm is involved in conception is more important in determining parentage than mating events per se. Perhaps parentage systems rather than mating systems would be more appropriate. This difference in interpretation relative to methodology exemplifies how behavioral ecology might change if we examine systems from the female perspective; similar changes may occur for other fields. Another example comes from studies of whole-organism performance. Here, jumping, running, and swimming have been measured in males, usually with the deliberate removal of females and the major facet of female physiology, that is, reproduction. However, female biology may actually set the limits of performance given the need to carry extra weight and the extensive changes in body shape required for reproduction. Female performance is a valuable area for research. In fact, novel insights into metabolic ceilings arose from examining energetics, including metabolic rates, during lactation. In the symposium and the associated papers, our contributors explored the various ways in which a female-focused framework shifts our research conclusions and programs. As a way forward, we also include a table of sex-neutral terminology to replace terms that are currently androcentric or value-laden.

A novel method of quantifying sperm to determine the potential for sperm depletion in male American lobstersHomarus americanus(H. Milne Edwards, 1837) (Decapoda: Astacidea: Nephropidae)

AbstractSperm limitation is a concern for a number of heavily fished decapods; however, work to assess this concern is sometimes hampered by a lack of simple techniques to quantify sperm transferred during reproduction. Our primary goal was to determine if DNA measurements could be used to quantify the sperm content of spermatophores and thus facilitate investigations of sperm limitation in American lobsters (Homarus americanus H. Milne Edwards, 1837). This was achieved by measuring the amount of DNA in a sample and then calibrating those values by using flow cytometry to count the number of individual sperm present in the sample. Our results show that the DNA quantification technique provides a fast and accurate way to quantify sperm. We then demonstrated the utility of the method by using it to examine the rate at which males can produce sperm under simulated conditions of repeated mating events, a situation that might lead to a reduction in the number of sperm per spermatophore. While spermatophores obtained from male lobsters at three-day intervals varied substantially in the number of sperm they contained (range 427,090–5,028,996; mean 2,306,473), there was no clear decline in sperm count over time. These results suggest that male lobsters replenish their sperm supplies rapidly, and that sperm recharge rate is unlikely to be a factor that could lead to sperm limitation in American lobster populations.

Spatially explicit capture recapture density estimates: Robustness, accuracy and precision in a long-term study of jaguars (Panthera onca).

Camera trapping is the standard field method of monitoring cryptic, low-density mammal populations. Typically, researchers run camera surveys for 60 to 90 days and estimate density using closed population spatially explicit capture-recapture (SCR) models. The SCR models estimate density, capture probability (g0), and a scale parameter (σ) that reflects ranging behaviour. We used a year of camera data from 20 camera stations to estimate the density of male jaguars (Panthera onca) in the Cockscomb Basin Wildlife Sanctuary in Belize, using closed population SCR models. We subsampled the dataset into 276 90-day sessions and 186 180-day sessions. Estimated density fluctuated from 0.51 to 5.30 male jaguars / 100 km2 between the 90-day sessions, with comparatively robust and precise estimates for the 180-day sessions (0.73 to 3.75 male jaguars / 100 km2). We explain the variation in density estimates from the 90-day sessions in terms of temporal variation in social behaviour, specifically male competition and mating events during the three-month wet season. Density estimates from the 90-day sessions varied with σ, but not with the number of individuals detected, suggesting that variation in density was almost fully attributable to changes in estimated ranging behaviour. We found that the models overestimated σ when compared to the mean ranging distance derived from GPS tracking data from two collared individuals in the camera grid. Overestimation of σ when compared to GPS collar data was more pronounced for the 180-day sessions than the 90-day sessions. We conclude that one-off ('snap-shot') short-term, small-scale camera trap surveys do not sufficiently sample wide-ranging large carnivores. When using SCR models to estimate the density from these data, we caution against the use of poor sampling designs and/or misinterpretation of scope of inference. Although the density estimates from one-off, short-term, small-scale camera trap surveys may be statistically accurate within each short-term sampling period, the variation between density estimates from multiple sessions throughout the year illustrate that the estimates obtained should be carefully interpreted and extrapolated, because different factors, such as temporal stochasticity in behaviour of a few individuals, may have strong repercussions on density estimates. Because of temporal variation in behaviour, reliable density estimates will require larger samples of individuals and spatial recaptures than those presented in this study (mean +/- SD = 14.2 +/- 1.2 individuals, 37.7 +/- 4.7 spatial recaptures, N = 276 sessions), which are representative of, or higher than published sample sizes. To satisfy the need for larger samples, camera surveys will need to be more expansive with a higher density of stations. In the absence of this, we advocate longer sampling periods and subsampling through time as a means of understanding and describing stability or variation between density estimates.

Mitochondrial Genome Polymorphisms in the Human Pathogenic Fungus Cryptococcus neoformans.

The Cryptococcus complex consists of at least seven evolutionary divergent lineages and causes ∼200,000 fatal human infections each year worldwide. The dominant lineage is Cryptococcus neoformans which consists of three haploid clades VNI, VNII, and VNB, their haploid hybrids, and various diploids derived from intra- and inter-clade mating events. In this study, we analyzed the mitogenomes of 184 strains of C. neoformans. Our analyses revealed that all 184 mitogenomes contained the same 15 protein-coding genes in the same gene order. However, their mitogenome sizes varied between 24,740 and 31,327 bp, primarily due to differences in the number and size of mitochondrial introns. Twelve nucleotide sites within five mitochondrial genes were found to contain introns in at least one of the 184 strains, ranging from 2 to 7 introns within each mitogenome. The concatenated mitochondrial exon sequences of the 15 protein-coding genes and two rRNA genes showed that VNI, VNII, and VNB strains were separated into distinct clades or sub-clades, largely consistent with results based on nuclear genome SNPs. However, several novel findings were observed. First, one strain of the VNB clade contained mitogenome exon sequences identical to the main VNI mitogenome type but was distant to other VNB mitogenomes. Second, hybrids among clades VNI, VNII, and VNB identified based on their nuclear genome SNPs contained mitogenomes from different clades, with evidence of their mitogenomes inherited from either the MATa or the MATα parents. Third, the eight diploid VNB (C. neoformans) × VNIV (C. deneoformans) hybrids contained recombinant mitogenomes. Fourth, analyses of intron distribution and the paired exon–intron phylogenies for each of the 12 exon–intron pairs suggested frequent gains and losses of mitochondrial introns during the evolution of C. neoformans. The combined mitogenome exon-based phylogeny and intron distributions suggested that clades VNI, VNII and VNB could be further divided into sub-clades. Together, our results revealed a dynamic evolution of mitochondrial genomes in this important human fungal pathogen.

Reproductive behavior drives female space use in a sedentary Neotropical frog.

Longer-range movements of anuran amphibians such as mass migrations and habitat invasion have received a lot of attention, but fine-scale spatial behavior remains largely understudied. This gap is especially striking for species that show long-term site fidelity and display their whole behavioral repertoire in a small area. Studying fine-scale movement with conventional capture-mark-recapture techniques is difficult in inconspicuous amphibians: individuals are hard to find, repeated captures might affect their behavior and the number of data points is too low to allow a detailed interpretation of individual space use and time budgeting. In this study, we overcame these limitations by equipping females of the Brilliant-Thighed Poison Frog (Allobates femoralis) with a tag allowing frequent monitoring of their location and behavior. Neotropical poison frogs are well known for their complex behavior and diverse reproductive and parental care strategies. Although the ecology and behavior of the polygamous leaf-litter frog Allobates femoralis is well studied, little is known about the fine-scale space use of the non-territorial females who do not engage in acoustic and visual displays. We tracked 17 females for 6 to 17 days using a harmonic direction finder to provide the first precise analysis of female space use in this species. Females moved on average 1 m per hour and the fastest movement, over 20 m per hour, was related to a subsequent mating event. Traveled distances and activity patterns on days of courtship and mating differed considerably from days without reproduction. Frogs moved more on days with lower temperature and more precipitation, but mating seemed to be the main trigger for female movement. We observed 21 courtships of 12 tagged females. For seven females, we observed two consecutive mating events. Estimated home ranges after 14 days varied considerably between individuals and courtship and mating associated space use made up for ∼30% of the home range. Allobates femoralis females spent large parts of their time in one to three small centers of use. Females did not adjust their time or space use to the density of males in their surroundings and did not show wide-ranging exploratory behavior. Our study demonstrates how tracking combined with detailed behavioral observations can reveal the patterns and drivers of fine-scale spatial behavior in sedentary species.

Siring success in kangaroos: size matters for those in the right place at the right time

Abstract In polygynous species, male reproductive success is predicted to be monopolized by a few dominant males. This prediction is often not supported, suggesting that ecological and alternative mating tactics influence siring success. The spatiotemporal distribution of individuals and the number of males competing for each receptive female are often overlooked because they are difficult to monitor in wild animals. We examined how spatial overlap of female–male pairs, the time spent by a male on the breeding site, number of competitors, and morphological traits influence siring probability in eastern gray kangaroos (Macropus giganteus). We compared home range overlap for 12 208 dam–male pairs and 295 known dam–sire pairs to define local competitive groups and to estimate every male’s opportunity to sire the young of each female. We compared models considering morphological traits relative to the entire population or to local competitive groups. Including local competition improved model performance because it estimated the intensity of competition and compared each male’s morphological traits to those of its competitive group. Regardless of size, males can increase their probability to sire a young by increasing their mating opportunity relative to the mother. We underline the importance of considering spatial structure to assess the intensity of competition in species where males cannot equally access all females in a population. The estimation of mating opportunity and intensity of local competition improves our understanding of how morphological traits affect siring success when each mating event involves a different set of competing males, a characteristic of most wild species.

Choosing mates wisely

Hybridization Hybridization between species has long been seen as an accidental contributor to evolution in some cases and as a dead end in others. New evidence is emerging, however, that hybridization may have played important, and nonrandom, roles in adaptation. Chen and Pfennig describe just such a case where female Plains spadefoot toads preferentially choose males from another toad species, the Mexican spadefoot, as mates, but only under certain environmental conditions (see the Perspective by Zuk). The offspring of this preferred hybrid mating event have higher fitness than nonhybrids in the same environment. Thus, not only do hybrids have an advantage, but females of one species are exerting a selective influence on the other species. Science , this issue p. [1377][1]; see also p. [1304][2] [1]: /lookup/doi/10.1126/science.aaz5109 [2]: /lookup/doi/10.1126/science.abb2398

Modeling the impacts of a simple meiotic gene drive on small, homeostatic populations.

Gene drives offer unprecedented control over the fate of natural ecosystems by leveraging non-Mendelian inheritance mechanisms to proliferate synthetic genes across wild populations. However, these benefits are offset by a need to avoid the potentially disastrous consequences of unintended ecological interactions. The efficacy of many gene-editing drives has been brought into question due to predictions that they will inevitably be thwarted by the emergence of drive-resistant mutations, but these predictions derive largely from models of large or infinite populations that cannot be driven to extinction faster than mutations can fixate. To address this issue, we characterize the impact of a simple, meiotic gene drive on a small, homeostatic population whose genotypic composition may vary due to the stochasticity inherent in natural mating events (e.g., partner choice, number of offspring) or the genetic inheritance process (e.g., mutation rate, gene drive fitness). To determine whether the ultimate genotypic fate of such a population is sensitive to such stochastic fluctuations, we compare the results of two dynamical models: a deterministic model that attempts to predict how the genetics of an average population evolve over successive generations, and an agent-based model that examines how stable these predictions are to fluctuations. We find that, even on average, our stochastic model makes qualitatively distinct predictions from those of the deterministic model, and we identify the source of these discrepancies as a dynamic instability that arises at short times, when genetic diversity is maximized as a consequence of the gene drive's rapid proliferation. While we ultimately conclude that extinction can only beat out the fixation of drive-resistant mutations over a limited region of parameter space, the reason for this is more complex than previously understood, which could open new avenues for engineered gene drives to circumvent this weakness.

The effect of mating on the sex pheromone system of the yellow mealworm beetle, Tenebrio molitor L. (Coleoptera: Tenebrionidae)

The mating behavior of the yellow mealworm beetle (Tenebrio molitor L.) is mediated by several pheromones, including a female-produced male attractant, (R)-(+)-4-methylnonanol (4-MNol); a male-produced female attractant, (Z)-3-dodecenyl acetate; a male-produced anti-aphrodisiac; and at least one copulation pheromone. The objective of this study was to investigate the effect of mating on this complicated pheromone system. Glass rod bioassays were conducted to determine the response of virgin adult male beetles to the surface extracts of adult female beetles, prepared from virgin females, females allowed to mate once (extracted 0, 0.5, 1 or 2 h after mating), and females allowed to mate over an extended period of time (0, 1, or 21 h). Mating caused an immediate but temporary inhibition of the ability of the female extracts (FEs) to attract the males. This wore off relatively quickly, since FEs prepared 0.5–1 h after mating were as attractive as the virgin FE. Two hours after mating a second inhibition of attraction was observed, which was likely due to a drop in the titer of 4-MNol. Gas chromatographic analyses confirmed that the level of 4-MNol dropped after mating, from ∼40 ng per virgin female to below our levels of detection in mated females. A single mating event, or the 1 h extended mating, did not significantly affect the ability of the FEs to elicit copulation behavior (CB) from the males. However, FEs prepared after an extended mating (21 h) were significantly less able to attract males and to elicit CB. This is the first in depth study of the effect of a single and extended mating on sex pheromone production by a coleopteran species. In the long term, a greater understanding of the regulation of pheromone production could be useful for the manipulation of pest populations.

Adaptive genetic management: assessing the benefits of translocations

Declines in abundance and genetic diversity in plant and animal populations are increasingly of conservation concern. Genetic rescue, or the supplementation of declining populations with individuals from genetically different sources, may aid in demographic and genetic recovery efforts, assuming introduced individuals successfully reproduce following translocation. However, the relative reproductive contributions of resident and translocated individuals are not frequently evaluated. In the northern lower peninsula of Michigan, USA, fourteen brown trout (Salmo trutta) from each of three different tributaries were introduced into a research stream (Hunt Creek) to supplement a small, isolated resident brown trout population. Mean expected heterozygosity and mean allelic richness differed between the three translocated populations compared to residents. Additionally, inter-population variance in allele frequency (FST) between resident and translocated populations ranged from 0.024 to 0.098. Using genetic parentage assignments, we documented that translocated and resident brown trout did interbreed; however, intra-population mating events were more common. Simulations indicated that increases in genetic diversity among age-1 offspring were the result of reproduction by translocated adults, as genetic variation was significantly above levels expected by reproduction among residents alone (p < 0.001). To achieve management goals for genetic rescue programs, managers would be advised to conduct simulations and hypothesis testing in addition to collection of empirical genetic data to evaluate introduction outcomes.

Female size and pre-copulatory sexual selection by males of intertidal snail (Littorina saxatilis)

Littorina saxatilis, the rough periwinkle, is highly promiscuous and polyandrous; female L. saxatilis snails rarely reject male advances. Sexual selection by males has been observed in this species. Sexual selection is one of the driving forces of evolution and may be a significant contributor to partial reproductive isolation between two ecotypes of L. saxatilis. Male sexual selection based on female size was investigated for wave-exposed crab ecotype snails in this study. Males and females were measured and placed in mating arenas. Males were presented with a choice of a smaller or larger female relative to themselves. Mating frequency and duration was recorded. A total of 19 successful trials were performed. A significantly higher mating frequency (p&lt;0.005) was associated with larger females, indicating that males exhibit strong pre-copulatory sexual selection. Mating duration was significantly longer for larger female mating events (p&lt;0.05) but was also equally determined by male size (p&lt;0.05) as larger males tended to mate for longer. These results indicate that a strong sexual selection by males exists for L. saxatilis, in which larger females are preferred. This behavior may be a response to perceived fecundity of females, and/or may be a product of selection against hybrids.

Sociosexual behavioral patterns involving nulliparous female orangutans (Pongo sp.) reflect unique challenges during the adolescent period.

The primate adolescent period is characterized by a series of changes in physiology, behavior, and social relationships. Orangutans have the slowest life history and the longest period of dependency of all primates. As members of a semisolitary species with high levels of sexual coercion, adolescent female orangutans face a unique combination of challenges when achieving independence from their mother. This study examined the mating behavior of adolescent female orangutans and compared it with that of adult females to assess whether mating behavior reflects distinct strategies at these different points in the life cycle. Data were collected in Gunung Palung National Park on the island of Borneo over 20 years. Mating events from adolescent (n = 19) and adult females (n = 26) were scored and compared. Adolescent female mating events had significantly higher mating scores (indicating more proceptivity) than those of adult females (β = 1.948, p = .001). Adolescent females also engaged in elaborate sociosexual interactions with different flanged males, behaviors that were never observed during mating events of adult females. These interactions involved characteristic behavior on the part of both the adolescent females and the flanged males. Given these findings and the documentation of similar accounts of adolescent female-flanged male mating from the island of Sumatra, we propose that adolescent female orangutans display distinctive behavioral repertoires throughout the genus Pongo which serves to overcome male ambivalence toward nulliparous females, establish familiarity, and evaluate coercive tendencies in flanged males. We suggest that these behavioral patterns are an integral part of female social development in a female philopatric, but highly dispersed species where consistent social support is absent after ranging independence is achieved.