Mating Season Research Articles

Season and reproductive activity influence cortisol levels in the Malagasy primate Lepilemur edwardsi.

Throughout the year, wild animals are exposed to a variety of challenges such as changing environmental conditions and reproductive activity. These challenges may affect their stress hormone levels for varying durations and in varying intensities and impacts. Measurements of the glucocorticoid hormone cortisol in the hair of mammals are considered a good biomarker for measuring physiological stress and are increasingly used to evaluate stress hormone levels of wild animals. Here, we examined the influence of season, reproductive activity, sex, as well as body condition on hair cortisol concentrations (HCC) in Lepilemur edwardsi, a small Malagasy primate species. L. edwardsi lives in the seasonal dry forests of western Madagascar, which are characterized by a strongly changing resource availability throughout the year. We hypothesized that these seasonal changes of resource availability and additionally the reproductive cycle of this species would influence HCC of L. edwardsi. Results revealed that hair cortisol concentration of females did not change seasonally or with the reproductive cycle. However, we found a significant increase of hair cortisol levels in males from the early wet season during the early dry season (mating season). This increase is presumably due to changed behavior during the mating season, as sportive lemurs travel more and show aggressive behavior during this time of the year. This behavior is energy-costly and stressful, and presumably leads to elevated HCC. As elevated cortisol levels may impair immune function, L. edwardsi males might also be more susceptible to parasites and diseases, which is unfavorable in particular during a period of low resource availability (dry season).

An Approach for Investigating Sexual Maturity in Wild Boar Males: Testosterone and 17β-Estradiol Analysis.

Simple SummaryWild boar numbers have increased constantly over the last three decades, as have their related conflicts with modern society. For this reason, wild boars have become a frequent topic of discussion. This article describes and explains the concentrations of the two main sexual steroids, testosterone and estradiol, as well as our effort to define threshold levels to recognize the sexual maturation of wild boar males and differentiate between immature and adult boars. With the help of additional analyses on spermatozoa and morphological data, it was shown that prepubertal boars at 8 months of age could be clearly differentiated from postpubertal boars, showing significantly lower concentrations of hormones. Wild boar males older than 11 months of age, in contrast, presented hormonal values like adults. Before the completion of their first year, wild boars are physiologically able to reproduce and may take part in reproduction. The high hormonal concentrations at the end of the breeding season suggest that the mating period could last longer than usually supposed, shifting farrowing into the summer.Analyses of sexual steroid hormones in wild boars are rarely described. Testosterone (T) and 17β-estradiol (E2) concentrations are useful to recognize sexual maturation. As threshold values for this species are unknown, additional parameters are required. A total of 127 blood samples from wild boar males were collected to measure T and E2. Age and weight were recorded. Thirty-one epididymides were sampled too. Males were sorted into pre-and postpubertal groups based on the absence/presence of spermatozoa in epididymides and on morphological data following previous results. Forty-four males were prepubertal: the mean age and weight were 10 months and 23 kg, respectively. They showed no spermatozoa. The mean concentrations of T and E2 were 1.2 ± 1.2 ng/mL and 39.7 ± 120.3 pg/mL, respectively. Sixty-six males were postpubertal, twenty-nine of which presented spermatozoa. Their mean concentration of T was 7.6 ± 6.3 ng/mL and E2 was 664.3 ± 250.4 pg/mL. Seventeen samples could not be defined; the hormone concentrations between the two groups suggested a transitional phase consistent with puberty. Wild boars before 12 months of age had high hormone levels like older boars, indicating that they could attempt to reproduce. Hormones at the end of the mating season (January) were high so that reproduction could occur thereafter, shifting farrowing from spring to summer.

Fission-fusion dynamics in a wild group of Japanese macaques (Macaca fuscata) on Kinkazan Island caused by the repeated separation of an alpha male being followed by females.

The spatiotemporal cohesion of a group is an essential element of primate society. It is thus important to clarify the factors that influence the extent of variation in spatial cohesion and individual membership in a group over time, known as fission-fusion dynamics. During the mating season of 2019, the alpha male (TY) in a wild group of Japanese macaques on Kinkazan Island repeatedly disappeared from the group, and we observed fission-fusion dynamics caused by his movement. The group seemed to have split when TY left the group or its home range, and females who followed him had the most affiliative relationships with TY or were the relatives of those females. Although TY disappeared from the group in the post-mating season, these fission-fusion dynamics only occurred during the mating season probably because females had a more substantial need for protection against aggression from the other males during the mating season. These results indicate that, although rare, fission-fusion dynamics based on affiliative relationships between males and females can occur with the separation of alpha males from the group. More studies in other populations are needed to clarify the influence of group males on the spatial cohesion of groups.

The Investigation of the Effects of Different Seminal Plasma Heating Processes on Short Term Storage of the Akkaraman Kangal Ram Sperm

Bu araştırma, koç spermasında bulunan seminal plazmanın, spermler üzerindeki etkisini incelemek ve reprodüktif açıdan kullanımını değerlendirmek amacıyla yapılmıştır. Araştırma için, 24-36 aylık yaşlarda, 8 adet ergin koçtan alınan spermalar kullanılmıştır. Spermalar çiftleşme mevsimi dışında olan koçlardan elektro ejekülatör yardımı ile alınmıştır. Spermalar seminal plazmalarından santrifüj edilerek ayrılıp, 60 ⁰C'lik ve 80 ⁰C'lik 10 dakikalık ısıtma işleminden geçirilmiştir. 60 ⁰C'lik ve 80 ⁰C'lik gruplar ile hiçbir işlem uygulanmayan kontrol gurubu 4 ⁰C'lik ortamda bekletilmeye alınmıştır. Ortalama 8 saatte bir kontrol edilen 3 grupta gözlenen motilite, canlı/ölü oranı ve spermatazoon anormallikleri kaydedilmiştir. Araştırmadan elde edilen sonuçlara göre, kontrol grubu ve deneme grupları karşılaştırıldığında en uzun süre canlılık ve motilitenin 80 ⁰C'lik grup olduğu belirlenmiştir. Bu sonuca göre spermanın seminal plazmasının içerisinde bulunan çeşitli proteinlerin ve enzimlerin denatürasyonu ile yaşam süresinin, normal spermatazoon oranının ve motilitenin doğru orantılı bir şekilde arttığını kanıtlar niteliktedir.

The combination of melatonin implants and prostaglandin F2α improves lamb production in a late-autumn mating season

To determine the effect of the combination of melatonin implants and prostaglandin (PG) F2α on reproductive performance in the late breeding season (Dec at the northern hemisphere), 500 Lacaune ewes were divided into four groups. On day 0 (7 Nov), 150 ewes were treated with a melatonin (M) implant. From that group, 64 ewes (M + 1PGF group) were injected with 10-mg prostaglandin (PG) F2α 34 d after melatonin implantation (11 Dec). The remaining 86 ewes (M group) were treated with melatonin, only. Another group of 75 ewes (2PGF group) was treated with double injection of PGF2α (9 days between the first and second application) (2 and 11 Dec), and 75 non-treated ewes (C group) were the control group. The remaining 200 ewes of the flock were not considered in the study. Rams (n = 23) were introduced on 11 Dec. The percentage of prolificacy, lambing and fecundity rates were calculated. Lambing rate did not differ among groups (M: 79%; M + 1PGF: 78%; 2PGF: 69%; C: 71%). The M + 1PGF group had a higher % of prolificacy than the 2PGF group (P < 0.10) and the C group (P = 0.06) (M: 1.65 ± 0.07; M + 1PGF: 1.74 ± 0.09; 2PGF: 1.54 ± 0.08; C: 1.54 ± 0.07 lambs/lambing) (P < 0.05), and a higher fecundity than the 2PGF group (P < 0.05) and the C group (P < 0.10) (M: 1.30 ± 0.09; M + 1PGF: 1.36 ± 0.11; 2PGF: 1.07 ± 0.10; C: 1.08 ± 0.09 lambs/ewe). Ewes implanted with melatonin had significantly higher prolificacy (1.69 ± 0.06 lambs/lambing) (P < 0.05) and fecundity (1.33 ± 0.07 lambs/ewe) (P = 0.01) than did ewes that did not receive melatonin (1.54 ± 0.04 and 1.08 ± 0.04, resp.). In conclusion, melatonin implants increased the number of lambs born per ewe in a late-autumn mating season, and the effect was greatest if it was given in combination with PGF2α administration at ram introduction.

Ethogram of Ghost Bat (Macroderma gigas) Behaviours and Associated Social Vocalisations

The ghost bat (Macroderma gigas) is a carnivorous species of bat endemic to northern Australia that roosts in colonies of up to 1,500 individuals. The ghost bat produces a number of social vocalisations, but little is known about the species' behaviour and what role social vocalisations play in interactions between conspecifics. The aim of this study was to construct an ethogram of ghost bat behaviours and to determine the associations between behaviours and social vocalisations. To achieve our aims, we filmed the behaviour of a captive ghost bat colony (one male, five females) using four trail cameras installed within the enclosure over a six-week period, coinciding with the estimated mating season. Video recordings were examined by eye, and solitary and social behaviours were catalogued into distinct behavioural units (e.g. hang-alert, chew, wing-groom, etc.) along with social context and associated social vocalisations, if applicable. To assess the associations between behavioural interactions and social vocalisation types, we combined each of the catalogued social behavioural units into six behavioural classes (eating, grooming, mating, huddling, flying, and fighting) and used generalised linear models to determine which social behavioural classes significantly predicted the production of each vocalisation. There was a strong association between flight behaviour by a member of the colony and the production of the ‘Chirp-trill’ vocalisation by the male member of the colony, suggesting a territorial or mate attraction function. There was also a strong association between fighting behaviour and the production of the ‘Squabble’, ‘Rasp’ and ‘Grumble’ vocalisations, with the Squabble and Rasp likely representing levels of agonistic vocalisations produced by aggressive bats during altercations. The Grumble, on the other hand, was produced by the target of the aggressor and so may function as an appeasement call. The ethogram with its associated social vocalisations provides a formal basis for future behavioural studies in this species and can serve as a template for such studies in other echolocating bats. Our study revealed an unexpected degree of complexity in the behaviour and associated vocalisations in this species and highlights the need for studies of this kind in other bats.

Inferring Social Interactions Over a Lifespan from Space-Use Patterns in a Tropical Agamid

Establishing the social system of a population is key to studying the evolution of behaviors. However, observations of social interactions needed to infer social systems are difficult to obtain for many species. An alternative way of understanding social systems is by studying the space-use pattern of individuals. Along with ecological factors, space use is largely governed by interactions among individuals: typically, competing individuals avoid each other, and individuals benefitting from each other share space. We investigated the social system, specifically the mating system, and the nature of intrasexual interactions between adults, by quantifying space-use patterns of individuals over their adult lifespan in the tropical Psammophilus dorsalis lizard. Males had substantially larger home ranges than females during the mating season, but not during the nonmating season. Female home ranges were small, and showed minimal overlap with other females throughout their lifespan, suggesting consistent intrasexual competition among females. In contrast, males showed minimal overlap with other males in the nonmating season but increased overlap in the mating season, suggesting that males resolve intrasexual competition through other means, like contests, during the mating season. Patterns of overlap between male and female home ranges in the mating season indicated a socially polygynous mating system. Our study provides an initial understanding of home-range patterns and associated inferences of within- and between-sex interactions across the lifespan of a tropical lizard, Psammophilus dorsalis. It highlights the insights into the social structure of a population gained from dispersion patterns of individuals.

Tutoring new song elements to male birds in the wild

Many vocalisations of songbirds are sexually selected and socially learnt behavioural traits that are subject to cultural evolution. For cultural inheritance, it is required that individuals imitate the song elements and build them into their repertoire, but little is known about how such learning mechanisms take place in natural populations of birds with large repertoire size. Using a Hungarian population of the collared flycatcher (Ficedula albicollis) as a model, we tested how often adult males can build new song elements (artificially modified or originated from distant populations) into their repertoire during mating season by using a playback approach. We predicted that when individuals incorporate new elements into their repertoire, the formerly unfamiliar elements from the playback songs would be recovered in the recorded songs of the focal males. We performed a teaching procedure with 26 males, in which we played back song sequences containing three artificially modified and three foreign syllables for each male. We recorded the song of the focal males twice a day for 2–6 days long. Then, we applied a thorough search based on a combined automatic and manual identification method to detect the tutorial syllables in the recorded songs. We found one foreign syllable type in the recordings from one male which indicates that male collared flycatchers may learn new syllable types in the courtship season. As our study has some limits, we highlight some general challenges concerning the use of playback approaches in the field for demonstrating the incidences of learning of particular song elements.

Seasonal Differences in Expression of Neuropeptide Y (NPY) in Visual Centers of Spotted Munia (Lonchura punctulata)

The visual perception of birds is an incredibly exciting subject of research. Birds have significantly higher visual acuity than most other animals, which helps them stay safe in flight and detect their prey. Understanding how the eyes send information to the brain for additional processing is crucial. The brain has sections (nuclei) that accept input from the retina. The key areas where information is processed are the hyperpallium apicale (HA), hippocampus (HP), optic tectum (TeO), nucleus rotundus (RoT), and the geniculatus lateralis ventralis (Glv); among these, the RoT is one of the most investigated nuclei for vision. This study looked at how the visual centers of non-photoperiodic songbirds (Spotted Munia) adapt in different life history stages by looking at NPY expression. We immunohistochemically quantified NPY expression in four different seasons, including pre-breeding (June), breeding (September), post-breeding (December), and regressed (March) in the brain of Spotted Munia. We evaluated changes in the expression levels of the peptide throughout the year, by determining the expression at four different periods throughout the year. Peptide expression levels were projected to fluctuate within photoperiod-induced seasons. It was discovered that the parts of the brain related to vision (RoT, HA, and HP) have a higher number of immunoreactive cells during their mating season, i.e., during the summer. The appearance of NPY, a non-photic marker, in brain areas linked with light perception, was fascinating. Indirectly, NPY aids avian reproduction in a variety of ways. These findings demonstrate the importance of these nuclei in the process of reproduction, as well as the involvement of NPY in the visual brain areas of Spotted Munia.

Romanian wild cherry genotypes (Prunus avium var. sylvestris Ser.) suitable for processing

This paper presents the important features of indigenous wild cherry genotypes suitable for processing. The research took place between 2017–2020, having ten Romanian wild cherry genotypes as study material. The harvesting maturity was recorded in the first decade of June for the early cultivar (G10) and decades two and three of June for the other studied genotypes, all of them with a middle season maturation. The number of days between the end of the flowering and the maturation was between 54 days (G10) and 66 days (G9). The average weight of the fruit and the equatorial diameter varied between 2.1 g and 13.80 mm for G4, respectively, and 5.5 g and 21.35 mm for G10. The proportion (%) between the pulp and waste (stone and peduncle) was measured as 81.95% pulp (G4) and 93.64% pulp (G10). The values of the soluble dry substance content were between 13.1–24.0 °Brix, the titratable acidity was between 0.48–1.16 mg malic acid/100 mL juice and the total content of the polyphenols was between 229.00–720.00 mg GAE/100 mL fresh juice. In terms of the bitter taste intensity, G10 has a weak intensity, G3, G7, G8 and G9 have an average intensity and G1, G3, G4, G5 and G6 have a high intensity.

Cytological characteristics of vaginal smears in ewes during the sexual cycle and during pregnancy

New criteria for cytological analysis of sheep vaginal swabs (cytovaginal examination) during sexual hunting, during the sexual cycle, after insemination and depending on the effectiveness of insemination have been developed. Cytological material was collected from the area of the upper vaginal vault using a sterile vaginal mirror, forceps and cotton gauze swab. Staining of brushstrokes was performed according to Gimza-Romanovsky. To improve the method of cytovaginal examination, the division of smear epitheliocytes into groups: functional, destroyed, non-nuclear and cells with nuclear pyknosis is proposed. In turn, among the functional cells it is advisable to distinguish between cells of the deep layers of the epithelium (basal-parabasal), intermediate and surface layer (superficial nuclear). The main types of ratio of particles of different groups and subgroups and their prognostic value in the mating season during sexual hunting are revealed. It was found that during the inhibition stage there is an intensive desquamation of the epithelial level, which was manifested by a 2.5-fold decrease in the number of basal / parabasal epitheliocytes and almost four - destroyed epitheliocytes. And already from the 13th day there is an increase in the cells of the functional level due to the proportion of cells of the deep and intermediate level. On the 18th day, the cellular composition of vaginal smears in sheep acquired characteristics characteristic of the stage of arousal. Thus, compared with the 6-8th day of the cycle, the number of destroyed epitheliocytes (p &lt;0.001) and naked nuclei (up to 8.3 ± 1.6) doubled again (up to 12.0 ± 0.7) against the background of a decrease in 4 times (to the initial level) of cells with pyknosis of the nucleus. The main cytological sign of pregnancy from the fourth day after insemination was a 2.7-fold increase in the number of destroyed cells and "naked" nuclei. In the following days of the study, except for the 13th day, this difference ranged from 1.3 to 4.3 times (8.3 ± 5.4 to 14.7 ± 3.6%), compared with the corresponding figures in unfertilized ewes. Also on the 13th day after the introduction of sperm in fertilized females there is a tendency to increase the number of deep layer cells and the acquisition on the 18th day of a probable difference in the ratio between the number of deep and surface cells - 5: 1. Changes in the distribution of deep and surface cell particles in unfertilized animals indicate the manifestation of the next stage of excitation and the predominance of epithelial cell differentiation. In contrast, in pregnant females, the proliferation of the deep layers of the vaginal epithelium increased. Key words: ewes, sexual cycle, sexual hunting, vaginal smear, cytological composition, pregnancy.

External nasal gland morphology of Eurycea bislineata (Amphibia, Urodela, Plethodontidae).

Plethodontid salamanders possess numerous courtship glands. Previous studies have shown that the glands are more prominent in male individuals than females, and often experience periods of atrophy and hypertrophy throughout the year that correlate to the nonmating and mating seasons, respectively. We sampled male and female Eurycea bislineata throughout the year to test the hypothesis that external nasal glands are courtship glands. External nasal glands are paired, branched tubular glands that extend from excretory ducts dorsal to the nares to terminal secretory units posterior to the eyes. We found that the glands hypertrophy and stain/react more intensely with histochemical procedures during the mating season. Hypertrophy of the glands is more pronounced in males, and seasonal variation in epithelial height of external nasal glands of males is significantly correlated to that of seasonal variation in mental gland epithelial height, a known courtship gland found in males, when compared throughout the year. This correlation was not as strong in females, confirming sexual dimorphism of external nasal glands in terms of seasonal variation. We found no ultrastructural differences between male and female external nasal glands. In all specimens, the glandular tubules were lined by a simple, columnar epithelium that was packed with secretory granules that often obscured other cytoplasmic contents.

The Design and Test of the Chassis of a Triangular Crawler-Type Ratooning Rice Harvester

Due to the high rolling rate of a regular crawler paddy harvester and the absence of mature first season harvester products of ratooning rice, combined with the planting mode and harvest requirements of ratooning rice, a triangular crawler ratooning rice harvester is specifically designed. The structure and steering principle of the triangular crawler chassis are described. The hydraulic system is simulated and analyzed by AMESim2020 (Guangzhou, China) to verify the rationality of its design; RecurDynV9R4 (Guangzhou, China) is used to simulate and analyze the field straight/turning situation of differential steering chassis and rear-axle steering chassis. The results show that the rear axle steering chassis has a smaller turning radius and lower rolling loss rate and the change of track tension is more stable during steering. The field test is conducted to verify the reliability of the simulation results. The field test shows that the rolling loss rate of the rear axle steering chassis is reduced by 27.9% compared with the differential steering chassis. The machine’s operating speed is 2.8 km/h, the minimum turning radius is 780 mm, and the straight rolling rate is 26.8%. The operating performance is stable, and the operational process is smooth. Compared with the existing conventional harvester, the linear rolling rate of the first harvest of ratooning rice is reduced by 26.1%, and the test results are consistent with the RecurDyn simulation results. The results are reliable, providing a reference for the theoretical research of the chassis of the later ratoon rice harvester.

Sheep and goat breeding

The beginnings of sheep and goat production go back to the dawn of human civilization. In the geographical areas where the first human civilizations began to develop, the domestication of sheep from wild animals that lived there began. The first domesticated animals did not differ much from their original forms and changes in morphological and production characteristics followed later during the development of sheep and goat production. Significant contributions to the development of these branches of animal husbandry were made by ancient world cultures such as Egyptian, Greek, and Roman. Changes in production were formed specifically to meet the needs of specific products such as wool, meat and milk. In this process, significant morphological modifications have occurred, such as changes in hair in wool in sheep, changes in the skin, deposition of adipose tissue, horn lessness and so on. In addition to this, there was a differentiation of breeds in accordance with the production goals that were primary, so that meat, dairy and wool production types were singled out. Along with the processes of differentiation of production types, a large number of breeds have developed, mainly according to geographical distribution. New breeds have characteristics that have been developed under the influence of man and are based on specialized or combined production of milk, meat and wool. In Europe, sheep production accounts for a significant share of total livestock production, especially in countries where cattle production has been reduced due to various geographical factors. In sheep and goat production in Europe, the leading countries are the Mediterranean countries, which have developed traditional sheep and goat products of high economic value. In Bosnia and Herzegovina, sheep and goat production are not at a satisfactory level. It is mostly about extensive sheep and goat farming without organized and systemic solutions to the problems in this production. The breed composition in Bosnia and Herzegovina is based mostly on strains of the autochthonous pramenka breed without organized selection work. Typically, sheep and goat products should be based on different technological processes such as the production of meat, milk, wool and combined output. The breeding system itself is based on the breeding of purebred breeding heads and the breeding of commercial heads for production and the market. An important element of breeding is reproduction, since these are seasonal animals whose mating season is in the fall. In order to increase the productivity and accumulativeness of these branches of livestock production, the method of estrus synchronization using various hormonal preparations is applied. Defining breeding goals is the main starting point when it comes to any livestock production, so this is the case with sheep and goat breeding. Animal selection is carried out in accordance with breeding goals. In addition to economic importance, sheep and goat production play an important role as an ecological factor in the use, preservation and conservation of pastures.

Sex-specific movement ecology of the shortest-lived tetrapod during the mating season

Sex-specific reproductive strategies are shaped by the distribution of potential mates in space and time. Labord’s chameleon (Furcifer labordi) from southwestern Madagascar is the shortest-lived tetrapod whose life-time mating opportunities are restricted to a few weeks. Given that these chameleons grow to sexual maturity within about three months and that all individuals die soon after breeding, their mating strategies should be adapted to these temporal constraints. The reproductive tactics of this or any other Malagasy chameleon species have not been studied, however. Radio-tracking and observations of 21 females and 18 males revealed that females exhibit high site fidelity, move small cumulative and linear distances, have low corresponding dispersal ratios and small occurrence distributions. In contrast, males moved larger distances in less predictable fashion, resulting in dispersal ratios and occurrence distributions 7–14 times larger than those of females, and males also had greater ranges of their vertical distribution. Despite synchronous hatching, males exhibited substantial inter-individual variation in body mass and snout-vent length that was significantly greater than in females, but apparently unrelated to their spatial tactics. Females mated with up to 6 individually-known mates, but frequent encounters with unmarked individuals indicate that much higher number of matings may be common, as are damaging fights among males. Thus, unlike perennial chameleons, F. labordi males do not seem to maintain and defend territories. Instead, they invest vastly more time and energy into locomotion for their body size than other species. Pronounced variation in key somatic traits may hint at the existence of alternative reproductive tactics, but its causes and consequences require further study. This first preliminary study of the mating system of a Malagasy chameleon indicates that, as in other semelparous tetrapods, accelerated life histories are tied to a mating system with intense contest and scramble competition among males.

Muscle testosterone supply keeps male birds topped up out of season

Many creatures live life on the energetic limit, so when they don't need a particular organ, they simply allow it to wither away to save energy until required again. Snakes’ digestive tracts atrophy between meals, migrating birds also reduce the mass of their digestive systems while en route and many male birds allow their testes to downsize out of the mating season. But this does not mean that male birds are not able to brag boastfully when their testes are out of action. Male woodpeckers are still capable of high-speed drumming, powered by their strong neck muscles, to warn other males off their territories, which made Eric Schuppe (University of California, San Francisco, USA) and Matthew Fuxjager (Brown University, USA) wonder whether the woodpecker's impressive out-of-season percussive performances could be due to testosterone produced in the muscle itself.Schuppe headed out into the North Carolina woods to capture territorial downy woodpeckers (Dryobates pubescens) during and after the mating season, to measure the quantity of testosterone circulating in their blood and in various tissues – including the powerfully drumming neck muscle and their testes. Back in the lab, Schuppe and Daniel Tobiansky (Brown University) discovered that the levels of testosterone in the drumming muscle during the breading season were six times higher than in the bird's flight muscles, which are required year-round. The testosterone levels even remained high in the percussive muscle during the winter and autumn, when the hormone had all but disappeared from other tissues in the body. And when the team checked for evidence of the key enzymes that are essential for producing the potent hormone from the basic cholesterol building block, all of the key enzymes turned up in the neck muscle at high levels. Woodpeckers are capable of beefing up their masculine drumming neck muscles by producing testosterone within the muscle itself. But could the magnificent performances of other males also benefit from a boost of in situ testosterone?This time, the team turned their attention to chattering male white-breasted nuthatches (Sitta carolinensis) and zebra finches (Taeniopygia guttata), both of which serenade females, to find out whether their superfast voice box muscles benefit from a self-produced shot of testosterone. Sure enough, all of the necessary enzymes for producing the masculine hormone from scratch turned up in the trilling birds’ voice boxes. Serenading nuthatches and zebra finches probably produce testosterone in their voice box muscles to enhance their acoustic pyrotechnics to attract females.Having confirmed that testosterone can be produced in organs that become souped up to catch the attention of passing females, Schuppe, Fuxjager and colleagues wondered whether the hormone could also enhance the performance of other superfast muscles, such as those that drive swift eye swivels. Sure enough, all of the critical enzymes turned up in the fast-contracting eye muscles of lab mice and at much higher levels than occur in other muscles that never contract as fast.It seems that the organs that male birds depend upon when courting females are capable of producing their own internal testosterone supply to enhance their performance, and it turns out that some other muscles that are capable of super-fast contractions can also produce the hormone, which may enhance blisteringly fast contractions. So male woodpeckers, nuthatches and zebra finches don't need to depend on testosterone produced by their testes when defending their territories and serenading females out of season: their own internal muscle supplies keep them topped up and in tip-top condition.

Male mastodon landscape use changed with maturation (late Pleistocene, North America)

Under harsh Pleistocene climates, migration and other forms of seasonally patterned landscape use were likely critical for reproductive success of mastodons (Mammut americanum) and other megafauna. However, little is known about how their geographic ranges and mobility fluctuated seasonally or changed with sexual maturity. We used a spatially explicit movement model that coupled strontium and oxygen isotopes from two serially sampled intervals (5+ adolescent years and 3+ adult years) in a male mastodon tusk to test for changes in landscape use associated with maturation and reproductive phenology. The mastodon's early adolescent home range was geographically restricted, with no evidence of seasonal preferences. Following inferred separation from the matriarchal herd (starting age 12 y), the adolescent male's mobility increased as landscape use expanded away from his natal home range (likely central Indiana). As an adult, the mastodon's monthly movements increased further. Landscape use also became seasonally structured, with some areas, including northeast Indiana, used only during the inferred mastodon mating season (spring/summer). The mastodon died in this area (>150 km from his core, nonsummer range) after sustaining a craniofacial injury consistent with a fatal blow from a competing male's tusk during a battle over access to mates. Northeast Indiana was likely a preferred mating area for this individual and may have been regionally significant for late Pleistocene mastodons. Similarities between mammutids and elephantids in herd structure, tusk dimorphism, tusk function, and the geographic component of male maturation indicate that these traits were likely inherited from a common ancestor.

In search of bachelorettes: Observations of male Leptonycteris yerbabuenae with dorsal patches across its range

The lesser long-nosed bat (Leptonycteris yerbabuenae) is a partially migratory, nectarivorous species that exhibits reproductive asynchrony across its range. Both migratory and resident populations of sexually active males of L. yerbabuenae may form an odoriferous dorsal patch during their mating season. This is created by smearing saliva, urogenital fluids, and anal secretions over the interscapular dorsal region with their feet. Dorsal patches are believed to influence female mate choice. We synthesized the sightings of male dorsal patches across the species’ range, including gathering new observations of male L. yerbabuenae with dorsal patches captured at the northern extent of their range and citing previously unreported observations that we obtained by contacting other researchers. We also conducted a literature review to include all previously documented records of male L. yerbabuenae presenting dorsal patches. We document the first observations of male L. yerbabuenae with dorsal patches in the southwestern United States. In the Big Hatchet Mountains in New Mexico, we captured 1 male with a developed dorsal patch (i. e., bare dorsal skin with sticky fur) on 25 July 2019 and two others on the night of 13 August 2019. New observations of males with developed dorsal patches were obtained from Hilltop Mine in Arizona (June 2006 or 2007) and at a hummingbird feeder at a residence near the Hilltop Mine (July 2013). A male with a recovering dorsal patch (i. e., bare dorsal skin with regenerating fur) was also captured in a roost near Patagonia, Arizona, in late August 2008 and at a hummingbird feeder at a residence near Silver City, New Mexico (September 2021). All previously published records of males with dorsal patches occurred in roosts in Mexico during known mating seasons. These new observations suggest that L. yerbabuenae may breed in New Mexico and Arizona between June and August, but follow-up studies are needed to confirm this behavior. Much of the reproductive biology of this important pollinator remains unknown. Therefore, identifying regions where males present dorsal patches may not only assist in locating and protecting mating roosts, but would also further our understanding of the population ecology of this migratory species.

Harvesters (Arachnida: Opiliones) mate more at cooler temperatures, but the effect of temperature on mating varies across years

AbstractTemperature impacts a wide range of mating behaviors, particularly in ectothermic organisms that tend to have body temperatures similar to ambient thermal conditions. Here, we test the effects of thermal variation on precopulatory and copulatory behavior in the harvester Leiobunum politum Weed 1889, which belongs to the group commonly known as daddy longlegs. We ran single choice mating trials across temperatures commonly experienced in the field during the mating season (18–34°C) for 2 years. We tested how temperature affected the likelihood to move, attempt to mate, and successfully mate, as well as the duration of copulation. Mating was highest at low to intermediate temperatures, and the temperature at which peak mating rates occurred varied across years. The wide range of temperatures across which L. politum is found to mate reflects thermal variability in the field and the flexibility in mating behavior in this fascinating animal.

Variation in Female Leverage: The Influence of Kinship and Market Effects on the Extent of Female Power Over Males in Verreaux’s Sifaka

Female mammals employ reproductive strategies (e.g., internal gestation) that result in power asymmetries specific to intersexual dyads. Because the number of eggs available for fertilization at any given time for most mammals is quite limited, having a fertilizable egg is potentially an important source of economic power for females. Control over mating opportunities is a source of intersexual leverage for female Verreaux’s sifaka (Propithecus verreauxi). We examined economic factors thought to influence the value of mating opportunities, and, thus, the extent of female leverage: kinship and market effects. Using a longitudinal dataset of agonistic interactions collected during focal animal sampling of all adult individuals in 10 social groups from 2008 to 2019, we tested the effects of relatedness, female parity, reproductive season, and adult sex ratio (population and group) on (1) the direction of submissive signaling and (2) which sex won a contested resource. While 96% of the acts of submission were directed from males toward females, females only won a third of their conflicts with males. Thus, our study has implications for evolutionary explanations of female-biased power. If female power evolved due to their greater need for food and other resources, then intersexual conflicts would be expected to result in males more consistently relinquishing control of resources. As expected, males were more likely to chatter submissively toward successful mothers, during the mating season, and when the sex ratio was male-biased. Although females generally had less power to win a conflict when their fertilizable egg was less valuable (when they were nulliparous or unsuccessful mothers or when interacting with male kin) and with an increasing female-bias in the sex ratio, this ability to win additionally was influenced by which sex initiated the conflict. Our study demonstrates that female leverage can be influenced by the supply and demand for mating opportunities, but evoking submission does not translate into winning a resource. Indeed, intersexual power is dynamic, contextual, and dependent on the individuals in the dyad.