Oral supplementation with Scabiosa artropurperea L. aqueous extract improves the in vivo sexual behaviour, sperm quality and androgen level in rams.

The effects of an aqueous extract of Scabiosa atropurpurea L. (AES) on the reproduction potential of Queue Fine de l'Ouest rams were evaluated over 9 weeks. Eighteen mature (4-6 years old) rams (52.8 ± 2.6 kg) were divided into three groups. The control (C) group was fed oat hay ad libitum with 700 g of concentrate and the other two groups were fed the same diet supplemented with AES at 1 and 2 mg/kg body weight (AES1 and AES2, respectively). Ram sperm was collected with an artificial vagina (2 × 2 days/week) to evaluate sperm production and quality, antioxidant activity, the adenosine triphosphate (ATP) and calcium concentrations. Sexual behaviour and plasma testosterone concentrations were also investigated. The administration of AES improved sexual behaviour (the duration of contact and the number of lateral approaches). The addition of AES also improved individual spermatozoa motility (C: 71.7% ± 6.3%; AES1: 78.3% ± 4.9%; AES2: 83.8% ± 4.4%), the sperm concentration (C: 5.6 ± 0.36; AES1: 6.4 ± 0.81; AES2: 6.7 ± 0.52 × 109 spermatozoa/mL), the ATP ratio (C: 1 ± 0.08; AES1: 2.1 ± 0.08; AES2: 3.3 ± 0.08) and the calcium concentration (C: 5.6 ± 0.24; AES1: 7.7 ± 0.21; AES2: 8.1 ± 0.24 mmol/L). AES treatment decreased the percentage of abnormal sperm (C: 18.5% ± 1.2%; AES1: 16.2% ± 1.1%; AES2: 14.8% ± 0.94%) and DNA damage (C: 62%; AES1: 27%; AES2: 33%) and was associated with elevated seminal fluid antioxidant activity (C: 22 ± 0.27; AES1: 27.1 ± 1.08 and AES2: 27.5 ± 0.36 mmol Trolox equivalents/L) and plasma testosterone (C: 8.3 ± 0.7; AES1: 11.7 ± 0.4; AES2: 15 ± 0.7 ng/L). In conclusion, our study suggests that S. atropurpurea may be potentially useful to enhance libido and sperm production and quality in ram.

Cloprostenol effect with and without male stimulation on oestrus synchronization in Peru guinea pigs.

Cloprostenol, a synthetic derivative of prostaglandin F2α, effectively triggers functional and morphological regression of the corpus luteum (luteolysis). In rural Peru, the guinea pig (Cavia porcellus) holds significance within the local economy and serves as a valuable protein source. Enhancing reproductive efficiency is crucial to achieve uniformity in weight, age, and litter size across commercial systems. Thus, our study aimed to evaluate the effect of cloprostenol with and without male stimulation on the onset, duration, and intensity of oestrus in Peru guinea pigs. A total of 128 guinea pigs (120 females and eight males) between 8 and 12 months of age, weighing between 800 and 1200 g, were distributed in cages of 15 females per treatment. Cloprostenol sodium (0 [control], 0.20, 0.25, and 0.30 mg/animal) was IM administered to the groups with and without male stimulation. Four isolated males in individual cages, different from the one used for the treatment, were considered to detect oestrus. The oestrus intensity was assessed by observing sexual behaviour signs such as restlessness, moaning, attempts to mount, pelvic elevation, loin stretching, and vulvar inflammation. The oestrus was manifested 2 days after the administration of cloprostenol sodium. At a dose of 0.30 mg/animal and with male stimulation, the earliest oestrus was observed at 46.9 h. There was a reduction in the oestrus duration (p < .05) in guinea pigs that received the three doses of cloprostenol sodium compared to the control group. The highest percentages of frank oestrus intensity (66.7%) were strongly associated with the administered doses of cloprostenol sodium (p < .01). In conclusion, the cloprostenol sodium administration was proper for rapid oestrus induction in Peru guinea pigs.

Imidacloprid reduces the mating success of males in bumblebees.

Bumblebees play a vital role in both natural and agricultural environments, but there has been a noticeable decline in their populations. Pesticides, particularly neonicotinoids, are widely regarded as a substantial contributing factor to the decline in bumblebee populations, as evidenced by the detrimental impacts documented across many stages of their life cycle. Mating is vital for the population maintenance of bumblebees. Nevertheless, there is a scarcity of research conducted on the effects of pesticides on the mating process. In this study, we individually examined the impact of imidacloprid on the mating behavior of bumblebee males and queens. A competitive mating experiment was conducted to evaluate the effect on the competitive prowess of male individuals and the mate selection behavior of female individuals. The study revealed that the mating rate of bumblebees exposed to a concentration of 10 ppb of imidacloprid was 3 %. This finding demonstrated a statistically significant impact when compared to the control group, which exhibited a mating rate of 58 % in the normal mating experiment. Furthermore, in the competitive mating experiment, we found that the competitive mating success rate of treated males (1 %) was significantly lower than that of untreated males (35 %). Hence, it provides evidence that neonicotinoid imidacloprid negatively affects bumblebee mating success and cautions us to protect bumblebees from pesticide exposure to prevent a severe impact on their populations.

Kisspeptin administration may promote precopulatory behavior in male rats independently or supplementally to testosterone and contribute to proceptive behavior in female partners, reducing mating failure.

Kisspeptin is a peptide that plays an important role through its effects on the hypothalamus-pituitary-gonadal (HPG) axis. It has also been implicated in sexual behavior. The present study investigated whether the relationship between kisspeptin and sexual behavior is independent of the HPG axis, i.e., testosterone. Sexual behavior was examined after the administration of kisspeptin to gonadally intact male rats and gonadectomized male rats that received testosterone supplementation. Other male rats were also observed for sexual behavior once a week from 2 to 5 weeks after gonadectomy and receiving kisspeptin for the sixth postoperative week. Sexual behavior in female rats serving as the partner for each male was also observed. Female rats were not administered kisspeptin in the present study. The results obtained showed that the administration of kisspeptin increased precopulatory behavior in gonadally intact male rats and gonadectomized male rats that received testosterone supplementation and proceptive behavior in their female partners. Precopulatory behavior in males and receptive behavior in females increased, while copulatory behavior in males and receptive behavior in females remained unchanged. Furthermore, the administration of kisspeptin increased precopulatory behavior in gonadectomized males, but did not affect receptive behavior in females. These results suggest that kisspeptin affected males independently and/or supplementally to testosterone, and also that changes in the presence of testosterone in males had an impact on proceptive behavior in their female partners. In conclusion, kisspeptin may involve an as-yet-unidentified neural pathway in sexual desire independently of the HPG axis.

Low dose of propyl-pyrazole-triol, an agonist of estrogen receptor alpha, administration stimulates the Coolidge effect in fadrozole-treated male rats.

Estrogen receptor (ER) α is involved in male sexual function. Here, we aim to investigate how ERα activation influences sexual satiety and the Coolidge effect (i.e., when a rat, that has reached sexual satiety, experiences an increased arousal after exposure to a novel sexual partner) in estrogen-deprived male rats. Male rats (8 per group) were treated daily for 29 days with either saline (Control group) or fadrozole dissolved in saline (1 mg/kg/day) 1 h before mating. On Days 13 and 29, rats treated with fadrozole received either no additional treatment (fadrozole group) or a single injection of propyl-pyrazole-triol (ERα-agonist group, dissolved in sesame oil, 1 mg/kg). Rats mated until reaching sexual satiety on Days 13 and 29. In these sessions, the Control group displayed higher frequency of intromission and ejaculation than the other groups. The ERα-agonist group mounted more frequently but reached sexual satiety sooner than the Control group. On Day 29, when exposed to a new sexual partner, the fadrozole-treated rats were less likely to display intromission than the other groups, or ejaculation than the Control group, or mounting than the ERα-agonist group. The Control group showed more ejaculatory behavior and shorter ejaculation latency than the other groups. Body weights, testosterone levels, estradiol levels, and ERα-immunoreactive cell counts in brain regions for sexual behavior were comparable between groups after 29 days of treatments. Our data suggest that estrogen helps regulate sexual satiety and the Coolidge effect in male rats.

Estrogenic influences on agonistic behavior in teleost fishes.

Teleost fishes show an extraordinary diversity of sexual patterns, social structures, and sociosexual behaviors. Sex steroid hormones are key modulators of social behaviors in teleosts as in other vertebrates and act on sex steroid receptor-containing brain nuclei that form the evolutionarily conserved vertebrate social behavior network (SBN). Fishes also display important differences relative to tetrapod vertebrates that make them particularly well-suited to study the physiological mechanisms modulating social behavior. Specifically, fishes exhibit high levels of brain aromatization and have what has been proposed to be a lifelong, steroid hormone dependent plasticity in the neural substrates mediating sociosexual behavior. In this review, we examine how estrogenic signaling modulates sociosexual behaviors in teleosts with a particular focus on agonistic behavior. Estrogens have been shown to mediate agonistic behaviors in a broad range of fishes, from sexually monomorphic gonochoristic species to highly dimorphic sex changers with alternate reproductive phenotypes. These similarities across such diverse taxa contribute to a growing body of evidence that estrogens play a crucial role in the modulation of aggression in vertebrates. As analytical techniques and genomic tools rapidly advance, methods such as LC-MS/MS, snRNAseq, and CRISPR-based mutagenesis show great promise to further elucidate the mechanistic basis of estrogenic effects on social behavior in the diverse teleost lineage.

Replenishment of Drosophila Male Pheromone After Mating.

Insect exocrine gland products can be involved in sexual communication, defense, territory labelling, aggregation and alarm. In the vinegar fly Drosophila melanogaster the ejaculatory bulb synthesizes and releases 11-cis-Vaccenyl acetate (cVa). This pheromone, transferred to the female during copulation, affects aggregation, courtship and male-male aggressive behaviors. To determine the ability of male flies to replenish their cVa levels, males of a control laboratory strain and from the desat1 pheromone-defective mutant strain were allowed to mate successively with several females. We measured mating frequency, duration and latency, the amount of cVa transferred to mated females and the residual cVa in tested males. Mating duration remained constant with multiple matings, but we found that the amount of cVa transferred to females declined with multiple matings, indicating that, over short, biologically-relevant periods, replenishment of the pheromone does not keep up with mating frequency, resulting in the transfer of varying quantities of cVa. Adult responses to cVa are affected by early developmental exposure to this pheromone; our revelation of quantitative variation in the amount of cVa transferred to females in the event of multiple matings by a male suggests variable responses to cVa shown by adults produced by such matings. This implies that the natural role of this compound may be richer than suggested by laboratory experiments that study only one mating event and its immediate behavioral or neurobiological consequences.

Daily GnRH agonist treatment effectively delayed puberty in female rats without long-term effects on sexual behavior or estrous cyclicity.

The present study examined the long-term effects of suppressing puberty with a GnRH agonist on reproductive physiology and behavior in female rats. We have recently reported that administration of the GnRH agonist leuprolide acetate (25 µg/kg) daily between postnatal day (PD) 25-50 delayed puberty and disrupted the development of copulatory behavior and sexual motivation in male rats. However, pilot data from our lab suggest that this low dose of leuprolide acetate (25 µg/kg) was not high enough to significantly delay puberty in female rats. Therefore, we injected female Long-Evans rats with leuprolide acetate at a higher dose (50 µg/kg) or 0.9% sterile saline, daily , starting on PD 25 and ending on PD 50. Vaginal opening was monitored daily starting on PD 30 for signs of pubertal onset and first estrous cycle. In addition, we measured estrous cyclicity starting approximately 2 weeks after the last injection of leuprolide (∼PD 64). Immediately after monitoring estrous cyclicity, the female rats were mated on their first day in behavioral estrus using the partner-preference paradigm, with and without physical contact (PD 95-110). We found that this dose of leuprolide (50 µg/kg) significantly delayed puberty; however, neither estrous cyclicity nor sexual motivation was significantly affected by periadolescent exposure to leuprolide. Together with our findings in male rats, these results add to our understanding of the developmental effects of chemically suppressing puberty in rats.

Brain and testicular metabonomics revealed the protective effects of Guilingji on senile sexual dysfunction rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Guilingji (GLJ), which has been used to treat male diseases in China for centuries, contains 28 Chinese herbs and was previously established as an effective treatment for male sexual dysfunction. However, its mechanism of action remains unclear. AIM OF THE STUDY: To explore the efficacy and mechanism of action of GLJ in improving senile sexual dysfunction (SSD) in aging rats. MATERIALS AND METHODS: An aging rat model of SSD was induced by the subcutaneous injection of d-galactose (300 mg⋅kg-1) and used to analyse the effects of GLJ (different concentrations of 37.5, 75, and 150 mg⋅kg-1) on the mating of aging rats. At the end of the 8th week, histopathological analysis of testicular tissues, assessment of the hypothalamic-pituitary-gonadal (HPG) axis hormone levels in serum or brain, and metabonomics analysis of the brain and testicular tissue with liquid chromatography-mass spectrometry was performed to explore the mechanism of action of GLJ. RESULT: After treatment with GLJ, the mount and ejaculation latency levels were increased in the treatment group than those in model group (P < 0.05), moreover, the testicular morphology was improved. Gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) levels in rats were also improved significant (P < 0.05) compared with those in the model group. Furthermore, the metabonomics results in the testicular and brain tissue showed that GLJ improved SSD by adjusting amino acid and lipid metabolism. CONCLUSION: This study integrated the complementary metabolic profiles of the target tissues. GLJ might affect SSD rats by regulating amino acid and lipid metabolism and may modulate sensitivity to the signaling pathway in the HPG axis. This study provides an essential basis for the broad clinical application of GLJ.

Apelin-13 facilitates lordosis behavior following infusions to the ventromedial hypothalamus or preoptic area in ovariectomized, estrogen-primed rats.

In normal hormonal conditions, increased neuronal activity in the ventromedial hypothalamus (VMH) induces lordosis whereas activation of the preoptic area (POA) exerts an opposite effect. In the present work, we explored the effect of bilateral infusion of different doses of the apelin-13 (0.37, 0.75, 1.5, and 15 µg) in both brain areas on the expression of lordosis behavior. Lordosis quotient and lordosis reflex score were performed at 30, 120, and 240 min. Weak lordosis was observed following the 0.37 µg dose of apelin-13 at 30 min in the VMH of EB-primed rats; however, the rest of the doses induced significant lordosis relative to the control group. At 120 min, all doses induced lordosis behavior, while at 240 min, the highest dose of 15 µg did not induce significant differences. Interestingly, only the 0.75 µg infusion of apelin in the POA induced significant lordosis at 120 and 240 min. These results indicate that apelin-13 acts preferably in HVM and slightly in POA to initiate lordosis behavior in estrogen-primed rats.

Effects of 3, 4-divanillyltetrahydrofuran from Urtica fissa on sexual dysfunction in diabetic mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Urtica fissa E. Pritz. are important herbs and have been traditionally used as ethnic medicine to treat rheumatism, inflammation, diabetes, and benign prostatic hyperplasia by the Han, Uighur, and other minorities in China, and also as an aphrodisiac in Uighur medicine. AIMS OF THE STUDY: To determine the effect and potential mechanism of 3, 4-divanillyltetrahydrofuran (DVTF), one of the main active components isolated from U. fissa on hypogonadism in diabetic mice. MATERIALS AND METHODS: The active compound DVTF was extracted and separated from the roots of U. fissa and identified using mass spectrometry and nuclear magnetic resonance spectroscopy. A mouse model of diabetes was established using high fat and sugar diet combined with streptozotocin. In the treatment groups, mice were received different doses of DVTF for 4 weeks. Fasting blood glucose levels, physiological and biochemical indices, and the mating behavior of DM mice were analyzed. Changes in testicular morphology were assessed using light microscopy and transmission electron microscopy. The expression of testosterone synthesis-related signaling proteins was detected using western blotting. Molecular docking was used to determine the binding ability of DVTF to Nur77. RESULTS: In diabetic mice, body weight and fasting blood glucose levels decreased. Mating behavior, including mount latency, mount number, and intromission number, was improved following DVTF treatment. Plasma total testosterone, free testosterone, and insulin resistance were positively associated with the recovery of testicular pathological structures in diabetic mice. DVTF treatment increased the expression of Nur77, StAR, and P450scc in the testes of diabetic mice. DVTF and Nur77 formed chemical bonds at five sites. CONCLUSION: As one of the main active components of U. fissa, DVTF exert potential therapeutic effects on testicular injury and hypogonadism caused by diabetes through activating the expression of Nur77 and testosterone synthesis related proteins. Our result will provide new insight for the clinical application of Urtica fissa E. Pritz., especially DVTF, as a potential drug candidate in the treatment of hypogonadism in diabetes.

Sulfasalazine exposure during pregnancy and lactation induces alterations in reproductive behavior in adult female rat offspring.

AIMS: Sulfasalazine (SAS) is the first line drug in the treatment of chronic inflammatory bowel diseases in pregnant women. SAS and its metabolites cross the placenta and can be transferred through the milk. However, the long-term consequences to the reproductive system of offspring from dams exposed to SAS have not yet been studied. Thus, our study investigated the effects of SAS treatment during gestational and lactational periods on maternal care in F0 and reproductive outcomes in F1 females. MAIN METHODS: Wistar female rats (n = 10/group) received 300 mg/kg/day of SAS dissolved in carboxymethyl cellulose (CMC), by gavage, from gestational day 0 to lactation day 21 and 3 mg/kg/day of folic acid during gestation. The control group received CMC only. On PND 21, the female pups were selected for reproductive evaluation at different time points: infancy and adulthood. The reproductive parameters evaluated were installation of puberty (vaginal opening and first estrus), estrous cyclicity, reproductive organs weight, histological analysis of the ovary follicles and uterus, analysis of oxidative stress in ovarian tissue, reproductive behavior (sexual and maternal), and fertility. KEY FINDINGS: SAS treatment decreased the retrieving behavior in F0 females. The F1 females presented an increase in the lordosis score, frequency of lordosis of magnitude 3, and lipid peroxidation of ovarian tissues in both infancy and adult life. SIGNIFICANCE: The SAS effects observed in the current study represent a relevant concern for public health, as they demonstrated that treatment with SAS compromised the maternal motivation of dams and induced reproductive alterations in F1 females.

An intergenerational androgenic mechanism of female intrasexual competition in the cooperatively breeding meerkat.

Female intrasexual competition can be intense in cooperatively breeding species, with some dominant breeders (matriarchs) limiting reproduction in subordinates via aggression, eviction or infanticide. In males, such tendencies bidirectionally link to testosterone, but in females, there has been little systematic investigation of androgen-mediated behaviour within and across generations. In 22 clans of wild meerkats (Suricata suricatta), we show that matriarchs 1) express peak androgen concentrations during late gestation, 2) when displaying peak feeding competition, dominance behaviour, and evictions, and 3) relative to subordinates, produce offspring that are more aggressive in early development. Late-gestation antiandrogen treatment of matriarchs 4) specifically reduces dominance behaviour, is associated with infrequent evictions, decreases social centrality within the clan, 5) increases aggression in cohabiting subordinate dams, and 6) reduces offspring aggression. These effects implicate androgen-mediated aggression in the operation of female sexual selection, and intergenerational transmission of masculinised phenotypes in the evolution of meerkat cooperative breeding.

Nutritional status and prey energy density govern reproductive success in a small cetacean.

A variety of mammals suppress reproduction when they experience poor physical condition or environmental harshness. In many marine mammal species, reproductive impairment has been correlated to polychlorinated biphenyls (PCBs), the most frequently measured chemical pollutants, while the relative importance of other factors remains understudied. We investigate whether reproductively active females abandon investment in their foetus when conditions are poor, exemplified using an extensively studied cetacean species; the harbour porpoise (Phocoena phocoena). Data on disease, fat and muscle mass and diet obtained from necropsies in The Netherlands were used as proxies of health and nutritional status and related to pregnancy and foetal growth. This was combined with published life history parameters for 16 other areas to correlate to parameters reflecting environmental condition: mean energy density of prey constituting diets (MEDD), cumulative human impact and PCB contamination. Maternal nutritional status had significant effects on foetal size and females in poor health had lower probabilities of being pregnant and generally did not sustain pregnancy throughout gestation. Pregnancy rates across the Northern Hemisphere were best explained by MEDD. We demonstrate the importance of having undisturbed access to prey with high energy densities in determining reproductive success and ultimately population size for small cetaceans.

Prenatal exposure to valproic acid and treatment with intranasal oxytocin have sex-specific effects on behavior in Long Evans rats.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social behaviors and communication. In rodents and humans, prenatal exposure to antiepileptic valproic acid is associated with an increased risk for autistic-like characteristics. One potential treatment is oxytocin, a prosocial neuropeptide that can be delivered intranasally. However, the sex-specific effects of valproic acid exposure and intranasal oxytocin treatment on behavior have not been fully explored. Pregnant Long Evans rats were administered valproic acid (500 mg/kg) or saline midday on gestational day 12, and after weaning, male and female pups were assigned to control (saline-saline), valproic acid-saline, or valproic acid-oxytocin groups. Oxytocin (0.8 IU/kg) or saline was delivered intranasally 30-60 min before tests for anxiety-like behaviors (elevated plus maze), social interactions (sociability) and sociosexual behaviors (partner preference, 50 kHz vocalizations and scent marking). Prenatal exposure to valproic acid resulted in sex-specific differences in behavior. When compared to controls, valproic acid males showed enhanced anxiety-like behaviors in adolescence and fewer scent marks in adulthood, while valproic acid females showed reduced sexual (partner) preference as adults. Intranasal oxytocin was anxiolytic for valproic acid males, but moderately anxiogenic for valproic acid females, and in both sexes it surprisingly impaired social interactions in the sociability test. Furthermore, intranasal oxytocin failed to improve sociosexual deficits in valproic acid rats. These findings highlight the importance of conducting preclinical studies in both sexes, and suggest that oxytocin may be an effective treatment in animal models with heightened anxiety-like behaviors.

Intranasal oxytocin drives coordinated social approach.

Coordinated responses to challenge are essential to survival for bonded monogamous animals and may depend on behavioral compatibility. Oxytocin (OT) context-dependently regulates social affiliation and vocal communication, but its role in pair members' decision to jointly respond to challenge is unclear. To test for OT effects, California mouse females received an intranasal dose of OT (IN-OT) or saline after bonding with males either matched or mismatched in their approach response to an aggressive vocal challenge. Pair mates were re-tested jointly for approach response, time spent together, and vocalizations. Females and males converged in their approach after pairing, but mismatched pairs with females given a single dose of IN-OT displayed a greater convergence that resulted from behavioral changes by both pair members. Unpaired females given IN-OT did not change their approach, indicating a social partner was necessary for effects to emerge. Moreover, IN-OT increased time spent approaching together, suggesting behavioral coordination beyond a further increase in bonding. This OT-induced increase in joint approach was associated with a decrease in the proportion of sustained vocalizations, a type of vocalization that can be associated with intra-pair conflict. Our results expand OT's effects on behavioral coordination and underscore the importance of emergent social context.

Noradrenergic alpha-2A receptor activation suppresses courtship vocalization in male Japanese quail.

Male Japanese quail produce high-frequency crow vocalizations to attract females during the breeding season. The nucleus of intercollicularis (ICo) is the midbrain vocal center in birds and electrical stimulation of the ICo produces calls that include crowing. Noradrenaline plays a significant role in sexual behavior but the contribution of noradrenaline in the control of courtship vocalizations in quail has not been well established. Using dose-dependent intracerebroventricular injection of clonidine, an α2-adrenergic receptor-specific agonist, crowing vocalization was immediately suppressed. At the same time as crow suppression by clonidine there was a reduction of immediate early gene, zenk mRNA, in the ICo; no zenk mRNA expression was detected in the dorsomedial division of the nucleus. Using histochemistry, we determined that the ICo receives noradrenergic innervation and expresses α2A-adrenergic receptor mRNA. Taken together, these data suggest that noradrenaline regulates courtship vocalization in quail, possibly via the α2A-adrenergic receptor expressed on ICo neurons.

The Sex Pheromone of the Pine Brown-Tail Moth, Euproctis terminalis (Lepidoptera: Erebidae).

The pine brown tail moth, Euproctis terminalis (Walker 1855), is a periodic pest in pine plantations in South Africa. The larvae feed on pine needles and can cause severe defoliation when population densities are high. Population densities fluctuate temporally and spatially, complicating the prediction of potential growth loss and tree mortality. The aim of this study was to identify the sex pheromone of the pine brown tail moth to provide stakeholders with a tool for monitoring it. Gas chromatography-electroantennogram detection and gas chromatography/mass spectrometry analyses of female pheromone gland extracts identified the major component as (Z,Z,Z,Z)-7,13,16,19-docosatetraen-1-ol isobutyrate. Traps baited with (Z,Z,Z,Z)-7,13,16,19-docosatetraen-1-ol isobutyrate caught more males than unbaited traps. A delta trap was shown to be a superior design compared to a bucket funnel trap. This pheromone can now be used for monitoring E. terminalis in pine plantations.

Neural and Hormonal Basis of Opposite-Sex Preference by Chemosensory Signals.

In mammalian reproduction, sexually active males seek female conspecifics, while estrous females try to approach males. This sex-specific response tendency is called sexual preference. In small rodents, sexual preference cues are mainly chemosensory signals, including pheromones. In this article, we review the physiological mechanisms involved in sexual preference for opposite-sex chemosensory signals in well-studied laboratory rodents, mice, rats, and hamsters of both sexes, especially an overview of peripheral sensory receptors, and hormonal and central regulation. In the hormonal regulation section, we discuss potential rodent brain bisexuality, as it includes neural substrates controlling both masculine and feminine sexual preferences, i.e., masculine preference for female odors and the opposite. In the central regulation section, we show the substantial circuit regulating sexual preference and also the influence of sexual experience that innate attractants activate in the brain reward system to establish the learned attractant. Finally, we review the regulation of sexual preference by neuropeptides, oxytocin, vasopressin, and kisspeptin. Through this review, we clarified the contradictions and deficiencies in our current knowledge on the neuroendocrine regulation of sexual preference and sought to present problems requiring further study.