Copulatory Behavior Research Articles

Sexual dialogue in Pachyloides thorellii (Opiliones: Gonyleptidae): a Neotropical harvestman with much to say

Describing the signals involved in sexual interactions is crucial to understand how mating and fertilization success is achieved. We analyzed sexual interactions in the gonyleptid harvestman Pachyloides thorellii Holmberg, 1878 to test the possibility of associations between female and male behaviors. For that purpose, we recorded 21 sexual interactions of P. thorellii under laboratory conditions and performed fine scaled analyses of the videos. We found three female pre-copulatory behaviors (“Mouth parts protrusion,” “Genital operculum opening,” and “Ovipositor eversion”) that seem to be related to sexual receptivity and cooperation with mating occurrence, and four copulatory behaviors (“Bucking,” “Pulling,” “Body lowering,” and “Leg II movements”) that could be indicating to the male that further stimulation is required or that mating is about to end. We also found that males use multimodal courtship displays that include the exchange of tactile and possibly chemical signals between sexes. This study shows that courtship and copulation in P. thorellii include intense information flow between sexes and female evaluation from the beginning until the end of the sexual interaction.

Hormone-dependent sexual responses of female mice in response to manual genital stimulation

Although copulatory behavior is thought to have a strong innate basis in mice, there is also clear evidence that sexual experience shapes its expression. Reinforcement of behavior through rewarding genital tactile stimulation is a primary candidate mechanism for this modification. In rats, manual tactile clitoral stimulation is rewarding only when it is temporally distributed, which is hypothesized to result from an innate preference for species-typical copulatory patterning. Here we test this hypothesis using mice, which have a temporal copulatory pattern which is distinctly less temporally distributed than that of rats. Female mice received manual clitoral stimulation which was either temporally continuous every second, or stimulation which was temporally distributed, occurring every 5 s, This pattern of stimulation was paired with environmental cues in a conditioned place preference apparatus to assess reward. Neural activation in response to this stimulation was evaluated by measuring FOS immunoreactivity. Results indicated that both temporal patterns of clitoral stimulation were rewarding, but that continuous stimulation better reproduced brain activation associated with sexual reward. Furthermore, continuous, but not distributed stimulation elicited a lordosis response in some females, and this response increased within and across days. Sexual reward, neural activation and lordosis resulting from tactile genital stimulation were eliminated by ovariectomy and restored with combined 17β-estradiol and progesterone treatment but not 17β-estradiol treatment alone. These observations are consistent with the hypothesis that sexual reward resulting from species-typical genital tactile stimulation has a permissive effect on copulatory behavior of female mice.

The Effect of a Synthetic Scent on Cheetah Behaviour.

In cheetahs, age at first parturition correlates negatively with reproductive lifespan (asymmetric reproductive aging); therefore, breeding cheetahs at a young age is essential to maximize reproductive performance in this species. However, younger females display a significantly reduced frequency of copulatory behaviour, which negatively affects breeding. Volatile organic compounds (VOCs) are known to regulate appropriate behavioural responses in various species, including reproductive behaviour; moreover, they have proven to play a role in captive breeding methods in cheetahs, as well as mate choice. Therefore, the objective of this study was to evaluate the effect of a synthetic scent (SS) on the frequency of the five oestrous behaviour(s) (sniff, rub, roll, spray, and meow-chirp) known to be indicative of oestrus in female cheetahs. Based on the results of a previous study from our research group, five VOCs, identified in the marking fluid of male cheetahs, and known to be pheromones involved in reproductive behaviour, were used to create the SS. This was accomplished by mixing benzaldehyde, acetophenone, indole, dimethyl disulphide and phenol with (99.9%) ethanol. Seven female cheetahs were then observed for one oestrus cycle without stimulation (control) and then once again while exposed to the SS (treatment), which was sprayed on foil trays placed around the outside of each enclosure. The occurrence of the five oestrous behaviours was recorded and tallied per day of observations. Although the SS did not have a significant effect on the frequency of oestrous behaviours displayed by the females used in this study, five of the seven (71%) did show an increase in their behaviour with the SS when oestrogen concentrations were at their highest (peak oestrus), including three of the four younger females. The SS also significantly increased the sniffing behaviour in general. Although the results of this study do indicate that VOCs influence cheetahs and their behaviour, firm conclusions cannot be drawn due to the low number of animals used, as well as the significant effect the observation methods had on the results. Nonetheless, this study represents the first of this kind in cheetahs, therefore representing an important step in determining the role of VOCs in aiding breeding in captivity.

Protein feeding mediates sex pheromone biosynthesis in an insect.

Protein feeding is critical for male reproductive success in many insect species. However, how protein affects the reproduction remains largely unknown. Using Bactrocera dorsalis as the study model, we investigated how protein feeding regulated sex pheromone synthesis. We show that protein ingestion is essential for sex pheromone synthesis in male. While protein feeding or deprivation did not affect Bacillus abundance, transcriptome analysis revealed that sarcosine dehydrogenase (Sardh) in protein-fed males regulates the biosynthesis of sex pheromones by increasing glycine and threonine (sex pheromone precursors) contents. RNAi-mediated loss-of-function of Sardh decreases glycine, threonine, and sex pheromone contents and results in decreased mating ability in males. The study links male feeding behavior with discrete patterns of gene expression that plays role in sex pheromone synthesis, which in turn translates to successful copulatory behavior of the males.

Chronic periadolescent leuprolide exposure affects the development of reproductive physiology and behavior of female and male rats differently, but both mature after treatment termination

BackgroundGnRH agonists have been used to halt the development of puberty in children with precocious puberty since the 1980s. Recently, drugs like Lupron Depot® (leuprolide acetate), have been used to suppress pubertal progression in adolescents who are questioning their gender identity. However, few preclinical studies have been conducted to investigate potential effects of using GnRH agonists in this context.MethodsThe present study tested the effects of daily leuprolide treatment (50 µg/kg, postnatal day (PD) 25–50) on pubertal onset in female (i.e., vaginal opening) and male (i.e., preputial separation) Long-Evans rats. The first estrous cycle immediately after vaginal opening was also measured. Sexual behavior and sexual motivation were tested using the partner-preference paradigm. Female rats were tested during the first behavioral estrus after treatment ended (between PD 51–64). Male rats were tested weekly for four consecutive weeks starting three days after treatment ended (PD 53).ResultsConsistent with previous findings, leuprolide significantly delayed pubertal onset in both female and male rats. In addition, the first estrous cycle during the treatment period was disrupted by leuprolide, as indicated by a failure to cycle into estrus after vaginal opening until treatment ended. However, leuprolide affected neither sexual motivation nor fertility when female rats were tested within 14 days of leuprolide treatment ending. In contrast, the development of copulatory behavior and sexual motivation was significantly delayed by leuprolide in male rats; however, mature reproductive behavior was observed by the fourth week post-treatment.ConclusionsTaken together with previous findings, the present results indicate that male rats may be more sensitive to periadolescent leuprolide administration, taking longer to overcome the effects of leuprolide than female rats. Nevertheless, not long after leuprolide treatment is discontinued, sex-typical reproductive physiology and behavior emerge fully in female and male rats, indicating that the drug’s effects are not permanent. If translatable to humans, leuprolide may be a reversible option to give adolescents more time to consider their gender identity with minimal long-term effects on sexual development.

Reciprocal effects of single or repeated exposure to methylphenidate or sex in adult male rats

Exposure to rewards can alter behavioral reactivity to them. For example, stimulants sensitize locomotor activation, whereas sexual experience sensitizes copulatory behaviors. Moreover, rewards can cross-sensitize one another. Although stimulants are known to cross-sensitize locomotor effects, the evidence for cross-sensitization between stimulants and sex is less clear. This study determined the effects of single and repeated pre-exposure to methylphenidate (MPH) or sex on one another in adult male rats. Cross-sensitization between MPH (5mg/kg) and sex (30min with sexually experienced female) was examined. Adult male rats were pre-exposed to 0, 1, or 10 trials of either sex or MPH before being exposed to the other reward. Locomotor chambers were used in MPH trials. Bilevel chambers were used in sexual trials, and sexual behaviors were video scored. The amount of prior sexual experience differentially influenced the ceiling of MPH-dependent sensitization; in the last drug trial, locomotion was highest in males given 1 previous sexual trial compared with 0 or 10. Compared with MPH-naive males, pre-exposure to MPH (1 and 10 trials) reduced the number of ejaculations without impacting sexual performance (intromission/mount latency and frequency). These findings indicate that the degree of pre-exposure to a reward can differentially affect reactivity to novel rewards. The results showed that previous findings of cross-sensitization between amphetamine and sex do not extend to MPH. However, exposure to MPH prior to sexual experience can increase the amount of sexual stimulation needed to achieve ejaculation.

Courtship, copulation, and territorialistic behaviors of Tropidurus torquatus (Tropiduridae) in a fragment of Cerrado in Central-West Brazil

This study observed and recorded courtship, copulation, and territorialistic behaviors in Tropidurus torquatus. Males of this species used a head bobbing or “push-up” display, which is the main communication sign with other males. Females, in turn, performed tail lifting, a specific sexual stimulus behavior indicating acceptance of copulation. Courtship took place with coordinated movements for both males and females and could result in effective copulation; females seemed to prefer dominant males during the reproductive period. Territorialistic behaviors occurred before and after courtship, demonstrating the efforts made by dominant males of T. torquatus to maintain their territory during the reproductive season.

Female-Female Spring Fling in American Kestrels: An Observation of a Female–Female Pair and Copulation Behavior

ABSTRACT Same-sex copulations by raptors, and birds in general, have been rarely reported. In American Kestrels (Falco sparverius), there have been no previous reports of a female copulating with a female. Here, we summarize our observations of a pair of female kestrels that were documented to copulate repeatedly with each other over a 5-wk period in north Texas. Two females were first observed together on 17 March 2020, when they copulated 23 times. That same day, we trapped and marked both females with coded anodized color bands. Between 17 March and 20 April 2020, we observed the pair copulate an average of 9.2 times/hr (7 d of observation, 7.9 hr), with both kestrels being present during 74.9% of our observations. The kestrels alternated which bird was in the top position during copulations, with the female with band code E/17 on top during 55.8% of copulations (n = 45) and female E/20 on top during 44.2%. One or both kestrels vocalized during 75.6% of copulations. We recorded other behaviors typical of breeding kestrels, including nest-site inspection, territorial defense, and an apparent aerial courtship display. Contrary to published speculations on same-sex pairs in birds, our observations do not support the hypothesis that the females typically adopt separate sex-specific behavioral roles. We propose probable benefits of a female-female pairing may include (1) stimulating ovulation, (2) sharing incubation and provisioning duties that could result in a greater number of young fledged, and (3) the ability to more easily defend and hold territory by two females, which typically hold higher-quality territories than males in American Kestrels.

Fertilization modes and the evolution of sperm characteristics in marine fishes: Paired comparisons of externally and internally fertilizing species.

Fertilization mode may affect sperm characteristics, such as morphology, velocity, and motility. However, there is little information on how fertilization mode affects sperm evolution because several factors (e.g., sperm competition) are intricately intertwined when phylogenetically distant species are compared. Here, we investigated sperm characteristics by comparing seven externally and four internally fertilizing marine fishes from three different groups containing close relatives, considering sperm competition levels. The sperm head was significantly slenderer in internal fertilizers than in external fertilizers, suggesting that a slender head is advantageous for swimming in viscous ovarian fluid or in narrow spaces of the ovary. In addition, sperm motility differed between external and internal fertilizers; sperm of external fertilizers were only motile in seawater, whereas sperm of internal fertilizers were only motile in an isotonic solution. These results suggest that sperm motility was adapted according to fertilization mode. By contrast, total sperm length and sperm velocity were not associated with fertilization mode, perhaps because of the different levels of sperm competition. Relative testis mass (an index of sperm competition level) was positively correlated with sperm velocity and negatively correlated with the ratio of sperm head length to total sperm length. These findings suggest that species with higher levels of sperm competition have faster sperm with longer flagella relative to the head length. These results contradict the previous assumption that the evolution of internal fertilization increases the total sperm length. In addition, copulatory behavior with internal insemination may involve a large genital morphology, but this is not essential in fish, suggesting the existence of various sperm transfer methods. Although the power of our analyses is not strong because of the limited number of species, we propose a new scenario of sperm evolution in which internal fertilization would increase sperm head length, but not total sperm length, and change sperm motility.

Observations of Adult–Calf Nonreproductive Copulatory Behavior in North Atlantic Right Whales (Eubalaena glacialis)

Observations of Adult–Calf Nonreproductive Copulatory Behavior in North Atlantic Right Whales (Eubalaena glacialis)

Description of the courtship and copulation behaviours of the wall spider Oecobius concinnus (Oecobiidae)

Courtship and copulation behaviours are yet scantily described in many spider families, and this lack of information limits our understanding of the evolution of such behaviours within and across families. Here, we provide a detailed description of both courtship and copulation behaviour for Oecobius concinnus Simon, 1893. A striking characteristic of the male courtship is the construction of a tubular web (mating web) in which most courtship and copulation occurs. This web likely functions to restrain the female in a reduced space and as a substrate for male pheromones. The courtship consists of a complex web of interactions between both sexes, with some interactions being non-randomly performed.

Transcription factor gene Pea3 regulates erectile function during copulation in mice.

Male mice with homozygous loss of function mutations of the transcription factor gene Pea3 (Pea3 null) are infertile due to their inability to inseminate females, however the specific deficits in male sexual behaviors that drive this phenotype are unknown. Here, the copulatory behavior of male mice (Pea3 null and control) with hormonally primed ovariectomized females was monitored via high-speed and high-resolution digital videography to assess for differences in female-directed social behaviors, gross sexual behaviors (mounting, thrusting), and erectile and ejaculatory function. Pea3 null male mice exhibit greatly reduced erectile function, with 44% of males displaying no visible erections during copulation, and 0% achieving sustained erections. As such, Pea3 null males are incapable of intromission and copulatory plug deposition, despite displaying largely normal female-directed social behaviors, mounting behaviors, and ejaculatory grasping behavior. Additionally, the organization and timing of thrusting behaviors is impaired in Pea3 null males. Our results show that the transcription factor gene Pea3 regulates the ability to achieve and maintain erections during copulation in mice.

Comportamiento de apareamiento del tiburón limón Negaprion brevirostris (Carcharhiniformes: Carcharhinidae), revelado por la ciencia ciudadana en el Océano Atlántico Ecuatorial

Introduction: Knowledge on the copulatory behavior and mating ground requirements of large sharks, including the lemon shark, Negaprion brevirostris, is scarce, hampering conservation efforts. Objective: To describe an area in the Equatorial Atlantic used as a mating ground by N. brevirostris, as well as part of the species pre-copulatory behaviors based on citizen reports. Methods: Between 2004 and 2019, recreational divers, dive guides and rangers from the Marine Protected Area (MPA) in Fernando de Noronha Archipelago (FEN) recorded courtship behaviour, females with mating scars, pregnant females, and adult males. Results: N. brevirostris was recorded mating in shallow waters (0.5-2 m deep) during the austral summer (December to March). A specific location in the MPA, Buraco da Raquel lagoon, was the main aggregation and mating site for adult N. brevirostris in FEN. Conclusions: Citizen science records allowed the identification of shallow waters as key sites for the reproduction of this shark in FEN. Results highlight the potential of citizen science contributions to knowledge of sharks in nature and show MPAs as essential for habitat conservation of sharks with decreasing populations along the Brazilian coast, such as N. brevirostris. We present management recommendations to protect N. brevirostris there and elsewhere.

Postcopulatory Behavior of Tephritid Flies.

Mating produces profound changes in the behavior of female flies, such as an increase in oviposition, reduction in sexual receptivity, increase in feeding, and even excretion. Many of these changes are produced by copulation, sperm, and accessory gland products that males transfer to females during mating. Our knowledge on the function of the male ejaculate and its effect on female insects is still incipient. In this article, we review peri- and postcopulatory behaviors in tephritid flies. We address the effects of male copulatory behavior; copula duration; and the male ejaculate, sperm, and accessory gland products on female remating behavior. Many species from these families are pests of economic importance; thus, understanding male mating effects on female behavior contributes to both developing more effective environmentally friendly control methods and furthering our understanding of evolutionary implications of intersexual competition and sexual conflict.

Callosobruchus larval competition and its consequences for male and female adults

AbstractThe struggle for life is generally the most intense among individuals of the same species because they compete to access the same food, territory, and mates. In the current study, we used Callosobruchus maculatus to investigate how males and females respond to a competitor's presence inside a bean. We monitored males' and females' from egg to adult developmental time, adult emergence, copulation success, copulatory behaviors, fecundity, egg hatching percentage, and adult longevity. Our findings revealed that a competitor's presence during immature life did not influence developmental time and adult longevity in females and males. Also, the environmental condition of living with a potential competitor in the immature stages could not significantly affect adult beetle mating behaviors compared to beetles reared alone. However, female larvae were more likely to interfere with competitors than males. Females' neighbors died sooner (mainly in the larval stage) than males (primarily as pupae). Also, when we paired males and females whose competitors died in the larval stage, female adult longevity decreased compared to without competitor control pairs. However, male adult longevity in all examined pairs was similar and was not affected by their mate's conditions. A competitor's presence during larval development decreased the insect fecundity and, at the same time, increased egg hatching percentage in all treatments regardless of the competitor's sex, or if the competitor died, compared to the control (reared alone individuals). In all, females show more interference than males toward a potential competitor.

Does timing of post-stressor exposure mating matter for parental effect?

Stress and harsh environmental conditions affect an organism's life-history traits and may impact the following generation/s features and stress resistance by parental effect. However, it is unknown which time point after stressor exposure is better for mating and subsequent parental effect transfer to future generation/s. We assessed post-stressor exposure mating to evaluate whether early mating (an hour) or late mating (24 h) post stressors exposure would affect the parental effect. To address this issue, we used seed beetle Callosobruchus maculatus and mint and rosemary essential oils as environmental stressors to evaluate biological parameters, including immature development time, adult emergence, sex ratio, longevity, egg number, egg hatch, and copulatory behaviors. Results showed that the interval between stress exposure and mating affected parents' fitness. Thus, early-mated post-stressor-exposed females lived longer than late-mated females. However, mating timing did not influence male adult longevity. In the late-mated group, stress did not affect insects' mating behaviors, whereas adverse effects were recorded in early-mated beetles. Parents' stress exposure also did not alter biological parameters in the unexposed F1 generation. Then we let the F2 generation experience the same stressor as F0. Rosemary essential oil exposed late-mated grandparents produced grand offspring that laid more eggs with higher hatching rates than grand offspring of the control in response to rosemary essential oil. In other words, late-mated grandparents generated grand offspring who could better cope with the same stressor as F0. This study indicated that the interval between stress exposure and mating is important in the quality of parental effects. Parents having enough time for recovery could produce offspring and subsequently grand offspring more capable of coping with the same stressor.

Protective Effects of Epigallocatechin Gallate for Male Sexual Dysfunction in Streptozotocin-Induced Diabetic Rats.

Sexual dysfunction is a common problem for men with diabetes. Epigallocatechin gallate (EGCG) is known to ameliorate erectile function in aging rats. However, there has not yet been a report to evaluate its effects on diabetic male rat sexual behavior in the literature. In this study, we investigated the effects of EGCG on male sexual behavior in diabetic rats. Diabetic rats were induced by a single intraperitoneal injection of 65 mg/kg of streptozotocin. After streptozotocin injection for one week, animals were then orally treated with 40 mg/kg of EGCG or vehicle. Copulatory behavior and fasting blood glucose levels were recorded before treatment, as well as 7 and 14 days after treatment. Serum LH, testosterone, and PDE5a levels were measured by EIA assay after the last behavioral test. Data showed that diabetic rats who had diminished sexual functions demonstrated significantly increased latencies in mount, intromission, and ejaculation, as well as significant decreases in frequencies of intromission and ejaculation, compared to non-diabetic controls, indicating sexual function recovery. Lower blood glucose levels were also found in diabetic rats after EGCG treatment. Additionally, the lower LH and higher PDE5a levels in diabetic rats than controls were also noted. The findings declared that EGCG had a protective effect on male sexual behavior in diabetic rats.

Are superficial neuromasts proprioceptors underlying fast copulatory behavior?

In male Poeciliid fishes, the modified anal fin (i.e., gonopodium) and its axial and appendicular support are repositioned within the axial skeleton, creating a novel sexually dimorphic ano-urogenital region. During copulation, the relative location of the gonopodium is crucial for successful insemination. Therefore, the repositioning of these structures and organ relied on the reorganization of the efferent circuitry that controls spinal motor neurons innervating appendicular muscles critical for the movement of the gonopodium, including the fast and synchronous torque-trust motion during insemination attempts. Copulation occurs when a male positions himself largely outside a female’s field of view, circumducts his gonopodium, and performs a rapid, complex maneuver to properly contact the female urogenital sinus with the distal tip of the gonopodium and transfers sperm. Although understanding of the efferent circuitry has significantly increased in the last 24 years, nothing is known about the cutaneous receptors involved in gonopodium movement, or how the afferent signals are processed to determine the location of this organ during copulation. Using Western mosquitofish, Gambusia affinis, as our model, we attempt to fill this gap in knowledge. Preliminary data showed cutaneous nerves and sensory neurons innervating superficial neuromasts surrounding the base of adult male gonopodium; those cutaneous nerves projected ventrally from the spinal cord through the 14th dorsal root ganglion and its corresponding ventral root towards the base and fin rays of the gonopodium. We asked what role the cutaneous superficial neuromasts play in controlling the positioning and timing of the gonopodium’s fast and synchronous movements for effective sperm transfer. First, we found a greater number of superficial neuromasts surrounding the base of the male’s gonopodium compared to the base of the female’s anal fin. Second, we systemically removed superficial neuromasts surrounding the gonopodium base and observed significant impairment of the positioning and timing of gonopodial movements. Our findings provide a first step to supporting the following hypothesis: during radical reorganization of the Poeciliid body plan, superficial neuromasts have been partially co-opted as proprioceptors that allow the gonopodium to control precise positioning and timing during copulatory attempts.

Regulation of male sex hormones strongly heightens copulation behavior indices in rat's model administered Cocos nucifera husks extract.

Cocos nucifera (Coconut, Arecaceae family) is consumed as dietary fruit but little is known of it as sex enhancer. To investigate male sex hormones and copulation behavior indices in male Wistar rats administered husks extract. Rats were grouped into control A, and treatment B to E (n=4); and administered husks extract at varying doses: 125mg/kg, 250mg/kg, 375mg/kg and 500mg/kg for 48days by oral intubation. Copulation behavior was assessed by introducing female rats to males (1:1) in a rectangular Plexiglas chamber and monitored by veterinary Anatomists. Blood samples for male sex hormones were collected and assayed by ELISA method. Copulation behavior (500mg/kg treatment): mounting (9.66±0.79 to 29.08±2.16), ejaculation (7.66±0.38 to 16.93±0.76), intromission (22.01±1.67 to 38.11±3.35) frequencies, and ejaculation latency (7.92±0.43 to 12.28±0.41) increased remarkably (Group E). Correspondingly, mounting (133.31±1.18 to 93.39±0.43) and, intromission (88.13±3.12 to 74.55±1.19) latencies; post-ejaculation (3.16±0.14 to 2.18±0.34), inter-intromission (19.48±0.26 to 14.32±1.65) intervals reduced significantly (P≤0.05). Testosterone levels (Group E) increased: 3.82±0.6ng/dL to 5.14±0.3ng/dL while, LH and FSH values reduced: 2.92±0.6IU/L to 2.13±0.3IU/L and 2.28±0.7IU/L to 1.58±0.3IU/L significantly (p ≤ 0.05) while changes were dose-related. C. nucifera husks extract improves sexuality indices by regulating male sex hormones in male Wistar rats.

EFFICACY OF Nigella sativa OIL TO RELIEVE EFFECTS OF THE LEAD MONOXIDE TOXICITY ON TESTICULAR EFFICIENCY AND SEXUAL BEHAVIOUR DISORDERS IN ALBINO RATS

The prevalence of testicular toxicity induced via contamination with heavy metals is increasing worldwide, and a close connection between testicular toxicity and lead has recently been identified. The present study demonstrated the possible therapeutic and protection properties of Nigella sativa oil (NSO) against dangerous testicular toxicity and sexual behaviour disorders in rat models induced by lead monoxide (PbO) food poisoning. A total of 24 male rats were used and divided into four groups, consisting of Group 1: Control (1 mL of distilled water); Group 2: PbO (80 mg/kg); Group 3: NSO (0.5 mL/rat); and Group 4: (NSO+PbO) 0.5 mL/rat of NSO, followed by PbO (80 mg/kg/day) respectively for 60 days. The testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17 beta-hydroxysteroid dehydrogenase activity (17β-HSD), sperm parameters, and sexual behaviour (copulation behaviour test) were measured. The results showed that sex hormone levels were significantly decreased (p<0.05) in rats exposed to PbO, while the levels of these hormones were significantly higher in rats exposed to NSO and NSO+PbO. The sperm parameters (numbers, concentrations, motilities, and abnormality) were lower in rats exposed to PbO compared to those in the control, NSO, and NSO+PbO groups that showed significant increases. Sperm abnormality and 17β-HSD activity showed a significant increase at p<0.05 in the group exposed to the PbO compared to those of the control, NSO, and NSO+PbO groups. The results also significantly suppressed sexual behaviour in rats exposed to PbO compared to those in the control, NSO, and NSO+PbO groups, rats were administered NSO+PbO showed improvement in sexual behaviour parameters compared to PbO groups. PbO toxicity was obvious in the reproductive tract through severe histopathological changes. The impact of lead on tissues was partially mitigated by NSO. The study showed protective effects of N. sativa oil against changes in sex hormones, sperm characteristics, and sexual behaviour in male rats exposed to lead monoxide-induced testicular toxicity.