Brain size varies greatly at all taxonomic levels. Feeding ecology, life history and sexual selection have been proposed as key components in generating contemporary diversity in brain size across vertebrates. Analyses of brain size evolution have, however, been limited to lineages where males predominantly compete for mating and females choose mates. Here, we present the first original data set of brain sizes in pipefishes and seahorses (Syngnathidae) a group in which intense female mating competition occurs in many species. After controlling for the effect of shared ancestry and overall body size, brain size was positively correlated with relative snout length. Moreover, we found that females, on average, had 4.3% heavier brains than males and that polyandrous species demonstrated more pronounced (11.7%) female-biased brain size dimorphism. Our results suggest that adaptations for feeding on mobile prey items and sexual selection in females are important factors in brain size evolution of pipefishes and seahorses. Most importantly, our study supports the idea that sexual selection plays a major role in brain size evolution, regardless of on which sex sexual selection acts stronger.
Matched MeSH terms: Sexual Behavior; Sexual Behavior, Animal*
This paper examines data on the sexual activities of 1,200 Malaysian adolescents aged 15-21 years based on a probability household sampled survey carried out in Kuala Lumpur in 1986. Sexual behaviours like premarital sexual intercourse, contraceptive usage and masturbation were presented. Of the 1,181 unmarried respondents, 9% (105) reported having had sexual intercourse; males were significantly more experienced compared to females. Older age groups were also found to be more sexually active than the younger ones. Among those who had experience dating (n = 521), 20% (105) have experienced sexual intercourse, 44% (228) have kissed and necked, and 35% (183) have experienced petting, while 24% (130) have had no physical intimacies. Poor use of contraception was also revealed. The most commonly used were condoms, oral contraceptives and withdrawal. With regard to masturbation, males begin this practice relatively earlier than females. Almost half of those who indulged in masturbation were worried by the act, especially the females. Implications of the findings are discussed.
Delayed tooth eruption (DTE) is the emergence of a tooth into oral cavity that
deviates from norms established for different races, ethnics and sexes, which commonly caused
either by local or systemic conditions. (Copied from article).
With the availability of the Internet, pornographic materials are readily accessible. Pornographic materials may have a link to addiction and other deviant sexual behaviour. In this case report, we highlighted a link between voyeuristic disorder and internet sex addiction. Mr. SK is a 22-year-old single gentleman who was referred for psychiatric assessment due to voyeuristic acts. He had been watching pornographic materials since 16 years old and became addicted to it.
Mating behavior between Aedes aegypti and Ae. albopictus, established colony strains were examined under laboratory conditions (30-cm(3) screened cages) for 5 consecutive days. The effect of selected male densities (30, 20, 10) and female density (20) on the number of swarming, mating pairs, eggs produced, and inseminated females were evaluated. Male densities significantly increased swarming behavior, mating pairs, and egg production of heterospecific females, but female insemination was reduced. Aedes aegypti males mate more readily with heterospecific females than do Ae. albopictus males. The current study suggests that Ae. aegypti males were not species-specific in mating, and if released into the field as practiced in genetically modified mosquito techniques, they may mate with both Ae. aegypti and Ae. albopictus females, hence reducing populations of both species by producing infertile eggs.
We examined the growth, reproduction, rutting behavior, and health status of sambar deer (Cervus unicolor brookei) in secondary Acacia mangium plantation. The data were collected over 11 years from a breeding herd of 21 stags and 33 hinds in Sabal Forest Reserve, Sarawak, Malaysia. Brody's growth model of the pooled data is Y t = 148.56 (1 - 0.98e(-0.023t)), which estimates that maximum weights of adults are 184 and 115 kg for males and females respectively. Sambar deer are nonseasonal breeders with the breeding peak in February. Although the earliest age at which a female reached sexual maturity was 11 months, the mean age was 23 ± 7 months. Mean age of first fawning was 32 ± 8 months. Mean gestation period was 259 ± 12 days (n = 82). Stags shed antlers mostly between March and July. Velvet hardens at 103 ± 27 days (n = 23), and velvet harvesting is best at 7-9 weeks when antler length is 25-30 cm. Sambar deer are suitable as a farm species in forest plantations and have a vast potential to uplift rural living standards.
We conducted the world's first experiments under semi-field conditions (ACL-2 field house) to assess the mating competitiveness of genetically sterile RIDL male mosquitoes (513A strain). The field house is a state-of-the-art, fully-contained trial facility, simulating the living space for a household of 2-4 people in Peninsular Malaysia. Ten genetically sterile RIDL male A. aegypti mosquitoes competed with ten wild type males inside this field house to mate with ten wild type females. Hatched larvae from mated females were screened under a fluorescent microscope for genetic markers to determine if they were fathered by RIDL male or wild type male, and all results were cross-checked by PCR. Two such experiments were conducted, each repeated sufficient number of times. All strains were on a Malaysian lab strain background for the first experiment, while the RIDL males alone were on a recently-colonised Mexican strain background for the second experiment. A total of 52 % of the matings were with RIDL males in the first experiment, while 45 % of the matings were with RIDL (Mexican) males in the second experiment. Statistically, this is not significantly different from 50 % of the matings expected to take place with RIDL males if the latter were as competitive as that of the wild type males. This shows that A. aegypti RIDL-513A has excellent mating competitiveness under semi-field conditions, verifying earlier trends obtained in small lab cages. We also observed high mating compatibility between recently-colonised Mexican RIDL males and lab-reared Malaysian wild type females.
Matched MeSH terms: Sexual Behavior, Animal/physiology
BACKGROUND: International students make up an increasing proportion of university students in Australia. Research suggests that they have poor sexual health knowledge compared with local students.
METHODS: Thematic analysis was undertaken on focus groups carried out at the University of Adelaide (South Australia), with 21 female international students from Malaysia and China.
RESULTS: Four themes were identified: poor sexual health knowledge; complex attitudes about premarital sex; difficulty accessing sexual health information, and poor understanding the role of general practitioners in this area; and ideas about future education.
DISCUSSION: Participants believed that international students have insufficient sexual health education when they arrive in Australia. They were concerned that some students may become more sexually active in Australia, and may not have adequate access to health services and information. All participants felt it was necessary for international students to receive better sexual health education. International students are important to Australian universities, and it should be mandatory to ensure that culturally appropriate sex education is made available to this group.
Extra-group paternity (EGP) occurs commonly among group-living mammals and plays an important role in mating systems and the dynamics of sexual selection; however, socio-ecological and genetic correlates of EGP have been underexplored. We use 23 years of demographic and genetic data from a high-density European badger (Meles meles) population, to investigate the relationship between the rate of EGP in litters and mate availability, mate incompatibility and mate quality (heterozygosity). Relatedness between within-group assigned mothers and candidate fathers had a negative quadratic effect on EGP, whereas the number of neighbouring-group candidate fathers had a linear positive effect. We detected no effect of mean or maximum heterozygosity of within-group candidate fathers on EGP. Consequently, EGP was associated primarily with mate availability, subject to within-group genetic effects, potentially to mitigate mate incompatibility and inbreeding. In badgers, cryptic female choice, facilitated by superfecundation, superfoetation and delayed implantation, prevents males from monopolizing within-group females. This resonates with a meta-analysis in group-living mammals, which proposed that higher rates of EGP occur when within-group males cannot monopolize within-group females. In contrast to the positive meta-analytic association, however, we found that EGP associated negatively with the number of within-group assigned mothers and the number of within-group candidate fathers; potentially a strategy to counter within-group males committing infanticide. The relationship between the rate of EGP and socio-ecological or genetic factors can therefore be intricate, and the potential for cryptic female choice must be accounted for in comparative studies.
A module entitled 'SayangKU' (MyLove), based on the Islamic perspective, was developed as an instrument to assist adolescents that involved in premarital sexual activity. The module comprises four phases: Love of God (Allah), Love of the Prophet, Love of Oneself, and Love of the Ummah (world). From analysis of Rasch, the value of item reliability was .80 and an individual reliability was .95. Dimensionality value was more than 40 % variance explained by measures, and level of agreement among experts was 86.88 %. The posttest shows the better result from pretest and proves the effectiveness of the module.
The mating behaviors of the proboscis monkey were observed in a riverine forest along a tributary of the Kinabatangan River, Sabah, Malaysia, for a period of 30 months. Solicitation for copulation was initiated frequently by males and occasionally by females. Most copulations involved only one mount; however, some multiple-mount copulations were observed and a maximum of six mounts per copulation were recorded. The mean duration of mounts was about 27 sec. Nonsexual mounts (female-female, female-juvenile/infant, juvenile-juvenile, and juvenile-infant) were also observed. Female-female mounts occurred shortly after failed solicitations toward males were observed. Harassment by juveniles and/or infants was observed during copulation; however, these harassments apparently did not interfere with copulation. Sexual swelling was evident in 77.4% of copulating females, with copulating subadult females showing the most distinct swelling.
Many groups of land snails show great interspecific diversity in shell ornamentation, which may include spines on the shell and flanges on the aperture. Such structures have been explained as camouflage or defence, but the possibility that they might be under sexual selection has not previously been explored.
Matched MeSH terms: Sexual Behavior, Animal/physiology*
The aim of this study is to provide evidence on the aphrodisiac property of Eurycoma longifolia Jack. An electric grid was used as an obstruction in the electrical copulation cage in order to determine how much an aversive stimulus the sexually naive male rat for both the treated with E. longifolia Jack and control groups were willing to overcome to reach the estrous receptive female in the goal cage. The intensity of the grid current was maintained at 0.12 mA and this was the intensity in which the male rats in the control group failed to crossover to reach the goal cage. Results showed that E. longifolia Jack continued to enhance and also maintain a high level of both the total number of successful crossovers, mountings, intromissions and ejaculations during the 9-12th week observation period. In conclusion, these results further enhanced and strengthened the aphrodisiac property of E. longifolia Jack.
Matched MeSH terms: Sexual Behavior, Animal/drug effects*
The effects of Eurycoma longifolia JACK were studied on the orientation activities of sexually experienced male rats towards receptive females (mounting, licking, anogenital sniffing), environment (exploration, raring, climbing), themselves (genital grooming, non-genital grooming) and mobility (unrestricted, restricted) after dosing them with 200, 400 and 800 mg/kg body weight twice daily for 10 d prior to the test. The results showed that E. longifolia JACK modified the orientation activities of the treated male rats in that they significantly displayed more frequent and vigorous mounting, licking and anogenital sniffing towards the receptive females, and it further intensified self orientation as indicated by the increased grooming of the genitals compared to the controls (p<0.05). In addition, rats treated with 800 mg/kg of methanol, water and butanol extracts of E. longifolia JACK continued to show confinement to a particular area of the cage (around the female), thus showing restriction in movement as compared to the controls (p<0.05). However, the treated males possessed a lack of interest in the external environment as indicated by a reduction in exploration, raring and climbing on the cage wall. Hence, the present study further supports the folk use of E. longifolia JACK as an aphrodisiac.
Matched MeSH terms: Sexual Behavior, Animal/drug effects*
Reciprocal and homologous mating experiments between Malaysian Aedes aegypti and Aedes albopictus mosquitoes were conducted in the laboratory. Two methods were employed, namely an artificial mating technique and a natural cage mating technique. The study demonstrated there exists a strong reproductive isolation between Ae. aegypti and Ae. albopictus. Insemination occurred in cross-mating experiments between Ae. aegypti females and Ae. albopictus males and also between Ae. albopictus females and Ae. aegypti males. Cross mating between Ae. aegypti females and Ae. albopictus males produced more eggs than that between Ae. albopictus females and Ae. aegypti males with both artificial mating and natural cage mating techniques. The matings did not result in the production of viable eggs by the females. No embryonation of these eggs was observed when the eggs were bleached. With homologous mating Aedes aegypti produced significantly greater numbers of eggs compared to Aedes albopictus mosquitoes, and all the eggs hatched successfully.
Matched MeSH terms: Sexual Behavior, Animal/physiology*