Females benefit from mating with different males in the scorpionfly Panorpa cognata

The adaptive significance of female polyandry has become a recurrentsubject of recent theoretical and empirical research. It hasbeen argued that in addition to direct benefits, such as nuptialgifts or an adequate sperm supply, females may gain geneticbenefits from mating with different males. Females of the scorpionflyPanorpa cognata mate with several males during their lifetime.In an experiment designed to rule out any direct nutritionalbenefit of multiple matings, I found that polyandrous femalesthat mated with two different males achieved a significantlyhigher egg-hatching success than monandrous females that matedtwice with the same male. However, individual males did nottrigger the same response in different females as the egg-hatchingsuccess of different females that mated with one and same maledid not correlate. The results, thus, do not conform to predictionsfrom hypotheses assuming that genetic benefits of polyandryare influenced by the intrinsic genetic quality of males. Theresults are, however, consistent with the genetic incompatibilityhypothesis. Nevertheless, substances from different males transferredduring copulation may synergistically affect zygote viability.Furthermore, I discuss why paternity studies can only explicitlytest the genetic incompatibility hypothesis if there are a prioriexpectations of female-male genome compatibilities.     

An evolutionary perspective of the origin of males from unisexual ancestral females

正The urge to understand the cause and evolution of sex both scientifically and philosophically is the result of the development of human civilization and a fascination regarding the existing phenomenon of sexual reproduction.Theories regarding the evolution of sex have been developed by many scientists such as Aristotle,Charles Darwin,August Weismann,Hermann Henking,Nettie Stevens,John Maynard Smith,the Charlesworths,Sarah P.Otto,and A.S.Kondrashov(Maynard Smith,1978;Kondrashov,1993;Bachtrog et al.,2014).Many theories tried to provide reasons behind the maintenance of sex,but a sequence in the     

Dwarf males

Dwarf males are often found in species with sedentary females, where they typically cohabit in varying degrees of intimacy. This is short of true parasitism because, in return for room and board, males provide the benefit of sperm. Sexual selection rarely seems to be an option to explain male dwarfing, whereas natural selection often can.     

Non-polar extracts of serum from males contain covert radioimmunoassayable testosterone

Non-polar extracts of sera from human males contain immunoreactive testosterone in a form that is released by mild alkaline hydrolysis. The non-polar derivative shows no immunoreactivity with testosterone antibody prior to hydrolysis. Hydrolyzed non-polar serum extracts from ten adult male volunteers contained 2.0 +/- 0.8 (SD) ng/mL of testosterone. Neither non-polar serum extracts of normal females nor a water blank substituted for non-polar extract of serum yields any immunoreactive testosterone after alkaline hydrolysis. Testosterone palmitate hydrolyzed alone or after addition to non-polar extract of serum yields the expected quantities of radioimmunoassayable testosterone. Previously described conjugates of testosterone are polar and are neither extractable by petroleum ether nor hydrolyzable by alkali. These observations suggest that fatty acid esters of testosterone may be present in serum of human males.     

Guarding males protect females from predation in a wild insect

Males frequently remain in close proximity to their mate immediately postcopulation. This behavior has generally been interpreted as a guarding tactic designed to reduce the likelihood that a rival male can rapidly displace the ejaculate of the guarding male [1, 2]. Such attempts by males to control their mates represent a potential source of conflict [3-5], but guarding behaviors in species where it is difficult for males to control their mates suggest that conflict is not inevitable [6, 7]. We employed a network of infrared video cameras to study a wild population of individually marked and genotyped field crickets (Gryllus campestris). Lone females or males suffer similar rates of predation, but when a pair is attacked, the male allows the female priority access to their burrow, and in doing so dramatically increases his probability of being killed. In compensation for this increased predation risk, paired males mate more frequently and father more of the female's offspring. By staying with a male, females increase the sperm contribution of preferred males as well as reducing their predation risk. In contrast to conclusions based on previous lab studies, our field study suggests that mate guarding can evolve in a context of cooperation rather than conflict between the sexes.     

Drosophila dosage compensation: males are from Mars, females are from Venus

Dosage compensation of X-linked genes is a phenomenon of concerted, chromosome-wide regulation of gene expression underpinned by sustained and tightly regulated histone modifications and chromatin remodeling, coupled with constrains of nuclear architecture. This elaborate process allows the accomplishment of regulated expression of genes on the single male X chromosome to levels comparable to those expressed from the two X chromosomes in females. The ribonucleoprotein Male Specific Lethal (MSL) complex is enriched on the male X chromosome and is intricately involved in this process in Drosophila melanogaster. In this review we discuss the recent advances that highlight the complexity lying behind regulation of gene expression by just two-fold.     

Exoskeleton anomalies in taiga tick males from populations of the Asian part of Russia

Variation of the exoskeleton is described for 2630 males of the taiga tick Ixodes persulcatus Schulze, 1930 collected by flagging from vegetation in the Far Eastern, Siberian, and Ural Federal Districts of Russia. Two types of conscutum anomalies were found to be prevalent in all the samples. Exoskeleton anomalies were less frequently recorded in the Far Eastern Federal District than in the Siberian and Ural Federal Districts: 6.5 ± 1.05, 29.7 ± 1.03, and 25.8 ± 3.93%, respectively. The observed phenotypic variation seems to be unrelated to anthropogenic impact. In the meridional direction, the taiga tick samples with different frequencies of exoskeleton anomalies correspond to two races of the species.     

The physique of young males in east Africa from the biosocial point of view

The aim of this study is to show the correlation between the physique of Africans from Kenya, Tanzania, Sudan and the conditions of their biosocial environment. All the young men examined were from Kenya (N=423), Tanzania (N= 153) and Sudan (N=154) aged 18 to 30. Based on the taken measurements (height, weight, sitting height, physiognomic leg length and chest, waist, hip, left thigh and left arm circumferences) the following indices were calculated: Body Mass Index (BMI), Rohrer's index and skelic index. The birth date, the number of children per ménage (in family), and the birth sequence of the examined subject were inquired. The measurement results were elaborated (worked out) statistically in accordance with commonly accepted standards. All the information contained in the collected material within the analysed countries was compared. On the basis of the measured traits and calculated indices it was found that the morphological constitution of the men from Sudan differed. Typical for this group are the largest stature length and the lowest weight and waist measurements. Kenyans are similar to Tanzanians, although the latter have higher weight, hip and thigh measurements and lower chest circumference. The characteristics of the examined Africans' morphological structure were analysed in comparison with the data available in literature and relating to the number of children in family, population density, illiteracy and the growth of income and of the HIV/AIDS problem.     

The occurrence of reactive oxygen species in the semen of males from infertile couples

The aim of this pilot study was to establish a reactive oxygen species (ROS) evaluation method as a step in the routine diagnosis of men from infertile couples, which attend the Centre of Assisted Reproduction at the Teaching Hospital in Olomouc. Standard semen analyses were performed manually according to WHO guidelines. The number of peroxidase-positive leukocytes in the semen was determined using the Endtz test. The levels of ROS were estimated by chemiluminescence assay using luminol (5-amino-2,3 dihydro-1,4 phthalazinedione) as a probe. The semen samples were collected from 68 patients. Normospermia was found in 15 patients (22.1 %). The semen samples of 3 normospermic patients were classified as ROS-positive. Elevated ROS production was recorded in all subgroups of patients irrespective of any pathology found. We confirmed that spermatozoa might be the source of ROS as well as the seminal leukocytes. Apart from the leukocytes, sperm cells with residual cytoplasm and immature spermatozoa are considered to be a major source of ROS. Thus it is suggested that sperm morphology abnormalities should be evaluated more carefully.     

The sodium-22 influx in erythrocytes from black males and females

In order to establish a standard for sodium influx in erythrocytes for the black population, 22Na+ uptake was measured in 29 normotensive black volunteers. Nineteen males and 10 females during the follicular phase of the menstrual cycle were studied utilizing the procedure of Gambhir et al. (1). In the males, cell concentrations ranging from 0.64 to 2.0 X 10(9)/ml showed an influx of 0.42 to 1.34% of the total 22Na+ added, and in the females, using the same erythrocyte concentrations, the 22Na+ influx ranged from 0.37 to 1.1%; these differences were not significant. Intraassay variation of the 22Na+ data was 4.8%. Interassay variations have been explained elsewhere (1). These data provided a range of observed values for 22Na+ uptake in erythrocytes from a subpopulation of normotensive black males and females for comparison with hypertensive patients.     

Characteristics of associated microflora of ejaculate from males with gonococcal infections

Species composition and biological properties of aerobic and anaerobic microflora from an ejaculate from males with acute and chronic gonococcal infection and from healthy men were studied. Patients with gonococcal infection were shown to present quantitative and qualitative changes in microbiocenosis of the reproductive tract. Patients with acute gonorrhea displayed decreased species diversity in contrast to healthy persons, while different species of associated with gonococci microbes with high persistent potential, were cultured in patients suffering from a chronic form of infection. The role of revealed pathological biocenosis patterns in developing chronic infection as well as postgonorrheal gonococci-free urethritis is discussed.     

Serotonin contents in the hypothalamus of adult males, females and males castrated during the neonatal period

The aim of the present work was to study the character of the change in serotonin level in the anterior and medial basal hypothalamus of adult rats after the effect of testicular hormones had been switched off on the first day of postnatal life. It was shown in our work that in males serotonin level was significantly lower than that in females by 67 and 46% in the anterior and medial basal hypothalamus, respectively. Castration of newborn males resulted in a significant increase in serotonin level in both anterior and medial basal hypothalamus-up to the level observed in females. It is supposed that the male sex hormones affect differentiation of serotoninergic system of the brain.     

Volatile compounds from young peach shoots attract males of oriental fruit moth in the field

Abstract

The oriental fruit moth (OFM) is one of the most serious pests of commercial fruit orchards worldwide. Newly planted peach trees in particular, can be very attractive for mated OFM females for oviposition. Samples of airborne host plant volatiles from intact young peach shoot tips and old leaves of the same potted plants were collected and analyzed with a gas chromatograph-mass spectrometer. Chemicals present in young shoot tips, but not in old leaves, were used for field trials. Moth capture by traps with the synthetic chemicals was compared to that of the standard terpinyl acetate (TA) food trap. The TA food trap caught OFM males and mated females, but tested synthetic chemicals trapped only OFM males. We observed that the mixture of (Z)-3-hexenyl acetate: (E)-β-ocimene: (E)-β-farnesene in proportion 1:2:2 attracted OFM males. Further, 1 mg of (E)-β-ocimene, and that of (E)-β-farnesene also attracted OFM males.     

Natural selection and genetic variation for female resistance to harm from males

The sexual conflict hypothesis predicts that males evolve traits that exploit the higher parental investment of females, which generates selection for females to counter-evolve resistance. In Drosophila melanogaster it is now established that males harm females and that there is genetic variation among males for the degree of this harm. Genetic variation among females for resistance to harm from males, and the corresponding strength of selection on this variation, however, have not been quantified previously. Here we carryout a genome-wide screen for female resistance to harm from males. We estimate that the cost of interactions with males depresses lifetime fecundity of females by 15% (95% CI: 8.2-22.0), that genetic variation for female resistance constitutes 17% of total genetic variation for female adult fitness, and that propensity to remate in response to persistent male courtship is a major factor contributing to genetic variation for female resistance.     

Supernumerary chromosomal elements in lymphocytes cultured from phenotypically normal human adult males

In a group of phenotypically normal men there were approximately 0.24% of metaphase lymphocytes with extra chromosomal elements along with the regular 46 chromosomes. They ranged in size from small acrocentric-acentric elements to elements longer than any chromosome arm. These elements have been referred to as supernumerary chromosomal elements. No significant effects due to donor's age, smoking history, season, storage of blood samples prior to culture, or culture medium, were found either in the frequency of supernumerary elements per cell or in the frequency of cells with supernumerary elements. Furthermore, the same subject did not consistently exhibit supernumerary elements. Furthermore, the same subject did not consistently exhibit supernumerary elements when sampled during four successive quarters of the year. Some of these elements in pairs were identified by G-banding technique as translocation chromosomes bearing long arms of chromosome number 2 and presumptive short arms of chromosome 8, acentric long arms of chromosome 4, and iso-acentric chromosomes for the long arms of chromosome 5. Presumably, more than one type of cytogenetic event occurred in their formation. Circumstantial evidence has been presented to show that the means of elimination of these supernumerary elements is a process of chromosomal disintegration.     

Y chromosome microdeletions in infertile males from Andhra Pradesh, South India

Studies on the frequency of Y chromosome microdeletions were carried out in 70 idiopathic infertile males with normal karyotypes. Genomic DNA was isolated from blood and PCR analysis was carried out with AZFa, AZFb, and AZFc STS markers SY 84, SY 87, SY 127, SY 254, and SY 158 to detect the deletions. In 9/70 (12.8%) subjects AZF deletions were observed. In 4/9 (44.4%) subjects were azoospermic, 4/9 (44.4%) of cases were severe oligozoospermic, and 1/9 (11.1%) cases was oligozoospermic.