Sexually dimorphic body proportions in the catshark genus Scyliorhinus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae)

Intersexual differences in morphometrics were investigated in five species of the catshark genus Scyliorhinus. ANCOVA was used to test 59 measurements, considering capture location and total length as covariates. In all examined species, pelvic–anal distances and pelvic-fin inner margin lengths were greater in males than in females, representing a clear pattern for the genus.     

Biochemical and physiological characteristics of semen of sex-reversed female rainbow trout (Oncorhynchus mykiss, Walbaum)

This works studies the biochemical (protein concentration, osmolality, antitrypsin activity, lactate dehydrogenase activity) and physiological characteristics (sperm motility characteristics) of semen of sex-reversed female rainbow trout (n = 42) obtained with the application of 11β-hydroksyandrostendione for sex reversal. All data were arbitrarily divided into three classes depending on the percentage of sperm motility: I XX < 25%; II XX 25-50% and III XX > 50%. The average percentage of sperm motility was 18 ± 7% n = 12 (group I XX); 42 ± 6% n = 15 (group II XX) and 65 ± 12% n = 15 for group III XX, respectively) to link the values of semen parameters to the maturation stage of semen. Semen from 12 normal males of the same age was used as a reference group. Sperm concentration as well as protein concentration, osmolality, antitrypsin activity, and lactate dehydrogenase activity in seminal plasma of sex-reversed females were higher compared with the values obtained for normal male rainbow trout. The values of these parameters declined with the increasing percentage of sperm motility toward values established for normal males. The fertilization success of semen (3 × 10⁶ spermatozoa/egg) of sex-reversed females was very high (above 90%) for both the percentage of eyed embryos and hatched larvae and was related to sperm motility classes. Correlations between the quality parameters of sex-reversed females semen corresponded to those established previously for the semen of normal male rainbow trout. Antitrypsin activity, lactate dehydrogenase, protein concentration, and osmolality were found to be characteristic of seminal plasma of sex-reversed females. The maturity of sex-reversed female spermatozoa seems to be associated with the decline in the values of those parameters toward the values characteristic for seminal plasma of normal males.     

Do old female monkeys have a specific social role?

The role of the aged in human society has received much attention from gerontologists, and the notion of a social role for aged monkeys is common in primatology. Four hundred and fifty hours of focal animal data were collected on a sample of 40 adult female Japanese monkeys. The animals are semi-free ranging and of known age. These data were analyzed in an attempt to determine whether old females constitute a behaviorally distinct subgroup. Very little behavioral variation based on age could be documented. Where age related variation occurs, it is better explained as a function of youth, rather than as a function of old age. The expectation that old monkeys will occupy a distinct social role because of their advanced age is discussed in terms of biological versus social aging, human versus non human aging, the evolution of behavioral change in old age, and the application of the social role concept to old female monkeys. It is concluded that there is little evidence that the behavior of the aged females differs significantly from that of the other adult females, and it does not appear that the fact of biological aging creates any radically different social situation which would cue the onset of specific role behavior for aged animals.     

Circadian rhythm of cholesterol synthesis in mouse liver: a statistical analysis of the post-squalene metabolites in wild-type and Crem-knock-out mice

Circadian rhythms affect the total cholesterol levels in humans and animals, although their effect on cholesterol synthesis remain poorly understood. Here, we show for the first time that intermediates of the post-squalene portion of cholesterol synthesis also follow a circadian rhythm in the mouse liver. We used Crem-knock-out mice to investigate the effects of cAMP response element modulator (CREM) isoforms on cholesterol synthesis over time, as compared to wild-type mice. Multiple linear regression and cosinor statistical analysis were carried out on data obtained from 166 liver samples of mice, and the 24-h profiles were modelled across genotype, gender and zeitgeber time for lanosterol, 24,25-dihydrolanosterol, testis meiosis-activating sterol, and 7-dehydrocholesterol, along with cholesterol. The levels of these sterols were higher in female mice compared to males, although the genotype/gender factors showed no effects on the circadian oscillation of these sterols, except for 24,25-dihydrolanosterol. This study also highlights the importance of the statistical methods, where time, genotype and gender are the studied variables.     

Social factors increase fecal testosterone levels in wild male gray-cheeked mangabeys (Lophocebus albigena)

Testosterone can be expected to play a significant role in mediating behavior and life history in social animals, but the number of species with data from the wild is still too small to make generalizations. We investigated the influence of social factors (social status, aggression, and reproductive females) and environmental variation (rainfall and temperature) on fecal testosterone concentrations in wild male gray-cheeked mangabeys (Lophocebus albigena) living in five groups in Kibale National Park, Uganda. This species is phylogenetically closely related to baboons, but is arboreal, with multi-male, multi-female groups rarely exceeding 20 individuals. We analyzed 358 fecal samples from 21 adult males. We found that the highest-ranking males had the highest testosterone concentrations while immigrant males had the lowest testosterone concentrations. Aggression was not correlated with testosterone levels. The presence of females with sexual swellings at their most tumescent stage increased testosterone concentrations in all males. Finally, individuals tended to have lower testosterone when the temperature was higher.     

Response of workers of Atta sexdens rubropilosa (Hymenoptera: Formicidae) to mandibular gland compounds of virgin males and females

Abstract.  The secretion from the mandibular glands of males of the leaf-cutting ant Atta sexdens rubropilosa is responsible for the reaction of workers outside the nest at the time of sexual swarming. Workers respond with excitability and aggression when presented with the natural mixture of 4-methyl-3-heptanol and 4-methyl-3-heptanone, which is contained in the secretion of the male mandibular glands. Workers respond quickly to fractional amounts of one male equivalent. 4-Methyl-3-heptanone, from the virgin female mandibular glands causes much less response in workers, whereas an equimolar mixture of male and female pheromones gives a still less clear response. The male pheromone plays the most important part in the communication of workers outside the nest at this time.     

Association of ANRIL polymorphism (rs1333049:C>G) with myocardial infarction and its pharmacogenomic role in hypercholesterolemia

Single nucleotide polymorphisms (SNPs) of non-coding RNA in the INK4 locus (ANRIL) have been found to be associated with myocardial infarction (MI). However, the effect of rs1333049:C>G in INK4 locus in familial hypercholesterolemia patients and on lipid profile of the patients has not been studied in Pakistan. We therefore investigated the association of SNP rs1333049:C>G with MI as well as familial hypercholesterolemia patients and also determined the effect of genotype on lipid levels in a northern Pakistani population. A case–control association study was performed in which 611 individuals (294 patients, 290 healthy controls and 27 patients from hypercholesterolemia families) were genotyped for rs1333049:C>G, using an Allele specific polymerase chain reaction. We found a significant association of rs1333049:C>G with MI (χ² = 22.3, p < 0.001). The frequency of risk genotype CC was significantly different from the healthy controls (p < 0.001, χ² = 22.3). The risk allele C was at a higher frequency in the MI patients as compared to the controls (odds ratio [OR] = 1.55 (95% confidence interval [CI] = 1.22–1.96), p < 0.001). The logistic regression analysis for the genotype distribution resulted in strong association of risk allele C with MI under recessive model (OR = 3.17 (95% CI = 1.85–5.44) p < 0.001). When the data were further analyzed along the lines of gender, a significant association with both males and females was observed.     

Social organization of white‐headed langurs (Trachypithecus leucocephalus) in the Nongguan Karst Hills,Guangxi, China

The number of males per group is the most variable aspect of primate social organization and is often related to the monopolizability of females, which is mainly determined by the number of females per group and their reproductive synchrony. Colobines show both inter‐specific and intra‐specific variations in the number of males per group. Compared with other colobine species, little is known about the social organization of white‐headed langur (Trachypithecus leucocephalus), despite its endangered status and unusual limestone habitat. As a part of a long‐term study of the white‐headed langurs in the Nongguan Karst Hills, Guangxi, China, we quantitatively investigated their social organization by analyzing census data from 1998 to 2003. The population censuses revealed that the predominant social organization of bisexual groups was the one‐male group, similar to a previous report on this species and many other Asian colobines. In such groups, one adult male associated with 5.1 adult females, 0.1 sub‐adult males, 2.6 juveniles and 2.9 infants on average, with a mean group size of 11.7 individuals. In addition, three multi‐male groups were recorded, consisting of 2–3 adult males, 1–5 adult females, 0–2 sub‐adult males, 0–7 juveniles and 0–2 infants. They did not contain more adult females than the one‐male groups and were unstable in group membership. The langurs outside bisexual groups were organized into small nonreproductive groups or lived as solitaries. The nonreproductive groups averaged 1.3 adult males, 1.3 sub‐adult males and 2.6 juveniles. Juvenile females were present in such groups on 52.4% of all occasions. As predicted by the monopolization model, the prevalence of the one‐male pattern in this species may mainly be attributed to the small number of females in the group. The possible reasons for the occurrence of multi‐male groups and the presence of juvenile females in nonreproductive groups are also discussed. Am. J. Primatol. 71:206–213, 2009. © 2008 Wiley‐Liss, Inc.     

Effects of three organophosphorus pesticides on population growth and sexual reproduction of rotifer Brachionus calyciflorus Pallas

Effects of organophosphorus pesticides including dichlorvos, triazophos and chlorpyrifos on population growth and sexual reproduction of freshwater rotifer Brachionus calyciflorus were studied by 3-d population growth and 4-d resting egg production tests. The results showed that all the three organophosphorus pesticides influenced significantly the population growth rate, the ratio ovigerous females/non-ovigerous females in the rotifer populations and the resting egg production of the rotifers. Both dichlorvos and chlorpyrifos influenced markedly the mictic rate of the rotifers, but triazophos did not. Compared to the controls, both dichlorvos at 10.0–1000.0 μg/L and chlorpyrifos at 0.01–100.0 μg/L increased the population growth rate, but the reverse was also true for dichlorvos and triazophos both at 10000.0 μg/L. Chlorpyrifos at 10000.0 μg/L made the rotifers dead after 24-hr exposure. Dichlorvos and triazophos both at 10000.0 μg/L, and chlorpyrifos at 1000.0 μg/L all increased the ratio ovigerous females/non-ovigerous females. Both dichlorvos at 10000.0 μg/L and chlorpyrifos at 0.1–100.0 μg/L increased the mictic rate. Dichlorvos at 10.0 μg/L and 100.0 μg/L, and triazophos and chlorpyrifos both at 0.1–100.0 μg/L increased the resting egg production. Both population growth rate and ratio ovigerous females/non-ovigerous females are suitable endpoints for assessing the effects of dichlorvos, triazophos and chlorpyrifos, and mictic rate is a suitable endpoint for monitoring the effects of dichlorvos and chlorpyrifos on the reproduction of the rotifers. Both population growth rate and ratio ovigerous females/non-ovigerous females are more sensitive to dichlorvos and chlorpyrifos than mictic rate.     

Reproductive tactics influence cortisol levels in individual male gray-cheeked mangabeys (Lophocebus albigena)

Concentration of the hormone cortisol is often used as an indicator of stress, and chronically high cortisol levels are often associated with poor health. Among group living animals that compete for resources, agonistic social interactions can be expected to contribute to variation in cortisol levels within and among individuals over time. Reproductive tactics of males can change with individual quality, relatedness, and social structure, and affect cortisol levels. In gray-cheeked mangabey (Lophocebus albigena) groups, male rank is an important factor in social interactions, and males also move between groups while actively competing for females or sneaking copulations. During a 20-month study we observed the social behavior and collected 461 fecal samples from 24 adult male gray-cheeked mangabeys from five groups in Kibale National Park, Uganda. Aggressive interactions and the presence of females at the peak of sexual swelling were associated with elevated cortisol concentrations in all males. Independently, dominant (i.e., highest-ranking) males within groups had higher cortisol concentrations than subordinate males, and immigrant males had higher cortisol concentrations than dominant males.