Male Density Research Articles

Abstract 422: Protease-Activated Receptor 2 is Critical for the Formation and Progression of Atherosclerosis

Objective: Protease-activated receptor 2 (PAR-2)-dependent signaling results in augmented inflammation and has been implicated in the pathogenesis of several autoimmune conditions. While PAR-2 protein is present in coronary atherosclerotic lesions, the relevance of this finding has not been investigated in experimental models. The objective of this study was to determine the effects of PAR-2 on the development of atherosclerosis. Methods and Results: Relative expression of PAR-2 is increased in human coronary artery (21 fold) and mouse aortic arch (16 fold) atheromas versus control coronary and aortic arch arteries, respectively (P = 0.001). To determine the effect of PAR-2 deficiency on atherosclerosis, male low density lipoprotein receptor deficient ( Ldlr -/- ) mice (8-12 weeks old) that were Par-2 +/+ or Par-2 -/- were fed a fat and cholesterol-enriched diet for 12 (n = 10 each group) or 24 weeks (n = 5 each group). PAR-2 deficiency attenuated atherosclerosis in the aortic sinus and aortic root with no effects on total plasma cholesterol concentrations or lipoprotein distributions after 12 (P = 0.000433) and 24 (P = 0.037) weeks. These reductions were attributable to both hematopoietic and non-hematopoietic-derived PAR-2 from analysis of bone marrow experiments (n = 15 for each of 4 chimeric groups; P < 0.05). Mechanistic studies using ex vivo macrophages show that activation of PAR-2 results in augmented foam cell formation and apoptosis with treatment of oxidized low-density lipoprotein in conjunction with decreased expression of the nuclear receptor LXR-alpha and several cholesterol transporters. In addition, PAR-2 activation of ex-vivo cultured vascular smooth muscle cells (VSMCs) augments their transition to a macrophage-like state (after cholesterol treatment) via upregulation of human antigen R (HuR) and resultant stabilization of the transcription factor Krüppel-like factor 4 (KLF4). Conclusion: Our results indicate PAR-2 deficiency significantly attenuates the initiation (12 weeks) and reduces the progression (24 weeks) of atherosclerosis potentially via regulation of both lipid efflux from macrophages and the phenotypic modulation of VSMCs.

Ski areas affect Pacific marten movement, habitat use, and density

ABSTRACTAlpine ski recreation is one of the most popular outdoor winter sports globally but often involves habitat modification and dense human activity, both of which can harm wildlife. We investigated the effects of ski area development and winter recreation activities on movement, occupancy, and density of Pacific martens (Martes caurina) in the Lake Tahoe region of California and Nevada, USA by comparing 3 ski and 3 control study areas. We systematically surveyed martens using live traps and hair snares during spring–summer and winter seasons from 2009 through 2011 to identify how martens responded to the year‐round effects of habitat fragmentation from ski area development and the seasonal effects of winter recreation activities. Martens selectively moved between remnant forest patches with the shortest crossing distances across open, non‐forested ski runs in both seasons, with the effect more pronounced in females. Overall, habitat connectivity was reduced by 41% in ski areas compared to habitat not fragmented by ski runs. During spring–summer, occupancy rates were not different between habitat within or outside of ski operations areas. During winter, however, occupancy was significantly lower inside (52%) ski area boundaries than outside (88%) them. Reduced detection probability in ski areas indicated martens also reduced the frequency of use of operations areas in winter. Using spatially explicit capture‐recapture models, we found that marten density did not differ between ski areas and controls during spring, but during winter female density declined at ski areas by 63% compared to spring–summer and was <50% of female density compared to controls. This suggests that females seasonally avoid habitat in ski areas by shifting their habitat use to areas outside ski operations boundaries during winter. Although male marten density did not differ, the lack of resident males >3 years old coupled with higher annual turnover rates suggests male densities at ski areas may be reliant on annual male immigration. In winter, martens avoided using habitat in ski operations areas when recreation activity was greatest. Winter ski recreation may not be incompatible with marten use of habitat in ski areas, but habitat fragmentation from ski areas affects marten movement and recreation activities affect seasonal habitat occupancy and female density. Maintaining functional habitat connectivity, via networks of short ski run crossings that link habitat in and out of ski areas, will be important for maintaining or improving marten use of remnant habitat in developed ski areas. © 2017 The Wildlife Society

Neonatal Inhibition of DNA Methylation Alters Cell Phenotype in Sexually Dimorphic Regions of the Mouse Brain.

Many of the best-studied neural sex differences relate to differences in cell number and are due to the hormonal control of developmental cell death. However, several prominent neural sex differences persist even if cell death is eliminated. We hypothesized that these may reflect cell phenotype "decisions" that depend on epigenetic mechanisms, such as DNA methylation. To test this, we treated newborn mice with the DNA methyltransferase (DNMT) inhibitor zebularine, or vehicle, and examined two sexually dimorphic markers at weaning. As expected, control males had more cells immunoreactive for calbindin-D28k (CALB) in the medial preoptic area (mPOA) and fewer cells immunoreactive for estrogen receptor α (ERα) in the ventrolateral portion of the ventromedial nucleus of the hypothalamus (VMHvl) and the mPOA than did females. Neonatal DNMT inhibition markedly increased CALB cell number in both sexes and ERα cell density in males; as a result, the sex differences in ERα in the VMHvl and mPOA were completely eliminated in zebularine-treated animals. Zebularine treatment did not affect developmental cell death or the total density of Nissl-stained cells at weaning. Thus, a neonatal disruption of DNA methylation apparently has long-term effects on the proportion of cells expressing CALB and ERα, and some of these effects are sex specific. We also found that sex differences in CALB in the mPOA and ERα in the VMHvl persist in mice with a neuron-specific depletion of either Dnmt1 or Dnmt3b, indicating that neither DNMT alone is likely to be required for the sexually dimorphic expression of these markers.

Demographics and behaviour ofHeteragrion cooki, a forest damselfly endemic to Ecuador (Odonata)

Damselflies adapted to forest habitats are expected to be negatively affected by the disturbance of riparian forests, due to the change in insolation when trees are cleared. In this paper, we compare survivorship and behaviour of two populations of Heteragrion cooki by means of mark-recapture methods and focal observations of adults. We found similar densities of males (but not of females) in both streams, and similar recapture rates, higher for males (50%) than for females (20%). Body size was also significantly different between populations, with smaller individuals in the shadiest stream. The analysis of daily survival rates indicated that in the shaded stream, males survived better than females, whereas in the sunnier stream survival was similar between sexes, but varied over time. Furthermore, in the sunny stream, body size was negatively correlated with survival. Males arrived earlier than females to the stream, with a maximum activity between 13 and 16 hours. They defended small patches of the stre...

Density-dependent selection on mate search and evolution of Allee effects.

Sexually reproducing organisms require males and females to find each other. Increased difficulty of females finding mates as male density declines is the most frequently reported mechanism of Allee effects in animals. Evolving more effective mate search may alleviate Allee effects, but may depend on density regimes a population experiences. In particular, high-density populations may evolve mechanisms that induce Allee effects which become detrimental when populations are reduced and maintained at a low density. We develop an individual-based, eco-genetic model to study how mating systems and fitness trade-offs interact with changes in population density to drive evolution of the rate at which males or females search for mates. Finite mate search rate triggers Allee effects in our model and we explore how these Allee effects respond to such evolution. We allow a population to adapt to several population density regimes and examine whether high-density populations are likely to reverse adaptations attained at low densities. We find density-dependent selection in most of scenarios, leading to search rates that result in lower Allee thresholds in populations kept at lower densities. This mainly occurs when fecundity costs are imposed on mate search, and provides an explanation for why Allee effects are often observed in anthropogenically rare species. Optimizing selection, where the attained trait value minimizes the Allee threshold independent of population density, depended on the trade-off between search and survival, combined with monogamy when females were searching. Other scenarios led to runaway selection on the mate search rate, including evolutionary suicide. Trade-offs involved in mate search may thus be crucial to determining how density influences the evolution of Allee effects. Previous studies did not examine evolution of a trait related to the strength of Allee effects under density variation. We emphasize the crucial role that mating systems, fitness trade-offs and the evolving sex have in determining the density threshold for population persistence, in particular since evolution need not always take the Allee threshold to its minimum value.

Social cues affect synchronization of male waving displays in a fiddler crab (Crustacea: Ocypodidae)

The influence of social context in animal signals can lead to complex communicational patterns. In particular, the interaction between individuals can lead to intriguing collective dynamics, such as the temporal synchronization of signals. A fascinating example of such temporal synchronization involves the waving displays of fiddler crabs, in which males raise and lower their enlarged claws in species-specific rhythms. The adaptive significance of this phenomenon is still obscure, but possibly involves female preference for leading waving displays. However, waving displays are highly complex social signals that might be involved in a variety of forms of communication other than simply attracting females, but little is known about the influence of social context on wave synchronization. In this study we carried out field experiments to investigate the effect of two social factors, male density and female presence, on the level of waving synchronization in the fiddler crab Uca leptodactyla. Groups of males at varying densities were established in enclosures and recorded either in the presence or absence of a female. Our results indicate that the main factor driving synchronization is the presence of the female, with males not only changing the timing of their waving displays, but also altering their spatial distribution in the arenas. On the other hand, male density had a negligible effect on synchronization (despite significantly increasing waving rate), suggesting that male–male communication plays a minor role in the emergence of waving synchronization in this species.

Spawning aggregation of white-streaked grouper Epinephelus ongus: spatial distribution and annual variation in the fish density within a spawning ground.

White-streaked grouper (Epinephelus ongus) is an important fisheries target and forms spawning aggregations at particular spawning grounds. The aims of the present study were to investigate the ecological characteristics of annual spawning aggregations such as (1) spatial variations in the density of E. ongus at the spawning ground, (2) the relationship between fish density and environmental variables, (3) inter-annual variations in the spawning aggregation, (4) the proportion of males to females at the spawning ground for several days pre—and post-spawning and (5) the relationship between male density and female density at the protected spawning ground, based on observations over five years at an Okinawan coral reef. Although the protected spawning ground area was large (ca. 2,500 m × 700 m), high density of E. ongus (over 25 individuals per 100 m2) was found in a limited area (within c.a. 750 m × 50 m). Current velocity and coverage of rocks had significant positive effects on the spatial distribution of E. ongus at the spawning ground. Inter-annual variation in the degree of aggregation was found and this variation was explained by the annual variation of mean seawater temperature during 40 days before the spawning day. The male–female ratio (male:female) at the spawning ground was ca. 3:1 for three years (May 2012, May 2014 and May 2015) whereas >13:1 for one year (May 2013). Significant positive relationships between male density and female density were found at the aggregation sites. It is suggested that E. ongus use aggregation sites with greater current velocity to reduce the risk of egg predation and seawater temperature is one of the main factors that is responsible for determining the degree of aggregation. It is also suggested that females possibly select sites with a greater density of males and this selection behavior might be the reason why females arrived at the spawning ground after the arrival of the males. For effective management of spawning grounds, precise site selection as well as the duration of the protection period are suggested to be key aspects to protect the spawning aggregations of E. ongus, which have been currently achieved at the spawning ground.

Determinants of multiple paternity in a fluctuating population of ground squirrels

Multiple paternity is common in vertebrates that produce several offspring in the same reproductive bout, but the rate often varies among and within populations. Three primary explanations for this variation have been advanced: null models based on encounter rate of mates, socioecological models dependent on the ability of males to monopolize females, and age- or condition-dependent models of female choice. We used 18 years of genetic and demographic data to examine the mating system and patterns of multiple paternity in a free-living population of golden-mantled ground squirrels (Callospermophilus lateralis). The mating system was polygynandrous, but opportunity for sexual selection was lower for females than for males. Annual reproductive success of males was low for yearlings and new immigrants and increased with breeding tenure in the population. Multiple paternity was evident in 62% of litters. In accordance with the socioecological model of male monopolization, rates of multiple paternity decreased with female spatial clustering, unless male–male competition, as indicated by male density, was also high. From Bateman gradients, we found no direct fitness benefit of multiple paternity for females. Though not statistically significant, multiple paternity appeared to decrease with maternal age and peri-oestrous mass, in possible support of the female choice model. Together, our results suggest that variation in the rate of multiple paternity in golden-mantled ground squirrels was determined by density and the active strategies of males and females. Since the advent of molecular parentage assignment several decades ago, we have known that females of many species produce offspring with different fathers. Several theories have been developed for why females produce multiply-sired clutches or litters, but rarely are we able to identify the environmental, social, or individual conditions under which they do so. In this study, we genotyped offspring produced in one population of ground squirrels over 18 years, and found that the frequency of multiple paternity varied considerably from year to year, that density of female kin interacted with male density to influence multiple paternity, and that older and heavier females tended to be less likely to produce multiply-sired litters. These results demonstrate how dynamic population and individual characteristics of breeding males and females contribute to mating system variation in the same population over time.

Adult Male Density Influences Juvenile Microhabitat Use in a Territorial Lizard

AbstractHabitat choice often has strong effects on performance and fitness. For many animals, optimal habitats differ across age or size classes, and individuals shift habitat use through ontogeny. Although many studies document ontogenetic habitat shifts for various taxa, most are observational and do not identify the causal factor of size‐specific habitat variation. Field observations of the brown anole lizard (Anolis sagrei) show that juveniles perch on shorter and thinner vegetation than adults. We hypothesized that this variation is due to adult males forcing smaller juveniles to less preferred habitat. To test this assertion, we manipulated adult male densities in mesh enclosures with artificial trees to examine the response of juvenile microhabitat choice. We found that adult male density had strong effects on juvenile perch height, perch width, and substrate use, suggesting that age‐class competition contributes to the observed ontogenetic differences in habitat choice. We also found that time of day significantly affected juvenile perch height and substrate use. In many cases, our results suggest that juveniles distance themselves from adults using different microhabitats from those used in our control ‘no‐adult’ treatment. However, these findings were often body size dependent and varied depending upon time of day. This study highlights the complexity of juvenile perching behavior and demonstrates the role of intraspecific interactions in shaping habitat use by juvenile animals.

Metabolic rate and hypoxia tolerance are affected by group interactions and sex in the fruit fly (Drosophila melanogaster): new data and a literature survey.

ABSTRACTPopulation density and associated behavioral adjustments are potentially important in regulating physiological performance in many animals. In r-selected species like the fruit fly (Drosophila), where population density rapidly shifts in unpredictable and unstable environments, density-dependent physiological adjustments may aid survival of individuals living in a social environment. Yet, how population density (and associated social behaviors) affects physiological functions like metabolism is poorly understood in insects. Additionally, insects often show marked sexual dimorphism (larger females). Thus, in this study on D. melanogaster, we characterized the effects of fly density and sex on both mass-specific routine oxygen consumption (V̇O2) and hypoxia tolerance (PCrit). Females had significantly lower routine V̇O2 (∼4 µl O2 mg−1 h−1) than males (∼6 µl O2 mg−1 h−1) at an average fly density of 28 flies·respirometer chamber−1. However, V̇O2 was inversely related to fly density in males, with V̇O2 ranging from 4 to 11 µl O2 mg−1 h−1 at a density of 10 and 40 flies·chamber−1, respectively (r2=0.58, P<0.001). Female flies showed a similar but less pronounced effect, with a V̇O2 of 4 and 7 µl O2 mg−1 h−1 at a density of 10 and 40 flies·chamber−1, respectively (r2=0.43, P<0.001). PCrit (∼5.5 to 7.5 kPa) varied significantly with density in male (r2=0.50, P<0.01) but not female (r2=0.02, P>0.5) flies, with higher fly densities having a lower PCrit. An extensive survey of the literature on metabolism in fruit flies indicates that not all studies control for, or even report on, fly density and gender, both of which may affect metabolic measurements.

Relationship of Physical Activity Type, Nutrition, and Bone Mineral Density in Korean Adolescents

Background and Objective Bone density reaches its peak in the mid-20s and manifests as osteoporosis and osteopenia with aging. Bone density is affected by body mass index, muscle mass, nutritional calcium and vitamin D, as well as Lifestyle, type and duration of physical activity, and level of physical strength. The purpose of this study was to investigate the difference in diet and bone density according to physical activity level in growing male and female adolescents. Material and Methods This study involved 646 male and 581 female adolescents using data from the Korea National Health and Nutrition Examination in 2009-2011. The measurement of bone density consisted of dual-energy X-ray absorptiometry, and was classified into low-, middle-, and high-density groups at different ages based on total bone mineral density. The Korean version of the International Physical Activity Questionnaire by the World Health Organization was used to measure physical activity level, and a survey regarding strength, exercise, and stretching was conducted. In the nutritional survey, data from a 24-hour recall were analyzed. One-way analysis of variance and chi-square tests were conducted to examine the presence and significance of any differences. Results Even though there was no difference among groups in both males and females, there was a significant difference in weight (p 0.05). In males, the high-density group showed significantly higher intake of calories (p=0.032), protein (p=0.015), calcium (p=0.043), and phosphorus (p=0.013) compared with the low group. There was a significant difference in bone density related to physical activity level. In the low and high bone density groups, the proportion of strength exercises increased to more than 3 times a week was 18.1% and 27.2%, respectively in males (p=0.046), and was 1.0% and 6.1% respectively in females (p=0.014). The proportion of high-intensity exercise 6–7 times a week also showed a significant difference as the low, middle, and high bone density groups showed 5.1%, 5.5%, and 14.1%, respectively (p<0.001). Conclusion Among adolescents, bone density in females was affected by strength exercise, and bone density in males was affected by physical activity level and nutrition, showing a clearer tendency in the males. Particularly, regarding physical activity level, high intensity and strength exercise had more positive effects.

Sex prediction using ridge density and thickness among the Hausa ethnic group of Kano state, Nigeria

The aim of the study was to determine sexual dimorphism and to predict sex using thumbprint ridge density and thickness among the Hausa ethnic group of Nigeria. A total of 283 subjects comprising 147 males and 136 females participated in the study. The density was determined from the count of ridges found diagonally within 25 mm2 using an indirect method of ridge thickness measurement. The results showed that the ulnar ridge density of males (10.01 ± 1.31) was significantly (p < 0.05) lower than that of females (10.91 ± 1.69) in the right thumb. The ridge thickness was observed to have an inverse relation with ridge density. It was also noted that the right ulnar ridge count was the single best variable to predict sex (63.4% accuracy). For the left thumbprints, the proximal ridge thickness predicted the sex (62.8% accuracy). The predicted probabilities of binary logistic regression showed that ulnar ridge count and proximal ridge thickness were the best predictors with a higher area under the curve (>0.5) in the right and left thumbprints respectively. In conclusion, different regions of thumbprints have different potentials in term of sex prediction. Ridge density and thickness hold potential as tools for sex inference among the Hausa population of Nigeria.

Conservation of large predator populations: Demographic and spatial responses of African lions to the intensity of trophy hunting

Large predators are in decline globally with growing concerns over the impacts of human activity on conservation status and range of many populations. The role of trophy hunting in the conservation or decline of predators is hotly debated, though opposing views are often poorly supported by empirical evidence. Nevertheless an understanding of effects of trophy hunting on populations and behaviour is critical to the conservation of large carnivore populations. The impacts of trophy hunting on African lion population demographics, social structure and spatial behaviour were investigated in Hwange National Park, Zimbabwe, from 1999 to 2012, a period characterized by different trophy hunting intensities. Adult males were primarily targeted by trophy hunters, but survival of all age and sex classes were lowest when male lion off-takes were highest. Reduction in hunting quotas over the study period resulted in a 62% increase in the total population and a 200% increase in adult male density. Adult sex ratios were highly skewed towards females when hunting was intense. Intensity of hunting affected male and female home-range size, which declined in periods of low hunting corresponding to increases in adult males and male coalitions. Trophy hunting on the park boundary exerted a measurable edge effect with lower survival for animals of all age and sex classes living on the park boundary compared to those distant from it. This study provides evidence for negative impacts of uncontrolled trophy hunting on lion population and behaviour. However, limited, well regulated quotas may be compatible with large carnivore conservation.

Female fruit production depends on female flower production and crown size rather than male density in a continuous population of a tropical dioecious tree (Virola surinamensis).

Factors related to pollen and resource limitation were evaluated to predict female fruit production in a tropical dioecious tree. Pollen limitation via variation in the male density at local scales is expected to limit female reproduction success in dioecious plants. We modeled the roles of local male density, female crown size, crown illumination, and female flower production on female fruit initiation and mature fruit production in a continuous population (62 ha plot) of a tropical dioecious tree (Virola surinamensis). In addition, we used microsatellites to describe the scale of effective pollen flow, the male effective population size, and the spatial genetic structure within/between progenies and males. The local male density was not related to female fruit initiation or mature fruit production. Female floral production had a positive effect on fruit initiation. The female crown size was positively related to fruit maturation. Seeds from the same female and seeds from different but spatially proximal females were generally half-siblings; however, proximal females showed greater variation. Proximal male-female adult pairs were not significantly more genetically related than distant pairs. The probability of paternity was negatively affected by the distance between seeds and males; most effective pollen dispersal events (∼85%) occurred from males located less than 150 m from females. The number of males siring progenies was greater than the number of males found at local scales. Female fecundity in this continuous population of Virola surinamensis is not limited by the availability of pollen from proximal males. Rather, resource allocation to floral production may ultimately determine female reproductive success.

The prevalence and risk factors of metabolic syndrome in different nationalities in Linxia

A multi-stratified cluster sampling method was used in this study. A total of 1 357 residents who underwent physical examinations in Linxia were included. The prevalence and risk factors of metabolic syndrome(MS)in Lixia was investigated and analyzed according to the modified 2005 National Cholesterol Education Program Adult Treatment Panel Ⅲ(ATP Ⅲ)standard, the 2004 Chinese Diabetes Society(CDS)standard, and the International Diabetes Federation(IDF)Standard. Using the ATP Ⅲ criterion for diagnosis, the total prevalence of MS was 26.01%, and increased with the age. Using the standard CDS, the total prevalence of MS was 12.97%, and fluctuated with aging. Besides, the total prevalence of MS was 12.45% according to IDF standard, and increased with age. Regardless of standard types, the prevalence of MS in males was higher than that in females. Under ATP Ⅲ standards, the prevalences of MS in Han and Hui population were 28.11% and 27.53%, respectively. Dongxiang population had the lowest prevalence of 8.54%. Under CDS standard, the highest prevalence of MS was among Hui population(16.23%), and Tibetan population had the lowest prevalence(5.45%). Furthermore, the prevalence of MS in Han population was the highest of 13.83% and Tibetan people was the lowest of 3.64% when based on the IDF standard. Regardless of standards types, the prevalences of MS in various nationalities were significantly different(P<0.05). Among all the components of MS, hypertriglyceridemia was the highest in male and lower high density lipoprotein-cholesterol, as well as higher rate of elevated blood glucose levels in females. (Chin J Endocrinol Metab, 2016, 32: 837-840) Key words: Metabolic syndrome; Prevalence; Diagnostic standard

An experimental demonstration of the impact of predation on sexual segregation and primary sex ratios among ungulates

AbstractUnderlying mechanisms of sexual segregation among ungulates, and Trivers and Willard's hypothesis that mothers can influence primary sex ratios, continue to be topical theoretical issues. Over 2 years, using monthly repeated road transects, we determined the habitat and social segregation of male vs. female impala (Aepyceros melampus) and kudu (Tragelaphus strepsiceros) in a predator‐free, vs. a predator‐laden, South African reserve. We also determined, by the same technique but over 4 years, the primary sex ratio of the impala population free from predation. Significant overlap in habitat usage (Schoener's Index 0.63–0.8) was found between the two sexes when free from predation, but not (Schoener's Index 0.46–0.47) when under predation. While occupying the same habitats impala, kudu and wildebeest (Connochaetes taurinus) male and female groups maintained rigid social segregation throughout the year, even when at close quarters. Impala primary sex ratios were significantly biased towards females (male/female = 0.72; χ² = 4.3175, d.f. = 1, P‐value = 0.038) in the absence of predation. Our findings suggest that while risk of predation is a proximal cause of sexual segregation, thus lending support to the predator‐risk hypothesis, the underlying, functional mechanism of sexual segregation is the difference in the activity budgets of males vs. females (the activity‐budget hypothesis). Our findings also suggest that mothers may indeed be able to adjust primary sex ratios, with the postulated driver in this case being an abnormally high density of adult males.

Submitted, Not Presented: Stomach.

Introduction: Osteoporosis is often regarded as the disease specific to female, whereas male patients with osteoporosis are increasing as well. Although the main factor of osteoporosis in female is the decrease of estrogen production, the etiology is not clear for men. In Western countries, infection of H. pylori, particularly CagA-positive strain, has been shown as a possible risk for osteoporosis in male. The absorption of calcium is affected by acidity of gastrointestinal tract. In Japan, most H. pylori strains are CagA-positive and severe gastric mucosal atrophy is often observed in infected patients causing the reduction of gastric acid secretion. Thus, there could be more clear relationship between H. pylori infection and loss of bone density in Japan comparing with Western populations. The aim of this study was to examine whether H. pylori infection associates with loss of bone density in Japanese healthy males. Methods: 295 healthy male adults who attended the mass survey in 2014 were enrolled into the study (mean age: 50.2 ± 15.4 years old). We measured H. pylori stool antigen and the titer of serum antibodies to H. pylori. H. pylori status was defined as positive or negative when both tests showed concordant results. The bone density was examined calcaneal osteo sono-assessment index (OSI) using quantitative ultrasound. Osteopenia was defined when measured OSI was less than 1.0 SD from the mean OSI of the young age (20-44 years old) according to WHO diagnostic criteria. We performed logistic regression models and calculated the adjusted odds ratio (OR) for having osteopenia as a dependent variable. The independent variables were age, BMI, serum level of estradiol, the intake of calcium per day, smoking, drinking, periodical exercise, last educational background and H. pylori infection. Results: Bivariate and multivariate analyses revealed that only age was significantly different between subjects with or without osteopenia. In multivariate analysis, the adjusted OR of age for osteopenia was 2.88 (95%CI: 1.46-5.68, p < 0.001). On the other hand, the adjusted OR of H. pylori infection for osteopenia was 0.92 (0.47-1.81; p=0.81). Conclusion: Age was a significant risk for developing osteopenia in Japanese males. Unlike Western populations, no significant association was found between H. pylori infection and osteopenia in this series of adult males.

Differences in Growth and Calcification Rates in the Reef-Building Coral Porites lobata: The Implications of Morphotype and Gender on Coral Growth

Corals display different growth forms as an adaptive response to both local and global environmental conditions. Despite the importance of morphologic variability on corals, growth and calcification rates of different coral morphotypes have been poorly recorded in the Eastern Pacific. The purpose of this study was to compare annual extension rate (cm yr-1), skeletal density (g cm-3), calcification rate (g cm-2 yr-1) and tissue thickness (mm) of males and females colonies in three different morphotypes of the common reef-building coral Porites lobata; columnar, massive, and free-living (corallith) forms. The results show significant differences in all 4-growth parameters between morphotypes over a 6-year interval, and also differences between males and females in most morphotypes. Massive colonies presented 15-33% faster annual rates compared with columnar and free-living. Male colonies showed 30-40% faster annual rates than females for both columnar and corallith morphologies. These data exhibit the extensive plasticity of this species and highlight the fact that each morphotype x gender group produced a different physiological response to environmental conditions. Therefore, these information reveal that P. lobata from the Eastern Tropical Pacific develops different morphologies to allow it to maintain coral species population, characteristics that enhance the species possibility to further its distribution across the reef-framework

Age-dependent male mating tactics in a spider mite-A life-history perspective.

Males often fight with rival males for access to females. However, some males display nonfighting tactics such as sneaking, satellite behavior, or female mimicking. When these mating tactics comprise a conditional strategy, they are often thought to be explained by resource holding potential (RHP), that is, nonfighting tactics are displayed by less competitive males who are more likely to lose a fight. The alternative mating tactics, however, can also be explained by life‐history theory, which predicts that young males avoid fighting, regardless of their RHP, if it pays off to wait for future reproduction. Here, we test whether the sneaking tactic displayed by young males of the two‐spotted spider mite can be explained by life‐history theory. We tested whether young sneaker males survive longer than young fighter males after a bout of mild or strong competition with old fighter males. We also investigated whether old males have a more protective outer skin—a possible proxy for RHP—by measuring cuticle hardness and elasticity using nanoindentation. We found that young sneaker males survived longer than young fighter males after mild male competition. This difference was not found after strong male competition, which suggests that induction of sneaking tactic is affected by male density. Hardness and elasticity of the skin did not vary with male age. Given that earlier work could also not detect morphometric differences between fighter and sneaker males, we conclude that there is no apparent increase in RHP with age in the mite and age‐dependent male mating tactics in the mite can be explained only by life‐history theory. Because it is likely that fighting incurs a survival cost, age‐dependent alternative mating tactics may be explained by life‐history theory in many species when reproduction of old males is a significant factor in fitness.

Territory Availability at Different Spatial Scales does not Affect Fighting Investment in Males of the Lycaenid Butterfly Strymon mulucha

AbstractIn territorial species, rivals investment in fights over territories may increase when the availability of suitable areas for defense is low. This should occur because low territory availability may increase the costs to maintain and acquire territories. Although such process occurs in small spatial scales (local scale), territory availability in larger scales (regional scale) may also affect fighting investment, as losers should incur additional dispersing costs to find new territories. In this study, we used males of the hilltopping butterfly Strymon mulucha to evaluate the hypothesis that males should invest more in territorial fights when the costs to find new territories are higher (both at local and at regional scale). We timed male–male contests for territories located in 12 hilltops and measured male density per territory in each hilltop (local scale). We also quantified the distance between hilltops containing suitable areas for territories (regional scale). Male–male contests lasted 21 s on average, and copulations did not occur during the observations. The duration of contests was unrelated to the male density per territory or to the distance among hilltops, indicating that the investment in fights was unaffected by the availability of territorial sites, independent of the spatial scale. As male–male contests in S. mulucha are longer than the mean contest duration in other butterfly species and mating is extremely rare, we suggest that the value of each territory may be high enough to favor males that always invest as much as possible in contests.