Locomotor behaviour in males,females and groups of Orchestia montagui (Amphipoda,Talitridae) in the supralittoral zone of Bizerte lagoon

Locomotor activity rhythm of Orchestia montagui was investigated under constant darkness in a population collected in spring from the supralittoral zone of Bizerte lagoon (northern region of Tunisia) at Menzel Jmil in spring. This rhythm was recorded in individual and groups of animal by infrared actography every 20 min by multichannel data loggers, at a constant temperature of 18 ± 0.5 °C. According to double-plotted actograms, wave forms and periodogram analysis, results revealed different locomotor pattern. However, locomotor activity rhythm of males was more stable than females. Furthermore, the mortality was statistically higher in unmixed groups than in mixed groups.     

不同性别赛艇运动员肱二头肌微循环血流灌注量的比较

目的：探讨不同性别赛艇运动员肱二头肌微循环血流储备能力的变化差异,以便为微循环指标更好的应用于运动实践提供参考。方法：在晨起空腹状态下,用PeriFlux System5000系列激光多普勒血流仪对60名不同性别的赛艇运动员（其中男、女各30名）右侧肱二头肌微循环血流储备能力进行无创测试。结果：男子赛艇运动员微循环血流灌注量基础值大于女子赛艇运动员,其储备能力小于女子赛艇员,但二者差异均不显著。结论：赛艇运动员微循环血流灌注量不存在明显的性别差异,相关研究可不必针对性别进行分组,若综合微循环血流灌注量影响因子的变化应针对性别这一因素加以注意。     

A one‐locus model of androdioecy with two homomorphic self‐incompatibility groups: expected vs. observed male frequencies

Androdioecy, the occurrence of males and hermaphrodites in a single population, is a rare breeding system because the conditions for maintenance of males are restrictive. In the androdioecious shrub Phillyrea angustifolia, high male frequencies are observed in some populations. The species has a sporophytic self‐incompatibility (SI) system with two self‐incompatibility groups, which ensures that two groups of hermaphrodites can each mate only with the other group, whereas males can fertilize hermaphrodites of both groups. Here, we analyse a population genetic model to investigate the dynamics of such an androdioecious species, assuming that self‐incompatibility and sex phenotypes are determined by a single locus. Our model confirms a previous prediction that a slight reproductive advantage of males relative to hermaphrodites allows the maintenance of males at high equilibrium frequencies. The model predicts different equilibria between hermaphrodites of the two SI groups and males, depending on the male advantage, the initial composition of the population and the population size, whose effect is studied through stochastic simulations. Although the model can generate high male frequencies, observed frequencies are considerably higher than the model predicts. We finally discuss how this model may help explain the large male frequency variation observed in other androdioecious species of Oleaceae: some species show only androdioecious populations, as P. angustifolia, whereas others show populations either completely hermaphrodite or androdioecious.