Effects of annual rainfall and habitat types on the body mass of impala (Aepyceros melampus) in the Zambezi Valley, Zimbabwe

Body mass is often considered as a good indicator of body condition of individuals in ungulates, hence of their fitness, and thus, may be used as an index to monitor the status of populations subject to harvesting schemes. Here, we report the influence of annual rainfall (a proxy for primary production) and habitat on the body mass of impala in a population cropped for meat in a communal area of Zimbabwe. We analyzed the data from 2 contrasted years for rainfall, in two different habitats. In the good year (i.e. high annual rainfall) impala were heavier than in the poor year, and adult females seemed to be less affected than males by variation in primary production. We show that adult males were suffering from a seasonal decrease in body mass, supposedly linked to the rut, particularly in good habitat. Overall, the habitat effect appeared to be dominated by the rainfall effect, and this may be due to the very high animal densities in the good habitat, i.e. fast resource depletion. Our results also suggest that males (juvenile and adult) are more susceptible to changes in food resource abundance and quality than females, which supports previous studies on sexually dimorphic and polygynous species.     

Preliminary Evidence of the Importance of ENSO in Modifying Food Availability for White‐tailed Deer in a Mexican Tropical Dry Forest1

The influence of El Niño/Southern Oscillation (ENSO) on rainfall and its possible effect on availability of food for white‐tailed deer (Odocoileus virginianus) in a tropical dry forest in the Pacific coast of Mexico was studied. From 1977 to 2003 there were three significant El Niño and La Niña events. During El Niño years rainfall decreased during the wet season ( June to October) and increased during the dry season (November to May), with the opposite effect during La Niña years. Plant diversity was monitored in permanent plots during the wet and dry seasons of 1989–1993. The results provide evidence that ENSO events affect deer food availability, particularly in the dry season.     

海南国家公园霸王岭片区无尾两栖类鸣声多样性:基于自动录音技术

海南热带雨林国家公园霸王岭片区属于我国生物多样性热点地区,其自然环境非常适合两栖类生存,但该区域的无尾两栖类多样性情况尚不清楚。本研究利用新兴的生物声学方法,调查该地区无尾两栖动物的多样性,并了解蛙类鸣叫与环境的关系。我们在国家公园霸王岭片区选择5个生境不同的区域,每个区域设置一条样线,每条样线上布设3台录音设备,于2021年6月、8-9月和12月以及2022年1-3月分别收集至少半个月的声音数据。本次调查共记录到蛙类17种,隶属6科11属。四季的物种组成存在差异,其中冬季(12月)出现的物种最少。不同区域的物种组成也存在差异,其中飞列地区发现的物种最多。记录到的17种蛙中,有12种仅在夜晚鸣叫,有3种主要在夜晚鸣叫,偶尔也在白天鸣叫,有2种全天都活跃鸣叫。不同生境蛙类对降雨的响应也存在差异。永久水体中的小湍蛙(Amolops torrentis)和沼水蛙(Hylarana guentheri),以及栖息环境多样的饰纹姬蛙(Microhyla fissipes),鸣叫活性不受降雨影响,但浅水溪流中的脆皮大头蛙(Limnonectes fragilis)和地面上的海南拟髭蟾(Leptob...     

Climate and reproductive seasonality in two free-ranging island populations of rhesus macaques (Macaca mulatto)

We gathered data over a 3-year period (1988–1990) on two free-ranging, island populations of rhesus macaques (Macaca mulatta)to test hypotheses concerning birth seasonal asynchrony and the relationship between climate and reproductive seasonality. Rhesus macaques from Kashmir, India, were translocated to Key Lois in 1973 and from Key Lois to Raccoon Key in 1978. Both sites are low-lying mangrove islands in the Florida Keys. Floral diversity and abundance are greater on Raccoon Key than on Key Lois. Average maximal and minimal temperatures per month did not vary significantly between Raccoon Key and Key Lois over the 3-year period. Average minimal temperatures per month on Key Lois, but not Raccoon Key, varied significantly between years. There were no significant variations in either the amount or the dates of rainfall over the 3-year period for the study area. A combined total of 1524 births was recorded for Raccoon Key (N = 879) and Key Lois (N =645). The birth season on Raccoon Key began 6 weeks earlier than on Key Lois. Births were associated with warmer, rainier months on both islands. Conceptions were associated with cooler, drier months at both study sites. No significant correlations were found between the date of the onset of the summer rains and either median conception or median birth dates on Raccoon Key or Key Lois. Our results do not substantiate the hypothesis that the onset of rainfall, within the temporal period set by photoperiod, regulates seasonal reproduction in rhesus macaques. We suggest that reproductive seasonality in the study populations may be influenced by a variety of factors.     

不同季节亚热带常绿阔叶林6个树种凋落叶钙、镁、锰的释放特征

采用凋落物分解袋法,研究了亚热带常绿阔叶林区马尾松、柳杉、杉木、香樟、红椿、麻栎6个典型树种凋落叶的Ca、Mg、Mn在第一个分解年不同雨热季节的释放特征.结果表明：经历1年的分解,6种凋落叶Ca、Mg、Mn释放率分别为-13.8%～92.3%、4.0%～64.8%和41.6%～81.1%.马尾松和香樟凋落叶Ca释放动态呈现富集-释放模式,其余4种凋落叶整体上呈现释放的模式;香樟凋落叶Mg释放动态呈现富集-释放模式,其余5种凋落叶呈现直接释放模式;柳杉和红椿凋落叶Mn释放动态呈现富集-释放模式,其余4种凋落叶呈现直接释放模式.凋落叶Ca、Mg、Mn的释放明显受到季节性降雨的影响,且因凋落叶种类不同而有差异.Ca、Mg、Mn在雨季的释放率和释放量均高于旱季.初始养分含量和降雨量是影响凋落物分解过程元素释放的重要因子.     

Distribution of domestic triatominae and stratification of Chagas Disease transmission in Oaxaca, Mexico

Mexico has 18 species of Triatomine bugs (Hemiptera: Reduviidae) reported to be vectors of Trypanosoma cruzi. Chagas Disease is widespread in Mexico, with up to 3.5% seropositivity of human transfusion blood. The State of Oaxaca has the longest history of endemic Chagas Disease, based on acute and chronic case reports, and of entomological surveys in the country. However, the State health care services need more information on current risks of vector transmission. In order to identify and characterize areas of transmission in Oaxaca and to stratify the vector potential, the distribution of domestic Triatominae was surveyed during 1996-98 in collaboration with the primary health care services and local communities. Villages were studied in 11% of 570 municipalities in Oaxaca. Eight triatomine species were found in domestic and peri-domestic habitats: Triatoma barberi Usinger, T. bolivari Carcavallo et al., T. dimidiata (Latreille), T. mazzottii Usinger, T. nitida Usinger, T. pallidipennis (Stal), T. phyllosoma (Burmeister) and Rhodnius prolixus Stal. For each triatomine species in Oaxaca, the range of distribution and habitat characteristics are described. Habitat partitioning, principally based on altitude and mean annual precipitation, limited the overlap of distribution between species. Relatively consistent altitude of human settlements facilitates the dispersion of individual species within microregions. Entomological indices of house infestation were used to estimate that approximately 50% of the human population (1,874,320 inhabitants) would be at risk of vector transmission, with a minimum of 134,320 infected people and 40,280 chronic cases of Chagas Disease currently in Oaxaca.     

<Emphasis Type="Italic">In vitro</Emphasis> regeneration of <Emphasis Type="Italic">Bambusa balcooa</Emphasis> Roxb.: Factors affecting changes of morphogenetic competence in the axillary buds

Axillary buds from field-grown culms of Bambusa balcooa were used as explants to induce multiple shoots in liquid Murashige and Skoogs (MS) medium supplemented with 11.25 M of 6-benzylaminopurine (BAP) and 4.5 M kinetin (Kn). A clump of at least 3 shoots was used for root induction in half strength MS medium with 1.0 M of 3-indolebutyric acid (IBA). Morphogenetic competence of the axillary buds varied widely in different months of two consecutive calendar years. The highest morphogenetic potentials were observed in October. The major problem encountered was presence of systemic fungal contaminants. Perhaps, rainfall positively contributed to induce morphogenetic competence. A moderately high phenolic content of the nodal explant was also detrimental for in vitro morphogenesis. The morphogenetic competence of B. balcooa correlated with the season in which the explants were excised from the natural stands. To the best of our knowledge this is the first report on in vitro regeneration of B. balcooa from mature field-grown axillary buds.     

福建长泰椪柑产量丰欠与气温、雨量的关系

统计分析表明,对福建长泰椪柑产量丰欠有显著影响的气象因子主要有3月雨量和气温,1~2月雨量,9月1日~11月15日雨量。3月上旬~10月下旬,是椪柑产量形成关键期。采用回归积分分析,求出各时段的生长函数,定量描述气温、雨量每增加或减少一个单位对椪柑产量形成的影响。     

The hatching time of Locusta migratoria under outdoor conditions: role of temperature and adaptive significance

The present study investigates the time of hatching of the migratory locust Locusta migratoria using egg pods that are artificially buried in the soil under outdoor conditions. Most eggs hatch in the mid‐morning, with a peak between 11.00 and 12.00 h, and none hatch before 09.00 or after 16.00 h. Furthermore, most egg pods complete hatching within a day, although some take 2 or 3 days, and egg hatching is interrupted by rain. There are no large differences in hatching time from May to September. Laboratory experiments in which the eggs are exposed to temperatures simulating outdoor conditions show that soil temperature is the main factor controlling hatching activity. The increase in temperature in the morning appears to trigger egg hatching, as confirmed by laboratory experiments, which may explain the similar hatching times between seasons. The seasonal patterns of temperature variation and hatching time suggest that the hatching time of L. migratoria eggs may be adjusted to allow the hatchlings to be exposed to high temperatures in the afternoon so that they can harden their bodies quickly.