Exclusive core areas and intrasexual territoriality in Eurasian red squirrels (<Emphasis Type="Italic">Sciurus vulgaris</Emphasis>) revealed by incremental cluster polygon analysis

When animal home ranges overlap extensively in species lacking overt territorial behaviours, identifying exclusive core areas within individual ranges can be difficult. By analysing the size and overlap of successively smaller core areas among individual Eurasian red squirrels (Sciurus vulgaris), we determined exclusive areas within the home ranges of resident males and females. Possible effects of habitat composition and food supplies were explored by monitoring squirrels in different conifer forests and during years with low and high tree seed production. Using outlier-exclusive cores (OEC) revealed that the total ranges consisted of large sally zones (on average, 35% of the total minimum convex polygon [MCP] range) around home ranges with multi-nucleate cores. The mean OEC home range size did not differ between the sexes but was larger with poor food availability. Home ranges (99% incremental cluster polygons [ICP]) overlapped extensively between sexes (average overlap high food–low food: males by females 21–40%, females by males 43–45%) and among males (males by males 26–44%), while intrasexual overlap among females was low (9–10%). The overlap of inner cores among females rapidly approached zero, suggesting the intrasexual territoriality of 75% core areas. This was not the case among male squirrels, for which intrasexual overlap averaged only 4% at 50% but 18% at 75% core areas. Even the smallest inner cores had some degree of intersexual overlap, indicating that complete territoriality did not occur in this species. Female home ranges were more strongly affected by annual fluctuations in food supplies than male ranges. Females reduced the size of their food-based intrasexual territories when food availability increases. Males probably benefit from using larger home ranges and core areas, which overlap with the ranges of several females, by increasing their probability of successful mating.     

The relationship among egg size,density and food level on larval development in the wood frog (Rana sylvatica)

Summary Although inter- and intraspecific variation in egg size among amphibians has been well documented, the relationship between egg size and fitness remains unclear. Recent attempts to correlate egg size intraspecifically with larval developmental patterns have been equivocal. In this study the development of larvae derived from large eggs and small eggs, from a single population in Maryland were compared under a range of food levels and larval population densities. Both food level and density had significant effects on the length of the larval period and size at metamorphosis. However, the response among larvae derived from different egg sizes was not additive. At low densities and high food levels, larvae from small eggs had longer larval periods and a larger size at metamorphosis than larvae derived from large eggs. In contrast, at high densities larvae from small eggs had longer developmental periods but were smaller at metamorphosis than larvae from large eggs. In addition, larvae from small eggs were more sensitive to density irrespective of food level. These results suggest that optimal egg size is correlated with environmental factors, which may explain the maintenance of both geographic and within population variation in egg size commonly observed in amphibians.     

随机限食和重喂食小鼠能量收支和生长发育的可塑性

为阐明能量收支和生长发育的可塑性对动物适应食物资源变化的作用和意义,将断乳后的雄性KM小鼠40只随机限食4周,再重喂食4周。采用封闭式流体压力呼吸计测定基础代谢率(BMR)。限食使摄食量显著增加,BMR和活动行为降低,胴体和生殖腺重量显著降低。重喂食后上述指标均恢复到对照组水平,表现出显著的可塑性变化。结果表明,KM小鼠能通过摄食量、BMR、活动行为和身体组成的可塑性调节以适应难以预测的食物资源变化。     

The Analysis of Copper,Selenium, and Molybdenum Contents in Frequently Consumed Foods and an Estimation of Their Daily Intake in Korean Adults

This study aimed to analyze the amounts of copper, selenium, and molybdenum among trace minerals in foods and to evaluate their daily intakes in Korean adults. Contents of copper, selenium, and molybdenum in 366 varieties of foods commonly consumed by Koreans were analyzed using inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry, techniques with low detection limits as well as high reproducibility and precision. Next, we evaluated the status of trace mineral intake using the 24-h recall method after conducting anthropometric measurements on 249 male and 344 female adults aged 20 or older. The average daily energy intake for males was 7,452.8 kJ, significantly higher than the 6,118.3 kJ for females (p < 0.001). The average daily copper, selenium, and molybdenum intakes by males were 1,156.7, 135.5, and 12.2 μg, respectively, compared to 1,028.5, 122.9, and 10.1 μg, respectively, by females. In males, the intake levels of copper and molybdenum were both significantly higher than in females. By continuously evaluating intake levels in this manner, it is anticipated that reference intakes of trace minerals will be established.     

Effect of soil texture and its organic content on the efficacy of Trichoderma harzianum (MIAU 145 C) in controlling Meloidogyne javanica and stimulating the growth of kidney beans

The efficiency of Trichoderma harzianum (MIAU 145 C) in promoting kidney bean (cv. Goli) growth in different soil texture (sandy loam, loam and clay loam) and organic matter content (0.5 and 2% of leaf litter) was assessed in a factorial experiment in the absence of Meloidogyne javanica. In another factorial experiment, the effect of soil texture, soil organic content and control measure (no control, 10?ml of T. harzianum containing 10⁶ spore ml^?1 and 2?mg ai cadusafos kg^?1 soil) was determined on nematode-infected kidney bean’s growth, fungus controlling activity and M. javanica reproduction. Except for the shoot length, the fungus improved plant growth. Clay loam was not a proper soil type for the cultivation of kidney bean plants (even in the soil without nematode), but the plant grew better in sandy loam and loam soil. The presence of leaf litter in the soil enhanced plant growth, increased fungal efficiency and increased nematode reproduction. It seems that T. harzianum can activate the plant defence system in sandy loam soil. T. harzianum was more effective in sandy loam or loam soil containing 2% organic matter (leaf litter) and reduced the reproduction factor of the nematode in the tested soil textures equally to the chemical nematicide treatment.     

Synergistic effects of food shortage and an insecticide on a <Emphasis Type="Italic">Daphnia</Emphasis> population: rapid decline of food density at the peak of population density reduces tolerance to the chemical and induces a large population crash

Laboratory populations of cloned Daphnia magna were exposed at different population phases (growing phase, density peak, stable phase) to the insecticide carbaryl at 15 μg 1⁻¹, which was harmful to juveniles but not to adults, and their population dynamics were analyzed. The population declined most at the density peak, when not only juveniles but also many adult individuals died. To analyze the factors affecting population vulnerability to carbaryl, acute toxicity tests were conducted using Daphnia individuals of different body sizes under different food conditions. The test revealed that daphnid sensitivity to carbaryl increased greatly when food density was changed from a high food level to a low level. This food condition, of low availability, might be the condition to which the Daphnia populations were exposed at their density peak. The synergism of the negative impacts of anthropogenic and natural stresses such as insecticides and food shortage may control aquatic populations.     

Community Structure of Fishes and Habitat Complexity on a Tropical Rocky Shore

The relationship between the variables of reef fish community structure (fish richness, fish diversity and total number of fishes) and those of habitat complexity (total surface area, substratum diversity, topographic complexity, number of holes, percent cover of turf algae, zoanthids, millepores, massive corals, bare rock, encrusting calcareous algae, urchins, other sessile organisms and Sargassum) were examined on three different rocky shores (FA, FB and FT) at Arraial do Cabo, a tropical region located on Brazilian southeastern coast (23° S, 42° W). Fish abundance and vertical distribution were assessed by a visual census technique using strip transects. Percentage cover of benthic organisms and other substratum types were calculated by replicated transects using a chain laid down on the substratum. Topographic complexity was determined by the chain link method and number of holes were estimated by direct counts on replicated transects. More than 91 fishes belonging to 37 families were seen in all study sites during one year of visual census effort. FA and FB sites had similar fish community structure and habitat complexity characteristics, while FT showed different habitat characteristics and higher fish diversity and richness, plus total number of fishes. Vertical distribution of fishes along the rocky shores studied seemed to be predictable and was determined by factors such as feeding habits and behavior, availability of refuges and social interactions. The habitat variables that best explained the higher diversity and number of fishes observed in FT site were total surface area of rocky shores and the abundance of benthic sessile invertebrates; these conditions were typical of rocky shores more exposed to wave surge.     

夜鹭繁殖习性与生长发育研究

１９９４～１９９８年对夜鹭繁殖习性与生长发育进行了研究。夜鹭于４月中下旬迁到浙江,９月下旬、１０月初迁离,居留期１６５天。巢距地高８．５１ｍ。平均窝卵３．４９枚,孵卵期２２～２６天,育雏期３０～３５天。年繁殖力３．５０只。雏鸟体重生长模型为：Ｗｔ＝５６０１＋ｅ＾－０．２３１（ｔ－１２）（Ｒ＾２＝０．９９）;体长、体重关系式为：Ｗ＝０．０００２４６Ｌ＾２．５０２９。雏鸟体温发育分为３个时期：