横斑锦蛇的现状

结合近几年来的野外调查,对横斑锦蛇的现状进行了报道。横斑锦蛇目前仅见于四川省西部的汶川、宝兴、石棉、泸定和雅安5个县、市,其中石棉和宝兴两县为其新分布区。横斑锦蛇栖息于海拔1650－2500m的湿润山地落叶阔叶林及灌草丛中,数量稀少,亟待加强保护和研究。 此外,还对唯一的幼蛇标本进行了描述。     

蕹菜的DAPI显带核型

利用一种新的DAPI显带技术分析了蕹菜染色体的DAPI带型及其异染色质的分布,建立了类似于G带的蕹菜DA PI带模式图,为蕹菜的细胞遗传学研究、育种和资源的开发利用提供帮助。     

华南兔组织乳酸脱氢酶同工酶的研究

本文以聚丙烯酰胺凝胶电泳法分析华南兔(Lepus sinensis sinensis)11种组织乳酸脱氢酶同工酶的分布待征。分析结果:骨骼肌和肝组织5条同工酶带俱全;脑、肺、卵巢和盲肠等组织各含有4条谱带(LDH-1,-2,-3和-4);胃和肾组织含有3条谱带(LDH-1,-2,和-3);眼晶状体和睾丸组织也含有3条谱带,但前者是LDH-3,-4和-5,后者是LDH-1,-2和-5;谱带最少的是心肌组织,只有2条(LDH-1和-2)。此外,还对各组织中的亚基活性分布及电泳图谱特征进行了分析。     

Influence of proximal stimuli on swimming in the sea hare Aplysia brasiliana

Although the neurobiology and physiology of sea hares are extensively studied, comparatively little is known about their behaviour or ecology. Several species of sea hares swim, but the function of swimming is unclear. In this paper, we tested the hypotheses that swimming in Aplysia brasiliana serves to find food and mates, and to escape predators. Our data strongly support the hypothesis that swimming in A. brasiliana is related to feeding. Sea hares deprived of food overnight swam 12 times longer than ones that had been fed. When sea hares contacted food while swimming they invariably stopped, while those contacting a plastic algal mimic mostly continued to swim. Our experiments provided no evidence to support the hypothesis that swimming in sea hares is related to social behaviour. Sea hares deprived of copulatory mates for 3 days did not swim longer than ones held in copulating groups. Moreover, swimming sea hares never stopped swimming upon encountering a conspecific. Our experiments also supported the hypothesis that swimming in sea hares is related to predation. Sea hares stimulated with a standardised tail pinch and exposed to ink of conspecifics swam four times longer than control individuals, and tail-pinched sea hares that released ink swam five times longer than ones that did not release ink. However, because predators of adult sea hares are mostly lacking and because sea hares often swim spontaneously without predators being present, we conclude that swimming behaviour in A. brasiliana is primarily related to food-finding.     

Assessment of Canada Lynx Research and Conservation Needs in the Southern Range: Another Kick at the Cat

Abstract The ecology of Canada lynx (Lynx canadensis) and their main prey, snowshoe hares (Lepus americanus), is poorly understood in southern Canada and the contiguous United States compared to the boreal forest of Canada and Alaska, USA, where both species are well studied. However, given recent listing of lynx under the Endangered Species Act, accurate understanding of lynx and snowshoe hare ecology and conservation requirements in the United States is a high priority. We critically examined unchallenged perceptions and important research needs related to lynx and hare ecology and conservation at the southern extent of their range. Contrary to popular dogma, lynx do not require old-growth forest for denning, but further research on lynx and hare use of fragmented landscapes at lower latitudes is required. The contention that southern lynx are subject to higher interference or exploitative competition compared to their northern counterparts remains without strong empirical support. Lynx rely more on red squirrels (Tamiasciurus hudsonicus) and possibly other alternate prey at lower latitudes, but hares are the predominant food type for lynx across their range. Southern lynx and hare populations do not exhibit periodic cyclicity, but harvest statistics suggest that lynx abundance in the southern range is highly variable, implying that numerical fluctuations likely are fueled by immigration from Canada. Southern lynx population viability in the absence of ingress is suspect and thus maintaining connectivity with northern areas of occupancy should be a priority. Successful conservation of lynx populations in the contiguous United States will require 1) improved understanding of lynx population and habitat ecology at lower latitudes, 2) protection and management of large tracts of lynx and snowshoe hare habitat, and 3) ensured connectivity between lynx populations at the core and periphery of the species' range. However, in light of the numerous challenges facing conservation of populations of many species at their southern distributional limit, the long-term prognosis for lynx in the southern range currently is uncertain.     

Genetic polymorphism of sorbitol dehydrogenase in the brown hare and the distribution of the variation in Central Europe

A genetic polymorphism of sorbitol dehydrogenase (SDH; EC 1.1.1.14) for two allozymes is demonstrated in the brown hare (Lepus europaeus) by means of horizontal starch gel electrophoresis. Segregation analysis was performed in a sample of four matings with 12 offspring and confirmed the genetic hypothesis: two alleles at an autosomal locus. The calculated gene frequencies in the brown hare breed studied areSdh ^a =0.712 andSdh ^b =0.288. The distribution of the polymorphism in free-ranging brown hare populations from Austria, Czechoslovakia, Hungary, and Poland is described.This research was supported by a grant from the Fonds zur Förderung der Wissenschaftlichen Forschung, Austria (project P6767B).     

Winter Habitat Selection by Canada Lynx in Maine: Prey Abundance or Accessibility?

Abstract: We related winter habitat selection by Canada lynx (Lynx canadensis), relative abundance of snowshoe hares (Lepus americanus), and understory stem densities to evaluate whether lynx select stands with the greatest snowshoe hare densities or the greatest prey accessibility. Lynx (3 F, 3 M) selected tall (4.4-7.3 m) regenerating clear-cuts (11-26 yr postharvest) and established partially harvested stands (11-21 yr postharvest) and selected against short (3.4-4.3 m) regenerating clear-cuts, recent partially harvested stands (1-10 yr), mature second-growth stands (>40 yr), and roads and their edges (30 m on either side of roads). Lynx selected stands that provided intermediate to high hare density and intermediate cover for hares (i.e., prey access) but exhibited lower relative preference for stand types with highest hare densities where coniferous saplings exceeded 14,000 stems/ha.