长春市南湖公园两栖类的生境选择和营养生态的初步研究

本文研究了1997年4-7月吉林省长春市南湖公园五种两栖类的生境和食性特点．结果表明：五种两栖类生境及食物多样性指数不同,生境及食物相似性指数亦有较大差异．食物多样性和相似性差异与栖息生境有关．研究结果为公园规划提供科学依据．     

Reproductive phenology and pre‐dispersal seed‐feeding in Protium tovarense (Burseraceae), with a description of the first known phytophagous “Bracon” species (Hymenoptera: Braconidae: Braconinae)

The reproductive phenology of the cloud forest tree Protium tovarense (Burseraceae) is analysed for one population in northern Venezuela. Reproductive phenophases were monitored using both long‐term(21 years) and detailed short‐term (4 years) surveys of flower and fruit set. The reproductive phenology of this tree varies, with periods in which the species behaves as a supra‐annual reproducer, and other periods in which it reproduces annually, at the end of the rainy season. Marked spatial variation in reproductive condition was also observed, with subpopulations separated by less than 2 km showing contrasting phenological stages. Larval infestation of seeds by a braconid wasp was observed for a period of 1 year and is described. This wasp, the first obligately phytophagous species of Braconinae, is described as Bracon phytophagus Quicke sp. n. Percentage fruit infestation by this wasp was relatively high (50–60%) during the entire period (～10 months) of fruit development. The larval stages are described and illustrated, and compared with those of other phytophagous Ichneumonoidea. DNA sequencing of wasp colour variants provided no indication that multiple species were involved. Two related braconine species described in the genus Iphiaulax are transferred to Bracon, hence, B. flavipalpisimus replacement name (Szépligeti) ( = Iphiaulax flavipalpis Szépligeti, 1901 Szépligeti, G v. 1901. Tropische Cenocoeliden und Braconidae aus der Sammlung des Ungarischens National‐Museums.. Természetrajzi Füzetek, 24: 353–402.  [Google Scholar] not B. flavipalpis Thomson, 1892) and B. glabrescens (Szépligeti) n. comb. ( = Iphiaulax glabrescens Szépligeti, 1901 Szépligeti, G v. 1901. Tropische Cenocoeliden und Braconidae aus der Sammlung des Ungarischens National‐Museums.. Természetrajzi Füzetek, 24: 353–402.  [Google Scholar]). Evolutionary routes to phytophagy in braconid wasps and hypothetical scenarios in which this plant–seed predator interaction can be maintained are discussed.     

大眼隐翅虫对萝卜蚜捕食功能反应与寻找效应研究

在室内条件下，对大眼隐翅虫Stenus(Stenus，s．str．)sp．1成虫对萝卜蚜Lipaphis erysimi(Kaltenbach)的捕食作用及寻找效应进行了定量研究，结果表明大眼隐翅虫对萝卜蚜的功能反应符合Holling Ⅱ型模型，理论方程为Na=0．7937N／(1 0．1582N)，日最大捕食量为5.018头．大眼隐翅虫寻找效应随自身密度增加而降低，其数学模型为α=6．0131 P^-0.6254，其捕食作用与个体间相互干扰作用关系用Hasseu模型拟合为E=0．2530 P^-0.1468．     

全氟辛磺酸对于爪蟾的甲状腺激素干扰效应

运用两栖类变态实验(AMA)研究了全氟辛磺酸(PFOS)对于非洲爪蟾(Xenopus laevis)蝌蚪的生长、变态和甲状腺组织结构的影响.结果显示,与对照组相比,7d后,10,50和250μg.L-1PFOS暴露组蝌蚪的后肢长分别减小了17%,11%和18%,蝌蚪的发育延缓了1~2个阶段;19d后,10,50和250μg.L-1PFOS组蝌蚪的体重分别增加了17%,10%和20%,体长分别增加了5%,4%和6%,而10μg.L-1和250μg.L-1PFOS组蝌蚪的后肢长分别减小了12%和13%;暴露组甲状腺组织结构出现滤泡数目减少、上皮细胞增生、胶质减少甚至滤泡溶通等现象.结论是,在本实验浓度下,PFOS对于非洲爪蟾的蝌蚪生长有促进作用,对于变态发育过程却有抑制作用.参照AMA的方法,可以判断PFOS为抗甲状腺激素干扰物.     

茂兰自然保护区药用两栖动物资源

介绍了茂兰自然保护区药用两栖动物的种类及其用途,经整理,茂兰保护区药用两栖动物隶属于5科6属14种。属于国家Ⅱ级重点保护野生动物2种;国家重点保护野生药材1种;国家保护的有益的或者有重要经济、科学研究价值的陆生野生动物11种。     

Ecology and behaviour of the ‘road tarantulas’ Eupalaestrus weijenberghi and Acanthoscurria suina (Araneae,Theraphosidae) from Uruguay

Spatial distribution, burrow morphology, phenology, defensive displays and predation of two theraphosid spiders living in meadows were studied in Uruguay. Exhaustive field studies complemented with laboratory observations were carried out. Eupalaestrus weijenberghi occurred throughout the country while Acanthoscurria suina occurred only in the southern half. Both species seemed to be the most abundant theraphosid spiders in Uruguay as they live in the dominant landscape of the country. Burrows from both species showed a similar morphological pattern but a terminal narrow tube was found only in E. weijenberghi. We observed that A. suina always co‐occurred with E. weijenberghi but this species frequently occurred in the absence of the former. When co‐occurring A. suina showed an aggregated distribution while E. weijenberghi was randomly distributed. A restricted reproductive period was found for both species, mainly between March and April, evidenced by the massive presence of walking adult males and then confirmed by pit‐fall traps. Moulting, oviposition and longevity were also studied. Conspicuous species‐specific defensive behaviours were displayed by the tarantulas in all cases, when collected. These tarantulas showed spatial co‐occurrence and temporal coexistence with the beetle Diloboderus abderus, an important pest of grasslands. Tarantula predation on adult beetles was confirmed, these spiders being one of the few beetle predators. Their maximal efficiency in beetle predation could reach 65?000 prey captured per hectare by month. These polyphagous tarantulas seem to be potential agents for the biological control of beetle pests.     

Mixed‐species social aggregations in Madagascan tadpoles—determinants and species composition

The frequency, species composition, and determinants of mixed‐species tadpole aggregations were analysed under natural conditions in a dry forest of western Madagascar. Most aggregations (73%) were formed by more than one species, with up to four species per individual aggregation. Dyscophus insularis (Microhylidae) and Aglyptodactylus securifer (Mantellidae) were the most abundant species in these aggregations. Using a logistic regression model we analysed to what extent the presence and absence of aggregations in a pond can be predicted by its biotic and abiotic habitat variables. Aggregations are more likely in deep, clear ponds with little leaf litter cover on the bottom, while the overall density of invertebrate predators in the pond seems to play a minor role. Our observations suggest that the formation of mixed‐species aggregations in tadpoles of the Kirindy Forest in our system is primarily a reaction to vertebrate predators. Therefore, aggregation behaviour may play a key role in the ability of several anuran species to utilize these spawning waters that are unpredictable in regard to the presence of fish and other vertebrates.     

Seed predation heterogeneity in the loculate fruits of a Mediterranean bushy plant

The effects of the number of locules per fruit on seed predation in a Mediterranean woody plant (Cistus ladanifer) were analysed. Plants produced fruits with a similar number of locules (fruits with a small, intermediate or large number of locules). Nevertheless, there were no differences in the number of fruits produced or predated per plant. Different types of fruits did not differ in size, seed weight, fruit to wall ratio, insect predation rate or mean proportion of destroyed locules. They did differ, however, in the variation of the proportion of destroyed locules; fruits with few locules had a wider variation than fruits with a large number of locules. Our results suggest that phenotypic selection pressure on insect predation could give rise to more between‐fruit variation in the seed output saved from predation in those plants producing fruits with a small number of locules.     

两栖类动物皮肤分泌抗菌肽的研究进展(动物科学)

近年因病原性细菌耐药性日趋严重,迫切需要从各种自然资源中寻找新的抗菌药物;因两栖类抗菌肽具有分子量小、水溶性好、抗原性低、抗菌作用强等优点,成为筛选抗菌药物的重要研究对象。本文就两栖抗菌肽的生物活性、分子结构、家族分类、抗菌分子机制、应用价值及研究前景等方面进行了综述。当前的研究表明,两栖类抗菌肽除具有抗菌作用外还有抗病毒抗肿瘤溶血等作用;它们因结构可分为3类:线性α-螺旋多肽、环性肽和含10～13个氨基酸残基长度的多肽;目前已发现抗菌肽有很多家族如Magainin家族、Aurein家族、Bombinin家族、Bombinin-like家族Brevinin家族等抗菌肽家族不同其生物活性也不同;它们杀菌主要通过膜裂解或膜不裂解机制完成;已发现两栖类抗菌肽在临床医药、食品保鲜防腐、农业生产等领域具有广阔的应用价值。随着在分子水平上深入的研究,两栖类抗菌肽将突破表达量低、特异性差、产量小、成本高等局限性,为人类制备新型抗菌药提供更多可用的资源。