池鹭的夏季食性及生态的初步观察

本文报告了池鹭的夏季食性分析及部分生态的观察。池鹭主要以动物性食物为食,占总食物频次的95.09％;占检出食物总数的97.79％,池鹭所吞食的动物种类涉及到4门7纲17目32科以上。在动物性食物中,又以蛛形纲的蜘蛛目,昆虫纲的蜻蜓目、鞘翅目、直翅目、半翅目、双翅目,鱼纲的鲤形目和两栖纲的无尾目的种类为主。池鹭的有益系数为-22.41％,就食性而言,证明池鹭是一种害鸟,不过其有害程度较低。雌雄个体间的食性无明显差异。 池鹭营群巢,且巢非常粗糙,并有与它鸟同树营巢现象。其取食范围随环境的不同而有变化。     

浙江东部牛蛙的自然种群及潜在危害

牛蛙(Rana catesbeiana)的入侵已成为一些本地两栖类种群数量下降或灭绝的主要因素之一。1959年牛蛙被引入中国大陆,但直到1990年才开始在国内大范围饲养。牛蛙的自然种群在国内一直未见报道。我们于2003年9—11月调查了浙江省东部5区3县的牛蛙种群,发现在岱山、秀山、六横及佛渡岛上有牛蛙分布,共捕获23只牛蛙,包括4只成年个体,18个亚成体和1只蝌蚪。于2004年1月和2月在岱山捕获28只蝌蚪。结果显示：(1)牛蛙的蝌蚪能在当地越冬成活,说明牛蛙在上述4岛成功地建立了自然种群;(2)牛蛙主要分布于水库、池塘和溪流,牛蛙的生境与6种当地蛙有部分重叠;(3)养殖时管理不善造成的牛蛙逃逸,以及牛蛙价格过低而导致养殖户将牛蛙弃置野外可能是牛蛙入侵的主要原因。牛蛙对当地蛙的潜在威胁很大,开展牛蛙的分布、食性和种群动态研究是当务之急。     

千岛湖花臭蛙个体发育过程中的食性变化

个体发育过程中的食性变化普遍存在于无尾目类群中。我们于2012~2013年,对千岛湖地区的花臭蛙(Odorrana schmackeri)进行抓捕采样,测量体长、体重以及头宽等身体指标,同时鉴定胃内食物并加以测量和分析。调查期间,共捕获花臭蛙838只,测量胃内食物2 178个。结果表明,花臭蛙食物种类丰富,食物类群隶属78科,但食谱宽度较窄。随着花臭蛙体长增加,其摄食的食物总体积和单个食物体积显著增加,但摄食食物数量显著减少。同时,不同体长的花臭蛙对不同食物的摄食频率也有不同。半翅目、膜翅目以及等翅目等小型食物的摄食频率随花臭蛙体长的增加而变小,而直翅目以及鳞翅目幼虫等大型食物的摄食频率随花臭蛙体长的增加而变大。综上所述,千岛湖地区花臭蛙在个体发育过程中存在食性变化,因此在以后无尾目类群的食性研究中,应将个体发育的因素考虑在内。     

昆明滇蛙的取食策略

目前国内研究两栖类食性选择或偏好多未考虑蛙胃内不同食物的丰盈程度与栖境不同食物资源是否存在相关性.在分析了采自昆明白龙寺和昆明石林西街口的494只滇蛙(Rana pleuraden)的食性的同时,分析了采自对应栖境中的食物资源组成.结果表明,滇蛙的食物成份与食物资源相具有稳定性,主要类群均为直翅目、同翅目、半翅目、鞘翅目、双翅目、鳞翅目、膜翅目和蛛形纲等8类.但又存在变异性,不同产地、不同年份和不同月份之间的蛙标本胃内的食物成分各类群的比例均不相同.主要食物成份与食物资源相的差异显著性分析、相关性分析和选择性分析等方面的结果均支持或证明:滇蛙对食物具有选择性或取食偏好.栖境的食物资源相与蛙胃内的食物成分不存在相关性(白龙寺:r=0.077,P=0.575;西街口:r=-0.086,P=0.500).直翅目(Ei＜-0.35)和同翅目(Ei＜-0.37)昆虫是滇蛙取食时回避的食物,而对鞘翅目、鳞翅目、膜翅目和蛛形纲等4个类群(Ei＞0.45)具有明显偏好.     

鄂尔多斯地区密点麻蜥的食性分析

对采自内蒙古自治区鄂尔多斯库布齐沙漠85只密点麻蜥Eremias multiocellata,采用胃剖法作食性分析,分别计算出它们的食物数量和频次百分比、营养生态位宽度、营养生态位重叠值和有益系数等。结果显示,密点麻蜥以觅食昆虫为主,其次为蛛形类和植物种子;其中包括2纲13目41科的节肢动物门物种。雌、雄个体的取食食性差异不显著,但幼体、亚成体和成体间食性有显著的差异。雌、雄个体的营养生态位重叠值较大。亚成体的营养生态位宽度与食物多样性指数最大,而成体最小。密点麻蜥的总有益系数为正值,表明该物种摄食较多的害虫。     

江西南矶湿地斑背大尾莺食性初步分析

为了填补斑背大尾莺食性研究的空白和比较其繁殖期和非繁殖期是否有食性差异,于2011年4月繁殖期,在江西南矶湿地用望远镜观察和录像机拍摄斑背大尾莺亲鸟育雏行为,记录育雏食物的种类和数量;在11月秋季非繁殖期,斑背大尾莺专项环志过程中采集7只意外死亡的个体,进行实验室胃容物解剖分析。两种分析方法分别得出:1)春季取食动物性食物,主要有直翅目蝼蛄科成虫或幼虫、鳞翅目成虫或幼虫、蜻蜓目的成虫,蛛形纲的小型蜘蛛;2)秋季食物由动物性食物(70.24%)和植物性食物(29.76%)组成,动物性食物主要为鞘翅目、直翅目、蜻蜓目、鳞翅目、蜘蛛目等节肢动物,植物性食物为一些植物种子和少量的叶片组织。本研究表明,繁殖期和非繁殖期斑背大尾莺食性有差异,这种差异性是随季节变化生境中的食物组成不同,及育雏期雏鸟需高蛋白营养食物而导致的。     

昆明滇蛙的取食策略

目前国内研究两栖类食性选择或偏好多未考虑蛙胃内不同食物的丰盈程度与栖境不同食物资源是否存在相关性。在分析了采自昆明白龙寺和昆明石林西街口的494只滇蛙(Rana pleuraden)的食性的同时，分析了采自对应栖境中的食物资源组成。结果表明，滇蛙的食物成份与食物资源相具有稳定性，主要类群均为直翅目、同翅目、半翅目、鞘翅目、双翅目、鳞翅目、膜翅目和蛛形纲等8类。但又存在变异性，不同产地、不同年份和不同月份之间的蛙标本胃内的食物成分各类群的比例均不相同。主要食物成份与食物资源相的差异显著性分析、相关性分析和选择性分析等方面的结果均支持或证明：滇蛙对食物具有选择性或取食偏好。栖境的食物资源相与蛙胃内的食物成分不存在相关性 (白龙寺：r=0.077, P=0.575; 西街口：r=-0.086, P=0.500)。直翅目(Ei<-0.35)和同翅目(Ei<-0.37)昆虫是滇蛙取食时回避的食物，而对鞘翅目、鳞翅目、膜翅目和蛛形纲等4个类群(Ei>0.45)具有明显偏好。     

云南昆明不同产地滇蛙的食物变化比较

要真正了解一种蛙的生态习性及食性,调查和分析其不同种群、不同生长阶段和不同性别的年周期食物组成是必要的。自1998年5月至2003年11月在昆明白龙寺、花红洞和西街口逐月采集滇蛙Rana pleuraglen标本进行食性分析,结果表明,滇蛙种群间和不同生长阶段、及雌雄个体间的食量百分比上有差异。Kruskal-Wallis检验结果显示,不同种群间和不同生长阶段的食物量组成无显著差异。Mann—Whitney U检验和Kolmogorov—Smirnov Z检验结果显示,各产地雌雄滇蛙食物量组成均无显著差异。滇蛙的食物类群相对丰富,反映它是捕食的多面手。昆明地区气候稳定,不同小地域农田生境的昆虫相几乎相同。这是食物成分相同的主要原因。而滇蛙不同种群的食物成分中,一些类群所占的比例不完全相同,又反映出三地气候和／或昆虫相的微小差异。幼年组食物中双翅目和膜翅的成分高于成年Ⅰ、Ⅱ组的。这可能与上述食物类群富含幼年组个体所需要的营养成分或者比例较高有关,所以它们食之较多。     

草原沙蜥秋季食性分析

利用剖胃法对采自内蒙古自治区鄂尔多斯库布齐沙漠的草原沙蜥(Phrynocephalus frontalis)进行食性分析研究。结果表明,该地区的草原沙蜥在8～9月间,以昆虫类动物为主要食物,占全部食物的95.8%。不同性别草原沙蜥取食的食物种类差异不显著,雌雄个体的食物百分率相似性指数及营养生态位重叠值均较大,雄性的食物多样性指数(IFD)及营养生态位宽度(BTN)均大于雌性。成体和亚成体之间以及亚成体和幼体之间食物种类存在差异但不显著,而成体和幼体间的食物种类差异极显著,不同年龄草原沙蜥的食物百分率相似性指数较小,IFD值与BTN值均是成体最大,幼体最小。总有益系数、不同性别的有益系数分别为V总=22.44%,V雌=12.76%,V雄=9.83%,草原沙蜥是对荒漠化草原有益的类群。     

水稻无脊椎动物多样性的K-L变换编目分析

K-L变换可消除样品各特征间的相关性,去除信息量较少或信息虚假的坐标轴,降低特征空间的维数,用较少量的特征描述样品,是目前最为有效的数据信息压缩抽取方法。利用K-L变换,样品之间变化较小的分类单元（目或功能群等）,不会作为重要特征保留下来。因此,数量上占优势、或害虫防治中有重要地位的分类单元并不一定是识别样品的重要特征。可以藉K-L变换明确构成样品变异的主要分类单元,从而对不同地区、不同季节的取样实践有一定的指导意义、用通常的多样性指数分析及多样性差异显著性分析无法解决这个问题。用K-L变换可大大压缩数据存储空间。对数据量很大的生物多样性分析有较大的应用价值。反映样品所携信息量的热带水稻田无脊椎动物目主要是半翅目,中腹足目,以及表腹亚目。其中,在旱季半翅目占主要地位,而在雨季中腹足目占主要地位。就无脊椎动物目的组成而言,它们是构成样品变异的主要类群,是取样中需要得到特别注意的目。反映样品信息的无脊椎动物功能群主要是外部植食类,植食多食性类,半水生水面爬行类,粗粒残物取食类,以及陆生爬行、跳跃或猎者类,是取样中要重点考虑的一些类群。     

Diet composition of post-metamorphic bullfrogs (Rana catesbeiana) in the Zhoushan archipelago, Zhejiang Province, China

Bullfrogs (Runa catesbeiana) are listed as one of the 100 worst invasive alien species in the world.They are generalist predators and thus may affect native species through predation.In previous studies,the food contents of bullfrogs were mostly examined at a single site.In the present study,the diet composition of post-metamorphic bullfrogs on eight islands (Daishan,Liuheng,Xiushan,Fodu,Taohua,Xiashi,Cezi,and Putuoshan) in the Zhoushan Archipelago,Zhejiang Province of China,were examined by using the stomach flushing method from June 30 to August 11 in 2005.A total 0f391 individual frogs were measured,including 113 adults and 278 juveniles.The analysis of the stomach contents shows that,for adult bullfrogs,the most important prey (by diet volume) overall were Decapoda,Coleoptera,Odonata,Mesogastropoda,Raniformes,and Cypriniformes.For juvenile bullfrogs,these were Decapoda,Coleoptera,Cypriniformes,Odonata,Orthoptera,Hymenoptera,Lepidoptera larvae,Mesogastropoda,and Raniformes.Moreover,the prey size and diet volume increased with the body size of both adult and juvenile bullfrogs.The diet composition of primary preys of bullfrogs was significantly different among the islands.The results indicate that bullfrogs exert different predatory influences on native fauna at different sites and that bullfrogs are generalist predators with extensive ecological impacts on native fauna.     

Diet composition of post-metamorphic bullfrogs (Rana catesbeiana) in the Zhoushan archipelago, Zhejiang Province, China

Bullfrogs (Rana catesbeiana) are listed as one of the 100 worst invasive alien species in the world. They are generalist predators and thus may affect native species through predation. In previous studies, the food contents of bullfrogs were mostly examined at a single site. In the present study, the diet composition of post-metamorphic bullfrogs on eight islands (Daishan, Liuheng, Xiushan, Fodu, Taohua, Xiashi, Cezi, and Putuoshan) in the Zhoushan Archipelago, Zhejiang Province of China, were examined by using the stomach flushing method from June 30 to August 11 in 2005. A total of 391 individual frogs were measured, including 113 adults and 278 juveniles. The analysis of the stomach contents shows that, for adult bullfrogs, the most important prey (by diet volume) overall were Decapoda, Coleoptera, Odonata, Mesogastropoda, Raniformes, and Cypriniformes. For juvenile bullfrogs, these were Decapoda, Coleoptera, Cypriniformes, Odonata, Orthoptera, Hymenoptera, Lepidoptera larvae, Mesogastropoda, and Raniformes. Moreover, the prey size and diet volume increased with the body size of both adult and juvenile bullfrogs. The diet composition of primary preys of bullfrogs was significantly different among the islands. The results indicate that bullfrogs exert different predatory influences on native fauna at different sites and that bullfrogs are generalist predators with extensive ecological impacts on native fauna. __________ Translated from Biodiversity Science, 2006, 14 (5): 363–371 [译自: 生 物多样性]     

年龄和性别因素对奇台沙蜥食性的影响

采用胃容物分析法研究年龄和性别因素对奇台沙蜥(Phrynocephalus grumgrzimailoi)食性的影响.共解剖220号浸制标本,取出整胃分离胃容物,鉴别胃容物中的食物种类,统计各种食物组分的数量频率、重量比例、出现频率和相对重要性指数(index of relative importance,IRI).结...     

Who eats whom in a pool? A comparative study of prey selectivity by predatory aquatic insects

Predatory aquatic insects are a diverse group comprising top predators in small fishless water bodies. Knowledge of their diet composition is fragmentary, which hinders the understanding of mechanisms maintaining their high local diversity and of their impacts on local food web structure and dynamics. We conducted multiple-choice predation experiments using nine common species of predatory aquatic insects, including adult and larval Coleoptera, adult Heteroptera and larval Odonata, and complemented them with literature survey of similar experiments. All predators in our experiments fed selectively on the seven prey species offered, and vulnerability to predation varied strongly between the prey. The predators most often preferred dipteran larvae; previous studies further reported preferences for cladocerans. Diet overlaps between all predator pairs and predator overlaps between all prey pairs were non-zero. Modularity analysis separated all primarily nectonic predator and prey species from two groups of large and small benthic predators and their prey. These results, together with limited evidence from the literature, suggest a highly interconnected food web with several modules, in which similarly sized predators from the same microhabitat are likely to compete strongly for resources in the field (observed Pianka's diet overlap indices >0.85). Our experiments further imply that ontogenetic diet shifts are common in predatory aquatic insects, although we observed higher diet overlaps than previously reported. Hence, individuals may or may not shift between food web modules during ontogeny.     

Diet composition of introduced bullfrog, <Emphasis Type="Italic">Rana catesbeiana</Emphasis>, in the Mizorogaike Pond of Kyoto,Japan

I analyzed stomach contents of the American bullfrog, Rana catesbeiana, in the Mizorogaike Pond of Kyoto, Japan. As a result, adult bullfrogs were found to feed predominantly on crayfish, and juveniles eat diverse arthropods. A wide variety of aquatic organisms occurred in the diet of both adult and juvenile bullfrogs.     

Food habits of the endangered Alabama Sturgeon, Scaphirhynchus suttkusi Williams and Clemmer, 1991 (Acipenseridae)

The gut contents of 12 museum specimens of the federally (USA) endangered Alabama sturgeon were analyzed. This collective series represents 32% of the known museum specimens. Gut contents were dominated by aquatic insects and fishes. At the taxonomic level of insect orders, Dipterans (174.3/fish) were the most numerically abundant food item consumed, followed by Ephemeroptera (19.0/fish), Trichoptera (4.0/fish), Coleoptera (2.4/fish), and Odonata (2.0/fish). Weight, which better reflects the caloric value of food items consumed, showed a similar consumption pattern. Dipterans (12.5%) made up the largest percentage of the total weight of insect prey, followed by Ephemeroptera (8.9%), Trichoptera (6.0%), Odonata, (4.5%) and Coleoptera (0.9%). Volumetric values were substantially higher than weights for Odonata (13.4%) and Ephemeroptera (14.3%), but were comparable for Diptera (10.6%), Trichoptera (4.7%), and Coleoptera (2.2%). The diet of the Alabama sturgeon is similar to the pallid and shovelnose sturgeon, eating both aquatic invertebrates and fish. In terms of piscivory, the volume of fish in the diet of the Alabama sturgeon (34.5%) is intermediate between that of the shovelnose (0% fish) and the pallid sturgeon (60% fish). Based upon the habitat preference of the prey family assemblages present from the 12 guts examined, probable feeding habitats of this sturgeon include sandy to rocky bottoms, slow to swift water velocities, and the water column. Conservation of fish prey may be important to the survival and recovery of the Alabama sturgeon.     

Prey selection by young trout fry (Salmo trutta)

Factors influencing the choice of invertebrate food by early feeding trout are sought, special attention being given to the dimensions of the prey. The stomach contents of fish of similar age feeding on lake plankton and drifting stream fauna are compared. Little consistent preference was displayed for the smaller planktonic organisms but prey size was of importance in the distribution of stream benthos among predators of different lengths. The width of the prey was of greater significance to selection than the mean volume or the area of the largest surface of the food items. When the fish were in obvious competition for food the correlation between predator length and all prey dimensions improved.     

黄海中部高眼鲽的摄食及随体长的变化

对2004年1月-2005年10月在黄海中部采集的622尾高眼鲽样品的胃含物进行分析.结果表明：高眼鲽摄食的食物种类包括11类38种,其中甲壳类和瓣鳃类为优势饵料类群,共占食物相对重要性指数百分比的99%;食物中的优势饵料种类为太平洋磷虾、脊腹褐虾和樱蛤.与20世纪80年代相比,黄海高眼鲽的摄食强度下降,食物组成发生了较大的变化;鱼类不再是优势饵料类群,鳀鱼在食物中所占的比例明显下降.通过聚类分析和列联表检验等方法对高眼鲽摄食随体长的变化进行研究,结果表明：体长在51～370 mm范围内的高眼鲽的摄食强度没有显著的体长变化,但不同体长组摄食的食物种类有一定差异.＜119 mm的主要以磷虾类和底层虾类为食;体长在120～199 mm的除以磷虾类和底层虾类为主要食物外,还摄食相当比例的瓣鳃类和鱼类;＞200 mm的则主要摄食底层虾类和鱼类,磷虾类所占比例减小.     

Length and weight estimates from diagnostic hard part structures of fish,crustacea and cephalopods forage species in the western Indian Ocean

To estimate the original prey size of well-digested prey (fish, cephalopod and crustacean) of large pelagic fish predators representing 17 species in eight families (Scombridae, Xiphiidae, Istiophoridae, Carangidae, Coryphaenidae, Alepisauridae, Sphyraenidae and Carcharhinidae), we presented regression equations relating the length and weight of the prey to lengths of diagnostic hard part structures recovered from stomach contents. Stomach samples were collected in the western Indian Ocean between 2000 and 2008 from predators caught by three fishing gears: longline, purse seine and troll lines. In addition, fresh specimens were collected from trawls nets carried out during scientific cruises at depths ranging from the surface to 500 m. Parameters of the least-square regression equations were estimated between different diagnostic hard parts and the length and the weight of the prey. These relationships are useful for estimating the reconstructed weight of the diet of top predators and for estimating the predator size-prey size ratios. This work is the first reference on such relationships for the forage fauna of the western Indian Ocean.     

Dietary composition and prey selectivity of juvenile porcupine rays Urogymnus asperrimus

Fifty‐five juvenile porcupine ray Urogymnus asperrimus were collected in the isolated St Joseph Atoll, Seychelles. Stomach contents were sampled using non‐lethal gastric lavage to determine the dietary composition, degree of prey selectivity and whether sex or size affected their diet. Sediment samples were collected to quantify prey availability so that prey selectivity could be estimated. Two phyla (Sipuncula and Nemertea) and 11 polychaete and crustacean families were recorded in stomach contents. Juvenile U. asperrimus appeared to specialize on one polychaete family, Capitellidae, which was the most important prey item (index of importance = 35%). This polychaete family was also most abundant in the sediment samples and U. asperrimus are thus considered opportunistic predators. There was evidence of a size‐related shift in the crustacean families consumed by juvenile U. asperrimus. Data collected at this remote location provides important baseline ecological information that may prove useful in developing conservation strategies for this ecologically important species.