青海门源地区大(狂鸟)和雕鸮的食性比较

1999～2002年的6～8月份,在青海门源地区收集了大(狂鸟)和雕鸮的吐弃块(pellets)和残留食物(food remains),带回实验室进行分检鉴定、研究分析.大(狂鸟)食物中共有736个猎物,其中高原鼢鼠28只、高原鼠兔139只、甘肃鼠兔142只、田鼠科动物422只、雀形目鸟类4只、香鼬1只;各猎物对大(狂鸟)食物的生物量贡献率分别为14.26%、40.79%、17.39%、26.99%、0.22%、0.35%.雕鸮食物中共有330个猎物,其中高原鼢鼠17只、高原鼠兔77只、甘肃鼠兔44只、田鼠科动物183只、雀形目鸟类2只、红脚鹬2只、高原兔5只;各猎物对雕鸮食物的生物量贡献率分别为11.83%、30.87%、7.36%、16.00%、0.15%、0.62%、33.17%.雕鸮的食物生态位宽度与大(狂鸟)的食物生态位宽度相近,食物生态位高度重叠,但是它们捕食同种猎物的比例显著不同.     

Body Form and Locomotion in Sharks

A revised interpretation of the mode of action of the heterocercaltail in sharks shows that the upturned tail axis tends to producea thrust directed downwards behind the centre of balance ofthe fish and thus gives a moment turning the head upwards. Thisis countered in two ways—by the rotation of the tail alongits longitudinal axis during each lateral beat, and throughthe action of the ventral hypochordal lobe. The shape of thetail and the mode of action of the tail in all sharks so farconsidered reflects a balance between these three factors, inall of them the net effect being the production of a forwardthrust from the tail that passes directly through the centreof balance of the fiish. There is normally therefore no tendencyfor the fish to turn around the centre of balance in a sagittalplane but there is a net sinking effect that is countered bythe planning effect of the pectoral fins and the ventral surfaceof the head. A study of 56 species of sharks shows that the tail is constructedaccording to a remarkably consistent common plan, the extremesbeing the high angled rather symmetrical tail of pelagic sharkssuch as hums, Lamna and Rhincodon and the straight tails ofbenthic sharks such as Ginglymostoma in which a ventral hypochordallobe is absent. When the general body shape of sharks, includingthe position of insertion of the median and paired fins andthe pattern of growth of fin surface areas is considered, theuniformity of the shark body plan and locomolor function isfurther emphasised. Four patterns of body form in sharks are recognised: 1) Thefast swimming pelagic sharks and the whale sharks have a tailwith a high aspect ratio, a conical head, a lateral fluke onthe caudal peduncle. 2) The generalised sharks typified by theCarcharhinidae, have lower heterocercal angles, a flattenedventral surface on the head and lack the caudal fluke. 3) Thedemersal sharks typified by the catsharks (Scyliorhinidae) havea very low, almost straight tail. The ventral hypochordal lobeis absent and the first dorsal fin is posterior in position.4) The squalomorph sharks are distinct in the absence of theanal fin, presence of a marked epicaudal lobe in the tail andoften an elevated insertion of the pectorals. The anal and second dorsal fins are always the smallest finsand the pectorals grow at the fastest rate. In general thereis an inverse relationship between size and rale of growth ofall fins and the ventral surface of the head. In hammerheadsthe growth data confirms that the head has a significant planingaction in swimming. The pectoral, second dorsal and anal finsshow an extreme constancy of position of insertion in all sharksstudied. The locomotor mechanism of sharks is adapted for anefficient cruising swimming but at the same time, the potentialinstability in the sagittal plan allows for the production ofturning moments that are used in attack and feeding.     

Arenavirus Coinfections Are Common in Snakes with Boid Inclusion Body Disease

Recently, novel arenaviruses were found in snakes with boid inclusion body disease (BIBD); these form the new genus Reptarenavirus within the family Arenaviridae. We used next-generation sequencing and de novo sequence assembly to investigate reptarenavirus isolates from our previous study. Four of the six isolates and all of the samples from snakes with BIBD contained at least two reptarenavirus species. The viruses sequenced comprise four novel reptarenavirus species and a representative of a new arenavirus genus.     

Predatory Attacks to the Head vs. Body Modify Behavioral Responses of Garter Snakes

An animal's response to predatory attack may depend upon which part of its body is the focus of that attack, because of differential vulnerability to injury. Many avian and mammalian predators direct attacks preferentially toward the prey's head, so simulated attacks that do not have this focus may elicit non‐natural responses. We ‘pecked’ 152 free‐ranging adult male garter snakes (Thamnophis sirtalis parietalis) in Manitoba either on the head or the midbody, and recorded their responses. The snakes’ antipredator tactics were affected not only by body size (larger snakes performed threat displays more often) and body temperature (hotter snakes were more likely to flee), but also by location of the attack. Pecks to the head generally resulted in snakes coiling and hiding their heads, often simultaneously elevating and wriggling their tails in an apparent distraction display. In contrast, pecks to the midbody stimulated either escape responses, or (in snakes that did not flee) open‐mouthed threat displays. More generally, antipredator tactics may respond in flexible ways to details of the predator–prey encounter (including attributes of the habitat as well as the morphology and behavior of both participants) and hence, experimental studies need to carefully simulate such details. The part of the body under attack may be an important factor in this respect.     

黑龙江省通河乌龙狩猎场野猪冬季食性的初步研究

野生动物食性的研究,在野生动物保护和管理方面具有重要的基础理论意义。野猪（Sus scrofa）是一种经济价值较高的有蹄类动物。国内对野猪食性的报道,仅见综述性献（巫露平,1980;李振营和罗泽殉,1983;杨伯然,1984）,野猪食性方面的研究尚未多见;国外对野猪食性的研究主要集中在食物组成的定量分析和食物营养质量的评价（Eriksson and Petrov,1995;Foumier-chambrillon et al．,1995;朝日念,1985）。因此,作从2000～2001年,分别在黑龙江省通河乌龙狩猎场收集粪样,利用粪便显微组织学分析方法并结合野外掘食痕迹对野猪冬季食性进行了初步研究。     

Communication and Displays of Snakes

With limitations imposed by the lack of appendages and elongatemorphology, snakes exhibit a variety of unique ritualistic behaviorsin the contexts of agonistic encounters and courtship and mating.During male combat rituals, actions involve high vertical displaystances (crotaline) to horizontal stances (colubrid) with eithermale attempting to force the other's head down. Superior positionappears to be important during these encounters. Dominant andsubordinate actions and postures are recognized. Courting snakesexhibit a variety of positions and movements, performed primarilyby the male, which appear to passify the female and induce herreceptivity. Actions involved may be chin rubbing, body jerksor caudocephalic waves, cephalocaudal waves, tail searching,pushing, nudging, biting, and tail raising. Sequences and phasesof the actions used vary with the species. Significant featuresof these behaviors are the different actions taking place separatelyor simultaneously along the elongate cylindrical snake. Visual,tactile, and olfactory communication each play a role.     

Body Form, Locomotion and Foraging in Aquatic Vertebrates

Four functional categories are denned to embrace the range oflocomotor diversity of aquatic vertebrates; (1) body/caudalfin (BCF) periodic propulsion where locomotor movements repeat,as occurs in cruising and sprint swimming; (2) BCF transientpropulsion where kinematics are brief and non-cylic, as occursin fast-starts and powered turns; (3) median and paired fin(MPF) propulsion, with very diverse fin kinematics, used inslow swimming and precise maneuver; (4) occasional propulsionor "non-swimming." Specialization in any one of these categoriescompromises performance in one or more of the others, therebyreducing locomotor diversity and hence behavioral options. Foodcharacteristics influencing the role of locomotion in searchand capture are; (1) distribution in space and/or time and (2)evasive capabilities. BCF periodic swimmers take food that iswidely dispersed in space/time; BCF transient swimmers consumelocally abundant evasive items and MPF swimmers consume non-evasivefood in structurally complex habitats. Locomotor specialistsunder-utilize smaller food items in exposed habitats. This resourceis exploited by smaller fish, which are locomotor generalistsbecause of predation pressures. For such locomotor generalists,locomotor adaptations for food capture are of diminished importanceand other adaptations such as suction and protrusible jaws infish are common.