OBSERVATIONS ON NOCTULE BATS (NYCTALUS NOCTULA) CAPTURED WHILE FEEDING

In the summer and early autumn of 1960, 1961 and 1962, noctule bats flying low, taking house crickets as these flew from a municipal rubbish tip, were captured in mist nets, ringed, released and in many cases recaptured a number of times. The flying bats showed no fear of human beings or predatory birds and did not learn to avoid the net. In June and July of each year the majority of bats caught were adult females, the flying young of the year first appearing in August though some did not fly until September and October. Young males did not reach sexual maturity in the year of their birth, though five out of fourteen females recaptured at a year old did. There was a considerable movement of adult males in the late summer, adult bats being captured in approximately equal numbers of both sexes during August and September. In October the females seemed to disappear, the majority of the bats caught during that month being males: by November the crickets had ceased to fly and no more bats could be captured though a few wero still flying on warm nights. There was a marked difference in feeding behaviour over these three years, the bats concentrating more on crickets in 1960 than in 1961 and 1962. Though the differences are not statistically significant there were indications of an increase in body weight between July and October in the years when less cricket feeding was occurring. About 50 per cent of the females captured in each of the years 1960 and 1961 were recaptured feeding on the same site in the following year: the recovery rate of males was about 30 per cent in 1961, 60 per cent in 1962.     

台湾铗蠓多次取食习性的观察(双翅目:蠓科)

吸血双翅目昆虫取食习性的研究,在蚊科和蚋科中广泛开展,但在吸血蠓类却做得很少。在工作中我们发现台湾铗蠓Forcipomyia(Lasiohelea)faiwana(shiraki)在一个生殖营养环内具有多次取食的习性。这种习性,特别足二次取食之间间隔很短的情况,可能会机械传播病原体,故有流行病学意义。现报道如下。     

摄食对鲇鱼幼鱼力竭性运动后过量耗氧的影响

为了检验鲇鱼(Silurus asotus Linnaeus)幼鱼力竭性运动(Exhaustive exercise)后过量耗氧(EPOC)是否受到摄食的影响,以阐明其在两种功能状态下的功率配置模式,在(25.0±1.0)℃条件下,分别测定了对照组(摄食前)、摄食组[摄食12 h,摄食水平为(8.74±0.40)%]、摄食代谢恢复组[摄食60 h,摄食水平为(8.84±0.25)%]鲇幼鱼力竭性运动后EPOC及力竭性运动后恢复过程中呼吸频率(Vf)的变化。研究结果显示:对照组、摄食组、摄食代谢恢复组力竭性运动前耗氧率(MO2)显著差异(P<0.05),而Vf差异不显著;力竭性运动后MO2和Vf均立即达到峰值,随后逐渐恢复到稳定状态;摄食组的耗氧率峰值(MO2peak)[(222.47±10.14)mgO2/(kg.h)]显著大于对照组[(180.53±6.79)mgO2/(kg.h)]和摄食代谢恢复组[(181.65±10.94)mgO2/(kg.h)](P<0.05),但三个组之间Vf无显著变化;摄食组的EPOC总量[(42.49±10.13)mgO2]显著小于对照组[(66.58±6.40)mgO2]和摄食代谢恢复组[(53.46±5.80)mgO2](P<0.05)。以上结果表明:(1)无论是摄食还是运动任一生理功能均不能诱导出鲇鱼幼鱼的最大的MO2;(2)当摄食和运动两种生理功能同时存在时,鲇鱼无氧运动能力减弱,同时力竭性运动后的恢复过程加快,可能与消化导致的内环境碱化减缓了运动后的内环境酸化有关。     

OBSERVATIONS ON FEEDING METHODS IN SOME FLORIDA ASCOGLOSSANS

Feeding methods are described for 12 Florida ascoglossans. Relationshipsbetween size and shape of radular teethand dimensions of foodalgae are analysed. Feeding in a diatom-eating species (Eylsiaevelinae) is described for the first time. The suctorial feedingof Ascobulla ulla and the structure of its radula and alimentarysystem clearly reveal that it is an ascoglossan, not a cephalaspid.The very complicated method of feeding in Oxynoe spp. is consideredan evolutionary "dead end", and the branching of the digestivegland and position of pharyngeal appendices seem to indicatethat the Elysiidae did not evolve from the Oxynoidae. New anddetailed observations on feeding in Elysia ornata, Placida kingstoni,and Ercolania funerea show that after cell sap has been suckedinto the pharynx, it is returned to the algal filament. Thisprocess may be repeated once or twice before the cell sap iseventually pumped into the stomach. Cell sap is probably mixedwith saliva in the pharynx to reduce its viscosity, and thepharyngeal regurgitation facilitates withdrawal of the remainingsap. ^*Present address: Ellebjergvej 22, 1 t.h., DK-2450 CopenhagenSV, Denmark. (Received 9 June 1980;     

FIELD OBSERVATIONS ON FEEDING OF THE LAND SNAIL HELIX ASPERSA MULLER

Feeding of the land snail Helix aspersa (Müller) was observedat monthly intervals. Three natural populations in Galicia (NW-Spain)were studied. At two sites only a few plants constituted thebulk of the diet and in spring the snails' diet had the highestdiversity (H'). In the third population feeding and distributionof Helix aspersa (Müller) were observed in a small plotwith permanent patches of Urtica dioica. Nearly one half offeeding snails fed upon Urtica dioica. Most of the other observations wereon Mentha suaveolens, Ranunculus repens and Gramineae. The diversity ofthe snails' diet showed seasonal variation with the maximumin the autumn months. Comparison between the availability ofthe different plant species and their contribution to the snails'diet showed that the snails did not eat at random; Urtica dioicawas eaten much more than expected from its occurrence and grasseswere strongly under-represented in the snails' diet. Temporalchanges of availability were significantly correlated with the amountseaten in the case of Urtica, but not for the other food plants.The distribution of the snails in the plot was significantlycorrelated with that of Urtica. Chemical analyses of the foodplants revealed Urtica as the species with the higher protein,ash and calcium contents. The strong preference of Helix aspersafor Urtica dioica could be explained by the value of Urticaas food or by its suitability as habitat for the snails. The largestproportions of green material in the snails' diet occurred inthe spring and juveniles ate more green material than adultsin the three populations. (Received 16 March 1998; accepted 30 November 1998)     

FURTHER OBSERVATIONS ON NATHORSTIANA (ISOETACEAE)

The patterns of root arrangement and stelar morphology in the Lower Cretaceous fossil Nathorstiana are essentially identical with those of extant Isoetes. These structural similarities imply a similar mode of development in both plants and are used to infer an Isoetes-like, linear, root-producing meristem along the lower end of the stele in Nathorstiana. The root-bearing base of Nathorstiana differs from that of Isoetes principally in two respects. In earlier developmental stages, the rooting base of Nathorstiana was unlobed and radially symmetrical, whereas Isoetes is originally bilobed. Unlike Isoetes, which lacks stelar elongation and sheds its root-bearing cortex at the periphery of the cortical lobes, the downward growth of the root-bearing base of Nathorstiana resulted in the accumulation of a substantial extent of axial root-bearing surface.     

EASTERN MEDITERRANEAN OPISTHOBRANCHIA: ELYSIIDAE (SACOGLOSSA = ASCOGLOSSA)

An account is given of the elysiid sacoglossans collected ondiving expeditions to the eastern Mediterranean shores of Yugoslaviaand Greece during the period 1978–1986, supplemented bymaterial collected around Naples and some preserved specimensfrom other Mediterranean localities. In all, 6 species of Elysiaand 1 of Bosellia were investigated, including one new to science,E. gordanae from the Yugoslav Istrian Peninsula. The enigmaticElysia translucens Pruvot-Fol, 1957 was found in the easternbasin for the first time. The presence of the Bermudan, CanaryIslands and Jamaican E. flava Verrill, 1901 was confirmed inthe Greek Ionian and Aegean Seas, as well as in the Gulf ofCorinth. The geographical ranges of the other species were extendedby these collections from the eastern basin. The 7 elysiid specieswere illustrated from life and the radulae compared; great differencesin the size, shape and denticulation of the teeth of the differentspecies were evident (Received 8 May 1987;     

囊鼠某些摄食行为的观察(英文)

囊鼠是一种营地下单洞穴居的鼠类,广泛分布于加利福尼亚州的农田、牧场和森林,危害甚大。作者在实验室条件下对两种襄鼠(Thomomys bottae和Thomomys mazama)的某些摄食行为进行了观察,得到以下结论: 1.囊鼠的摄食行为有8个组成部分,即:(1)暴露洞口;(2)探察洞外动静;(3)将食物拖入洞内;(4)储藏食物;(5)反复在洞外搜索剩余食物;(6)推土堵洞;(7)尝试及摄食;(8)对粪便和尿的处理。     

OBSERVATIONS ON THE GROWTH, REPRODUCTION AND FEEDING OF THE NUDIBRANCH ARMINA TIGRINA

One specimen of the sand-burrowing nudibranch Armina tigrinaRafinesque was collected from South Carolina in June. The specimendeposited a single egg mass of approximately 6500 white eggswhich developed into lecithotrophic veligers in 8 days at 23°C.Of the veligers which metamorphosed, 9 lived 4–5.5 months(i.e. the life cycle was subannual). Eight individuals reachedsexual maturity in about 80 days. Copulation began at a bodylength of 24 mm and oviposition at 28 mm. During the 1.5 monthegg-laying period, each individual laid 2–4 wavy egg masseswith 2000–7000 eggs per mass. Death followed oviposition.Average growth rate of fed and starved pre-ovipositional nudibranchswas 3.4% and 0.9% per day respectively. Growth rate of ovipositingspecimens was 0.6% or less per day. Based on average feedingrates, each nudibranch consumed approximately 1.6 g damp weightof Renilla reniformis (one small colony) between metamorphosisand egg laying and 6.1 g damp weight (about two average colonies)from egg laying to death. Feeding efficiency is presumably increasedby interlocking and abutting radular teeth. Egg diameters reportedfor Armina tigrina from South Carolina and Florida were 199µm and 82 µm respectively. This difference suggeststhe existence of two species of Armina or ne species with twogeographically separated developmental types. Current address: Marine Science Institute, Northeastern University,Nahant, Massachusetts 01908. U.S.A. (Received 10 April 1980;     

OBSERVATIONS ON ROOT-PARASITISM IN CORDYLANTHUS (SCROPHULARIACEAE)

Eight species of Cordylanthus (Scrophulariaeeae: tribe Euphrasieae) representing the three major sections of the genus were successfully grown both with and without a host plant, demonstrating that the plants are facultative hemi-parasites capable of completing their life cycle without a host under the favorable conditions of greenhouse culture. The plants are almost certainly parasitic in the wild. Even though haustorial connections were formed by Cordylanthus on the roots of all host plants provided, most species were more vigorous when growing with certain hosts (Quercus, Pinus, Helianthus) than with others (Plantago, Phleum). This indicates a difference in the ability of the parasite to obtain materials successfully from the various plants used as hosts. Natural hosts are inferred for 15 species of Cordylanthus from the presence of associated species in nature. The haustoria are exogenous in origin, being formed by dedifferentiation of several cells in the hypo-dermal or subhypodermal layers of the rootlets. Anatomically the haustoria differ from those reported for other members of Euphrasieae in having secondary vascular structure and abundant connecting strands. The vascular structure of haustoria is composed mainly of specialized vessel elements. Root-parasitism gives Cordylanthus the ability to grow in arid areas during the summer after most other annuals have died, thus successfully equipping the plants for survival and expansion in western North America.     

OBSERVATIONS ON LOPHODINIUM POLYLOPHUM (DINOPHYCEAE)1

Lophodinium polylophum (Daday) Lemmermann is reported from a Texas pond. Cells have distinctive longitudinal ridges, an apical carina and slit, numerous golden chloroplasts, an eyespot, and a typical dinoflagellate nucleus. The theca appears to be composed of hexagonal plates. The genus is allied to Woloszynskia Thompson, family Lophodiniaceae, but probably not to the fossil Dinogymnium.     

ON THE PROTONEPHRIDIA AND 'LARVAL KIDNEYS' OF NASSARIUS (HINIA) RETICULATUS (LINNAEUS) (CAENOGASTROPODA)

Protonephridia in marine streptoneuran gastropods are describedfor the first time. The organization of these paired organsof the intracapsular veliger larva of Nassarius reticulatusis described. The ciliary flame is formed by a single terminalcell. The duct is formed by one tubular cell and the aperturalcell, which forms the lips of the excretory pore. In addition,the surface of the apertural cell is covered to a great extentby the post-velar bud cell (usually termed ‘larval kidney’).Protonephridia like these are considered to be widely distributedamong streptoneuran gastropods. The homology of these organswith those of opis-thobranchs and pulmonates is suggested. Thepost-velar buds (= ‘larval kidneys’) are suggestedas a synapomorphous character of Caenogastropoda. The functionof the postvelar buds is discussed taking into considerationthe existence of a protonephridium and a possible functionalconnection between these two structures. (Received 14 June 1990; accepted 1 September 1990)     

AXENIC CULTIVATION OF THE HETEROTROPHIC DINOFLAGELLATE PFIESTERIA SHUMWAYAE AND OBSERVATIONS ON FEEDING BEHAVIOR1

Pfiesteria shumwayae Glasgow et J. M. Burkh. [=Pseudopfiesteria shumwayae (Glasgow et J. M. Burkh.) Litaker, Steid., P. L. Mason, Shields et P. A. Tester] is a heterotrophic dinoflagellate commonly found in temperate, estuarine waters. P. shumwayae can feed on other protists, fish, and invertebrates, but research on the biochemical requirements of this species has been restricted by the lack of axenic cultures. An undefined, biphasic culture medium was formulated that supported the axenic growth of two of three strains of P. shumwayae. The medium contained chicken egg yolk as a major component. Successful growth depended on the method used to sterilize the medium, and maximum cell yields (10⁴ · mL^?1) were similar to those attained in previous research when P. shumwayae was cultured with living fish or microalgae. Additionally, P. shumwayae flagellate cells ingested particles present in the biphasic medium, allowing detailed observations of feeding behavior. This research is an initial step toward a chemically defined axenic culture medium and determination of P. shumwayae metabolic requirements.