首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Parelaphostrongylosis has a rapid onset and is lethal in neonatal moose (Alces alces) when large numbers of third-stage Parelaphostrongylus tenuis larvae (L3) are given experimentally. Little is known, however, about the severity and prognosis of infections acquired naturally by accidentally ingesting terrestrial gastropods which are rarely infected and have few larvae. To investigate the relationship between infecting dose, age of moose, and severity of disease, five calves were given low doses of three to 10 L3 when five (n = 2) or 9.5 mo old (n = 3). Each of two animals initially given low doses were later challenged with a dose of 15 L3. As positive controls, two calves were given doses of 15 and 30 L3, considered to be high. All five calves given low doses showed abnormal locomotory signs at 20-28 days postinoculation (DPI) that progressively became more pronounced with hind quarter weakness and front lameness. However, after 77-130 DPI, signs diminished markedly in two of these animals and disappeared in another two. Challenge infections of 15 L3 given 199 days after initial infections had no noticeable effects although an immature worm, probably resulting from the challenge, was found in the spinal cord of one animal killed 51 days later. Two positive control animals given the high doses of 15 and 30 L3 showed moderate to severe, non-resolving, locomotory signs and had to be euthanized. Results demonstrate that single, low doses of three to 10 P. tenuis L3 cause moderate disease in moose calves but over time, some worms die and animals can recover. A degree of protection may develop against future infection.  相似文献   

2.
3.
The occurrence of Fosliella limitata and F. lejolisii at Bembridge, Isle of Wight is reported. F. limitata is newly recorded for Britain whilst F. lejolisii has been found only rarely since disease struck Zostera in the early 1930s. The two epiphytes both grow on Zostera; F. limitata also grows on large brown and red algae. Their vegetative and reproductive structures are described and illustrated and information given regarding their seasonal occurrence from May 1975 to April 1976. Previous records of both species are discussed and a table is given summarizing the differences between the species.  相似文献   

4.
5.
Timulla oculata (Fabr.) is redescribed and ten nominal species of Oriental Timulla are placed in synonymy with it. Fourteen subspecies, including two new ones (T. oculata rosemariae subsp.n. and T. oculata timorensis subsp.n.), are recognised and keys to the subspecies are given. Geographic variation and the application of the polytypic species concept are discussed. The structure of the male genitalia of Timulla is related to dispersal strategies. The distribution and subspeciation of T. oculata is discussed in relation to the geological history of South East Asia and the Malay Archipelago.  相似文献   

6.
7.
8.
A new species of Veronica vadiniense in section Veronica is described from material from the Cantabrian Range, in the north-east of the province of León (north-west Spain). Several morphological characters related to stems, leaves, racemes, flowers and capsules are given, and also those related to the indumentum of different parts of the plant, especially calyx lobes and capsule. Indications about distribution and habitat with reference to bioclimatic, biogeographical and phytosociological aspects are provided. Diagnostic features are also given to enable comparison with the most similar species, Veronica officinalis and V. allionii , particularly in the indumentum and consistency of leaves, and in the indumentum and shape of the capsule.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 119–124.  相似文献   

9.
All six naupliar and five copepodite stages of Tisbe gracilis (T. Scott, 1895) are described. A key for the identification of the nauplius stages is given. The oral appendages of all copepodite stages are described. Sexual dimorphism is visible from the copepodite IV stage on.  相似文献   

10.
Astragalus yildirimlii is described and illustrated from Central Anatolia-Turkey. Pollen and seed morphology and chromosome number is given as well. The relationships of the new species are discussed.  相似文献   

11.
The four species of hopping mouse studied, N. alexis, N. cervinus, N. fuscus and N. mitchellii , were found to have a basic repertoire of eight more or less discrete vocalizations: three in the young—the calls produced in the nest, ultrasonic pipping given when removed from the nest and a high intensity (pain) squeal—and five in the adult—a low intensity pip given during mutual grooming, a high intensity (pain) squeal, a medium intensity squeak given when "annoyed", twittering given during aggressive chases and ultrasonic pipping given during non-aggressive encounters. The calls of the different species varied in structure and in pitch. No vocalizations were associated with threat or fighting. Calls given in the nest by suckling young are well developed and the intensity of such calls appears to mirror the general motivational state of the caller. It is suggested that these calls may act to maintain maternal behaviour in the mother.  相似文献   

12.
Red foxes (Vulpes vulpes) were immobilized with one of the following drug combinations: ketamine/xylazine (n = 22), ketamine/promazine (n = 35), ketamine/midazolam (n = 13), or tiletamine/zolazepam (n = 22). Foxes given ketamine/xylazine had the shortest induction and longest recovery times relative to other drug combinations, whereas foxes given ketamine/midazolam had the longest induction times. Recommended doses for the various combinations are given. Foxes given ketamine/xylazine were given either 0.1, 0.2, 0.4 mg/kg yohimbine, or saline 40 min after anesthetic induction. Administration of yohimbine significantly shortened arousal and recovery times relative to control values (P less than 0.001).  相似文献   

13.
An overview is given of the species belonging to the family Rugosochonetidae known from the Carboniferous of the Cantabrian Mts. Their distribution is compared with other occurrences in Eurasia and elsewhere. Subfamily and generic assignments are discussed in some detail. Comments on palaeogeographic and palaeoecological aspects of the rugosochonetid faunas are presented.  相似文献   

14.
Male and female imagines, and pupal exuviae of Cricotopus (C.) nevadensis sp. n. are described. A discussion on the systematic position, a differential diagnosis and notes on the ecology of this new species are given.  相似文献   

15.
16.
A diatom assemblage found in bottom sediments of mountain oligotrophic lakes in the Amguema River basin (Ervynaigytgyn, Matachingaigytgyn, Ekitiki) is presented for the first time. For each taxon, data on the occurrence in the Beringia region are given. Three new combinations are suggested.  相似文献   

17.
18.
19.
The data on the ciliates species composition are given for the Baltic Sea, a brackish-water semi-closed water body where a considerable part of the planktonic fauna is presented by freshwater species. During the observation period, 789 species of ciliates were found, 160 of which are typical planktonic forms. The ecological characteristics of ciliates are given, along with an assessment of their role in the productivity of the Baltic Sea pelagic communities.  相似文献   

20.
A taxonomic review of Phlebotomus (Idiophlebotomus) (Psychodidae)   总被引:1,自引:0,他引:1  
Five known species (asperulus Quate & Fairchild, erebicolus Quate, pholetor Quate & Fairchild, sejunctus Quate, and stellae Quate) of the caverni-colous subgenus Phlebotomus (Idiophlebotomus) are discussed in relation to newly recognized species from West Malaysia and India. P. frondifer n.sp. and P. tubifer n.sp. are described and a key to the adults of all seven species is given. General features of the subgenus are discussed, with particular reference to the functional relationships between the specialized morphology of the mouthparts and the probable bat hosts of these species.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号