Feeding strategy of two sympatric anostracan species (Crustacea)

The transport rate of chalk, clay particles and algal cells (Scenedesmus sp.) through the digestive tract of Streptocephalus torvicornis and Branchipus schaefferi is described under experimental conditions. Differences in transport rate as well as in the degree of digestion at a fixed particle density of algae were found. In S. torvicornis, the transport rate is higher and the digestion of algae lower than in B. schaefferi. These differences might reflect trophic differences related to niche partitioning in these sympatric species. This revised version was published online in August 2006 with corrections to the Cover Date.     

Some notes on the ecology of a GermanBranchipus schaefferi population (Crustacea: Anostraca)

Habitat preference, seasonal occurrence, starvation resistance, hatching eggs ofBranchipus schaefferi, and effects of predation onB. schaefferi were studied.Branchipus was only present in turbid, unvegetated ponds and absent in ponds which contain higher aquatic vegetation and theSpirogyra sp. The first individuals ofB. schaefferi appeared in April when water temperature was 10 °C and the last adults in November at a water temperature of 3.5 °C. Up to 6 reproducing generations were observed during this period. Abundance ofB. schaefferi was higher in temporary ponds than in permanent ponds. Sex ratio was close to unity for most of the year. Body size ofB. schaefferi males and females was significantly positively correlated with pond volume. Without foodB. schaefferi could survive for 1.5 to 2 days at 20 °C and 4 to 5 days at 10 °C. Hatching success of eggs decreased when eggs were dried for 7 months. Freezing of eggs had no effect on hatching success. From] the predators tested,Chaoborus sp. larvae clearly selected smallB. schaefferi; one consumed approximately 6Branchipus d–1 at a density of 6 to 12 prey 1–1. The other predators, dragonfly larvae, and larvae and adults ofTriturus alpestris selected alternative prey types, for exampleTubifex sp. and ostracods.     

木犀科松林丁香复合体的分类修订

对松林丁香S. pinetorum W. W. Sm.复合体内各学者发表的5个新种进行了分类修订。根据居群取样、性状分析和主坐标分析结果, 圆叶丁香S. wardii W. W. Sm.、S. mairei (H. Lév.) Rehder、S. rugulosa McKelvey和川西丁香S. chuanxiensis S. Z. Qu &; X. L. Chen被处理为松林丁香的异名, 其中S. mairei为新异名。此复合体只有一种, 即松林丁香。     

中国野青茅属(禾本科)一些种类的修订(II)(英文)

在标本室研究和野外考察的基础上,对中国野青茅属Deyeuxia的一些种类进行了修订。归并了2个名称,即将Deyeuxia sikangensis Keng并入D. scabrescens (Griseb.) Munro ex Duthie作为异名; 将D.levipes Keng并入D. nivicola Hook. f. 作为异名。确认了D. dispar L. Liou和D. agrostioides L. Liou是两个未合格发表的名称,将前者归并于D. scabrescens,后者归并于D. diffusa Keng。     

中国蛇根草属(茜草科)几种植物的分类学订正

根据对中国蛇根草属Ophiorrhiza植物标本的研究和野外调查,将琼崖蛇根草O.aureolina f.qiongyaensis Lo和溪畔蛇根草O.humilis Tseng归并入短小蛇根草O.pumila Champ.ex Benth.,将海南蛇根草O.hainanensis Tseng归并入垂花蛇根草O.nutans C.B.Clarke,将广西蛇根草O.kwangsiensis Merr.exLi和变黑蛇根草O.nigricans Lo归并入日本蛇根草O.japonica Bl.,将龙州蛇根草O.longzhouensis Lo和圆锥蛇根草O.paniculiformis Lo归并入广州蛇根草O.cantoniensis Hance。     

国产赖草属(禾本科)两个类群的修订

根据标本研究、野外考察和实验观察,对国产赖草属Leymus两个类群进行了分类修订,将阿尔金山赖草Leymus arjinshanicus D．F．Cui和L．aerginshanicus D．F．Cui ssp．ruoqiangensis（S．L．Lu＆Y.H．Wu）D．F.Cui处理为若羌赖草L．ruoqiangensis S．L．Lu＆YH．Wu的新异名,将纤细赖草L．secalinus（Georgi）Tzvel．var．tenuis L．B．Cai提升为一个独立的种L．tenuis（L．B．Cai）L．B．Cai．     

Causes of a non-random pairing by size in the brine shrimp,Artemia salina: (Crustacea: Anostraca)

Summary Brine shrimp (Artemia salina) males and females entered precopula assortatively by size in the laboratory; large males also had a pairing advantage over smaller males. We investigated the causes of such nonrandom pairing to test hypotheses on size-assortative mating.We found precopulatory biases with respect to male size in the absence of direct competition among males (which produces pairing biases in other species). Large males encountered females significantly more often than did small males. Similarly, large females encountered males more often than did small females, but showed less willingness than small females to enter precopula when housed with small males. Consequently, large females took longer than small females to enter precopula with small males. Although large males entered precopula readily with small females, such size-mismatched pairs appeared short-lived.We conclude that non-random pairing by size in A. salina is determined by several factors including: encounter rates between males and females of different sizes, female behavior, and time following initial pair formation. Our results are likely applicable to other species and can help explain variation for selection on size or other traits.     

藤麻(荨麻科)的一个新异名

根据对Elatostema gagnepainianum H. Schröter模式材料的研究,为它指定了后选模式,并将其处理为藤麻Procris crenata C. B. Robinson的新异名。     

Taxonomic notes on the paper wasps of the genus Ropalidia in the Indian subcontinent (Hymenoptera: Vespidae)

The taxonomy of Ropalidia wasps in the Indian subcontinent is revised, recognizing 26 species in the subcontinent. Their diagnostic characteristics are summarized in a key to species. New synonymies proposed in the present study are: R. bicolorata shiva Das and Gupta, 1989 under R. bicolorata van der Vecht, 1962; R. colorata sordida van der Vecht, 1941 under R. colorata van der Vecht, 1941; R. rodialipa Lambert and Narendran, 2005 and R. anupama Lambert and Narendran, 2005, both under R. cyathiformis Fabricius, 1804; R. jacobsoni flavoscutellata Das and Gupta, 1989, and R. bangalorica Lambert and Narendran, 2005, both under R. jacobsoni du Buysson, 1908; R. travancorica Lambert and Narendran, 2005, under R. marginata Lepeletier, 1836; R. sridharani Lambert and Narendran, 2005, under R. rufocollaris Cameron, 1900; Ropalidia rufoplagiata nursei van der Vecht, 1941 under R. rufoplagiata Cameron, 1905; Icaria lugubris Smith, 1858, under R. sumatrae Weber, 1801; and a revised synonymy is Icaria pendula Smith, 1857, under R. variegata Smith, 1852. The new replacement name Ropalidia kasaragodensis Lambert and Narendran is proposed for R. indica Lambert and Narendran, 2005, non van der Vecht, 1941.     

Evidence for sex-related differences in phototactic bahaviour ofStreptocephalus proboscideus (Crustacea: Anostraca)

The phototactic behaviour of adults of the Sudanese fairy shrimpStreptocephalus probiscideus was studied under laboratory conditions. Males were less negatively phototactic than females. This was also evident when colour filters were used. females only became little less negatively phototactic under yellow light, whereas males showed a strong positively phototactic response. The response to the positioning of a yellow filter was stronger than to the use of a red or blue filter for both sexes. The laboratory findings were compared with casual field observations onStreptocaphalus torvicornis that indicate differential vertical distribution between the sexes and a nocturnal vertical migration. Migratory behaviour with ascent starting at dusk is also predicted forS. proboscideus. This behaviour may reduce common stress factors in desert pools such as photodamage, visual predation pressure, and high surface temperatures.     

Distribution,diversity and conservation of Anostraca (Crustacea: Branchiopoda) in southern Africa

Southern Africa is defined here as Africa south of the Zambezi and Kunene Rivers. Here, annual average rainfall, rainfall season, and effective temperature are climatic factors which influence anostracan distribution. The type of temporary pool also appears to have some effect on distribution. Areas of high species richness are not confined to any particular climatic region and such areas occur in arid, montane and subtropical regions of southern Africa. Forty-six anostracan species have been recorded from the subcontinent and 80% of these are endemic. IUCN Red Data assessment of species revealed that two species can be considered 'Critically Endangered', while a further four are 'Endangered', and three are 'Vulnerable'. Many parts of southern Africa have been inadequately sampled but in South Africa, where the anostracans are relatively well known, temporary pool inhabitants are threatened mainly by agriculture, urbanization, pollution and pesticides. This revised version was published online in August 2006 with corrections to the Cover Date.     

The filtration apparatus of Anostraca (Crustacea): species-specific setulation in the genus Streptocephalus

The structure of the setae, setules, spines and spinules on the limbs of males and females of Streptocephalus torvicornis, S. rubricaudatus and S. proboscideus are described, based on scanning electron micrographs. The data disclose significant variation among the three species in fine structure of the setules and inter-setular distance. The variation may be related to different trophic specialisations, facilitating the sympatric occurrence of congeneric species.     

A New Species of Streptocephalus Fairy Shrimp (Crustacea,Anostraca) with Tetrahedral Cysts from Central Thailand

A new species of fairy shrimp, Streptocephalus siamensis n. sp., is described from five temporary pools in Suphan Buri and Kanchana Buri Provinces, central Thailand. It sometimes co‐occurs with its congener, S. sirindhornae . This new species belongs to the subgenus Parastreptocephalus which is defined by bearing tetrahedral cysts. This is the third anostracan species reported from Thailand. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Biogeography and ecology of Anostraca (Crustacea) in middle Paroo catchment of the Australian arid-zone

Fourteen species of Branchinella and one each of Parartemia, Streptocephalus (Parastreptocephalus) and an undescribed branchipodid genus occur in a limited area (2000 km²) of the Paroo in northwestern New South Wales and southwestern Queensland. Syntopic coexistence was common (55% of collections) but to a large degree species interactions are minimized by habitat factors of turbidity, salinity and length of the wet phase in decreasing order of importance, and by a species factor of relative size. Discrete habitats such as claypans had a similar species composition each time they filled, but creek pools and other connected sites had variable species composition over time. The high biodiversity is explained by the presence of many distinct types of wetlands, each with their own characteristic anostracans.     

香槐属分类学研究随记

基于对标本和文献的比较研究,确认豆科香槐属(Cladrastis Raf.)中小叶香槐(C.parvifolia C.Y.Ma)、藤香槐(C.scandens C.Y.Ma)、秦氏香槐(C.chingii DuleyVincent)与本属分布最广的翅荚香槐[C.platycarpa(Maxim.)Makino]为同种植物。其中,小叶香槐被处理为翅荚香槐的一变种,即C.platycarpa var.parvifolia(C.Y.Ma)Z.Q.Song,D.X.XuS.J.Li,藤香槐与秦氏香槐被处理为翅荚香槐原变种的两个新异名。同时讨论了翅荚香槐的分类地位及其散布。     

Regional structuring of genetic variation in short-lived rock pool populations of Branchipodopsis wolfi (Crustacea: Anostraca)

The genetic structure of three metapopulations of the southern African anostracan Branchipodopsis wolfi was compared by analysing allozyme variation at four loci (PGM, GPI, APK, AAT). In total, 17 local populations from three sites (metapopulations) were analysed from rock pools in south-eastern Botswana ranging from 0.2 to 21 m² in surface area. In three populations we found significant deviations from Hardy-Weinberg (H-W) equilibrium at one or more loci due to heterozygote deficiencies. Genetic variability at one site was significantly lower than at the other sites, which may be linked to a greater incidence of extinction and recolonisation, as the basins at this site are shallower and have shorter hydrocycles. Across all local populations, a significant level of population differentiation was revealed. More than 90% of this variation was explained by differentiation among sites (metapopulations), although this differentiation did not correlate with geographic distance, or with environmental variables. Genetic differentiation among populations within metapopulations was low, but significant at all sites. At only one of the sites was a significantly positive association measured between genetic and geographic distance among local populations. Our data suggest that persistent stochastic events and limited effective long-range dispersal appear to dominate genetic differentiation among populations of B. wolfi inhabiting desert rock pools. The lack of association between geographic distance and genetic or ecological differences between rock pool sites is indicative of historical stochastic events. Low heterozygosity, the significant deviations from H-W equilibrium, and the large inter- but low intra-site differentiation are suggestive of the importance of short-range dispersal. Gene flow between metapopulations of B. wolfi appears to be seriously constrained by distances of 2 km or even less. Received: 28 June 1999 / Accepted: 10 January 2000     

Cyst Distribution and Hatching Pattern of Chirocephalus ruffoi (Crustacea,Anostraca) in an Experimental Undisturbed Pool

The pattern of cyst distribution in the absence of turbation and their hatching behaviour were studied in an outdoor artificial pool, where just differentiated adults of the anostracan Chirocephalus ruffoi (sex ratio 1:3) lived until it dried up. The horizontal and vertical distributions of cysts in the pool bed were determined. The comparison between cyst bank estimate (Mura , 2004) and the actual number of cysts counted in the pool bed revealed an estimate error of 20.9%. Resting eggs occurred only in the upper 2.5 cm thick soil sections and decreased within this section as depth increased. Peripheral areas of the pool contained significantly larger numbers of cysts than the central area. Multiway analysis on the results recorded in hatching success (nested ANOVA) revealed that the differences were significantly affected by initial soil conditions, treatment and vertical distribution of cysts. Among these factors, vertical distribution (sections nested in cores) was the most influential. Hatching success was significantly inversely related to depth. Differences in the timing of hatching depending on the above considered factors were also noted. A nearly synchronous hatching pattern was observed only for cysts from initially dry sediment of the uppermost layers. In all successively deeper layers, hatching showed multiple peaks and was increasingly delayed and erratic (already mentioned). ANCOVA within each of the experimental conditions revealed significant differences in hatching frequencies (time as covariate) depending on sediment depth. Within any given layer, ANCOVA revealed a significant influence of initial sediment conditions and treatment on the timing of hatching. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

A Possible Extra-Ovarian Site for Synthesis of Lipovitellin During Vitellogenesis in Artemia sp. (Crustacea; Anostraca)

Summary

Lipovitellin samples, extracted from yolk platelets of cysts, were applied to SDS-PAGE. A female specific antiserum was raised against the high molecular weight apoprotein lipovitellin alpha-1 (LV-α1) of the lipovitellin complex. This anti-LV-α1 was used in the peroxidase-anti-peroxidase staining method with frontal paraffin sections (of 4μm) of whole embedded Artemia. Females were studied during a complete vitellogenic cycle. The presence of exogenous yolk precursors in the fat storage cells of the thoracopods of female Artemia was demonstrated. The amount of the female specific yolk polypeptides and the number of positively stained cells changes during the vitellogenic cycle. In vitro experiments with ³⁵S-radiolabelled methionine show the synthesis of lipovitellin-like substances in the fat storage cells of vitellogenic females.     

On predatory tendencies in the feeding ecology of the fairy shrimp Streptocephalus proboscideus (Frauenfeld, 1873) (Crustacea: Anostraca)

The feeding habits of the filter-feeding fairy shrimp Streptocephalus proboscideus are documented experimentally by offering them ciliates, Volvox, rotifers, nematodes and small crustaceans as prey. Escape capabilities (e.g. swimming speed) rather than size or shape were found to determine these animals' vulnerability to predation by the fairy shrimp. Ingestion rates for Volvox increased hyperbolically with size and, at the high temperatures in which they live, fairy shrimps may daily remove the equivalent of their body weight from the environment.