New species in the rheophilous genus Nicsmirnovius Chiambeng & Dumont, 1999 (Branchiopoda: Anomopoda: Chydoridae) and reassignment of Alona eximia Kiser, 1948 and Alonella fitzpatricki Chien, 1970

A morphological comparison of specimens previously assigned to Alona eximia Kiser, 1948 from tropical Africa, Eastern Asia and the Americas shows that this species-group shares a number of morphological characters on the postabdomen, head pores, first antenna and second and fourth limb that separate them from Alona Baird, 1843 but unite them with Nicsmirnovius Chiambeng & Dumont, 1999. Alonella fitzpatricki Chien, 1970, formerly believed to be a junior synonym of A. eximia, is separated from the latter and assigned to the genus Nicsmirnovius. Two new taxa, from Africa and the Island of Socotra (Yemen) are added to the genus. The relationship between the specialised habitat of these chydorids and their morphology is discussed. The geographic range of all known populations is figured and a key to species is presented.     

Subdivision of the genus Pleuroxus (Anomopoda,Chydoridae) into subgenera worldwide

Examination of many species of Pleuroxus from the entire World has revealed a major dichotomy in morphology, one line related to aduncus: the other to laevis both from Europe. Pleuroxus trigonellus (the type species of the genus) and Peracantha truncata are in two other distinct lines. The new subgenus Tylopleuroxus is proposed for the species related to aduncus, and the subgenus Picripleuroxus for those related to laevis. Tylopleuroxus is primarily Southern Hemisphere in distribution, Picripleuroxus primarily Northern Hemisphere. Evidence thus far suggests that probably most, perhaps all, of the taxa are confined to single continents or land masses. Deceased     

Morphology and postembryonic development of males and females of Bosmina longispina Leydig (Crustacea, Anomopoda) from a North Iceland population

We investigated the morphology of adult and juvenile stages of females and males of Bosmina longispina Leydig from a North Icelandic population. There are additional setae near the basis of the second antenna and between its branches in adult males, not described in Bosmina, but known from other Anomopoda. New features of female morphology are also found. The development of the first limb and postabdomen of the male is described in detail. In juvenile males of B. longispina (belonging to subgenus Eubosmina), characteristics of morphology, similar to those in adult males of other subgenera are found.Abbreviations af antennal flap - as additional setae of male - bs basis of seta of clasper - bc basis of postabdominal claws - ch clasper hook - cl clasper - cs seta of clasper - cw claws of postabdomen - de distal endite of the first limb - dr dorsal row of denticles on male postabdomen - df dorsal fold of carapace - eh ejector hooks of limb I - ep epipodite - ex exopodite - fp frontal head pore - fs frontal seta - hs hair sensilla - in incision of juvenile male postabdomen - ir interrupted rows of setules on postabdomen - Ip lateral head pore - mp median head pore - mpr maxillar process of limb I - mr main row of denticles on postabdominal claws - pe predistal endite of limb I - pf preantennal fold of valve - pl plate above postabdominal setae - ps postabdominal setae - rs rudimentary setae - sr second row of denticles near basis of claws - vf ventral fold of valve - vr ventral row of denticles on male postabdomen     

Subfossil remains of an unknown chydorid (Anomopoda: Chydoridae) from Finland

Subfossil remains of an unknown chydorid taxon were found in sediments of three lake basins in Finland. Two of the sites lie in southern Finland and one in NW Finnish Lapland. Similar remains are also known from four lakes in eastern Finland. The headshields are small, with a broadly rounded posterior margin and an attenuated rostrum. The headshields resemble those of Rhynchotalona falcataSars, but have a unique pore arrangement. There is one oval median pore near the posterior margin and two lateral pores which are displaced quite far in position. The shell is very small and has faint, longitudinal striae. Also, unknown postabdomens were found. These resemble postabdomen of R. falcatain shape but had 5–6 pairs of teeth instead of the 2 seen in R. falcata. The age of the remains varies between ca. 8500 ¹⁴C yr BP and recent decades. The species appears to have been present in the entire country during most of the Holocene. On the basis of the pore arrangement, the new species cannot be put into any previously known genus. A tentative name Unapertura latensn. sp. is suggested until intact specimens are found and described.     

Subgeneric differentiation within Kurzia (Crustacea: Anomopoda: Chydoridae) and a new species from Central America

The genus Kurzia is divided into two subgenera: Kurzia s. str. and Rostrokurzia n. subg. Subgenus Kurzia includes Kurzia (K.) latissima Kurz, 1874, with a palearctic -, Kurzia (K.) polyspina n. sp. with a neotropic - , and Kurzia (K.) cf. media (Birge, 1879) with a nearctic distribution. Rostrokurzia includes Kurzia (R.) longirostris Daday, 1898 (pantropical distribution), and Kurzia (R.) brevilabris Rajapaksa & Fernando, 1986, from subtropical and tropical Asia. Kurzia latissima Kurz, 1874, from Central Europe is redescribed in detail.     

Development of 19 polymorphic microsatellite loci for the intermediate horseshoe bat, Rhinolophus affinis (Rhinolophidae, Chiroptera)

The intermediate horseshoe bat (Rhinolophus affinis) is a widespread species in Southeast Asia. We developed 19 novel microsatellite loci from an enriched genomic library of the bat, and tested their polymorphism using a single population from Guangdong province, southern China. The number of alleles ranged from 3 to 15 per locus with the expected and observed heterozygosity ranging from 0.397 to 0.920 and 0.280–0.926, respectively. Three markers significantly deviated from the Hardy-Weinberg expectations after Bonferroni correction and no linkage disequilibrium was detected in any of loci. These microsatellite loci will be useful in studying the phylogeography of this species.     

Surfactant-producing microorganisms isolated from the gut of a Eucalyptus-feeding sawfly,Perga affinis affinis

Summary Microorganisms which produce surfactants were isolated from the gut of a eucalypt-feeding sawfly. It is possible that surfactants in the guts of some defoliators may be microbiologically-produced.Deceased     

Some reflections on the structure of the mandibleplate ofEurytemora affinis (Copepoda,Calanoida)

The mandibleplates of several specimen of the copepodEurytemora affinis collected from the Westerschelde and the Gironde estuary were studied. Using the Edge index (ITOH, 1970) this species could be classified as an omnivore. Pictures obtained by light and scanning electron microscopy reveal that the mandible teeth ofE. affinis have a molar-like structure, which likely changes in functional morphology with developmental stage, sex and age of the adults. Based on these observations, the desirability to consider the three dimensional structure of copepod mandibles for feeding mode classification is discussed.Communication no. 540 of the Delta Institute for Hydrobiological Research, Vierstraat 28, 4401 EA Yerseke, The Netherlands.     

Reinstatement of the genus Paralona Sramek-Husek et al., 1962, and assessment of morphological variability in the Paralona pigra-group (Anomopoda: Chydoridae)

We studied the morphology of some members of the Chydorus piger-group, using populations from Karelia (Russia), France, Germany, the Azores, Magadan (East Siberia), Newfoundland (Canada), Venezuela, Zambia, and Bolivia, and move Chydorus piger Sars, 1861 to the genus Paralona Sramek-Husek et al., 1962, which we redefine using traditional characters (first antenna with subapical and apical esthetascs, second antenna with only six setae, ventral valve rim fully setulated with setae in marginal position except between anterior bend and well-developed anterior flange), as well as structural features of the trunk limbs, especially 1 and 2. Chydorus and Pleuroxus are the nearest relatives of Paralona.The genus presently contains only the species P. pigra (Sars, 1861). This, however, shows considerable morphological variation and might therefore be composed of several related taxa, in need of a closer definition.     

Species of Pleuroxus (Anomopoda,Chydoridae) from the subantarctic islands and southernmost South America: a partial unravelling of the Pleuroxus aduncus problem

Whereas previously all populations of Pleuroxus (now P.) known from the subantarctic islands and southernmost South America were considered to belong to a subspecies of P. aduncus (described from France), now there are five distinct species, only one of which resembles P. aduncus to any significant extent, but even it is a good species. Thus, the taxa are all distinctly different, and none of them could possibly be considered an infraspecies of P. aduncus sens. str. P. macquariensis from Macquarie Island and P. paroplesius and P. varidentatus from South America are new. Of the five species, P. varidentatus resembles P. aduncus most closely, but is separated from it by a number of significant characters. P. wittsteini is presently known from five islands in the south Indian Ocean, but there is considerable uncertainty as to whether all these populations really are the same taxon, because they differ somewhat in the shape of the labrum and in the intensity of sculpturing of the carapace and head. P. scopuliferus from South America is the most distinctive species of the group, having 9 gnathobasic filter setae on trunklimb III instead of the usual 8, a weak ridge on the shell, and a recurved rostrum extending beyond the tip of the labrum. No species of Pleuroxus (or of P., another subgenus of animals formerly assigned simply to Pleuroxus are known from the islands in the Scotia Arc between South America and Antarctica. The patterns of distribution cannot be explained by an on-going passive dispersal of resting eggs. No populations of species on the subantarctic islands are known from any of the southern land masses. Conditions on these islands intuitively must have been more severe during the glacial ages than during the present interglacial, suggesting that any anomopods present were eliminated during the severe glacial periods. Yet, the presence of isolated populations of endemic species on some islands and the complete lack of Pleuroxus on others (e.g. those in the Scotia Arc) argues that conditions, although more severe, still provided opportunities for the maintenance of active populations. Moreover, the morphological differences between populations of P. wittsteini on islands from a few hundred to several thousand kilometers apart likewise argue for genetic isolation over a very long period of time. Deceased     

Disruption of male sexual behavior in rats by tetrahydrofurandiols (THF-diols)

The mitogenic agent that disrupts male and female sexual behavior has been isolated from corncob bedding. The disrupting activity resides in an isomeric mixture of linoleic acid derivatives with a tetrahydrofuran ring and two hydroxyl groups (THF-diols) that include 9, (12)-oxy-10, 13-dihydroxtstearic acid and 10, (13)-oxy-9, 12-dihydroxystearic acid. We examined the effects of exposure of male rats to THF-diols in drinking water on several parameters of male sexual behavior. THF-diols disrupt sexual behavior in male rats by reducing mounting and intromission frequencies. The mount, intromission and ejaculatory latencies are enhanced while the ejaculatory responses are diminished. These findings suggest that the THF-diols modulate hypothalamo-pituitary axis to regulate steroid hormone-dependent male sexual behavior.     

Visual pigment,dark adaptation and rhodopsin renewal in the eye of Pontoporeia affinis (Crustacea,Amphipoda)

The benthic amphipod Pontoporeia affinis lives in the Baltic sea and in northern European lakes in an environment where very little light is available for vision. The eyes, consisting of 40–50 ommatidia, are correspondingly modified. Microspectrophotometric recordings on isolated eyes show the presence of at least two kinds of screening pigments in the ommatidia with maxima at 540–580 nm and 460–500 nm. Difference spectra obtained from the rhabdoms after exposure to red and blue light, respectively, give evidence of a single rhodopsin with its maximum at 548 nm and a 500-nm metarhodopsin. In ERG recordings sensitivity in the dark-adapted state, after saturating exposures to blue and to red light, stabilizes at levels determined by the rhodopsin concentration. No change is observed during 10–14 h after the beginning of dark adaptation. However, using animals pre-exposed with a strong red light and then kept in darkness, it is found that after a delay of 20–40 h sensitivity of the dark-adapted eye begins to increase and finally, after 5–6 days reaches a level corresponding to 100% rhodopsin. Thus, a slow renewal of rhodopsin appears to occur in darkness, where a photoisomerization of metarhodopsin is excluded.Abbreviations ERG electroretinogram - IR infrared - MSP microspectrophotometry     

Spatial and temporal variation of benthic Cladocera (Crustacea) studied with activity traps in Lake Myvatn, Iceland

Benthic Cladocera were studied with a modified type of an activity trap in Lake Myvatn in 1990–1992. After feasibility experiments, the operation time and the distance of the traps from the benthic substrate were adjusted in order to minimize the effects of diurnal variation and the trapping of planktonic organisms. The trap catches of Eurycercus lamellatus were positively correlated with their abundance at the bottom as estimated by grab sampling (r = 0.910, P < 0.001). The usefulness of the activity trap was demonstrated by: (1) a lake-wide survey of the benthic Cladocera; (2) a study of the seasonal variation in the size distribution, abundance and sex ratio of E. lamellatus; and (3) a study of the seasonal succession of Chydorus sphaericus and Alona affinis. The variation of benthic Cladocera among 21 trap sites distributed on a 1–2-km scale across the lake exceeded the within-site variation. The sampling sites could be divided into five main groups based on cluster analysis. Eurycercus lamellatus was the most common species in the mat of filamentous green algae (Cladophorales). Alonella nana dominated the area of spring water inflow in the north basin and Macrothrix hirsuticornis the area of spring water inflow in the southeastern part of the lake. In other parts of the lake either Chydorus sphaericus or Alona quadrangularis tended to dominate. The size distribution and sex ratio of E. lamellatus was followed at two sites through one summer. In early summer most individuals were females less than 1.45 mm long. Around mid-summer they had grown to 0.69–3.1 mm. By the end of August the size distribution had become bimodal, with a large number of small males and a smaller number of much larger females. The seasonal succession in the abundance of E. lamellatus, A. affinis and C. sphaericus was followed at four sites over two seasons. With some exceptions the abundance of a species followed a similar seasonal trajectory on the different stations in any one year. There was, however, a marked difference between the two years (1991 and 1992), probably related to different temperatures.     

Female perineal swelling and its effects on male sexual arousal: An apparent sexual releaser in the chacma baboon (Papio ursinus)

The function of the periodic perineal swelling that females of some primate species show in relation to their menstrual cycle has long puzzled many scientists. A role in female attractiveness was suspected, but fluctuations in female behaviors concomitant to these changes in female appearance have always prevented its assessment. By attaching a plastic reproduction of a fully swollen perineum to ovariectomized female chacma baboons, it has finally been demonstrated that the sexual swelling hasan important function in the sexual communication of this species. It induces sexual arousal in male conspecifics. The way the perineal swelling acts and other characteristic aspects of this feature appear to qualify it as a releaser for sexual behavior.     

Effects of large Saduria entomon (Isopoda) on spatial distribution of their small S. entomon and Monoporeia affinis (Amphipoda) prey

We performed laboratory experiments to investigate the effects of predator avoidance and numerical effects of predation on spatial distribution of small Saduria entomon (Isopoda) and Monoporeia affinis (Amphipoda), with large S. entomon as predators. The horizontal distribution and mortality of the prey species, separately and together, were studied in aquaria with a spatial horizontal refuge. We also estimated effects of refuge on mortality of small S. entomon and M. affinis by experiments without the refuge net. In addition, we investigated whether predation risk from large S. entomon influenced the swimming activity of M. affinis, to clarify the mechanisms behind the spatial distribution. Both small S. entomon and M. affinis avoided large S. entomon. The avoidance behaviour of M. fffinis contributed about 10 times more to the high proportion in the refuge than numerical effects of predation. Due to the low mortality of small S. entomon the avoidance behaviour of this species was even more important for the spatial distribution. The combined effect of avoidance behaviour and predation in both species was aggregation, producting a positive correlation between the species in density. M. affinis showed two types of avoidance behaviour. In the activity experiments they reduced activity by 36% and buried themselves in the sediment. In the refuge experiments we also observed avoidance behaviour with the emigration rate from the predator compartment being twice the immigration rate. The refuge did not lower predation mortality in M. affinis, probably due to the small scale of the experimental units in relation to the mobility of the species. Predation mortality in small S. entomon was higher in absence of a refuge and especially high in absence of M. affinis.     

Range extension of the predatory cladoceranBythotrephes longimanus Leydig 1860 (Crustacea,Onychopoda) in Western Europe

The long-spined waterfleaBythotrephes longimanus Leydig 1860 (Crustacea, Onychopoda), a predatory cladoceran, new for the Belgian fauna, has been recorded in the water storage reservoir Broechem. Several possible methods of entry ofB. longimanus into lakes far outside its known distribution area are discussed.     

The response of three chydorid species to temperature, pH and food

The responses of three chydorid species, Chydorus sphaericus(O.F. Müller), Alona affinis (Leydig) and Alonopsis elongata (Sars) to temperature, pH and food type were examined. Egg development time of all species decreased with increasing temperature, although the degree of change was different for each species. C. sphaericus had the fastest development time at all temperatures, and A. elongata the slowest. pH also affected the egg development time of each species differently. A. elongata failed to reproduce at low and medium pH, the egg development time of C. sphaericus was fastest at high pH while that of A. affinis was fastest at low pH. Food type was found to have significant effects on the population growth of individual species. C. sphaericus populations grew equally well in all three food types provided, and grew more than the other two species when fed on an algae culture, and filtered pond water. A. affinisand A. elongata populations grew best when fed on a detritus food source. The responses of each species to the different variables tested are discussed in relation to field observations of their distribution and abundance.     

Sexual behavior in aging male rhesus macaques: Effects of test duration on sexual performance

The sexual behavior displayed by nine old (20-year and older) rhesus (Macaca mulatta) males in 10-min tests was compared to that displayed in 1-hr tests. The tests were part of a long-term study on the decline in male sexual activity that accompanies old age. The males were paired with 10 ovariectomized, estrogentreated females in two blocks of 10 tests; each male was tested once with each female in each test block. The percentages of males that achieved intromissions and ejaculated in the two test blocks were the same (P < 0.05). Although the percentage of tests in which males displayed these behaviors was higher in the longer-test block (P > 0.05), there was a significant positive correlation of performance in 10-min tests with performance in 1-hr tests. Assuming a random distribution of contacting, mounting, intromission, and ejaculation throughout the hour, we would have predicted a significantly lower number of these behaviors in the first 10 min of the 1-hr tests than we actually observed. The mean percentages of 1-hr tests with contacting, mounting, intromission, and ejaculation was significantly lower than that of 10-min tests conducted with the same males 11 years earlier. Thus, the decline in sexual performance was not an artifact of the limited (10-min) test duration.