Reproduction in three sympatric lizard species from west-central Utah

Data on reproduction by the lizards Uta stansburiana, Crotaphytus collaris, and Cnemidophorus tigris are presented from a community where they are sympatric in west-central Utah. Data are compared to a previous study of these species at the same site and to data from other sites in the United States.     

Temperature responses and habitat sharing in two sympatric species of Okanagana (Homoptera: Cicadoidea)

Okanagana striatipes and O. utahensis are species synchronous in location of activity and utilization of host plants. They possess similar acoustic behavior. Analysis of calling songs shows that calls overlap in frequency but differ in temporal pattern. Based on characteristics of the cicada auditory system and the species recognition mechanism, the potential for acoustic interference exists. Both species are ectothermic behavioral thermoregulators. Measurements of thermal preference and body temperature during singing show that although thermal preferences are similar, O. utahensis sings at a significantly higher body temperature. Differences in body temperature required to coordinate singing in the 2 species provide a partial temporal separation of acoustic signaling. We suggest the physiological mechanisms that permit synchronous utilization of a habitat by the 2 species are the production of calling songs of different temporal patterns and the presence of different thermal requirements, which may permit and/or facilitate temporal separation of the acoustic environment during the day.     

Spatial distribution of three snail species, including the invader Potamopyrgus antipodarum , in a freshwater spring

The highly invasive New Zealand mudsnail, Potamopyrgus antipodarum , may compete with and displace native North American macroinvertebrates in freshwater systems wherever it becomes established. Densities and spatial distributions of 3 snail species including P. antipodarum and the threatened Taylorconcha serpenticola were compared among 3 adjacent habitat types (run, edge, and vegetation) in Banbury Springs, a tributary of the Snake River, near Hagerman, Idaho, USA. In all 3 habitats P. antipodarum was the most abundant snail species. All 3 species densities were highly variable within habitats, suggesting a nonrandom distribution pattern. Densities of P. antipodarum were significantly greatest in the vegetation habitat type, while densities of T. serpenticola were similar among habitats. Smallersized P. antipodarum were less abundant in the run habitat with its associated higher water velocities, and their densities were negatively correlated with velocity. Densities of P. antipodarum also were negatively correlated with distance from the highly infested, man-made Morgan Lake, while T. serpenticola densities were positively correlated with distance from Morgan Lake. Potamopyrgus antipodarum is a potential competitor with native aquatic species, although its colonization into some freshwater habitats may be limited.     

Some corallanid isopods associated with wood from Papua New Guinea,including three new species (Isopoda: Corallanidae)

Summary

The corallanid isopods, C. nodosa, C. estuaria sp. nov. C. bidentata sp. nov. and C. tridentata sp. nov. have been found within timbers of mangroves and man-made structures in marine and brackish waters around Papua New Guinea. Corallana estuaria, C. bidentata and C. tridentata are new to science and are described in detail. In addition, aspects of the ecology of all four species are considered, including their association with the marine-boring isopods, Sphaeroma terebrans and S. triste.     

New species of Astragalus (Leguminosae) from Mesa County, Colorado

Named and described is Astragalus debequaeus Welsh from Mesa County, Colorado.         

Size and seasonal activity patterns of abundant sympatric spider species in Cache County, Utah

Of the eight most frequently collected spiders at a northern Utah study site, each of two species employed one of the following hunting strategies: pursuing, web building, jumping, and ambushing. Within each pair, size differences between species were substantial for all but the ambushers. The ambushers had different seasonal activity patterns, as did the web builders.     

Synopsis of copepods associated with asteroid echinoderms,including new species from the Moluccas

Copepods associated with Asteroidea are listed, with their hosts and localities where found. Five new species and one new genus are included: Astericola carens sp. nov., Stellicola astrivagus sp. nov., Astroxynus choriasteris sp. nov., Chorioxynus moluccensis gen. nov., sp. nov., and Stellicomes bisphaerulifer sp. nov. New hosts and localities are recorded.     

Demographic and environmental relations of two rare Astragalus species endemic to Washington County, Utah: Astragalus holmgreniorum and A. ampullarioides

Two endemic locoweeds of Washington County, Utah, Astragalus holmgreniorum and A. ampullarioides , were recently listed as federally endangered plant species (Federal Register 2001). They both occur in few, small populations surrounded by increasing human activity in the St. George, Utah, area. Demographic and habitat studies have been ongoing since 1992 and results of those studies are presented here. Astragalus holmgreniorum (Holmgren locoweed) is presently limited to 1 larger population and 2 smaller, isolated populations on the eastern and western edges of its range. It is a short-lived perennial that grows primarily on the Virgin limestone member of the Moenkopi Formation. Density of A. holmgreniorum over the 10-year study averaged about 2 plants per m 2 . The number of living plants of this species perhaps never exceeds 10,000. In drought years A. holmgreniorum populations are as much as 95% smaller than in years with adequate water, and few plants produce flowers that successfully contribute to the seed bank. Astragalus ampullarioides (Shivwits locoweed) occurs in 4 populations where plant density fluctuated between 0.5 and 4.8 per m 2 during our study period (average = 2.6). This locoweed is restricted to clay soils of the Chinle Formation. Direct threats to both Astragalus species include widespread urbanization, road construction, population fragmentation, and off-highway vehicle use. Indirect threats include competition from aggressive, introduced annual species such as Bromus rubens, B. tectorum, Malcolmia africana , and Erodium cicutarium . Our data show that 3 of 4 species most closely associated with these Astragalus species are introduced. Studies of seed banks and reproduction biology, as well as continued monitoring of these Astragalus species, are critically needed. Studies of the consequences of competition from alien and native species on seedling establishment of these locoweeds are especially needed.     

Contributions to the biology of the woundfin, Plagopterus argentissimus (Pisces: Cyprinidae), an endangered species

The woundfin is a small, streamlined, omnivorous cyprinid that is now limited to the Virgin River basin where it was collected in the mainstream and one tributary during the present study. The woundfin occurred most frequently in runs and over sand substrates and less frequently in riffles and over rock substrates. It was common over at least half of its original range within the Virgin River. It was uncommon in the lower mainstream due to habitat alterations and, presumably, predation by and competition with exotic species.     

Differentiated use of pollen sources by two sympatric species of oil-collecting bees (Hymenoptera: Apidae)

We identified the food niche breadth of two sympatric species of oil-collecting bees, Centris (Heterocentris) analis (Fabricius, 1804) and Centris (Hemisiella) tarsata Smith, 1874, based on pollen analyses of larval food. We tested differences in the use of pollen sources considering the anther type and pollen size of the flowers. The species presented a low similarity in the use of pollen sources and C. analis had a wider niche breadth than C. tarsata. Centris analis mainly used Heteropterys spp. and other flowers with non-poricidal anthers. In contrast, C. tarsata commonly used Solanum lycocarpum A. St.-Hil., as well as other flowers with poricidal anthers. Despite the differences in pollen composition of larval food, both species predominantly used medium-sized pollen grains. Although C. analis and C. tarsata are sympatric species, belonging to the same functional group and presenting an overlap in nesting periods, they used different pollen sources, which suggests the occurrence of food niche partitioning.     

Reproductive strategies of two sympatric species of Hyalella Smith, 1874 (Amphipoda,Dogielinotidae) in laboratory conditions

This study was performed in order to test theoretical predictions that sympatric species might show different reproductive strategies to facilitate their coexistence. The duration of precopulatory mate‐guarding behaviour, body size of ovigerous females, embryonic and postembryonic development time, fecundity, and viability of the sympatric amphipod species Hyalella pleoacuta and H. castroi were investigated under laboratory conditions (19±1°C and 12 h light/dark photoperiod). Specimens were collected with nets in autumn and spring 2004, and summer and winter 2005 in the Vale das Trutas, São José dos Ausentes County, southern Brazil, and transported to the laboratory. Both species of Hyalella showed similar reproductive strategies, especially in respect to the duration of the precopula, duration of the embryonic period, and fecundity. However, these species differed in body size of ovigerous females, duration of the postembryonic period, viability, and body size of juveniles that remained in the marsupium and those released by females. These differences in the reproductive traits of H. pleoacuta and H. castroi may facilitate their coexistence in nature.     

Plants of Arizona: a new species of Astragalus from the Kaibab Plateau

Astragalus atwoodii Welsh and Thorne is named and described on the basis of materials collected on the Kaibab Plateau in Coconino County, Arizona.     

The Mediterranean species of Malmgreniella Hartman, 1967 (Polychaeta: Polynoidae: Polynoinae), including the description of a new species

The present review is based on material from different localities in the Mediterranean Sea, and where appropriate, on type material; it comprises all Malmgreniella species known to occur in this area: i.e. Malmgreniella andreapolis (McIntosh, 1874), M. castanea (McIntosh, 1876), M. darbouxi Pettibone, 1993, M. lilianae Pettibone, 1993, M. ljungmani (Malmgren, 1867), M. lunulata (Delle Chiaje, 1830), M. polypapillata sp. nov. Two species are new for the Mediterranean: M. lilianae, previously only known from the southwest Atlantic, represents a new record, and M. polypapillata is a new species, occurring not only in the Mediterranean, but probably also in the northeast Atlantic. The seven Malmgreniella species listed above are described and figured, and an identification key is provided. Furthermore, the subfamily affiliation of the genus Malmgreniella Hartman, 1967 and the validity of Malmgrenia McIntosh, 1874 are discussed.     

Egg production of two sympatric species of Hyalella Smith, 1874 (Crustacea,Amphipoda, Dogielinotidae) in aquaculture ponds in southern Brazil

This study tests the hypothesis that sympatric species of Hyalella may show different reproductive strategies that permit their coexistence. Ovigerous females were collected monthly with nets during a 1-year period in two aquaculture trout ponds in Vale das Trutas, São José dos Ausentes County, southern Brazil. In both species there was a decrease in the number of embryos in the brood pouch during embryonic development, and an increase in egg volume. However, the two species differed in the body size of ovigerous females, number of eggs and juveniles per female, brood mortality rate, egg size and hatching size of juveniles. Egg production continued throughout the year, with the highest number of eggs produced during winter and spring by Hyalella pleoacuta, and winter, spring and autumn by Hyalella castroi. These differences in the reproductive traits of species of Hyalella may permit their coexistence in nature.     

Records of ascidians from Bahrain,Arabian Gulf with three new species

Fifteen ascidian species were identified from 1 to 12 m depth in coastal waters of Bahrain, Arabian Gulf. Three new species, Aplidium rubripunctum, Didemnum yolky and Symplegma bahraini are described. Four species collected are cosmopolitan. This study increases knowledge of the ascidian fauna of an area for which only sporadic collections have previously been made.     

On the prezoeal stage: observations on three Pagurus species (Decapoda,Anomura)

Observation on prezoeas of three Pagurus species inhabiting the coasts of Hokkaido, P. lanuginosus de Haan, P. middendorffii Brandt, and P. brachiomastus (Thallwitz), were carried out using light and scanning electron microscopy. Hatching was produced at laboratory conditions of 17·5–18·2 °C and 32·5–33·2 ppt salinity, and after a short duration of 5–10 min, most of prezoeas moulted to the first zoeal stage. Prezoeal appendages are described and figured; previous observations on prezoeas in allied groups are summarized.