Predatory behavior of larval Ambystoma tigrinum nebulosum on Limnephilus (Trichoptera) larvae

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Feeding habits of metamorphosed Ambystoma tigrinum melanostictum in ponds of high pH (> 9)

During the spring breeding season throughout the channeled scablands of eastern Washington, metamorphosed male and female blotched tiger salamanders ( Ambystoma tigrinum melanostictum ) utilize oropharyngeal suction to capture large quantities of small aquatic invertebrates. Stomach content analysis on salamanders from three populations of this subspecies revealed that they consume the following taxa: Copepoda, Cladocera, Culicidae, Anostraca, and Chironomidae. Although the amount of energy obtained by adults via in-water feeding was not calculated, the large volume of aquatic invertebrate material flushed from salamander stomachs suggests that this feeding strategy should add significantly to their total annual nutrient consumption.     

Food habits of clouded salamanders ( Aneides ferreus ) in Curry County, Oregon (Amphibia: Caudata: Plethodontidae)

Stomach contents of 650 clouded salamanders ( Aneides ferreus ), collected monthly throughout the year from Curry County, Oregon, were examined. Samples from three age classes were involved: (1) 489 adults, (2) 131 juveniles, and (3) 30 hatchlings. Foods did not vary by sex, but did vary by age and by season. Hatchlings ate small items, particularly mites, springtails, flies, and small beetles. Juveniles fed mainly on flies, isopods (sowbugs), beetles, mites, and centipedes in winter; beetles, ants, and isopods in spring; ants and beetles in summer; and isopods, beetles, and ants in fall. Adults ate isopods and beetles as their major foods in winter, spring, and fall and isopods, ants, beetles, and earwigs in summer. Four species were exceedingly important as foods for these salamanders: an unidentified isopod, the snout beetle ( Trachyphloeus bifoveatus ), the European earwig ( Forficula auricularia ), and an ant ( Lasius alienus ).       

Karyotypes of the long-tailed vole ( Microtus longicaudus ) in isolated mountain ranges of the American Southwest

The long-tailed vole ( Microtus longicaudus ) exhibits karyotypic variation in western North America. In the American Southwest, the species has a disjunct, relict distribution. However, karyotypes obtained from 20 specimens in 5 isolated mountain ranges (White Mountains, Arizona; Mount Taylor and the Sangre de Cristo, Jemez, and Mogollon mountains, New Mexico) exhibited no variation. These and previously reported karyotypes from the region had a diploid number (2n) of 56 and fundamental number (FN) of 84, which is the most commonly reported karyotype for the species.     

Feeding ecology of Gila boraxobius (Osteichthyes: Cyprinidae) endemic to a thermal lake in southeastern Oregon

Gila boraxobius is a dwarf species of cyprinid endemic to a thermal lake in southeastern Oregon. Despite a relatively depauperate fauna and flora in the lake, 24 food items were found in intestines of G. boraxobius. Ten of the 24 foods, including six insects, were of terrestrial origin. The relative importance of food items fluctuated seasonally. Diatoms, chironomid larvae, microcrustaceans, and dipteran adults were the primary foods during spring. In summer, diatoms decreased and terrestrial insects increased in importance. During autumn important foods were terrestrial insects, chironomid larvae, and diatoms. Diatoms and microcrustaceans increased in importance during winter. Chironomid larvae were of importance in winter, when the importance of terrestrial food items decreased substantially. Similar food habits were observed between juveniles and adults, except that adults consumed more gastropods and diatoms and juveniles consumed more copepods and terrestrial insects. Gila boraxobius feeds opportunistically with individuals commonly containing mostly one food item. Fish typically feed by picking foods from soft bottom sediments or from rocks. However, fish will feed throughout the water column or on the surface if food is abundant there. Gila boraxobius feeds throughout the day, with a peak in feeding activity just after sunset. A daily ration of 11.1 percent body weight was calculated for the species during June. A comparison of food habits among G. boraxobius and populations of G. alvordensis during the summer shows that all are opportunistic in feeding, but that G. boraxobius relies more heavily on terrestrial foods.     

Extremalona timmsi gen. nov., sp. nov., a new cladoceran (Cladocera: Anomopoda: Chydoridae) from an acid saline lake in southwest Western Australia

A new species of Cladocera, Extremalona timmsi gen. nov., sp. nov., was found in acid saline lakes in the southwest of Western Australia. Extremalona gen. nov. belongs to the Coronatella-branch of Aloninae, but differs from all members of the group by the oval body with small high-set head (tip of rostrum located at half-height of the body), the exopodite III with uniform, well-developed setae 4–6 and male antennule with six lateral and nine terminal aesthetascs, and by numerous other characters. In our opinion, Extremalona gen. nov. is one of the ancestral genera of the Coronatella-branch of Aloninae, sharing numerous common features with the elegans-group of Alona s.l. Our data confirm a high level of endemism in Australian Chydoridae and Cladocera in general.     

Reproductive strategies used by moorhens (Gallinula chloropus) colonizing an artificial wetland habitat in south Wales

Over the last ten years, a high-density breeding population (c.180 individuals) of moorhens Gallinula chloropus (Linnaeus) has become established in an artificially created wetland habitat at the Wildfowl and Wetlands Trust (WWT) centre in Llanelli. The reproductive behaviour and success of this population was the subject of an intensive study between 1997–1999. Whilst monogamy was the dominant breeding system used at the site, some individuals bred annually in communal and co-operative groups. The majority of individuals within communal and co-operative groups in 1998 and 1999 were first order relatives. The number of communal groups recorded progressively declined whereas the number of co-operative groups increased over the period of study. Territory size of breeding groups was unrelated to either breeder type or group number. Most nests were constructed in Juncus although many birds also nested in trees and nest boxes intended for captive bred wildfowl. Vegetation height above nests strongly influenced breeding success, and nest site choice at the site was partially determined by vegetation management practices. Such practices may have been responsible for decreased nesting success in specific areas. Rats were the principal egg predators on site accounting for approximately 80% of eggs predated. The study reveals how the reproductive dynamics of this opportunistic bird influences its successful colonization of a new habitat.     

Cleavage pattern in Oscarella species (Porifera,Demospongiae, Homoscleromorpha): transmission of maternal cells and symbiotic bacteria

The cleavage and the first stages of development of larvae in five Oscarella species, from the north-west Mediterranean, O. lobularis, O. tuberculata, O. imperialis, O. microlobata and Oscarella sp., are investigated. Eggs are isolecithal, and rich in yolk inclusions. The cleavage is holoblastic, equal and asynchronous. During cleavage, there is no central cavity (blastocoel). The result of cleavage is the formation of a solid morula constituted by equal blastomeres. The polarity of the blastomeres is not expressed prior to the beginning of larva differentiation, i.e. approximately up to 64-cell stage. The superficial membrane of the blastomeres shows numerous filopodia which form blastomere contact. Symbiotic bacteria and cells with inclusions of the maternal mesohyl are present in the intercellular spaces of the embryo from the beginning of cleavage. Whereas maternal symbiotic bacteria are present in the embryo of the five species studied, maternal cells with inclusions are absent from two species (O. tuberculata and O. microlobata). The most original feature of early development in the genus Oscarella is the formation of a coeloblastula larva from a morula due to the progressive migration of the internal cells to the periphery.     

Use of space by the marsupials Gracilinanus microtarsus (Gardner and Creighton, 1989) and Marmosops incanus (Lund, 1840) in an Atlantic Forest of southeastern Brazil

The use of space by animals is determined by environmental conditions, biological and ecological adaptations and interactions and mostly by resource availability. We sampled two species of Neotropical mammals to investigate their use of different strata in Atlantic Forest habitat in Brazil, as well as the home range sizes and movements of both sexes of each species. We found no difference in home ranges and movements between the sexes and species, but we found differences in the use of strata, with Gracilinanus microtarsus mostly using the canopy and Marmosops incanus using the ground. Gracilinanus microtarsus males mostly use the understorey in the wet season and the canopy in the dry season. We believe that these patterns of strata use reflect intrinsic characteristics of the species; and the shifts in resources and interspecific competition, which are lower in the dry season, seem to be responsible for the shifts in space use observed for G. microtarsus males. We recommend studies with spool-and-line techniques or radio tracking to further test refined hypotheses regarding the use of space, including the role of territoriality in females.     

A new genus of Australian Tetrastichinae (Hymenoptera: Eulophidae): an introduced pest of Chamelaucium uncinatum (Myrtaceae) in California

A new genus of tetrastichine eulophid, Oncastichus LaSalle, is described to contain a single new species, Oncastichus goughi Headrick and LaSalle. This species is native to Australia, and is a gall former on the Geraldton waxflower, Chamelaucium uncinatum. Oncastichus goughi was accidentally introduced into California where it causes economic damage to the Californian horticultural industry. This is the first example of a tetrastichine Eulophidae becoming an economically important introduced pest species.     

Superparasitism of Eoxenos laboulbenei De Peyerimhoff (Strepsiptera: Mengenillidae) by Idiomacromerus gregarius (Silvestri) (Hymenoptera: Chalcidoidea) in southern Spain

A female puparium of Eoxenos laboulbenei De Peyerimhoff (Strepsiptera: Insecta) found in Mula, Murcia, Spain was parasitized by five larvae of Idiomacromerus gregarius (Silvestri) (Hymenoptera: Chalcidoidea: Torymidae). The parasitized puparium was kept in the laboratory until the following summer, when four I. gregarius adults emerged from it. This species of chalcidoid is rarely found. It was first described in 1943 from Italy by Silvestri and the present report is the first record from Spain. Here we re-examine and redescribe the newly discovered specimens of I. gregarius, add further details about its morphology and give a brief account of its biology including a new record (the mengenillid E. laboulbenei).     

Establishment of Shoshone sculpin ( Cottus greenei ) in a spring inhabited by mottled sculpin ( C. bairdi )

The Shoshone sculpin ( Cottus greenei ) is found only in springs of the Thousand Springs formation along the Snake River in Idaho. In 1983 a small population of Shoshone sculpin was introduced into an unnamed spring in the Thousand Springs formation in an attempt to increase the range of the species. Previously, the only sculpin in that spring was the mottled sculpin ( Cottus bairdi ). The Shoshone sculpin was able to establish itself and become the predominant fish within 8 years.     

Post-pleistocene dispersal in the Mexican vole ( Microtus mexicanus ): an example of an apparent trend in the distribution of southwestern mammals

The present distribution of the Mexican vole ( Microtus mexicanus ) is not entirely the product of post-Pleistocene forest fragmentation and extinction; recent dispersal also is indicated. Literature records further suggest that this phenomenon may reflect a general pattern of northward range expansion in many southwestern mammal species.     

Trend analysis shows decline of an endangered thermophilic springsnail ( Pyrgulopsis bruneauensis ) in southwestern Idaho

We analyzed population trend data during 1991–2004 for the Bruneau hot springsnail ( Pyrgulopsis bruneauensis ) from rangewide hot spring surveys completed along 4 km of Bruneau River. The objectives of this study were to analyze population trends and assess other measured parameters, such as water temperature, specific conductance, and groundwater decline, for changes that may influence population trends. We used simple linear regression to determine significant relationships between measured parameters. Total numbers of hot springs surveyed in the 4-km reach are declining at a rate of ～5 hot springs per year, and numbers of hot springs containing P. bruneauensis in the same reach are declining at a rate of 3.75 per year. We found that the decline of hot springs with and without P. bruneauensis was significantly related to the decline of the thermal aquifer which underlies this area.     

Patterns of insect flower visitation in Lavandula buchii Webb (Lamiaceae), an endemic shrub of Tenerife (Canary Islands)

The foraging ecology of insect visitors of the endemic lavender Lavandula buchii (Lamiaceae) was studied in a relict population of the plant in north-west Tenerife (Canary Islands). Timed observations were used to describe this pollination system in terms of the structure of the visitor assemblage, foraging patterns and efficiencies of the main insect species. The visitor pool was dominated by anthophorid solitary bees. Furthermore, it was characterized by a high level of endemicity and a small number of species compared with continental relatives of Lavandula. The main visitors, two anthophorids and a bombyliid fly, clearly differed in their foraging behaviour, i.e. visitation frequency, visit duration, rate of flower probing, and in anatomical traits (body size and proboscis length). In these terms, the bees were by far more efficient foragers than the fly. These results are discussed in the context of insect-flower interactions in insular pollination systems.     

The occurrence of an additional instar in the development of Chorthippus brunneus (Orthoptera: Gomphocerinae)

In two populations of Chorthippus brunneus in the Breckland district of East Anglia an additional instar is interposed between instars II and III during the development of female nymphs. The IIa nymph occurs with a frequency approaching 100%, in both heavily and very lightly grazed grasslands.

The IIa nymph is intermediate in morphological characteristics between the second and third instars. It is characterized by having wing buds similar to those of a second instar except with more extensive venation, while the genitalia are more like those of a third-instar nymph. The pronotum length: head length ratio is approximately 1·0 and there are 16 or more annuli in the antennae.

Members of the population taken from the very lightly grazed grassland and raised in the laboratory on grass that had been heavily grazed by rabbits omitted the IIa instar and so passed through only four stadia during their development. In contrast, members of the population taken from the heavily grazed field site continued to include the IIa instar in their development when fed in the laboratory on grazed grass.

Comparisons with other studies of this species show that there is geographical variation with respect to numbers of instars passed through during development. The additional instar has been found only in East Anglia where the warmer sunnier climate, which is semi-continental in the Breckland district, leads to earlier hatching. This allows more time for an extra instar to be included in the development.

The ecological implications of the observed variation in life history are discussed.     

Fate and characteristics of Picea damaged by Elatobium abietinum (Walker) (Homoptera: Aphididae) in the White Mountains of Arizona

Spruce aphid, Elatobium abietinum (Walker), is a new invasive pest in high-elevation forests of southwestern USA. Plots in the White Mountains of Arizona were evaluated over several years to assess the extent and severity of damage in high-elevation forests and to identify tree and site characteristics associated with defoliation and mortality. Large areas were defoliated in each of 4 recent outbreaks. Impact from a single defoliation episode included an overall mortality of 10.3% to Picea engelmannii Parry, 24%-41% in severely defoliated trees. Defoliation severity was much greater on P. engelmannii than on P. pungens Engelm. and was more severe in the lower canopy layers. Retention of foliage in the upper-crown third of individual trees was a critical factor in tree survivorship. Mortality was associated with defoliation severity and severe infection by Arceuthobium microcarpum (Engelmann) Hawksworth & Wiens. Picea pungens was much more susceptible to A. microcarpum more than was P. engelmannii . The combined effects of high levels of defoliation and mistletoe infection were lethal, resulting in almost 70% mortality. Mortality continued to occur at 3 years after defoliation. This aphid will affect natural disturbance regimes and tree population dynamics in mixed-conifer and spruce-fir forests of the American Southwest.     

Two new Encarsia species (Hymenoptera: Aphelinidae) reared from eggs of Cicadellidae (Hemiptera: Auchenorrhyncha) in Argentina: an unusual new host association

Males of two undescribed Encarsia species were reared from eggs of two cicadellid species during a study of egg parasitoids of corn leafhopper, Dalbulus maidis (DeLong and Wolcott) in northwestern Argentina. Samples were collected during the summer of 2004–2007 using sentinel eggs, and several males of a new species of Encarsia (Hymenoptera: Chalcidoidea: Aphelinidae) were obtained. A single male of a closely related Encarsia species, also previously undescribed, was reared from an egg of another cicadellid on maize, Plesiommata mollicella (Fowler). These are the first records of any Encarsia species reared from eggs of Cicadellidae. The two new species are described as Encarsia dalbulae Polaszek and Luft Albarracin sp. nov., and Encarsia mollicellae Polaszek and Luft Albarracin sp. nov.     

Development and demography of Phasmahyla jandaia (Bokermann and Sazima, 1978) (Anura,Hylidae) tadpoles in an Atlantic Forest site,southeastern Brazil

Mortality rates are often high during the anuran tadpole stage, making demographic parameters in this phase of their life cycle important to the understanding of population demography. Nevertheless, information on mortality rates or population size is lacking for most Brazilian anurans. Herein we report on the demographic parameters of Phasmahyla jandaia (Hylidae) during the larval stage, including number of individuals through time, mortality rates and time of recruitment. Tadpole recruitment occurred year‐round, although froglet recruitment to the terrestrial habitat was restricted to the warm, rainy season. This trend seems to result in high plasticity of the tadpole developmental period. Mortality rates decreased with advancing tadpole stage, totalling 77% during the whole aquatic phase. Survivorship can be regarded as intermediate compared with other anurans for which data are available, and is in accordance with a high investment in egg size and the low number of eggs laid by P. jandaia.