Nesting and predatory behavior of some Tachysphex from the western United States (Hymenoptera: Sphecidae)

The first published observations on the nesting and predatory behavior of Tachysphex antennatus Fox, T. occidentalis Pulawski, T. williamsi Bohart, T. yolo Pulawski, T. alpestris Rohwer, T. clarconis Viereck, T. apricus Pulawski, and T. cockerellae Rohwer are presented herein. Also included are host and behavioral data on T. tarsatus (Say), T. apicalis fusus Fox, T. similis Rohwer, T. ashmeadii Fox, and T. mundus exsectus Fox.         

Studies on the predatory biology of Oriental dacetine ants (Hymenoptera: Formicidae) II. Novel prey specialization in Pyramica benten

The predatory biology of the ant Pyramica benten, a short‐mandibulate form in the tribe Dacetini, Myrmicinae, was studied in the field and laboratory. Pyramica benten prefers disturbed habitats, where they hunt predominantly collembolans of Entomobryidae. Laboratory observation and experiments revealed that this ant hunted such entomobryids more efficiently than collembolans of Tomocelidae and Isotomidae. The hunting behaviour of the ants is characterized by their grabbing the prey near the mouthparts and ambushing without approaching the prey. Success in this stealthy hunting is most probably enhanced by luring the prey with body smearing using organic material. Strumigenys are closely related to Pyramica but they are long‐mandibulate forms. Both genera are speciose and specialized predators on Collembola. Coleoptera is another group that has evolved specialized predators on Collembola so these dacetines and the coleopterans are compared for their hunting tactics and species diversity.     

Caudal movements in western fence lizards ( Sceloporus occidentalis ) prior to attempted prey capture

Many snakes employ tail movements to attract prey, but this behavior is rare in lizards. Use of caudal movements to distract prey, however, is rare in all squamates. Recently, caudal movements in a Sceloporus occidentalis individual immediately prior to attempted prey capture were documented. We supplement this sole documentation of caudal movements in S. occidentalis with additional field observations. Additionally, video footage of the behavior was recorded on 2 occasions. From these additional observations, we hypothesize that this behavior might serve to distract prey.     

A comparison of mosquito consumption and prey selection between least chub ( Iotichthys phlegethontis ) and western mosquitofish ( Gambusia affinis )

We compared mosquito consumption and prey selection between least chub ( Iotichthys phlegethontis ) and western mosquitofish ( Gambusia affinis ) to determine the potential of least chub as an indigenous replacement for mosquito control in Utah. Mosquito consumption was compared between the 2 species in 2 experiments. The first tested consumption at 3 ratios of pupae and larvae ( Culex sp.; 1:3, 3:4, and 1:1), and the second tested consumption at varying densities of larvae (967 larvae ? m–3 , 1354 larvae ? m–3 , and 2258 larvae ? m–3 [30, 42, and 70 larvae per 31-L tank, respectively]). Western mosquitofish consumed more mosquitoes at lower pupae-to-larvae ratios than least chub, but least chub consumed more mosquitoes as the ratio of pupae to larvae increased. Western mosquitofish consumed significantly more larvae than least chub at all densities. Prey selection was compared between least chub and western mosquitofish, either individually or in intraspecific pairs, when the fish were fed equal abundances of 3 prey items: mosquito larvae, Daphnia magna , and midge larvae ( Chironomid sp.). Least chub consumed significantly fewer total prey items for both the 1- and 2-fish trials; western mosquitofish consumed significantly more individuals of each prey type except for Daphnia magna in the 1-fish trials. Least chub and western mosquitofish demonstrated no selection for prey items, indicating that both fish would consume mosquito larvae at rates relative to abundance. Feeding habits demonstrated in this study indicated that least chub could be a potential replacement for western mosquitofish for mosquito control; however, field studies should be conducted to assess the ability of both species to control mosquitoes in a natural setting.     

Observations on the prey and nests of seven species of Cerceris (Hymenoptera: Sphecidae)

Cerceris species are remarkably constant in their prey preferences. Records are presented from diverse localities that confirm prey constancy in five species. An apparent exception is noted in the case of C. crotonella Viereck & Cockerell. A mixed aggregation of C. fumipennis Say and C. californica Cresson is reported, both preying upon Buprestidae and using some of the same species. Nest and prey of C. conifrons Mickel are reported for the first time.     

Habitat use of leatherside chub ( Gila copei ) in the presence of predatory brown trout ( Salmo trutta )

The objectives of this study were to (1) examine distribution and habitat use of leatherside chub ( Gila copei ) in a creek with high densities of predatory brown trout ( Salmo trutta ), and (2) compare study results with published accounts of leatherside chub habitat use in streams with few or no brown trout. A 14-km section of Diamond Fork Creek, Utah, was point-shocked to determine macrohabitat (main channel and lateral habitat) and microhabitat (current, depth, substrate, and cover) use of leatherside chug. At the macrohabitat level, leatherside chub were most common in lower reaches of Diamond Fork Creek where the channel was braided and lateral habitats (cutoff pools and backwaters) were abundant. Only a single leatherside chub was found in the main channel of Diamond Fork. Investigations in other systems lacking brown trout indicated that leatherside chub occupy main channel habitats. At the microhabitat level, we found significant positive associations between presence of leatherside chub and both habitat depth and silt. In addition, we found a significant negative association between presence of leatherside chub and number of brown trout. Our results suggest predation by brown trout may limit leatherside chub to lateral habitats that could provide refugia against predation. The introduction of brown trout to systems with little lateral habitat could have serious effects on persistence of resident leatherside chub populations.     

Negative effects of the western thatching ant ( Formica obscuripes ) on spiders (Araneae) inhabiting big sagebrush ( Artemisia tridentata )

The effect of thatching ants ( Formica obscuripes ) on number of spiders found on sagebrush ( Artemisia tridentata ) was determined by comparing spider abundance on shrubs at different distances from ant mounds. Spider abundance was inversely related to proximity to mounds. Spider abundance on shrubs abound abandoned mounds revealed no effects of mound proximity. Two mounds in which ants were exterminated showed a declining effect of mound proximity 1 month after treatment. One year after treatment there was no effect.     

Nesting behaviour and prey of Pseudoplisus Ashmead (Hymenoptera: Sphecidae)

Nesting behaviour and prey of two species of Pseudoplisus, a gorytine wasp genus in the sphecid subfamily Nyssoninae, are described. P. natalensis is a solitary nester in southern Africa nesting often in the soil in flower-pots. P. ranosahae in Madagascar nests in the ground in large aggregations. Both species show a high degree of prey specificity. Nests are provisioned only with large adult froghoppers (Aphrophoridae), P. natalensis preying on Ptyelus grossus and P. ranosahae on Ptyelus goudoti.     

Patterns of prey use in four sympatric species of Philanthus (Hymenoptera: Sphecidae) with a review of prey selection in the genus

Summary

Observations were made on four sympatric species of sphecid wasps of the genus Philanthus that nest in late summer and prey upon Hymenoptera. All four species nest in a restricted locale, but with little overlap in nesting areas. Comparison of nest contents of females demonstrated limited overlap in prey utilization among the four species, but only when both size and taxonomic category of prey were considered. The ultimate cause of this resource partitioning is unknown. Review of 30 populations of 16 species of North American Philanthus reveals varying degrees of specialization on prey types. Although populations of one species, separated in either time or space, tend to have similar niche breadths, this is not always the case. Intra-and inter-populational comparisons of prey records suggest behavioural plasticity allowing response to variations in prey availability. Some of the divergence in prey use among species is due to differences in predator size.     

A case of leucism in the western bluebird ( Sialia mexicana )

Leucism in the western bluebird ( Sialia mexicana ) is reported from La Plata County, Colorado.     

Scorpion-flies of the Panorpa cognata-complex in the western palaearctic region (Mecoptera)

Summary

The Panorpa cognata-complex comprises four morphologically distinct species two of which, P. cognata and P. meridionalis, show a confusing degree of variation. P. meridionalis is separated by the bi-lobed ventral parameres, which are singlelobed in P. cognata, P. annexa and P. etrusca. P. meridionalis is also allopatric and has two geographical forms which may prove to be biologically distinct species. P. cognata is sympatric with, and closely related, to P. annexa. P. cognata and P. etrusca are also sympatric. There is a clear morphological and distributional division between P. annexa and P. etrusca, for which reason the latter is raised to species level. Based on morphological evidence P. ghilianii, P. cognata osellai and P. adnexa [sic] var. subalpina are synonymized with P. cognata and P. meridionalis var. commissa, P. meridionalis var. germanizans and P. meridionalis var. liberata are synonymized with P. meridionalis.     

Barn Owl (Tyto alba) prey in Evros (Greece) and the discovery of a new mammal for the Greek fauna

ABSTRACT

Small mammals are key elements of terrestrial ecosystems, yet in south-eastern Europe many questions about their taxonomy and distribution remain unanswered. This is particularly true for the small mammal fauna of Greece. We investigated the distribution of small mammals in the district of Evros (NE Greece) through Tyto alba pellet analysis and live-trapping in 19 localities (29 samplings). We collected remains from a total 2434 individual vertebrates through pellet analyses and captured 110 small mammals through live trapping. We provide data on the distribution and community composition in the corresponding localities, for 17 small mammal species (11 rodents and 6 insectivores). Our findings include the first record of Myomimus roachi in Greece, a result facilitated by the yearly dynamics of Microtus sp. populations, as well as the first record of Sorex minutus in Evros. The Barn owl’s main prey (by percentage, allocated to genera) were Crocidura (29.7%) Mus (27%) Microtus (23.2%) and Apodemus (13%).     

Freshwater sponges (Porifera: Spongillidae) of western Montana

Between May 1992 and April 1996, freshwater sponges (Porifera: Spongillidae) were collected at 24 sites, distributed among 6 sub-major drainage basins in western Montana, to determine the species present. Water samples also were analyzed from 16 of these sites and from 9 sites at which no sponges were detected to characterized sponge habitats chemically. Three species of sponges were identified: Ephydatia muelleri (Em), Eunapius fragilis (Ef), and Spongilla lacustris (Sl). A 4th type of specimen was present at 2 sites but could not be identified because of the absence of gemmules and gemmoscleres. At 46% of the sites containing sponges, more than 1 specimen type was present. Sponges were most commonly found near outlets of lakes, attached to sides or undersides of submerged rocks and logs. They appeared as encrusting (Em, Ef, Sl), lobate (Em), and fingerlike (Sl) growths, varying in color from light tan to green. Dimensions of the spicules varied greatly within each species and expanded previously recorded ranges. No factors limiting sponge distribution were identified, but ranges of conductivity (Em) and of silica (Em, Sl), calcium (Em), and magnesium (Em) concentrations were expanded beyond those reported previously.     

Ecology of Comandra umbellata (Santalaceae) in western Wyoming

Comandra umbellate is the alternate host of a hard pine canker rust disease induced by the fungus Cronartium comandrae . The occurrence and density of C. umbellata were recorded near lodgepole pine stands in the Wind River District, Shoshone National Forest, Wyoming. Comandra populations occurred most often on slopes with southern aspects, particularly southwestern, and on steep slopes; these sites tended to be dry and relatively open. Comandra was also found growing under heavy perennial shrub canopy covers. It was most often associated with sagebrush but was common near other perennial shrubs as well. Overall, C. umbellata appeared to be a poor competitor with dense grass populations. Comandra was found primarily on Abies lasiocarpa/Juniperus communis, Pinusflexilis/ Hesperochloa kingii , and Artemisia tridentata/Festuca idahoensis habitats. No comandra was found in the Abies lasiocarpa/Vaccinium scoporium habitat.     

Records of the northern grasshopper mouse ( Onychomys leucogaster ) in western Iowa

In Iowa, the northern grasshopper mouse ( Onychomys leucogaster ) previously was known only from the northwestern part of the state. Herein, we report records of O. leucogaster from the 1970s and 1980s that extend its distribution into west-central and southwestern Iowa. These records may represent dispersal movements into these parts of Iowa by southward movements from populations in northwestern Iowa or they may represent eastward movements of individuals from Nebraska prior to channelization of the Missouri River.     

Dispersal of sagebrush-steppe seeds by the western harvester ant ( Pogonomyrmex occidentalis )

Like many seed-harvesting ants, the western harvester ant ( Pogonomyrmex occidentalis ) can act as both a predator and a seed disperser. Dispersal results when seeds are dropped en route to the nest, are left in nest granaries when colonies die or are abandoned, or are removed from granaries and discarded in nest middens. This study examined the density and species identity of seeds discarded in harvester ant nest middens and compared them with those found in nearby soils. Nineteen species of seeds were recovered from middens, compared with 13 species in 5-m reference areas and 9 species in adjacent disk areas. Total density of sound seeds was nearly 3 times higher in middens than at 5 m from the nest and nearly 50 times higher than in disk soils. Moreover, 4 of the 6 most common species overall were significantly more abundant in middens. One species, Munro globemallow ( Sphaeralcea munroana ), was recovered from nearly 50% of middens but was not found in the other 2 areas. These findings suggest that the western harvester ant is a potentially important disperser of some sagebrush-steppe plant species.     

Two new termite-eating Diores species (Araneae,Zodariidae) and some observations on unique prey immobilization

Two new taxa, Diores termitophagus n. sp. and D. magicus n. sp. are described. The species have been observed to prey on termites (Hodotermes mossambicus Hagen) and are assumed to be compulsory termite-eaters. Similar prey-specialization has recently been observed in other Diores species. Termites were observed to be immobilized and die after superficial contact with the spiders; only thereafter were they bitten and eaten.     

Range expansion of the western gray squirrel ( Sciurus griseus ) in northeastern California

We report the first records of the western gray squirrel ( Sciurus griseus ) from Modoc County and eastern Lassen County in northeastern California. Specimens from Modoc County represent the first records of the species from the Great Basin geographic province. We conclude that these records represent a range expansion based upon previous fieldwork that did not report the species in the region.