Richard W. Rust

A Phylogenetic Analysis of Nesting Behavior in the Genus Osmia (Hymenoptera: Megachilidae)

Abstract Cladistic analysis is used to study the evolution of 29 biological characters related to nesting behavior, nest provisioning, oviposition, cocoon spinning, defecation, and life cycle (nest characters) in 11 species of Osmia bees (Hymenoptera: Megachilidae) and two outgroup genera. A molecular phylogeny based on 38 allozyme loci-as-characters and a combined character phylogeny are produced to compare with the nest character phylogeny. All phylogenetic trees support the monophyly of the genus Osmia and the subgenus Osmia (Osmia) with Osmia ribifloris Cockerell basal to the other species in this subgenus. The subgenus Helicosmia (=Chalcosmia) is resolved as a sister clade to O. (Osmia) in the molecular tree and as sister to the subgenus Cephalosmia in the nest character and combined trees. Incomplete biological information from additional species of all three subgenera is provided to support the consistency of nest characters at the subgeneric level and their use in the establishment of subgeneric phylogenies in the family Megachilidae.

Nesting Biology and Foraging Ecology of the Wood-boring Bee Lithurgus chrysurus (Hymenoptera: Megachilidae)

Abstract The biology of the wood-boring bee Lithurgus chrysurus Fonscolombe, 1834 is described and the biology of the genus Lithurgus is summarized. Lithurgus chrysurus is univoltine and over-winter as prepupae inside cocoons. The females excavate their own burrows in various dead woods and they do not reuse burrows. The cells are separated by partitions composed of cut wood pieces. To assess the diet breadth of L. chrysurus, pollen analyses were conducted on 8 samples of provisions from 3 nests and 2 feces samples from one nest. The provisions averaged 30,600 pollen grains per mg of dry matter. The proportion of broken pollen grains averaged 3.3% and was consistent among nests and for provisions and feces. Centaurea (Asteraceae, tribe Cynareae) was the dominant pollen type found in all provisions and feces, accounting for 98.0 to 99.9% of the pollen based on the number of grains. This proportion was similar among nests for both provisions and feces. These results indicate that, at the study site, L. chrysurus was strictly oligolectic on Centaurea pollen while nectar was probably collected on other plant species as well.

Bee associates of flowering Astragalus and Onobrychis germplasm accessions in eastern Washington

Abstract A 3 yr survey of the bee associates of flowering accessions of Astragalus and Onobrychis species was conducted in open-pollinated field nurseries at Central Ferry, Washington to gain insight into the potential for bee-mediated inter-accession out-crossing in these nurseries. Such nurseries are used by genebank managers at the USDA-ARS Western Regional Plant Introduction Station (WRPIS), Pullman, Washington, to multiply seed of accessions low in viability and/or supply. Fifty-two species of bees (Hymenoptera) in the Andrenidae (4 species), Apidae (18), Colletidae (1), Halictidae (5), and Megachilidae (24) were recorded. Species-rich genera were Bombus (8 species) and Osmia (16). One undescribed species of Osmia was collected. The bee fauna was more diverse on Astragalus (45 bee species) compared to Onobrychis (29 species). Among the 24 Astragalus and 13 Onobrychis species censused, bee diversity was highest on A. bungeanus Boiss. (24 bee species), A. chaborasicus Boiss. & Hausskn. (24 species), A. miser var. serotinus (A. Gray ex J.G. Cooper) Barney (14 species), A. cicer L. (13 species), A. schistosus Boiss. & Hohen. (12 species), A. onobrychis L. (11 species), A. podolobus Boiss. & Hohen. (11 species), and Onobrychis viciifolia Scop. (10 species). The presence of a rich bee fauna in WRPIS nurseries at Central Ferry, including documented pollinators of the allogamous species A. cicer and O. viciifolia, could complicate efforts to prevent hybridization and maintain genetic integrity of genebank accessions of allogamous plant species. Our results support a 1993 decision by WRPIS curators to discontinue the practice of clustering accessions of single species of Astragalus and Onobrychis in open-pollinated nurseries to regenerate seed.

Thermopsis thermophila n. gen. n. sp. from hot springs in Nevada, U.S.A. (Crustacea, Ostracoda)

Thermopsis thermophila n. gen. n. sp., a new freshwater ostracod species is described from hot springs in Nevada, U.S.A. The animals were collected within a temperature range of 40–55 °C. The new genus belongs to the Ostracoda Podocopida Cypridoidea Cyprididae Cypridopsinae.

Nested Coleoptera and Orthoptera on sand dunes in the Basin and Range Province of western North America

The sand dunes of the Basin and Range Province of western North America contain obligate and endemic species of Coleoptera and Orthoptera. These dune habitats represent islands on which the isolated insular faunas are in a state of relaxation. The calculated ‘temperature’ metric used in this study reflects the relative measure of disorder, by which the degree of nestedness can be determined. Sixteen dunes in the Basin and Range Province are shown to comprise a nested subset of obligate Coleoptera and Orthoptera. These sixteen sand dunes remain nested even when the endemic species are excluded from the analysis. The absence of endemic species slightly decreased the calculated ‘temperature’ of the island-dune archipelago. Therefore, endemic species present in the sand dunes do not significantly contribute to the high degree of nestedness of dune obligate Coleoptera and Orthoptera in the Basin and Range Province. The dunes can also be separated into five distinct sub-basins, two of which contain only one sand dune. These sub-basins are not significantly nested, but together define the nested structure of the Basin and Range Province.

Emergence patterns in the alkali bee, Nomia melanderi Cockerell 1906 (Hymenoptera: Halictidae): laboratory versus field

The development and adult emergence patterns of the alkali bee, Nomia melanderi Cockerell 1906, from diapausing prepupae for both laboratory and field reared individuals are compared. Males from both rearing conditions emerged approximately four days before females. Laboratory reared males began to pupate after 800 cumulative degrees centigrade (cdc) and 50 percent had pupated when 1200 cdc was reached. Female pupation began about 900 cdc and 50 percent had pupated when 1300 cdc was reached. Both male and females continued to pupate up to 1800 cdc. The field pupation rate was linear and did not show the sigmoid curve of the laboratory pupation rate. However, 50% pupation for both field and laboratory reared alkali bees was approximately the same at 1300 cdc.

Latitudinal Variation in the Size and Developmental Parameters of the Alkali Bee, Nomia melanderi (Hymenoptera: Halictidae)

Abstract Latitudinal variation in body size, over-wintering emergence time and weight loss during development in the alkali bee, Nomia melanderi Cockerell, were studied in individuals from 24 populations in the western United States when reared under controlled laboratory conditions. Individuals from northern latitude sites were significantly heavier and took less time to develop to adults, but lost comparable weight during the developmental process.

Biology of Nomioides variegatus (Olivier) (Hymenoptera: Halictidae)

Abstract The nesting biology, life history and pollen foraging of the minute Nomioides variegatus (Olivier) is described and illustrated. All Nomioides biological studies are reviewed. Nesting and foraging were observed over two years in a sandy natural area in the Rhône River delta region of southern France. Nest and cell structure was obtained from soil blocks removed from the nesting area and examined in the laboratory. Females, which were on average only 4.2 mm long, nested solitarily in loose aggregations in areas free of vegetation. Cells were placed from 6 to 12 cm deep, each terminating a lateral burrow off the main burrow. Cell walls were lined with a water proof wax-like lining. The pollen-nectar provision was a flattened sphere. The posterior end of the egg was embedded on the dorsal surface of the provision. Larval and pupal development was rapid, proceeding to adults by August, the over-wintering stage. Pollen foraging patterns were analyzed from both pollen provisions and fecal material for different nests (3) and cells (8). Nomioides variegatus is polylectic, but individuals bees exhibited a high degree of foraging consistency for the provisioning of single cells. Eleven different pollen types representing 10 plant families were found. In 1996, Ecballium elaterium (Cucurbitaceae) was the dominant pollen present in all samples but it was absent in 1997. Tamarix gallica (Tamaricaeae) was the dominant pollen type in 1997 and absent in 1996. A third pollen, Centaurium (Gentianaceae) was present in both years and represented 70% of some samples.

Resurrecting the Bee Osmia aglaia Sandhouse from Synonymy (Hymenoptera: Apiformes: Megachilidae)

Abstract The western US bee Osmia aglaia Sandhouse is resurrected from synonymy with O. laeta Sandhouse. Confusion resulted from errors in paratype identification, which are herein corrected. New distinguishing morphological characters are provided that justify the specific status of O. aglaia.