Showing papers in "Pan-pacific Entomologist in 1988"

Nesting biology of two North American species of Chelostoma, Hymenoptera: Megachilidae

Abstract: —Nests of Chelostoma phaceliae Michener and C. minutum Crawford are described for the first time. C. phaceliae nested in abandoned burrows that other insects bored in stems of elderberry (Sambucus). C. minutum nests were recovered from 2 mm diameter borings in trap blocks. Both species separated their cells and plugged the nest entrance with soil. Data on next architecture, provisions, cocoons, sex ratio, and nest associates are presented. Chalkbrood, a fungal disease of bees, killed 4.7% of the C. minutum larvae. Bees in the genus Chelostoma Latreille occur in both the old and new worlds, and their zoogeographical distribution includes the Holarctic and Oriental regions (Griswold 1985). Adults are small, non-metallic, and slender. Information on nesting biology is limited. Parker and Bohart (1966) noted C. phaceliae Michener was reared from trap-stems, Stephen et al. (1969) gave information on cell linings and material used in nest construction by C. minutum Crawford, and Eickwort (1981) discussed the biology of two adventive species now established in New York. In Europe, both of these latter species utilized beetle borings and one was reared from trap-stems (Bonelli 1967). Hurd (1979) reported that native North American Chelostoma were oligoleges of Hydrophyllaceae because of the numerous collections made from Phacelia and Eriodictyon flowers. This study presents more detailed data on the nesting biology of C. phaceliae and C. minutum, including nest architecture, factors affecting mortality of immatures, sex ratios, and identity of pollen used to provision cells. Methods and Materials Nests of C. phaceliae were obtained from stems removed from live plants of elderberry (Sambucus) that grew near the banks of the Truckee River north of Verdi, Nevada (Washoe Co.). The stems were collected during the winters of 1961-1964. Nest contents from such stems were recorded and individually placed in gelatin capsules and reared after a 2-month cold treatment at 5°C. In these earlier studies, placement of sexes within the nest and weight of the adults were not recorded. Nests of C. minutum were recovered from trap blocks placed at several sites in the mountains near Logan, Utah. At each site, 10 trap blocks (Fig. 1) with 5 layers of drilled wood (each layer had 10 holes, 2 each with diameter of 2, 4, 6, 8, and 10 mm

A new ant mimetic mirid from the Colorado tundra (Hemiptera: Miridae)

Abstract: In 1980, while examining a lot of ant mimetic Miridae kindly loaned to us by Dr. Joseph C. Schaffner ofTexasA&M University we came across two female specimens of an unusual Coquillettia species taken by Dr. Schaffner near Rollins Pass, Colorado. These females possessed small wing pads, a character state found in no other Coquillettia species except C. numata Bliven from California. Having no males at hand we hesitated to describe this new species, but the knowledge of its existence caused us to collect more carefully on the high tundra grasslands above timberline. In 1982 one of us (DAP) discovered this insect at over 3600 meters (approx. 12,000 ft.) on Mt. Goliath, a spur of the Mt. Evans massif west of Denver. Subsequent collecting at this locality produced a good series of both males and females, from which the species may now be described. We thank Dr. Schaffner for the generous loan of material held in the collections of TexasA&M University, College Station (TAM). Types are deposited in the United States National Museum of Natural History, Washington, D.C. (USNM). Paratypes are held in the above collections and in the J. T. Polhemus collection, Englewood, Colorado (JTPC). All measurements are in millimeters.