J. HYM. RES. Vol. 16(2), 2007, pp. 266-276 Multivoltinism and Usage of Multiple Nest Substrates in a West Texas Sand Dune Population of Pseudomasaris phaceliae Rohwer (Hymenoptera: Vespidae: Masarinae) John L. Neff and Allan W. Hook (JLN) Central Texas Melittological Institute, 7307 Running Rope, Austin, Texas 78731, USA; email:
[email protected] (AWH) Department of Biology, St. Edward's University, Austin, Texas 78704-6489, USA; email:
[email protected] Abstract. — A west Texas population of Pseudomasaris phaceliae was found to be multivoltine and active from April to September. Unlike previous reports of nests constructed only on stones, nests were commonly constructed on the stems and infructescences of its host plant, Phacelia integrifolia. Emergence data indicated the primary sex ratio is strongly female biased (53:14). Nest parasitism was rare, but predation was common. Data on nest architecture, nest construction, and foraging behavior are presented. Pseudomasaris is the only North Ameri-phaceliae, like most other Pseudomasaris can genus of the Masarinae, a relatively species, constructs its nests on stones small (300+ spp.) but widespread clade of (Parker 1967, Torchio 1970), we found that pollen and nectar provisioning vespid at Monahans, P. phaceliae was commonly wasps (Carpenter 1982, 2001, Gess 1996). attaching its nests to plant stems, and only Torchio (1970) reported in considerable rarely to stones. In addition, P. phaceliae, detail on the biology of Pseudomasaris like most other temperate masarine spe-edwardsii (Cresson) but little is known of cies, had previously been assumed to be the biology of the remaining 14 species, univoltine (Parker 1967, Gess 1996), but Brief reports on nest structure and /or nest wasps emerged in early July from a nest sites have been published for eight of these collected during June suggesting multi-species, including Pseudomasaris phaceliae voltinism. This prompted a series of visits Rohwer, but only floral records are avail-to this site to gather additional information able for four other species, and nothing at on the nests and behavior. Follow-up trips all has been published on the biology of the were made in July, August, and September remaining two. 2005 and April, May, June, and August During a brief visit to Monahans Sand-2006. hills State Park in June 2005, we encoun-Habitat. — Monahans Sandhills State Park tered a large population of Pseudomasaris (32.128'N, 103.953 W) is located in Ward phaceliae visiting flowers of Phacelia integri-County, Texas on the southern edge of folia Torr. (Boraginaceae). Pseudomasaris a large dune field of quartz-rich Quaterna-phaceliae is an infrequently collected but ry sands that stretch northward into sometimes locally abundant species of the southeastern New Mexico (Machenberg arid American Southwest (Arizona, New 1984, Muhs 2001). While much of the dune Mexico, west Texas, and adjacent Mexico) field is partially stabilized by shin oak (Richards 1966, and pers. obs.). Although (Quercus havardii Rydb.) and other peren-previous reports had indicated that P. nials, large moving dunes are common in
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