Boyd Deep Canyon Desert Research Center

22 May, 06 AM - 24 May, 03 AM

Many Hymenoptera (wasps, bees, and ants) have diversified in the deserts of North America forming a unique fauna. New World bees, for example, reach their highest diversity in the deserts of North America and Mexico (Michener 2000; Moldenke 1979). Another example is the wasp family Mutillidae (velvet ants), which has many arid-adapted genera, such as Dasymutilla, Odontophotopsis, and Sphaeropthalma, that have diversified extensively in the arid lands of North America. Velvet ants are solitary parasitic wasps that parasitize the larvae or pupae of other wasps and bees. While some velvet ant species are widespread throughout all of North America?s deserts, many are restricted to specific deserts or even specific portions of a desert. Dilophotopsis stenognatha, for instance, is a large nocturnal velvet ant that is only found in the eastern Sonoran Desert (Schuster, 1958). Many of the Western states contain desert or arid environments. California, however, is unique in that it contains portions of three of the four North American deserts and is home to more than 120 species of velvet ants. This wide array of habitats enabled southern California?s velvet ants to develop into a unique and diverse fauna, including numerous endemic taxa. California?s varied geologic history undoubtedly added to the velvet ant diversity and endemism found in its deserts. Throughout the Pleistocene, many areas in southern California maintained desert-like characteristics, while the remaining western North America was overtaken by cool mesic woodlands (Elias et al. 1992; Koehler et al. 2005). The high number of velvet ant taxa that are endemic to areas of southern California can likely be attributed to these Pleistocene refugia. For species that have disbursed since the Pleistocene, the Pleistocene climatic cycles? effects on the genetic population structure of these species can be observed using molecular techniques. The effects should be especially prevalent in southern California. Preliminary data for two species, Sphaeropthalma unicolor and S. difficilis, have shown significant genetic differences between sites in the Costal Sage and Chaparral region (Bautista Canyon) and sites in the Mojave Desert (Afton Canyon). The San Jacinto Mountains may be the barrier separating velvet ant populations. Similar phylogeographic patterns likely exist across many parts of southern California largely due to the varied topography of the area and its diverse geologic history. Furthermore, endemic velvet ants can be found in areas scattered throughout southern California. This study will focus on four areas that are known to have or are likely to have some endemic species and that will also yield specimens of more widespread taxa needed to do molecular population studies. These areas are the Algodones Sand Dune, Deep Canyon, Owens Lake Valley, and the Cadiz Dune Wilderness. The Algodones Sand Dune in Imperial County, for example, is home to at least three endemic velvet ant species. Dasymutilla imperialis, which is only known from six specimens, is found exclusively in the Algodones Dunes (Manley & Pitts 2004). Odontophotopsis villosa and Sphaeropthalma ecarinata are also largely restricted to the Algodones Sand Dunes (J.P. Pitts pers. comm.). The females of all three of these species are unknown. These dune areas, and others like it, are threatened by intense recreational-vehicle use (Luckenbach & Bury 1983). Another area that supports endemic velvet ant species is Deep Canyon, which is located approximately 8 km south of Palm Desert in Riverside County. Because of the unique biota found in this canyon, the Boyd Deep Canyon Desert Research Center was set up as part of the University of California Natural Reserve System. Based on collections made in the 1950?s, two undescribed Sphaeropthalma species, which are known from males only, have been collected in this area (J.P. Pitts pers. comm.); both species are likely restricted to Deep Canyon and its tributaries. Owens Lake Valley, located in Inyo County, is well known for its role in the California water wars. Increased urbanization of many areas in southern California has threatened the biota of this valley by depleting the ground water that supports the desert flora (Sorenson 1991). Owens Lake valley is home to one particularly interesting endemic velvet ant. This undescribed Sphaeropthalma species is only known from a limited number of wingless males and is likely the only species of velvet ant in North America that has males that are completely wingless. This species appears to be closely related to one of the undescribed species from Deep Canyon (J.P. Pitts pers. comm.) The female of this species is unknown. An additional area of interest is the Cadiz Dune Wilderness, located 65 km east of Twenty Nine Palms in San Bernardino County. This dune system was designated wilderness in 1994 because of its relative pristine nature and its rich flora. While no velvet ant collections have been made in this wilderness, a rich velvet ant fauna likely exists there because of the pristine state of the dunes. None of the aforementioned areas have been systematically sampled for velvet ants using light traps. All of the known specimens of the endemic species were collected using collecting methods that were targeting flying or crawling insects (i.e., pitfall traps and flight intercept traps) that rely on chance encounters. Many velvet ants, particularly the nocturnal taxa such as Odontophotopsis and Sphaeropthalma, can easily be collected at night using a florescent lantern and bowls filled with soapy water (Ferguson 1967). This method can easily collect over 100 males in an hour giving a truer representation of local velvet ant diversity compared to other methods (pers. obs.). Additionally, the use of florescent lanterns can aid in the collection of the females because they are attracted to the light also. A limited number of specimens are available from these sites from California museums. Pitts (pers. comm.) is preparing a taxonomic revision of the nocturnal velvet ant fauna of the North and Central America. He has studied over 10,000 specimens from California Academy of Science, California State University, Northridge, Chico State, Fresno County Department of Agriculture, Los Angeles County Museum, UC Berkeley, UC Davis, UC Riverside, and UC Santa Barbara. There are a limited number of male and, for some areas, female specimens from southern California. There are many female specimens from Owens Lake Valley (~50) and the Algodones Sand Dunes (~100), but few male specimens. There are few male specimens from Deep Canyon and Cadiz Sand Dune including two endemic species from Deep Canyon, but no female specimens. Most of these specimens were collected in the 1960?s and 1970?s and are, therefore, useless for molecular analyses. Fresh specimens will be necessary for molecular sex associations. This project has three primary objectives based on obtaining new specimens from southern California: 1) obtaining fresh specimens for molecular population studies to determine the effects of Pleistocene climatic cycles on widespread taxa; 2) obtaining fresh specimens for molecular sex associations; and 3) obtaining distributional data for nocturnal velvet ants to help in our understanding of the extent of endemism and for identifying areas of high velvet ant diversity. In order to gain an understanding of the extent of endemism, and the diversity of southern California velvet ants, we will conduct a survey focusing on four areas that house unique and diverse velvet ant populations. Collections will be made using techniques that have been effective in the collection of velvet ants (i.e., florescent lantern traps, black light traps, & hand collecting). Specimens will be collected directly into 95% ethanol to preserve DNA for molecular analyses, and will be sorted to species, and stored at the insect collection at Utah State University in Logan, Utah. Numbers of specimens and species will be compared across all sample sites. Genetic differences between populations of widespread species will be assessed using two nuclear genes, the rDNA internal transcribed spacer regions one and two (ITS1 & ITS2). These genes have been informative in discovering genetically isolated populations of velvet ants. Due to the extreme sexual dimorphism that is present in velvet ants, most of the nocturnal velvet ants (92%) are know from the easily-collected male only. We will make great efforts to collect both sexes of all taxa, including the endemic species. Sequences of rDNA internal transcribed spacer regions one and two (ITS1 & ITS2) will be used to make sex associations as proposed by Pilgrim & Pitts (2006) by comparing individuals from a given locality. The associated females will provide valuable information for future morphological phylogenetic and taxonomic studies. All collecting locations will be marked with a GPS unit. Collection sites and diversity and endemism data will be mapped using ArcView? 9.2, so accurate comparisons of species distributions and accepted desert boundaries can be made. Additional maps will be made comparing the boundaries of genetically distinct velvet and populations with desert boundaries and topography so an understanding of the mechanisms causing the genetic isolation can be obtained. To keep costs to a minimum, yet sample from both the early season fauna and the late season fauna, two week long collections will be made, one in early June, and one in late July. Collections will be focused on the four areas of interest previously discussed. Additional opportunistic collections made in areas between these four areas. This research would have the added benefit of aiding on-going nocturnal velvet ant systematics research in our lab. The specimens derived from this study would help complete revisions of the nocturnal velvet ant genera, and provide DNA for on-going molecular phylogenetic studies. The results of our study (population genetics/biogeographical data, new distributional data, new species, and sex associations) will be published in peer-reviewed journals. This study will give useful data necessary to complete a Bulletin of the California Insect Survey (University of California Publications) on the velvet ants of California and also to complete a publication on the female nocturnal velvet ants of the Algadones Sand Dunes, which has already been initiated. Because all previous collections of velvet ants, except Hurd (1951), used inefficient collection techniques, this focused study will likely uncover more endemic taxa, more areas of high diversity, provide fresh specimens necessary for phylogenetic, phylogeographic, and revisionary studies, and will likely reveal the unknown females of many of the endemic species, as well as the unknown females of other species. The results of this study will add a great deal to conservation efforts focusing on the deserts of southern California and will add greatly to the impact of my dissertation research.

Visit #12215 @Boyd Deep Canyon Desert Research Center

Approved

Under Project # 8003 | Research

Velvet and Endemism

graduate_student - Utah State University

Reservation Members(s)

Group of 2 Graduate Student May 22 - 24, 2007 (3 days)
Joseph Wilson May 22 - 24, 2007 (3 days)

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Mayhew housing facilities 3 May 22 - 24, 2007