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This chapter studies Coleopteran pests. The larvae of turfgrass-infesting species of the family Scarabaeidae constitute a large complex whose members (white grubs) are similar in general appearance, in habits, and in the turfgrass damage they cause. At least 10 species of scarabs, belonging to five subfamilies, are pests of turfgrass in the United States. The larvae of this family are known also as grubs, a term applied to the larvae of several Coleoptera (beetles) and Hymenoptera (ants, bees, and wasps) in general. Grubs of the Scarabaeidae are the most serious turfgrass pests in the northeastern United States, and are considered a major pest in the Midwest, Southeast, and parts of the southwestern United States. Their subterranean habits make them among the most difficult of turfgrass insects to manage.

Insects are diverse, abundant, and have numerous roles in rangeland ecosystems. More than 1600 species representing 238 families of insects have been recorded in the shortgrass steppe of northeastern Colorado (Kumar et al., 1976). Of this large assemblage, a much smaller subset—perhaps fewer than 50 species—is highly abundant with a large influence on community and ecosystem processes (Lauenroth and Milchunas, 1992). Even within abundant insect groups, such as grasshoppers, some species have far greater effects than others as herbivores (Capinera, 1987). In this chapter I consider a small number of insect groups that have various in) uences in shortgrass steppe ecosystems (Table 10.1). I focus on three insect taxa—grasshoppers, beetles, and ants—that are widespread, abundant, and ecologically important in semiarid environments. I also draw attention to neglected groups, such as termites and spiders, for their potentially important roles in the shortgrass steppe. My primary objective is to emphasize the linkages among insect populations, community interactions, and ecosystem function. From this approach stems several related issues: how population distributions affect community interactions, how population abundance affects the processing and redistribution of energy and nutrients in ecosystems, and how abundance and species diversity are important to the functional roles of species in ecosystems. I skirt issues of population regulation in insects, which are reviewed elsewhere (Cappuccino and Price, 1995), and instead consider how temporal and spatial patterns in insect populations relate to community and ecosystem processes. Understanding relationships among populations, communities, and ecosystems requires approaches that link patterns and processes across scales. Much of what is known about the roles of insects in the shortgrass steppe is based on studies conducted at relatively fine scales. To link insect population studies to community and ecosystem processes, however, I suggest that insect populations should also be studied across broader scales that encompass topographic variation. The rolling topography in the shortgrass steppe produces a gradient in soil texture, water availability, and nutrient retention from uplands to lowlands (Clark and Woodmansee, 1992; Schimel et al., 1985). Plant community structure also varies with topography in spatially repeating patterns across the landscape (Milchunas et al., 1989).

EDF was only a few months old with the DDT agitation still under way in Michigan when a phone call arrived from Lorrie Otto, an environmental leader in Milwaukee, Wisconsin (Fig. 4.1). Lorrie explained that DDT was to be used for attempted Dutch elm disease control in Milwaukee, and she wanted EDF to come to Wisconsin and stop it. She had been reading about our fireworks on Long Island and in Michigan and figured some of that might be good for Wisconsin. Other considerations were also favorable about Wisconsin. The use of DDT leads to contamination of meat, eggs, milk, and other dairy products, and the dairy industry is large and important in Wisconsin. Agriculture was therefore split in that state: One component wanted to use DDT on crops and trees, while the dairy industry wished to avoid DDT contamination of its products. Agriculture would not present a unified force on behalf of DDT, as it would in most states. The environmental movement was unusually strong in Wisconsin, and Lorrie Otto pledged to EDF the statewide support of the Citizens Natural Resources Association (CNRA). CNRA would raise money and provide all additional logistic support that might be necessary during whatever proceedings might develop. If EDF was going to make a difference on the national scene, this seemed like an invitation not to be refused. So here was an opportunity to stir up trouble again with an increase in complexity and confusion. On October 2, 1968, EDF filed a lawsuit in Federal Court in Milwaukee that was quite similar to the one filed nearly a year earlier in Michigan. It sought to block the Michigan Department of Agriculture (MDA) from applying dieldrin in Michigan against Japanese beetles (same case, same application as postponed last year) and to stop Milwaukee from spraying DDT on its elm trees. The allegations were the same: both DDT and dieldrin would kill nontarget birds and mammals, and both would threaten reproduction of the Coho salmon in Lake Michigan hatcheries.