Bees of New York State
Table of Contents
	Conservation	Additional Resources

RESEARCH NEEDS

Only a handful of the 477 total species of bees occurring in New York State have been carefully studied. We know much about the host plant associations of the pollen-collecting bees and the host associations of the parasitic bees. However, nesting biology has been studied for only a few species. Particularly important groups are the social halictid bees (such as Halictus and Lasioglossum) and the ground-nesting, specialist bees (such as Andrena, Colletes, Melitta, Macropis, Ptilothrix, Peponapis, Svastra and Melissodes).

Parasitic bees (such as Sphecodes and Nomada) are poorly known. For example, no species of Sphecodes has been studied in detail, so we know very little about the mode of parasitism of this interesting group. We also need to know more about the population dynamics of native bees. For example, if conserving native bees is of importance, we need to know how population size fluctuates over time. Are native bee populations stable over long periods of time, or are they characterized by frequent local extinction and recolonization? Does habitat fragmentation (due either to agricultural or suburban development) adversely affect native bee populations? Is population growth and stability limited by the availability of nesting substrates, food, or possibly by parasite pressure? To what extent are native bee populations fragmented genetically? In a recent review of the population genetics of pollinating insects, Packer and Owen (2001) emphasized the importance of gene flow studies for evaluating the conservation status of potentially endangered pollinators. According to Packer and Owen (2001), there is not a single study of gene flow in a ground-nesting, solitary bee species-the vast majority of bee species in the world.

Finally, we need to know much more about the role of native bees in pollination of native and agricultural plants. Bees play an extremely important role in natural ecosystems through their service as pollinators of angiosperm plants. Based on estimates from 1985 data, honey bee pollination contributed $9.1 billion to the value of U.S. crop production in that year, or approximately 31% of the total value of crops produced (Robinson et al. 1989). This estimate is widely quoted to illustrate the importance of honey bees to U.S. agriculture. However, as pointed out by Torchio (1990) and Southwick and Southwick (1989, 1992), this estimate fails to distinguish the contribution of native, wild bees to the value of U.S. agriculture. Native bees (most species in North America excluding honey bees) play a very important but often overlooked role in U.S. agriculture. For example, in north temperate regions of Europe, wild bees visit 50% of the agricultural plants grown (Corbet et al. 1991; Osborne et al. 1991) and certainly play a role in pollination. Prescott and Allen (1986) list seven U.S. crops (cashew, mango, highbush blueberry, cranberry, squash, cacao, and cardamom) that have a combined annual value of $1.2 billion and are predominantly pollinated by wild bees. Parker et al. (1987) list a number of important U.S. crops that are visited by native wild bee species as well as honey bees. In fact, many of these crops, including alfalfa, apples, and other orchard crops, are pollinated more effectively by native and introduced solitary bees than by honey bees. For example, the most important pollinator of alfalfa in North America is an introduced solitary bee, Megachile rotundata. Furthermore, the importance of native wild bees to U.S. pollination is expected to increase over time (Torchio 1990) due to a number of threats to the honey bee industry, including Varroa mites, tracheal mites, and the introduction of African bees (Watanabe 1994). More attention should be paid to how to preserve native pollinators through conservation of habitats that provide nesting sites as well as food resources.

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