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Copyright © 2001 by The Resilience Alliance
The following is the established format for referencing this article:
Kearns, C. A. 2001. North American dipteran pollinators: assessing their value and conservation status. Conservation Ecology 5(1): 5. [online] URL: http://www.consecol.org/vol5/iss1/art5/
Synthesis, part of Special Feature on Pollinator Decline North American Dipteran Pollinators: Assessing Their Value and Conservation Status Carol Ann Kearns
University of Colorado at Boulder
Recent attention to pollinator declines has focused largely on bees and vertebrates. However, few pollination systems are obligate, and pollinators that complement the role of bees may respond differently to environmental disturbance. The conservation status of North American fly pollinators remains undocumented. In this paper, methods for monitoring shifts in dipteran pollinator abundance are discussed. The need for further basic research into pollination by flies is addressed, and the significance of dipteran conservation is considered.
KEY WORDS: anthophilous flies, anthropogenic disturbance, conservation, Diptera, Dipteran conservation, generalist pollinators, North America, pollination, pollinator declines, population fluctuation, redundant pollination systems.
Published: April 5, 2001
Anthropogenic disruption of pollination systems will likely pose consequences to plant and pollinator diversity, and to linked organisms within communities (Kearns et al. 1998). Although attention is often focused on bees and vertebrate pollinators (Williams 1986, Gauld et al. 1990, Torchio 1990, Day 1991, Osborne et al. 1991, La Salle and Gauld 1993, Batra 1995, Buchmann and Nabhan 1996, Matheson et al. 1996, Watanabe 1994; Migratory pollinators and their corridors), other groups of insect pollinators play roles that are not thoroughly understood. Few pollination systems are obligate, and pollinators that complement the role of bees may respond differently to environmental disturbance. The value of North American fly pollinators is not thoroughly understood, and concerns relating to pollinator declines in North America have not extended to dipteran pollinators. In this paper, methods for monitoring shifts in dipteran pollinator abundance are discussed. The need for further basic research into fly pollination is addressed, and the significance of dipteran conservation is considered.
Dipterans are among the most common insects that visit flowers. At least 71 dipteran families contain anthophilous species (Larson et al. 2001). Flies have been mentioned as pollinators or regular visitors of at least 555 species of flowering plant (Larson et al. 2001) and pollinators of over 100 cultivated plants including cacao, mango, cashew, tea, and onions (B. M. H. Larson, D. W. Inouye, and P. G. Kevan, unpublished manuscript). Many families of North American flies contain pollinators. Some of the larger, more notable pollinating flies belong to the families Bombyliidae, Syrphidae, Anthomyiidae, Tachinidae, Calliphoridae, and Muscidae. Small nematoceran fly pollinators include, but are not restricted to, the Bibionidae, Chironomidae, Culicidae, Empididae, Mycetophilidae, and Cecidomyiidae (Kevan and Baker 1983).
Anthophilous flies are diverse, ranging from opportunistic nectar and pollen consumers to specialized nectarivores. Fly proboscides range from a few millimeters up to 70 mm in length in a South African nectarivorous, nemestrinid fly (Manning and Goldblatt 1995). In a distinct syndrome called sapromyophily, certain flies (e.g., Calliphoridae) are deceived into pollinating flowers that produce odors of decay and mimic the decaying flesh in which these flies normally oviposit. The diversity of forms of flower-visiting flies is great; consequently, flies vary significantly in the amount of pollen that they carry, in the time that they spend in flowers, and in their effectiveness as pollinators (B. M. H. Larson, D. W. Inouye, and P. G. Kevan, unpublished manuscript).
Some of the many antho