Symphagy Among Florivorous Fruit Flies (Diptera: Tephritidae) in Southern California

Abstract

Symphagy, as used in this chapter, is the collective sharing of flower heads of a single host-plant species of Asteraceae by more than one species from one or more genera of nonfrugivorous fruit flies (Diptera: Tephritidae) (Goeden 1987, 1989, 1992, 1993, 1994). The manner in which this symphagy is achieved, e.g., whether by spatial or temporal partitionings of the resource that a host-species’ flower heads collectively represent (Zwölfer 1987, 1988; Zwölfer and Arnold-Rinehart 1993), is beyond the scope of this chapter and best examined at the individual tephritid and host plant species level (cf. Zwölfer 1965, 1982, 1987, 1988, 1990; Goeden and Ricker 1986, 1987; Headrick and Goeden 1990; Goeden and Headrick 1991, 1992; Goeden et al. 1994). This chapter describes and analyzes 14 years of data on symphagy among 15 genera of florivorous Tephritidae and 12 tribes of Asteraceae in southern California. This is the first comprehensive analysis of symphagy by a multigeneric grouping of geographically defined, nonfrugivorous, Nearctic fruit flies, and was inspired in part by Helmut Zwölfer’s comprehensive, long-term field and laboratory studies of the biology, ecology, and evolution of Tephritidae, and other Palearctic insect associates of asteraceous thistles and knapweeds (Zwölfer 1965, 1982, 1988, 1990). I dedicate this analysis of original data as a token of my admiration, respect, and friendship for Helmut on the occasion of his recent retirement from the Faculty of the University of Bayreuth.