When one species is understood regarding distribution, abundance, and population dynamics, it is essential to test for the generality of the patterns discovered. “Study major, broad, repeatable patterns”; in nature, admonished Tilman (1989, p. 90). “Because the purpose of ecology is to understand the causes of patterns in nature, we should start by studying the largest, most general, and most repeatable patterns.” However, discovering broad repeatable patterns in nature offers a serious challenge, one that we have investigated for the last 15 years. In this chapter we discuss species related to Euura lasiolepis that have been studied by our research group. All are members of the common sawfly Family Tenthredinidae in the Order Hymenoptera. They form the focal group in which the patterns found for Euura lasiolepis are most likely to be repeated. And, if theory is the mechanistic explanation of broad patterns in nature, then finding such patterns in the family of common sawflies would provide the basis for theory. We have already described the mechanistic basis of pattern in distribution, abundance, and population dynamics in Euura lasiolepis. Do these patterns and mechanisms hold for a broad range of related species?

The family Tenthredinidae is composed mostly of free-feeding sawflies, but includes several gall-inducing genera and a few stem borers, leaf miners, fruit feeders, and catkin feeders (Table 5.1).