How well can relative specialist Rhagoletis flies learn to discriminate fruit for oviposition?

We show that blueberry maggot females [Rhagoletis mendax (Curran)], apple maggot females [Rhagoletis pomonella (Walsh)], and walnut husk fly females [Rhagoletis suavis (Loew)], all relative specialists in range of fruit species attacked in nature, are able to learn to discriminate between types of fruit in which they oviposit. It appears, however, that these relative specialists express less capacity to learn fruit characters than relative generalist tephritids. This difference in expression of learning ability may be associated in part with differences in assignments species are asked to learn. Apparent differences in learning capability between relative specialist and relative generalist tephritids may therefore depend as much upon differences in the physical and chemical nature of host fruit as upon species differences in the adaptive value of learning.