Specific Mining Pattern as a Result of Selective Feeding Within a Leaf by the Dipteran Leafminer Ophiomyia maura (Diptera: Agromyzidae)

Abstract

Abstract Leaf mines exhibit complicated patterns with crosses and branch structures. Mining patterns are hypothesized to be a result of selective feeding on leaf areas that are nutritionally rich or that are poor in chemical and structural defenses (the selective feeding hypothesis). The hypothesis was tested using the leafminer Ophiomyia maura Meigen (Diptera: Agromyzidae) by examining leaf anatomy and nutritional content of the host plant Aster microcephalus (Miq.) Franch. et Savat. variety ovatus (Franch. et Savat.) Soejima et Mot. Ito (Asteraceae). O. maura shows a specific mining pattern by preferentially mining the marginal part of the leaf. Cross sections of mined leaves revealed that O. maura consumed a layer of palisade parenchyma cells. The mining site of O. maura was limited to a particular area by the midrib and lateral veins, but not by minor veins, because midrib and lateral veins have well developed parenchyma cells around the vascular bundles and interrupted the palisade layer. By mining at the marginal part of the leaf, O. maura avoided the midrib and lateral veins, or pinnate venation of A. microcephalus. The nitrogen content of the marginal part of the leaf was higher than that of the inner part of the leaf, which also contributed to O. maura mining the marginal part of the leaf. The specific mining pattern of O. maura demonstrated that the leafminer could have developed an adaptive life-history strategy by responding in a most efficient manner to the arrangement of veins and the nutritional variability even at a within-leaf scale, following the selective feeding hypothesis.