Diversity and host plant-use in North American Phytomyza holly leafminers (Diptera: Agromyzidae): colonization, divergence, and specificity in a host-associated radiation

Authors: Scheffer, Sonja; Lewis, Matthew; JACOBSEN, FRODE - Cornell College - Iowa

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2019
Publication Date: 10/27/2020
Citation: Scheffer, S.J., Lewis, M.L., Jacobsen, F. 2020. Diversity and host plant-use in North American Phytomyza holly leafminers (Diptera: Agromyzidae): colonization, divergence, and specificity in a host-associated radiation. Annals of the Entomological Society of America. 114(1):59-69.
DOI: https://doi.org/10.1093/aesa/saaa034

Interpretive Summary: Insects that feed on plants result in millions of dollars in crop losses and pest managements expenses. For horticultural crops, even a small amount of unsightly damage can be costly. Here we report on the geographic distributions and host plant affiliations of 12 species of leafmining flies attacking various combinations of 13 species of hollies including several important horticultural plants. This information will be of interest to horticulturalists, pest managers, and scientists.

Technical Abstract: Insects that feed on plants are widely used for studies of host-plant-associated speciation due to their diversity and tractability. The value of these studies necessarily depends upon an accurate understanding of the diet of the focal insects. In North America, the 12 Phytomyza Fallén (Diptera: Agromyzidae) leafmining fly species feeding on hollies (Ilex spp. (Aquifoliaceae: Ilex)) initially appeared to be primarily a host-plant-associated radiation of largely monophagous species. However, our increased collecting efforts found that a majority of the morphospecies are oligophagous, feeding on multiple Ilex species. Patterns of host-associations suggest that colonization of new hosts followed by host-associated speciation may be an important feature of diversification. Analyses of mitochondrial COI data in three oligophagous species found evidence of host-associated genetic structure consistent with processes of host-associated divergence. However, in one of these species, evidence of geographic divergence as well as host-associated divergence was detected, illustrating complexity in factors relating to speciation and host-use evolution in this radiation of leafmining flies.