Feeding and oviposition performances of corn leafhopper (Dalbulus maidis) along maize’s evolutionary and domestication gradients

Feeding and oviposition performance of the corn leafhopper Dalbulus maidis (Hemiptera: Cicadellidae) were assessed in the 4^th to 5^th leaf of a suite of five taxa or genotypes representing the domestication and selection gradients of maize (Z. mays ssp. mays): 1 perennial teosinte (Zea diploperennis), 2 annual teosinte (Zea mays ssp. parviglumis), 1 Tuxpeno landrace maize, and a 1 Mexican commercial hybrid maize. Corn leafhopper is an economically important pest of maize and vector of maize pathogens, including Maize Rayado Fino Virus, Corn Stunt Spiroplasma, and Maize Bushy Stunt Phytoplasma. The performances of the leafhopper were assessed in terms of (i) number of honeydew droplets and oviposition events performed by the leafhopper during one hour, and determined through direct observation with the aid of a video camera; (ii) numbers of feeding scars and eggs found on leaves, as determined using McBride’s staining technique. At least 15 hours of observation were done per taxa/genotype, all the insects were adult females up to 7 days old.  The results of these experiments were compared with previously gathered data concerning leaf toughness, trait considered deterrent to oviposition and feeding. Altogether, our data contribute to understanding the role, if any, of physical antiherbivore defenses in corn leafhopper’s host range expansion from the wild relatives of maize to the crop following domestication ~9000 years ago.