Different egg size in the chrysanthemum lace bug Corythucha marmorata (Hemiptera: Tingidae) in response to novel host plant cultivars

The chrysanthemum lace bug Corythucha marmorata (Uhler) (Hemiptera: Tingidae) is a North American insect that has become invasive in Japan. While it exclusively feeds on Asteraceae plants in its origin, it has been reported to attack sweet potato, blue daze, eggplant, and pepino in Japan. This study assessed the preferences of C. marmorata on sweet potato cultivars in a field and explored ovipositional responses in the laboratory, i.e., pre-oviposition periods, number of eggs, and egg sizes. A 2-year field survey demonstrated that Caroline Lea, Kyukei 17-3028, and Benisengan were the most preferred cultivars based on adults captured. In the laboratory, females laid a significantly larger number of eggs and had shorter pre-oviposition periods on sweet potato cultivars such as Benisengan and Caroline Lea. When categorized into early- and late-laid egg periods, it was found that females on less preferred cultivars (e.g., Beniazuma) produced significantly larger late-laid eggs compared to females on preferred goldenrod or Benisengan cultivars. It was suggested that sweet potato cultivars with inferior nutritive qualities may encourage C. marmorata females to better provide for their eggs. Thus, host plant quality affected C. marmorata female performance which may, in turn, affect progeny survival and viability.