Lygus hesperus Knight (Hemiptera: Miridae) and Daucus carota L. (Umbelliflorae: Umbelliflerae): An Example of Relationships Between a Polyphagous Insect and One of Its Plant Hosts) 1

Abstract

The relationships between a plant bug, Lygus hesperrts Knight (Hemiptera: Miridae), and carrot, Daucus carota L. (Umbelliflorae: Umbellit1erae), arc examined as an example of interaction between a polyphagous insect and one of its host plants. Seed exposed ro L. llespem.1· feeding m:1y have signiticantly more indole acetic acid and a wound-induced chemical stored in the seed. Feeding of the herbivore reduces seed yield and germination and slows genninarion and early shoot growth. but accelerates subsequent plant growth. The resultant plants and roots are heavier. Some of these plants may exhibit a virus-like foliage disorder or premature bolting. The insect may pollinate carrot and be predaceous on soft-bodied insects harmful to the plant. Carrot umbels provide food and shelter for the lygus bugs. However. antibiosis is present in some plants and can be increased by selective inbreeding. This insect and plant have an intricate relationship even though they probably have been in contact less than 300 years. Each is benefilled and harmed, but neither is dependent on the other for survival. Many