Effects of Crowding and Host Plant Nutrition on a Wing‐Dimorphic Planthopper

Abstract
We investigated the effects of crowding and host plant nutrition on the development time and body length (a correlate of fecundity) of Prokelisia marginata, a wing—dimorphic planthopper that feeds on the phloem sap of the intertidal marsh grass Spartina alterniflora. Crowding delayed development time for males and females of both volant macropters and flightless brachypters; however, host plant nutrition did not affect development time. The body length of both sexes increased when they were raised on nutritionally superior hosts, but the nutritional effect on body size was greater for females than males. Body length exhibited a significant crowding x plant nutrition interaction; crowding had a greater reducing effect on body length if planthoppers were raised on marginal—quality hosts than on nutritionally superior hosts. These findings are discussed in the context of the performance, population dynamics, and migration behavior of P. marginata in its various habitats.