ABSTRACT

Fourth and fifth instars of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), were collected from wild hosts in the fall and reared in the laboratory to adults using their collection host as food. Adults were dissected when 7 d of age or older to determine whether they were reproductive or in diapause. Nymphs reared on pigweed, Amaranthus spp., goldenrod, Solidago altissima L., and white heath aster, Aster pilosus Willdenow, in October and early November 2002 produced adults which ranged from 48 to 80% in diapause. Adults from rearing nymphs on these same host species in October 2003 were mostly (>95%) in diapause. The lower percentages of adults in diapause found in 2002 were thought to be due to higher quality of host plants which resulted from excellent growing conditions (above average temperatures and rainfall). The percentage of adults in diapause produced on pinkweed, Polygonum pensylvanicum L., was consistently higher in both years compared to the percentages of adults in diapause found on the other hosts. Pinkweed grows primarily in wet areas in or near ditches and the quality of this host was probably less affected by temperature and rainfall than the other hosts studied. Reproductive females reared from all hosts in September had lower amounts of fat in reproductive females reared from these hosts in October and November. The fat content of the reproductive females reared in October and November was characteristic of adults in diapause, although their ovaries were expanded with mature or developing eggs and/or they were recently mated. The role that the reproductive females produced in October and November play in the adaptation of plant bugs to their winter habitat is unknown. Host plant species was found to influence the percentage of adult plant bugs which entered diapause in September through November in the mid-South, and host plant quality was probably another determining factor.