none A laboratory colony of Lygus lineolaris (Palisot de Beauvois) from New Jersey that had been maintained for 6-7 yr showed a high degree of reproductive isolation from Arizona colonies that had been cultured 6-7 yrs and from Arizona and Delaware (USA) colonies that were recently started from field-collected individuals. This reproductive isolation correlated with differential susceptibility to Leiophron uniformis (Gahan), a braconid parasite of Lygus spp. nymphs, found in other research.