Crowding leads to higher incidence of brachypterous females in the tobacco thrips,Frankliniella fusca (Hinds) (Thysanoptera: Thripidae)

The effects of larval density on the wing form determination of female tobacco thrips, Frankliniella fusca, were investigated by rearing thrips on leaf disks at 27.5 °C. The developmental period, head width, body length, and forewing length of individuals in each wing morph were determined to assess the relationships among larval density, growth, and wing form. Data showed that higher rearing densities increased the production of female F. fusca brachypters. There was no consistent difference in the mean developmental periods between the two wing morphs or among all 5 density treatments. The body length of females tended to decrease with increasing rearing density, but there was no significant difference in body size between the two wing morphs when they were reared under the same density level.