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

Abstract

• In wing-polyphenic insects, crowding generally promotes to macropter production. • Female of F. fusca exhibits wing diphenism governed by environmental conditions . • Effect of larval density on wing form determination was detected by rearing trials. • Percentage of female macropters decreased as larval density increased. • Developmental time and body length did not differ between two wing morphs. 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.