Unravelling unknown aspects of the biology of short-spined thrips

The arrival of the exotic pest Thrips parvispinus (Karny) to the continental US and South Florida has raised several questions about its biology. Several laboratory experiments were conducted in this study to evaluate the response of T. parvispinus to South Florida temperatures and cold fronts, reproduction mode, pupation site, and survival on different food sources. Life table parameters were used to calculate the developmental time and reproductive parameters of T. parvispinus when fed on beans (Phaseolus vulgaris L.). At the temperatures of 17, 22, 27 and 32 °C, this pest was able to develop and reproduce, but at 12 °C, eggs failed to hatch. The average annual temperature (27 °C) of South Florida provided the best conditions to develop and reproduce, with a life cycle of 12.77 ± 0.31 d and the highest intrinsic rate of increase. Thrips mortality increased significantly with exposure to low temperatures (5, 10 or 15 °C), reaching 100% at 5 °C after 5 d of exposure. Experiments also showed that in the absence of leaf tissue, T. parvispinus is less likely to survive more than 24 h and that it pupates in the soil at an average depth of 2.5 cm. Furthermore, reproductive biology bioassays indicated that the Florida T. parvispinus population reproduces through arrhenotokous parthenogenesis. These results address knowledge gaps regarding the T. parvispinus biology and its potential for expansion to new areas and provide the foundation for the development of an IPM program.