Unravelling unknown aspects of the biology of short-spined thrips

The arrival of the exotic pest <i>Thrips parvispinus</i> (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 <i>T. parvispinus</i> 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 <i>T. parvispinus</i> when fed on beans (<i>Phaseolus vulgaris</i> 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, <i>T. parvispinus</i> 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 <i>T. parvispinus</i> population reproduces through arrhenotokous parthenogenesis. These results address knowledge gaps regarding the <i>T. parvispinus</i> biology and its potential for expansion to new areas and provide the foundation for the development of an IPM program.