Author
Brianna M Foster
fostermbri@gmail.com
University of Florida
Fort Lauderdale
Coauthors
Jorge Leidi, USDA-ARS IPRL, Fort Lauderdale, FL
Allen Dray, USDA-ARS IPRL, Fort Lauderdale, FL
Dale Halbritter, USDA-ARS IPRL, Fort Lauderdale, FL
Abstract
The biological control agent Pseudophilothrips ichini (Hood) (Thysanoptera: Phlaeothripidae), native to Brasil, has been released in Florida since 2019 to manage the invasive shrub Brazilian peppertree (Schinus terebinthifolia Raddi). While P. ichini has successfully established at several sites, populations often decline during the summer months, suggesting that high temperatures may hinder persistence. Such maladaptation can be particularly consequential in haplodiploid insects, where unfavourable conditions may skew sex ratios, limiting long-term field efficacy. To assess thermal and population level responses, we compared three P. ichini populations with distinct genetic backgrounds: (1) the Minas Gerais population, currently established; (2) the Bahia population (in quarantine since 2022); and (3) hybrids produced through crosses of Minas Gerais and Bahia individuals. Each population was reared under two environmental chamber conditions: a high summer-relevant temperature (24-32 °C daily oscillations) and a standard laboratory temperature (24 °C). We measured performance based on offspring production, sex ratio, morphological metrics, and damage to the target plant. This design allowed us to test whether geographic origin of a population influences heat tolerance and whether hybridization alters performance either generally or in response to temperature. Our findings will clarify whether alternative populations or hybrids offer advantages under Florida summer conditions.
Keywords
Pseudophilothrips ichini
Brazilian peppertree
Thermal tolerance
Population performance
Highlights
Do differing Pseudophilothrips ichini populations vary in heat tolerance?
Does hybridization alter performance under thermal stress?
Does population origin help predict biocontrol success?