Myoporum Thrips Life History, Host Preference, and Biological Control
Temperature-driven development of myoporum thrips, Klambothrips myopori, (Thysanopetra: Phlaeothripidae) was examined at seven constant temperatures (15°, 17°, 20°, 25°, 30°, 34°, and 35.5° C) on Myoporum laetum. Thrips successfully completed development to adult stage between 15 and 35.5°C. One linear and three nonlinear models were fitted to describe developmental rates of K. myopori as a function of temperature, and for estimating thermal constants and bioclimatic thresholds (Tmin, Topt and Tmax). The Briere-1 model performed best in describing the developmental rate of cumulative life stages.
Two ecological niche models, CLIMEX and Maxent, were used to predict the geographic distribution of K. myopori in its native range and globally. Overall predictions of environmental suitability differed greatly across models. The CLIMEX model accurately predicted known invasive and native localities, while the Maxent model failed to predict the native localities and parts of the invasive range. Based on the CLIMEX model, K. myopori has the potential to establish in many regions of the globe.
Using field studies and laboratory feeding tests, we identified Myoporum laetum and M. ‘Pacificum’ as key host plants of K. myopori. In laboratory trials, K. myopori failed to complete development on M. ‘Clean n Green’ and M. ‘Putah Creek’. For the six varieties of Myoporum tested, K. myopori damage was only observed on M. laetum and M. ‘Pacificum’. Although K. myopori can successfully colonize and reproduce on several varieties of Myoporum, they demonstrated a preference for M. laetum and M. ‘Pacificum’ in laboratory and field trials.
Using field and laboratory studies, we identified Orius spp. (Hemiptera: Anthocoridae): Chrysoperla spp. (Neuroptera: Chrysopidae): Syrphidae: and Salticidae as possible key natural enemies of K. myopori in southern California. Laboratory studies determined the consumption rates of Orius insidiosus and Chrysoperla rufilabris at constant densities of K. myopori and defined the functional response of the predators. Both predators consumed more 2nd instar larvae than other prey stages. O. insidious displayed a type II functional response, while C. rufilabris displayed both type II and type III depending on prey stage, implying the predators should be most effective at suppressing thrips populations at lower densities.