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Title: Prey preference of Orius insidiosus (Hemiptera: Anthocoridae) for species of Frankliniella flower thrips (Thysanoptera: Thripidae) in pepper flowers


Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 9/15/2007
Publication Date: 10/25/2007
Citation: Baez, I., Reitz, S.R., Funderburk, J.E. 2007. Prey preference of Orius insidiosus (Hemiptera: Anthocoridae) for species of Frankliniella flower thrips (Thysanoptera: Thripidae) in pepper flowers. In: Kairo, M.T.K., Barber, J.A., Lu, J., Gardner, C., editors. Proceedings of the CESTA 2007 Research Forum. p. 17-18.

Interpretive Summary: Because of their direct feeding damage and the ability of some species to transmit plant viruses, thrips are the most significant insect pests of vegetable crops in the southeastern USA. Biological control could become a sustainable alternative to chemical insecticides, which do not provide satisfactory control thrips. Yet little is known of how predators such as the insidious flower bug, Orius insidiosus, respond to different types of thrips prey. Therefore, scientists at the FAMU Branch of the Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL, and the North Florida Research and Education Center, Quincy, FL, conducted a series of experiments to examine the behavior of different thrips and how Orius interacts with these different thrips. Adult western flower thrips disperse less than adults of eastern flower thrips. The predator preferred immature to adult thrips. Despite differences in movement patterns of adults, Orius was able to capture similar numbers of western flower thrips and the more active eastern flower thrips. The ability of O. insidiosus to prey successfully on different life stages and species of thrips in complex environments indicates that it is an efficient predator of thrips and is an important biological control agent of these serious pests.

Technical Abstract: Laboratory studies were conducted to determine prey preference of O. insidiosus between Frankliniella occidentalis and F. tritici, and between adult and 2nd instar of F. occidentalis in pepper flowers. Corresponding studies were conducted to determine the distribution of these thrips in the absence of the predator. For each experiment, two densities of thrips (10 and 20 total thrips) and two time exposures (10 and 34 hours) were tested. Each experiment was replicated ten times. Experiments were conducted in growth chambers at 28ºC, 60% RH, and a 14:10 h light:dark cycle. Frankliniella tritici tended to disperse more than F. occidentalis. Despite differences in prey movement, O. insidiosus successfully preyed on all types of prey that were offered. However, O. insidiosus dealt differently with each type of prey. Frankliniella tritici, an inherently more mobile species, was more vulnerable to predation at low densities due to higher chance of encounter with the predator. At a high density, the less mobile F. occidentalis was more vulnerable to predation by O. insidiosus. In trials with adults and 2nd instar larvae of F. occidentalis, larvae were more vulnerable to predation due to low mobility. Predation of thrips was more likely to occur inside the flower. This study shows that O. insidiosus is an efficient predator. Furthermore, it explains why O. insidiosus is an important regulator of thrips populations.