Dr. Nan-Yao Su: Research:
My research program aims to study the biology and control of termites, which is divided into two major areas of I) fundamental biology and II) management of termite pest species. Studies of fundamental biology is further divided into two areas of Ia) termite foraging behaviors at the individual, group, and colony level, and Ib) termite-microbe interaction and social immunity in termite colonies. Information generated from the fundamental studies are applied to second component of termite management studies that are sub-divided into two areas of IIa) development of noble tools for control of subterranean termites, and IIb) application of the noble control tools for area-wide management projects. Projects Ia, Ib and IIa are funded by the royalty income of my invention, the Sentricon system, and project IIb was funded by USDA-ARS.
I. Fundamental Biology of Termites
Ia) Foraging Behavior of Subterranean Termites
The objectives are to understand termite tunneling behaviors at the individual and group levels and to study the tunnel geometry in relation to foraging strategy and inter-colonial interaction. Studies in this area produced more than 37 refereed articles that provided us with a better understanding on how termites construct the tunnel networks to locate and transport food, and factors governing their tunneling and foraging behavior. The information will enable us to manipulate termites so as to develop a better baiting program.
Ib) Termite Microbe Interaction and Social Immunity in Termite Colonies
The objectives are to examine the mechanisms by which termites defend themselves from potential pathogens in soil environment. Our studies showed that termite social immunity included multilevel disease resistance mechanisms such as cellular encapsulation, mutual grooming, and gut antimicrobial activity. Termites also use its faeces as building material for the nest structure which supports the growth of Actinobacteria that in turn inhibit the growth of entomopathogens. Results of this project revealed a complex mutualism between termites and soil microorganisms that has co-evolved to benefit each other. Studies in this area yielded 17 refereed publications. From the lessons learned, the final goal is to formulate successful biological control measures for termites.
II. Management of Termite Pest Species
IIa) Development of Noble Tools for Control of Subterranean Termites
Bait systems use 600-fold less insecticide than conventional soil treatments, but despite of their safety features and the ability of population control, baits account for only 20% of market share. This is in large part due to the slow nature of a baiting program. The objectives of this project are to develop noble tools that will shorten the time needed for a bait system to control termites. One is a fluid-bait that can be injected into termite foraging galleries for an immediate consumption by termites. Results of laboratory and field studies resulted in the filing of a UF patent PCT/US14/20316, on March 3, 2014. The other is to explore the potential of molt-accelerating ecdysteroids or their analogs to reduce the lethal time of baits, which was described in UF patent, US007998496 B2. If successful, these tools will further promote the use of a bait system that is safer and more efficacious to control subterranean termites, and will increase the feasibility of a bait system to be incorporated in an IPM program.
IIb) Are-wide Management Program
Results of previous studies showed that even after the eliminations of all detectable termite colonies in the 35-acre Armstrong Park of New Orleans, termite populations could recover in four years if no control measures were applied. The objectives were to test the hypothesis that the application of durable and always-active baits (Sentricon HD) could be used to intercept and eliminate any invading colonies, with a goal of maintaining a lasting termite-free area. The Sentricon HD was the commercial product based on the concept of durable baits described in an UF patent (US7,169,403 B2). Sentricon HD baits have been applied in the Armstrong Park since 2009, and after the intense feeding in 2009-2011, termite activities have declined substantially, and by 2013, almost no termites were detected. The results validated the hypothesis. This project yielded 11 refereed papers, and the commercialization of Sentricon HD increased the gross sales of Sentricon system by 30% between 2007 and 2012.