Interactions between Subterranean Termites, Blue Stain Fungi, and Bark Beetles
Blue stain (Ophiostomatoid) fungi are ubiquitous from the arctic to the tropics and are vectored to trees by bark beetles and their phoretic mites. The fungi reduce the value of timber aesthetically by discoloring the sapwood, but do not cause any structural damage to wood. The ecology among bark beetles, trees, fungi, and mites has received much attention of late, but is still largely unknown due to the multitude of interacting species within these three kingdoms and their turnover across their global geography. Recently, my lab discovered that wood from trees killed and inoculated with blue stain fungi by bark beetles elicited a positive feeding response by native and non-native (Formosan) subterranean termites (Little et al 2012a, b, 2013; Riggins et al. 2014). This finding is the first instance of an interaction between subterranean termites and a non-decay fungus and the first direct link between bark beetles, a primary herbivore of pines, and subterranean termites, the primary invertebrate decomposers of pines in many forest ecosystems. The results and implications of our research investigating the relationship between termites and blue stain fungus are far-reaching. First, we are testing if technology derived from blue stain wood can be employed as commercially viable enhancement to current subterranean termite bait station technologies (Patent Pending). Second, we are investigating blue stained wood’s effects on termite physiology; namely immunocompetence, condition, and performance. Future research will focus on testing additional termite species from the U.S. and abroad, and identifying the metabolic byproduct(s) and mechanism(s) behind the termites’ exhibited feeding preference for blue stained wood. Lastly, we are investigating the ecological implications of this interaction because landscape-scale carbon and nutrient cycles in many forest ecosystems are likely mediated by this important multi-trophic interaction. Our experiments investigating the differences in decomposition rates, invertebrate communities, and nutrient availability between unstained and blue stained trees in a natural environment will elucidate novel ecological links between above- and belowground systems in forest ecosystems.