Submitted to: Annual Cumberland Shenandoah Fruit Workers Conference
Publication Type: Proceedings
Publication Acceptance Date: 3/11/2016
Publication Date: 8/2/2016
Citation: Morrison Iii, W.R., Mathews, C.R., Leskey, T.C. 2016. Hunting down the hunters: H. Halys egg damage and natural enemies. Proceedings of the 91st Annual Cumberland-Shenandoah Fruit Workers Conference, December 3-4, 2015, Winchester, Virginia. p. 41.
Technical Abstract: The brown marmorated stink bug, Halyomorpha halys, is an invasive pest from Asia (Lee et al., 2013) that was accidentally introduced into the United States in the mid-1990s (Hoebeke and Carter, 2003). One reason that it has done so well in the United States is due to the fact that it lacks effective natural enemies in its introduced range, often referred to as the enemy-release hypothesis. However, it has now been present in the country for almost 20 years, so an inevitable question that arises is whether native natural enemies are beginning to recognize H. halys as a potential prey item. Natural enemies may recognize prey through a variety of mechanisms, including through the emission of plant volatiles signaling herbivore damage and via the emissions of kairomones from the prey itself. A kairomone is any chemical signal that benefits the receiver but not the sender. One potential kairomone emitted by H. halys is the species’ recently identified two component male-produced aggregation pheromone (Khrimian et al., 2014). In the current study, we evaluated whether natural enemies were using this aggregation pheromone to preferentially attack H. halys egg masses in the vicinity. Specifically, our study evaluated whether deploying the pheromone with egg masses increased the predation rate, parasitism rate, or number of unemerged eggs remaining. To do this, we deployed freshly laid (<24 h old) sentinel egg masses, either with or without 42 mg of the H. halys aggregation pheromone, and left them out for 72 h. We did this at eight sites arranged in two transects of roughly 40 km in Jefferson County and Berkeley County, West Virginia, and in neighboring counties in Maryland and Virginia. Egg mass treatments were paired at each site with ~100 m between each treatment. We took photographs before and after sentinel egg mass deployment to record the damage. We found that the presence of the aggregation pheromone did not significantly affect the predation rate, parasitism rate, or the number of unemerged eggs remaining. This suggests that native natural enemies are not using the aggregation pheromone as a kairmone. Future work may investigate other potential kairomones and plant volatiles for use by natural enemies of H. halys.