Effects of colony and diet on the aggregation pheromone components in the termite Reticulitermes speratus (Isoptera: Heterotermitidae)

Abstract Subterranean termite workers forage for and exploit decaying wood for new food resources while forming high-density groups. Recently, Mitaka et al. (2020) reported that a worker aggregation pheromone of the subterranean termite Reticulitermes speratus (Kolbe) (Isoptera: Heterotermitidae) consisted of six compounds, including 2-phenylundecane, n -pentacosane, n -heptacosane, palmitic acid, trans -vaccenic acid, and cholesterol. However, the previous study only used some colonies collected around Kyoto, Japan, leaving it unclear whether the pheromonal composition remains consistent across colonies in other regions of Japan. Also, it was unclear whether the components remain unchanged even when the workers eat different diets and which body part secretes the pheromone. In this study, using the R. speratus workers removed from colonies collected from various locations in the Tokai and Kinki regions, Japan, I compared the pheromone components among their workers fed on different diets. Gas chromatography-mass spectrometry (GC-MS) analysis and bioassays demonstrated that not all colonies have workers producing 2-phenylundecane and that workers can be attracted even by a blend of artificial aggregation pheromone without 2-phenylundecane. Furthermore, GC-MS analysis of extracts of workers’ footprint substances and various body parts revealed that n -pentacosane and n -heptacosane were present in both body surface and footprint substances and that palmitic acid, trans -vaccenic acid, and cholesterol were predicted to be secreted from the midgut or hindgut. These results suggest that the production of 2-phenylundecane depends on the colony backgrounds. This study provides insights into the relationship between food and pheromone production in termites.