How granivorous Coreus marginatus (Heteroptera: Coreidae) recognises its food

Phytophagous insects select their host plant using multiple sensory modalities including vision, olfaction, gustation and mechanoreception. In the laboratory, we investigated the role of vision, olfaction and gustatory sense in the perception of cues released by seeds of different plant species in granivorous Coreus marginatus (Heteroptera: Coreidae). Juvenile insects were put in a choice arena and offered with different seeds on which they feed naturally (Polygonum, Rumex) and seeds which are not their natural food (Stellaria). Individual bugs were manipulated in one of three ways: 1. blackened compound eyes, 2. coated sensillae on antennae, 3. coated tip of labial pouch. Control individuals were not manipulated. The behaviour of each bug was observed for 12 h. Control bugs fed for a significantly longer time than manipulated ones. Individuals with any senses impaired fed on Stellaria, whereas, the control individuals ignored it. The results suggested that seed selection requires information from all three sensory organs: compound eyes, antennae and sensillae on labial pouch. Further research is required to unravel the importance of each sense for the seed selection.