GOYRET, Joaquin*; RAGUSO, Robert A.; Univ. of S. Carolina, Columbia: The role of mechanosensory input in flower handling efficiency and learning by Manduca sexta

Manduca sexta is a wide spread, generalist flower visiting hawkmoth whose sensory biology is highly tuned to floral cues. In an appetitive context, strong fragrances and bright objects attract these nocturnal moths and eventually trigger a feeding response. Flower nectar is usually concealed within the flowers visited by M. sexta; thus, successful detection of nectar tubes or spurs can enhance feeding success. We used arrays of artificial flowers to investigate the foraging behavior of free flying na�ve moths, looking specifically at: 1) how the shape and size of flat (2-D) artificial corollas affect nectar discovery, and 2) whether 3-D features of the corolla can be used by M. sexta to facilitate nectar discovery. In these experiments, we decoupled visual from tactile flower features to explore the role of mechanosensory input, putatively attained by the extended proboscides of hovering moths. In addition, we examined changes in nectar discovery times within single foraging bouts to test whether moths can learn to handle different artificial flowers. We found that corolla surface area negatively affects the efficiency of flower handling, and that reliable mechanosensory input is crucial for the moths� performance. We also found that 3-D features of the corolla, such as grooves, can significantly affect the foraging behavior, both positively (when grooves converge to the nectary) and negatively (when grooves are unnaturally oriented). Lastly, we observed that moths can decrease nectar discovery time during a single foraging bout. This learning ability seems to possible only when reliable mechanosensory input is available.