Intraspecific Combinations of Flower and Leaf Volatiles Act Together in Attracting Hawkmoth Pollinators

Abstract

Insects pinpoint mates, food and oviposition sites by olfactory cues. Recognizing and localizing a suitable target by olfaction is demanding. Odor sources emit characteristic blends of compounds that have to be identified against an environmentally derived olfactory background. This background, however, does not necessarily disturb the localization of a source. Rather, the contrary. Sex pheromones become more attractive to male moths when being presented against a relevant plant background. Here we asked whether such olfactory coaction also characterizes foraging cues. The tobacco hornworm Manduca sexta feeds on nectar from wild tobacco Nicotiana attenuata and sacred datura Datura wrightii flowers. We tested how leaf-derived volatile blends as a background affect the moths' approach to flower blends. We found coaction when a flower blend was presented against a conspecific leaf volatile background but not when the blend was presented against volatiles emitted by the other host plant or by a non-host plant. Hence, our results reveal a species-specific coaction between flower blend and leaf volatile background. The ability to integrate information from different odor sources on one plant might provide the moth with a fine-grained analysis of food site quality.

The Sensory Ecology of Ant Navigation: From Natural Environments to Neural Mechanisms

“…In another example of two cues in the case of the same modality, the attraction of the nectar-foraging sphingid moth Manduca sexta to flower odors of Datura or Nicotiana was significantly increased in the presence of green leaf odors. However, the synergy was restricted to cases in which flower odors were presented in combination with leaf odors of the same species (56). In summary, animals seem to benefit from the presence of many cues from overlapping or nonoverlapping modalities, especially when the combination is somehow ecologically valid.…”

Multisensory integration in Lepidoptera: Insights into flower‐visitor interactions

“…Of course, the situation is even more complex in nature, as not only would the vegetative scent of a plant always be present alongside the floral one, but so would countless other plant scents. In fact, floral scent with a conspecific leaf volatile background is more attractive for foraging M. sexta than either the floral scent alone or mixed with volatiles from other plant species .…”

“…However, moths are more sensitive than butterflies to odour and rely more heavily on olfaction. They readily learn to associate odours with nectar reward, and can track scents over distance when foraging for flowers . For instance, floral scent from the evening primrose ( Oenothera neomexicana ) initiates searching behaviour in sphinx hawkmoths ( M. sexta ) .…”

β-Ocimene, a Key Floral and Foliar Volatile Involved in Multiple Interactions between Plants and Other Organisms

“…Such spatial and temporal patterns of emission indicate a clear involvement of β-ocimene in the attraction of pollinators to flowers in these species [ 30 ]. However, the effects of β-ocimene on pollinators may be dependent on the context, i.e., on whether it is presented within the correct blend of floral and whole plant volatiles [ 44 ], and also with the correct combination of floral and plant traits other than scent.…”