Fuelling on the wing: sensory ecology of hawkmoth foraging

Abstract

Hawkmoths (Lepidoptera, Sphingidae) comprise around 1500 species, most of which forage on nectar from flowers in their adult stage, usually while hovering in front of the flower. The majority of species have a nocturnal lifestyle and are important nocturnal pollinators, but some species have turned to a diurnal lifestyle. Hawkmoths use visual and olfactory cues including CO 2 and humidity to detect and recognise rewarding flowers; they find the nectary in the flowers by means of mechanoreceptors on the proboscis and vision, evaluate it with gustatory receptors on the proboscis, and control their hovering flight position using antennal mechanoreception and vision. Here, we review what is presently known about the sensory organs and sensory-guided behaviour that control feeding behaviour of this fascinating pollinator taxon. We also suggest that more experiments on hawkmoth behaviour in natural settings are needed to fully appreciate their sensory capabilities.

Nocturnal Bees Feed on Diurnal Leftovers and Pay the Price of Day – Night Lifestyle Transition

“…The sensory and physiological basis of dim-light flower search in two classical nocturnal pollinators: moths (Heinrich, 1971;Raguso and Pichersky, 1995;Kelber et al, 2002;Raguso and Willis, 2003;Goyret et al, 2008;Okamoto et al, 2008;Kuenzinger et al, 2019;Stöckl and Kelber, 2019) and bats (Heithaus et al, 1975;von Helversen and von Helversen, 1999;Winter et al, 2003;Fleming et al, 2009;Simon et al, 2011) are well understood. Distinct floral traits associated with bat (Baker, 1961;von Helversen and von Helversen, 2003;Fleming et al, 2009) and moth pollination are well studied (Raguso et al, 1996;Svensson et al, 2011), although these pollinators may also opportunistically exploit flowers that do not strictly bear these characteristics (Ollerton et al, 2009;Borges et al, 2016;Borges, 2018).…”

Wing damage affects flight kinematics but not flower tracking performance in hummingbird hawkmoths

“…Taken together, hummingbird hawkmoths compensate for a loss in wing area by increases in wing beat frequency and amplitude, and track moving flowers without a performance impairment. This impressive tolerance to wing damage might be a testament to the immense importance that fast steering has for these animals: not only do they feed exclusively on the wing, and very rarely land on flowers, they also lay their eggs on their hostplant while hovering in front of the plants (Stöckl & Kelber 2019). Moreover, since hummingbird hawkmoths hibernate as adults, resulting in lifespans of several months (Pittaway 1993), optimising their flight abilities to tolerate wing damage might be paramount for the fitness of these insects.…”

Progress in the use of genetic methods to study insect behavior outside Drosophila

“…The crepuscular hawkmoth Manduca sexta uses both visual and olfactory cues to locate its host plant, the Western Jimsonweed, Datura wrightii [3,13], which produces a relatively large, white upright trumpet flower with a strong odor bouquet. Mediating the detection of this floral bouquet are a subset of diversely evolved insect chemosensory receptors, one group of which is encoded by the odorant receptor (OR) genes.…”

“…From the perspective of meeting the global challenges of the 21 st century D. melanogaster fails as it is neither a crop pest nor a disease vector and we are only beginning to understand its natural behaviors [2]. Paradoxically, only limited genetic tools are employed for insects with better studied behavior in their ecological context [3]. The application of genetic techniques in non-drosophilids is often directed by pioneering D. melanogaster studies that have uncovered phenotypes for candidate homologous gene targets.…”