The relative importance of olfaction and vision in a diurnal and a nocturnal hawkmoth

Nectar-feeding animals can use vision and olfaction to find rewarding flowers and different species may give different weight, to the two sensory modalities. We have studied how a diurnal or nocturnal lifestyle affects the weight given to vision and olfaction. We tested naive hawkmoths of two species in a wind tunnel, presenting an odour source and a visual stimulus. Although the two species belong to the same subfamily of sphingids, the Macroglossinae, their behaviour was quite different. The nocturnal Deilephila elpenor responded preferably to the odour while the diurnal Macroglossum stellatarum strongly favoured the visual stimulus. Since a nocturnal lifestyle is ancestral for sphingids, the diurnal species, M. stellatarum, has evolved from nocturnal moths that primarily used olfaction. During bright daylight visual cues may have became more important than odour

Insect Antenna-Based Biosensors for In Situ Detection of Volatiles

Insect antennae are among the most sensitive and selective chemical-sensing organs in the animal kingdom. Insects can perceive picograms of specific volatile organic compounds per cubic meter of air in milliseconds, which is far below the detection thresholds of current analytical devices. These exceptional sensing abilities have many uses in the context of insect biotechnology. Living specimens or parts of them, such as isolated antennae or individual proteins, can serve as biosensors in the field. As volatiles occur in a crude mixture in the environment, knowing which trigger-volatiles are crucial for the insects’ perception of specific incidents is of great value. This knowledge promotes the development of selective sensors for applications, such as fire detection. In this chapter, we discuss the different technical procedures for the preparation and use of insect-based biosensors for the detection of organic volatiles, including those based on insect behavior, insect olfactory proteins, and biomimetic sensing units. We also consider the use of these applications in portable devices outside the laboratory under field conditions