title: Gustatory sensitivity and food acceptance in two phylogenetically closely related papilionid species: Papilio hospiton and Papilio machaon.
abstract: In herbivorous insects, food selection depends on sensitivity to specific chemical stimuli from host-plants as well as to secondary metabolites (bitter) and to sugars (phagostimulatory). Bitter compounds are noxious, unpalatable or both and evoke an aversive feeding response. Instead, sugars and sugar alcohols play a critical role in determining and enhancing the palatability of foods. We assumed that peripheral taste sensitivity may be related to the width of the host selection. Our model consists of two closely phylogenetically related Papilionid species exhibiting a difference in host plant choice: Papilio hospiton and Papilio machaon. The spike activity of the lateral and medial maxillary styloconic taste sensilla was recorded following stimulation with several carbohydrates, nicotine and NaCl, with the aim of characterizing their gustatory receptor neurons and of comparing their response patterns in the light of their different acceptability in feeding behaviour. The results show that: a) each sensillum houses phagostimulant and phagodeterrent cells; b) the spike activity of the gustatory neurons in response to different taste stimuli is higher in P. hospiton than in P. machaon; c) sugar solutions inhibit the spike activity of the deterrent and salt cells, and the suppression is higher in P. machaon than in P. hospiton. In conclusion, we propose that the different balance between the phagostimulant and phagodeterrent inputs from GRNs of maxillary sensilla may contribute in determining the difference in food choice and host range.
authors: Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Cagliari, Italy.
authors: Giorgia
authors: G
authors: Sollai
authors: Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Cagliari, Italy.
authors: Iole
authors: I
authors: Tomassini Barbarossa
authors: Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Cagliari, Italy.
authors: Carla
authors: C
authors: Masala
authors: Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Cagliari, Italy.
authors: Paolo
authors: P
authors: Solari
authors: Department of Biomedical Sciences, Section of Physiology, University of Cagliari, Cagliari, Italy.
authors: Roberto
authors: R
authors: Crnjar
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002080:Butterflies / Q000187:drug effects / Q000502:physiology*; D002241:Carbohydrates / Q000494:pharmacology; D005247:Feeding Behavior / Q000187:drug effects; D005518:Food Preferences; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010802:Phylogeny; D011189:Potassium Chloride / Q000494:pharmacology; D058618:Sensilla / Q000187:drug effects / Q000502:physiology; D013045:Species Specificity; D013649:Taste / Q000187:drug effects / Q000502:physiology*
chemical_list: D002241:Carbohydrates; D011189:Potassium Chloride