Comparisons of Contact Chemoreception and Food Acceptance by Larvae of Polyphagous Helicoverpa armigera and Oligophagous Bombyx mori

Abstract

We compared food choice and the initial response to deterrent treated diet between fifth instars of Helicoverpa armigera, a polyphagous generalist pest, and Bombyx mori, an oligophagous specialist beneficial. Bombyx mori was more behaviorally sensitive to salicin than to caffeine. The relative sensitivities were reversed for H. armigera, which was tolerant to the highest levels of salicin found in natural sources but sensitive to caffeine. A single gustatory receptor neuron (GRN) in the medial styloconic sensillum of B. mori was highly sensitive to salicin and caffeine. The styloconic sensilla of H. armigera did not respond consistently to either of the bitter compounds. Phagostimulants also were tested. Myo-inositol and sucrose were detected specifically by two GRNs located in B. mori lateral styloconic sensillum, whereas, in H. armigera, sucrose was sensed by a GRN in the lateral sensillum, and myo-inositol by a GRN in the medial sensillum. Myo-inositol responsiveness in both species occurred at or below 10−3 mM, which is far below the naturally occurring concentration of 1 mM in plants. Larval responses to specific plant secondary compounds appear to have complex determinants that may include host range, metabolic capacity, and gustatory repertoire.Electronic supplementary materialThe online version of this article (doi:10.1007/s10886-013-0303-2) contains supplementary material, which is available to authorized users.

Pharmacological analysis of the feeding response of codling moth (Cydia pomonella; Lepidoptera: Tortricidae) neonates to bitter compounds

“…In caterpillars of Manduca sexta, these cells respond to substances that are perceived as bitter by humans: aristolochic acid, caffeine and salicin (Glendinning et al, 2006) and as a consequence, caterpillars reduce their feeding activity (Glendinning et al, 1999). Similar results are reported for caterpillars of Helicoverpa armigera and Bombyx mori (Zhang et al, 2013). Not much is known about the signal transduction involved in perceiving bitter substances by caterpillars, but it is postulated that Manduca sexta larvae have more than one transduction and one signalling pathway for perceiving bitter chemicals (Glendinning & Hills, 1997;Glendinning et al, 2002).…”

Larval experience of stable fly, Stomoxys calcitrans Linneaus, 1758 (Diptera: Muscidae) does not influence oviposition preference in gravid females

“…Barron (2001) also implicates the influence of genetic plasticity in insect host preference. Also, compared with specialist insects, the olfactory system of generalist insects is less sensitive (Zhang et al, 2013;Conchou et al, 2017), and according to the 'neural constraints hypothesis', generalist insects make less accurate decisions when selecting substrates (Sadtler et al, 2014;Wang, 2017). Furthermore, larvae of S. calcitrans are polyphagous; they feed and develop on a wide range of substrates, including dung (from camel, cow, horse, donkey and sheep), and decaying plant materials (such as hay, alfalfa, silage, sugarcane and compost).…”

Molecular characterization of sugar taste receptors in the cotton bollworm Helicoverpa armigera

“…Four sugar GRs (HarmGR5, HarmGR6, HarmGR10, and HarmGR12) are detected from larval mouthpart, which is a major gustatory tissue at larvae stage. Taken into account that in H. armigera 5th instar larvae, sucrose was sensed by a GR neuron (GRN) in the lateral sensillum, and myo-inositol by a GRN in the medial sensillum (Zhang et al 2013), HarmGR5, HarmGR6, HarmGR10, and HarmGR12 may be the candidate receptors for sucrose or myo-inositol. At adult stage, HarmGR4 was detected in female adult ovaries, tarsi, antennae, both male and female heads (with antennae), and male testes.…”