Trans-generational desensitization and within-generational resensitization of a sucrose-best neuron in the polyphagous herbivore Helicoverpa armigera (Lepidoptera: Noctuidae)

Abstract

Dietary exposure of insects to a feeding deterrent substance for hours to days can induce habituation and concomitant desensitization of the response of peripheral gustatory neurons to such a substance. In the present study, larvae of the herbivore Helicoverpa armigera were fed on diets containing either a high, medium or low concentration of sucrose, a major feeding stimulant. The responsiveness of the sucrose-best neuron in the lateral sensilla styloconica on the galea was quantified. Results showed the response of the sucrose-best neuron exposed to high-sucrose diets decreased gradually over successive generations, resulting in complete desensitization in the 5th and subsequent generations. However, the sensitivity was completely restored in the ninth generation after neonate larvae were exposed to low-sucrose diet. These findings demonstrate phenotypic plasticity and exclude inadvertent artificial selection for low sensitivity to sucrose. No significant changes were found in the sensitivity of caterpillars which experienced low- or medium-sucrose diets over the same generations. Such desensitization versus re-sensitization did not generalise to the phagosimulant myo-inositol-sensitive neuron or the feeding deterrent-sensitive neuron. Our results demonstrate that under conditions of high sucrose availability trans-generational desensitization of a neuron sensitive to this feeding stimulant becomes more pronounced whereas re-sensitization occurs within one generation.

Higher plasticity in feeding preference of a generalist than a specialist: experiments with two closely related Helicoverpa species

“…Feeding experience affected gustatory sensitivity of the sucrose-best neuron in maxillary taste sensilla of H . armigera caterpillars exposed to three artificial diets differing in sucrose content 60 . Differences in sugar concentrations in the three food sources tested and the effects on sucrose-best neuron sensitivity may have contributed to the changes in food preferences displayed by H .…”

Distribution of Serotonin-Immunoreactive Neurons in the Brain and Gnathal Ganglion of Caterpillar Helicoverpa armigera

“…The cotton bollworm Helicoverpa armigera (Hübner; Lepidoptera: Noctuidae), is an important agricultural pest in the world, feeding on more than 160 plant species (Fitt, 1989; Ma et al, 2016). The damage of H. armigera to plants occurs during its larval stage.…”

“…Feeding behavior of H. armigera larvae is mediated to a large extent by the gustatory sensillum, which detects palatable and unpalatable compounds in plants to acquire nutrients and avoid the toxins (Zhou et al, 2010). Behavioral and gustatory electrophysiological studies revealed that feeding experiences could induce changes in feeding preference of H. armigera for host plants (Zhou et al, 2010; Ma et al, 2016; Wang et al, 2017). Such feeding preference and plasticity is mediated by the signal transduction of the gustatory pathway and the modulation of the neural substance in the central nervous system (Glendinning et al, 1999, 2001).…”

Antifeedant activities of L-arabinose to caterpillars of the cotton bollwormHelicoverpa armigera(Hübner)

“…Experiment IV investigated whether LA have effects on the sensitivities of the GRNs sensitive to tobacco leaf saps in the medial sensillum. The sucrose best GRN in the lateral sensillum and the GRNs sensitive to tobacco-leaf-sap best in the medial sensillum have been identified in our previous work (Ma et al 2016; Tang et al 2014). The leaf saps were extracted as per our previous work (Tang et al 2014).…”