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

Abstract

Abstract. Feeding in codling moth neonate caterpillars was inhibited by 0.67 mM and 2.24 mM concentrations of denatonium benzoate. This inhibitory effect was abolished by phospholipase C inhibitor, U-73122 and the phosphodiesterase inhibitor, Rolipram. Quinine and quinidine did not have inhibitory effects at concentrations as high as 1.64 mM and 0.43 mM, respectively. The inhibitory effect of denatonium was partially reversed in the presence of the calcium ion chelator, EGTA, at concentrations ranging from 2.5 μM to 250 μM. These results indicate that transduction of the taste of denatonium in codling moth neonates relies on signalling pathways that involve phospholipase C, phosphodiesterase and calcium ion infl ux into cells.

High-Throughput Feeding Bioassay for Lepidoptera Larvae

“…Contrary to our expectations, ECB larvae did not avoid quinine and may even like it. Although this alkaloid is avoided by many animals belonging to different genera, scattered observations in the literature reported the absence of bitterness of quinine in a few species like another Lepidoptera, Cydia pomonella (Pszczolkowski 2017), and in two mantid and two spider species (Mebs et al 2019). While this observation is new for O. nubilalis, it remains to be tested whether the lack of response to quinine is species-or stage-specific.…”

A semi-automated design for high-throughput Lepidoptera larvae feeding bioassays

“…Interestingly, ECB larvae did not respond to quinine in our tests. Scattered observations in the literature reported the absence of bitterness of quinine in another Lepidoptera [34] or mantids [35]. While this observation is new for O. nubilalis, it remains to be tested if the lack of response to quinine is species-specific.…”