HPLC-MS/MS Determination of Melatonin in Brown Planthopper at Growth Stages

  Objective  Melatonin contents in brown planthopper, Nilaparvata lugens (Stl), at various developmental stages were determined.

  Method  HPLC-MS/MS was used to measure the melatonin contents in the 1^st to the 5^th instar nymphs as well as female and male macropterous and brachypterous adults of the insect.

  Result  At nymph stage, N. lugens had the lowest average melatonin content of 378.5 pg·g⁻¹ in the 1^st and the 2^nd instars, the highest of 856.6 pg·g⁻¹ in the 3^rd instar, 810.7 pg·g⁻¹ in the 4^th instar, and 574.5 pg·g⁻¹ in the 5^th instar. Adult N. lugens differed significantly on melatonin contents between male and female but not between the macropterous and brachypterous wing types. The male of macropterous and brachypterous wing types contained 978.3 pg·g⁻¹ and 969.6 pg·g⁻¹ melatonin, respectively, which were extremely significantly higher than the female counterparts at 76.1 pg·g⁻¹ and 176.8 pg·g⁻¹, respectively.

  Conclusion  The melatonin contents in N. lugens as nymphs and adults were determined.