Influence of green light illumination on several enzymes involved in energy metabolism in the oriental armyworm, Mythimna separata (Lepidoptera: Noctuidae)

Abstract

Abstract The oriental armyworm, Mythimna separata Walker, is an important insect pest in eastern Asia. Green (520 nm) light with an exposure time of >30 min can result in a stronger phototactic response than the wavelengths of other lights in M. separata moths. The present study was mainly focused to estimate the activities of several enzymes (such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glycerol-3-phosphate dehydrogenase (GPDH), lactate dehydrogenase (LDH) and 3-hydroxyacyl-CoA dehydrogenase (HOAD)) involved in the energy metabolism and a ratio of HOAD to GAPDH activity in M. separata moths exposed to the green light for different exposure times. Our results showed that when M. separata moths were exposed to the green light for 30 min, the activities of the two enzymes (GPDH and HOAD) and as well as the ratio of HOAD to GAPDH activity were significantly elevated. The activity of LDH was significantly increased in the moths exposed for 60 min. Furthermore, significant differences in enzyme activities between the male and female moths were recorded in 45 min exposure time group of the GAPDH, all light treatment groups of the LDH, and 45 min group of the ratio of HOAD to GAPDH activity, respectively. We suggest that when M. separata adult moths are exposed to the green light, these enzymes can be activated to produce energy for starting the phototactic behavior to the green light. Our findings may provide a theoretical basis for elucidating a reason of the phototactic behavior of nocturnal moths.