Dim Red Light During Scotophase Enhances Mating of a Moth Through Increased Male Antennal Sensitivity Against the Female Sex Pheromone

Qiuying Chen; Xi Yang; Dongrui You; Jiaojiao Luo; Xiaojing Hu; Zhifeng Xu; Wei Xiao

doi:10.3389/fgene.2021.611476

Dim Red Light During Scotophase Enhances Mating of a Moth Through Increased Male Antennal Sensitivity Against the Female Sex Pheromone

Front Genet. 2021 Feb 24:12:611476. doi: 10.3389/fgene.2021.611476. eCollection 2021.

Authors

Qiuying Chen^{1

2

3}, Xi Yang^{1

2

3}, Dongrui You^{1

2

3}, Jiaojiao Luo^{1

2

3}, Xiaojing Hu^{1

2

3}, Zhifeng Xu^{1

2

3}, Wei Xiao^{1

2

3}

Affiliations

¹ Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China.
² Academy of Agricultural Sciences, Southwest University, Chongqing, China.
³ State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, China.

Abstract

Insects are behaviorally and physiologically affected by different light conditions, including photoperiod, light intensity, and spectrum. Light at night has important influences on nocturnal insects, including most moth species. Moth copulation and mating usually occur at night. Although a few studies examine changes in insect mating under artificial light at night, detailed influences of light, such as that of monochromatic light, on moth mating remain largely unknown. In this study, on the basis of long-term insects rearing experience, dim red light (spectrum range: 610-710nm, with a peak at 660nm; 2.0 Lux) during scotophase was hypothesized to enhance mating in the yellow peach moth, Conogethes punctiferalis. To test the hypothesis, the mating of moths under dim red, blue, and white lights during scotophase was observed. Under the dim red light, the enhancement of mating in C. punctiferalis was observed. In addition, the electroantennografic response of males against the female sex pheromone increased with red light treatment during scotophase. In an analysis of the differentially expressed genes in the antennae of males under red light and dark conditions, the expression levels of two odorant-binding protein (OBP) genes, CpunOBP2 and CpunPBP5, were up-regulated. Two genes were then expressed in Escherichia coli, and the recombinant proteins showed strong binding to female pheromone components in fluorescence-binding assays. Thus, the results of this study indicated that dim red light at night enhanced the mating of C. punctiferalis. One of the mechanisms for the enhancement was probably an increase in the antennal sensitivity of males to the female sex pheromone under red light that was caused by increases in the expression levels of pheromone-binding protein genes in male antennae.

Keywords: Conogethes punctiferalis; dim red light; electroantennography; mating enhancement; odorant binding proteins; scotophase.