Abstract:

【Aim】 The aim of this study is to clarify the mating behavior and circadian rhythm of adults of the pear psyllid, Cocapsylla chinensis, in order to provide a theoretical foundation for understanding the hermaphroditic communication mechanisms and trapping technology of this insect. 【Methods】 Based on investigating the mating behavior of winterform adults of C. chinensis in pear orchard in Yangling, Shaanxi, Northwest China, the mating behaviors, including numbers of matings, and circadian rhythms of mating duration, of single-pair summerform and winterform adults of C. chinensis were examined under controlled laboratory conditions of temperature (25±1) ℃ and photoperiod 14L∶10D. 【Results】 During the mating of C. chinensis, males actively court females, with their bodies aligned or overlapping in the same direction. Mating mainly occurs during the photophase, while C. chinensis individuals rest on host plants during the scotophase, exhibiting a distinct circadian rhythm in mating behavior. During the photophase, single-pair summerform adults peaked in mating on the 3rd day after emergence, with 94.0% of the observed individuals exhibiting mating behavior by the 7th day after emergence. The newly emerged winterform adults, when placed under the conditions of temperature (25±1) ℃ and photoperiod 14L∶10D, exhibited mating behavior starting on the 5th day after emergence, peaking between the 7th and 9th day after emergence, with 84.0% of the observed individuals exhibiting mating behavior up to 9-day-old. The average numbers of matings of the summerform and winterform adults were 3.26±0.33 and 4.12±0.37, respectively. The average duration of a single mating event of the summerform and winterform adults was (20.32±1.25) and (48.36±1.38) min, respectively. While there was no significant difference in the number of matings between the two forms, the duration of mating of the winterform adults was significantly longer than that of the summerform adults. Analysis of number of matings and mating duration showed that the summerform adults predominantly mated 1-2 times and a single mating event lasted 10-30 min, accounting for 50.0% and 67.5%, respectively, whereas the winterform adults mated mostly 1-3 times and a single mating event lasted 30-60 min, accounting for 52.0% and 63.2%, respectively. 【Conclusion】 These results suggest that single-pair adults of C. chinensis engage in multiple mating events, exhibiting a circadian rhythm, and winterform adults mate more frequently and for longer duration under the same condition than summerform adults

Key words: Cacopsylla chinensis, summerform, winterform, mating behavior, circadian rhythm