Abstract
Diapause control is one of the successful methods for long-term cold storage of biological control organisms without decreasing their fitness. Sufficient preparation before diapause is essential for successful diapause initiation and maintenance. Harmonia axyridis, an important biocontrol agent in its native place, can enter reproductive diapause for overwintering. However, the key preparatory events before diapause in H. axyridis, such as specific developmental trajectory, timing, and physiological changes, remain unclear. We compared differences in the development of internal reproductive organs, feeding amount and nutrient storage between pre-diapause and pre-reproductive adult H. axyridis which had been reared at 20 °C under a short-day (10L:14D) and long-day (14L:10D) condition, respectively. The results showed that there were obvious morphological differences in internal reproductive organs of diapause and reproductive H. axyridis. The development of internal reproductive organs was suppressed at early adult stage in pre-diapause beetles compared to pre-reproductive beetles. Feeding amount in both pre-diapause and pre-reproductive beetles increased for more than ten days after eclosion. The feeding amount of pre-diapause beetles sharply decreased from the 15th day after eclosion in females and the 14th day after eclosion in males, which implied the initiation of diapause. During the pre-diapause stage, carbohydrates and lipids were mainly accumulated by females, whereas males mainly accumulated carbohydrates. Our results not only provide basic information about the diapause process of pre-diapause stage, but also give tips to better utilization of diapause strategy during mass production and storage of H. axyridis.
Highlights
The multicolored Asian lady beetle Harmonia axyridis is a well-known biological control agent for aphids and coccids in its native places, such as Japan and China [1,2,3,4]
H. axyridis is considered as an invasive species in Europe and North America [5,6,7,8], it is commercially reared and widely used as a biocontrol agent in its native places, due to its strong ability to control aphids and its environmental adaptation [4,9]
We found that the feeding amount of H. axyridis increased after eclosion and remained high for more than ten days after eclosion, with no significant difference in food amount between pre-diapause and pre-reproductive individuals during that period
Summary
The multicolored Asian lady beetle Harmonia axyridis is a well-known biological control agent for aphids and coccids in its native places, such as Japan and China [1,2,3,4]. H. axyridis is considered as an invasive species in Europe and North America [5,6,7,8], it is commercially reared and widely used as a biocontrol agent in its native places, due to its strong ability to control aphids and its environmental adaptation [4,9]. H. axyridis enters a long-term reproductive diapause phase to avoid adverse environmental conditions and maintain population during the overwintering process [10,11,12,13]. Long-term cold storage of some parasitoids, such as Trissolcus basalis, Telenomus podisi and Habrobracon hebetor, has been successfully
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
