Diapause-induced changes in cuticle defense compounds in Acantholyda posticalis larvae
[Aim]Acantholyda posticalis Matsumura is a defoliating insect.The cuticle of mature A.posticalis larva protects it from the external environment during overwintering.Understanding the ecological adaptability of the larval cuticle is essential for the integrated management of A.posticalis.[Methods]Variability in the quality and quantity of chitin,fats,and protein in the larval cuticle were investigated by dissolving fat in mineral ether,digesting chitin using saturated KOH,and detecting protein with Coomassie brilliant blue.Variation in the dynamic development of chitin and fats was investigated using Fluorescent Brightener 28(FB28)and Hematoxylin-eosin staining(HE).Colorimetry was used to determine the protein content and activity of polyphenol oxidase(PPO on the integument.[Results](1)The quality of chitin,total protein,and total fats in the cuticle gradually increased from prepupal diapause,through the soil diapause,the 5th instar and the 4th instar larva stages.There was a marked increase from the fifth instar to the point of entering the soil.(2)Chitin and fat thickness of the larval integument varied during development from soil diapause through to prepupal diapause,the 5th instar,and 4th instar stages.Thickness increased rapidly from the 5th instar stage to entering the soil.(3)There was minimal variation in total fat content,whereas chitin content showed a decreasing-increasing-decreasing trend.Total protein content also showed an increasing-decreasing-increasing trend during larval development.(4)The variation in protein content and PPO activity showed a complementarity trend.As the larvae developed,the protein content of PPO in the larval integument initially increased,then showed a consistent decrease.In contrast,PPO activity displayed the opposite trend.[Conclusion]The variation in chitin and protein content of larval integument exhibited an opposing but complementary pattern.The fluctuations in protein content and PPO activity appeared to be complimentary.These two forms of complimentary variation collectively establish a balanced defense system in the larval integument during winter-diapause and non-diapause.
NETL
NSTL
万方数据
