饲喂塑料对4种昆虫幼虫生长与肠道微生物的影响

Effects of feeding plastics on the growth and gut microbiota of the larvae of four insect species

摘要:

塑料污染是全球最关注的环境问题之一，目前利用昆虫肠道微生物降解塑料是解决塑料污染的新举措，昆虫肠道微生物菌群在塑料降解过程中起重要作用，但对昆虫取食塑料后肠道中微生物群落的组成和动态还缺乏了解。【目的】 探究取食塑料对4种昆虫幼虫生理指标以及肠道微生物的组成和动态的影响。【方法】 将聚苯乙烯塑料泡沫(polystyrene, PS)、聚乙烯塑料(polyethylene, PE)和麦麸(对照)作为唯一碳源分别饲喂大麦虫、黄粉虫、黑粉虫和大蜡螟，采用荧光原位杂交技术对4种幼虫肠道微生物菌群进行动态监测，并比较了它们的生理指标和肠道菌群的关联。【结果】 四种昆虫在取食PS和PE后，体重和体长的增长幅度都显著低于麦麸对照组；取食PS的黄粉虫和大麦虫的存活率比取食PE的分别高25.33%和11.75%；4种昆虫肠道中微生物优势细菌菌群为厚壁菌门(Firmicutes，丰度16.98%-54.93%)、变形菌门(Proteobacteria)中的β-变形菌纲(Betaproteobacteria，丰度5.91%-39.34%)和γ-变形菌纲(Gammaproteobacteria，丰度4.62%-30.86%)以及古菌(Euryarchaeota，丰度9.99%-58.05%)【结论】 除厚壁菌门和变形菌门外，古菌也是啮食PE和PS的大麦虫、黄粉虫、黑粉虫和大蜡螟幼虫肠道中的主要菌群。昆虫肠道中主要微生物菌群的丰度随时间呈动态变化，并受塑料类型以及昆虫种类的影响。大麦虫和黄粉虫的体重和体长与肠道微生物菌群显著相关。

Abstract:

Plastic pollution is an environmental problem that has aroused global concern, and plastics degradation by insect gut microbiota is a new initiative to solve this problem. Despite the important role of insect gut microbiota in the degradation of plastics, little is known about the composition and dynamics of insect gut microbiota. [Objective] To study the effects of feeding plastics on the physiological indices and the composition and dynamics of gut microbiota in the larvae of four insect species. [Methods] Polystyrene (PS), polyethylene (PE), and wheat bran (control) were used as the sole carbon source respectively to feed the larvae of Zophobas atratus Fab., Tenebrio molitor L., Tenebrio obscurus F., and Galleria mellonella L. The dynamics of gut microbiota in the larvae of the four insect species were investigated by fluorescence in situ hybridization, and the correlations between the physiological indices and gut microbiota were analyzed. [Results] All four insect species fed with PS and PE had significantly lower body weight gain and body length increase than those in the control. The survival rates of Z. atratus and T. molitor larvae fed with PS were 25.33% and 11.75%, respectively, higher than those fed with PE. The dominant microbial taxa of the gut microbiota in the four insect species were Firmicutes (relative abundance of 16.98%-54.93%), Betaproteobacteria (5.91%-39.34%), Gammaproteobacteria (4.62%-30.86%) of Proteobacteria, and Euryarchaeota (9.99%-58.05%). [Conclusion] In addition to Firmicutes and Proteobacteria, archaea were also dominant in the gut microbiota in the larvae of the four species fed with PE and PS. The relative abundance of the main microbial taxa in the insect gut varied dynamically over time and was influenced by the types of plastics as well as the insect species. The body weights and body lengths of Z. atratus and T. molitor were correlated with their gut microbiota.