Temporal and environmental factors drive community structure and function of methanotrophs in volcanic forest soils

Methanotrophs,organisms that obtain oxygen by oxidizing methane,are recognized as the only known biological sink for atmospheric CH_4,and forest soil methanotrophs play crucial roles in mitigating global warming.The succession patterns of methanotrophic communities and functions in Wudalianchi volcano forest soils could provide a basis for the study of evolutionary mechanisms between soil microorganisms,the environment,and carbon cycling of temperate forest ecosystems under climate change.In this study,the characteristics and drivers of methanotrophic community structure and function of two volcanic soils at different stages of development are analyzed,including an old volcano and a new volcano,which most recently erupted 300 years and 17-19×10^(5)years ago,respectively,and a non-volcano hills as control,based on space for time substitution and Miseq sequencing and bioinformation technology.The results showed that CH_(4) fluxes were significantly higher in old-stage volcano forest soils than new-stage forest soils and non-volcano forest soils.There were significant differences in the community composition and diversity of soil methanotrophs from different volcano forest soils.Methylococcus was the dominant genus in all soil samples.Additionally,the relative abundance of Methylococcus,along with Clonothrix,Methyloglobulus,Methylomagum,Methylomonas and Methylosarcina,were the important genera responsible for the differences in methanotrophic community structure in different volcano forest soils.The relative abundance of methanotroph belonging toγ-proteobacteria was significantly higher than that belonging toα-proteobacteria(P<0.05).Chao1,Shannon and Simpson indices of soil methanotrophic community were significantly lower in new-stage volcanos and were significantly affected by bulk density,total porosity,p H,nitrate,dissolved organic carbon and dissolved organic nitrogen.There were significant differences in community structure between new-stage and old-stage volcanoes.Bulk density and p H are important soil properties contributing to the divergence of methanotrophs community structure,and changes in soil properties due to soil development time are important factors driving differences in methanotrophs communities in Wudalianchi volcanic soils.

Possible functions of the microtrichia on the cuticle of Ulomoides dermestoides(Chevrolat)(Coleoptera:Tenebrionidae)

Ulomoides dermestoides （Chevrolat） （Coleop- tera： Tenebrionidae） is one of the most notorious pests in northeastern China. We examined microtrichia on the thorax, elytra and abdomen of U. dermestoides using scanning electron microscopy and recorded their confor- mations （size, shape and insertion method） and distribu- tions （length, width and location）. Possible functions of the microtrichia were （1） stridulation： microtrichia on the inner surface of the elytra interacted with microtrichia on the dorsoventral axis of the thorax or on the costal vein of the hind wing; （2） to increase friction： at the major surface on the middle of the abdominal tergum, hind-wings, inner surface of the medial edge of the elytra and the posterior end of the elytra; （3） protection： the microtrichia covering the posterior face of the abdomen conserved water in the body and protected the body from damage; and （4） sensing organ： the special shape of the microtrichia on the nerva- tion near the vannal fold of the hind wing, the anterio- metapleuron on the metathorax, and the posterior field of the abdomen could perceive the environment. In conclusion, the size and shape of the microtrichia are tightly related to their functions, which may have evolved with the beetles＇ lifestyle.