Morphological Characteristics Of Healing-elytron And Its Relationship With Habitat Selection Of The Darkling Beetles

Under extreme environmental stress,many darkling beetles distributed in desert and semi-desert areas and alpine areas evolved adaptive traits of healing of elytra and degeneration of hind wing,forming a special morphological structure device.The emergence of this structure can effectively alleviate the loss of water in beetle body,and help to reinforce the body wall and prevent heterogeneous invasion and other survival pressures.The seemingly degraded characteristics of elytra healing and hind wing degeneration are of great significance in the evolution of Tenebrionidae adapting to desert(semi-desert)and extreme cold environment and in the formation of rich species diversity.To reveal this feature is of great scientific value in explaining the natural selection process of natural selection,survival and reproduction of the fittest.In view of the scarcity of research reports in academic circles,this study shows certain exploratory value.It is expected to find out the relationship between the healing of the elytra of darkling beetles and the body wall structure as well as the environment through comparative study of specimen anatomy,micro-CT and scanning electron microscopy.Relevant results were obtained by microscopic CT observation,scanning,3D image reconstruction,preservation of preview image and section of 3D image,CTan measurement of sheath fin thickness and correlation analysis of body length index.Scanning electron microscopy(SEM)is mainly used to scan the sheath-wing section obtained in the process of specimen dissection,so as to obtain clear microstructures.In this study,the common connection structures have been found,and the biological significance of this phenomenon is summarized;the elytra scabbard beetles were preliminarily summarized into four adaptive structures: hollow structure,reinforced structure,special posture and other structures.The adaptability of these different types of beetles to the environment was analyzed and discussed.The relationship between sheath fin thickness and altitude was obtained,and the biological reasons were analyzed.The thicker and denser body walls of the healing elytra darkling beetles in desert(semi-desert)were compared with the fine structures of the alpine groups.The preliminary conclusions are as follows:(1)The healing phenomenon of elytra exists in the Tenebrioninae,Pimeliinae and Lagriinae of Tenebrioninae,and there is a common healing structure.(2)The healing of elytra provides the basis for the formation of closed cavity in the abdominal cavity of darkling beetles,enhances the mechanical strength of the body wall,changes the body shape,and generates new structures such as hollow inside the elytra and ridge reinforcement.(3)The evolution trend of healing elytra of desert groups is that the holes in the healing tumors gradually disappear to both sides,and the healing structure gradually homogenizes with the two sides of the sheath wing;the body wall is highly dense and tends to be thicker,forming a rigid body wall.(4)The healing structure of alpine groups gradually merged with the sheath wings on both sides to form a hollow structure;hollow structures in the body wall often appeared to cope with extreme temperatures;the altitude of the distribution area of the Gnaptorina Reitter,for example,was negative correlation to the thickness of the sheath wings,and the hollow structure in the body wall increased with the increase of altitude.(5)Elytra healing is an adaptive behavior of darkling beetles to extreme environments and an evolutionary type in degradation.Elytra healing and hind-wing degradation are complementary evolutionary phenomena.