Yunfei Peng

The mitochondrial genomes of three species of Elmidae were sequenced. The sizes were 16,309 bp (C. jaechi), 16,291 bp (G. longiusculus), and 15,480 bp (S. punctulata). Each genome includes 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs), and a control region (CR). All three mitogenomes show AT bias. Except for trnS1, lacking the dihydrouridine (DHU) arm, all tRNA genes had a typical cloverleaf structure. The codon usage preferences of the three species showed high similarity. The arrangement of the genes in the three mitogenomes was consistent among them but differed from that in the typical mitogenomes of Coleoptera. The Ka/Ks ratio indicated that COX1 and nad4L had a lower evolutionary rate, being relatively conserved genes among 13 PCGs. The phylogenetic analysis revealed that Elmidae belongs to the superfamily Dryopoidea within the suborder Polyphaga and is monophyletic. The results preliminarily indicate that the taxonomic groups at the subfamily, tribe, and genus levels within Elmidae are ambiguous, and further revisions may be required in the future.

Two new species, Heterlimnius luyashanensis sp. n. and Zaitzevia triangularis sp. n. are described from Shanxi Province, China. The genus Heterlimnius Hinton, 1935 and Zaitzevia Champion, 1923 are reported from Shanxi Province for the first time. Heterlimnius luyashanensis sp. n. belonging to the Heterlimnius trachys species group has the following characteristics: 1. anterior margin of pronotum strongly produced anteriad; 2. median longitudinal sulcus of pronotum extends from basal 0.3 to 0.8. Zaitzevia triangularis sp. n. has a larger body size and a triangular apex of penis.

The purpose of this study is to investigate the adaptive mechanism of morphological and structural changes to habits, during the metamorphosis development of Carposina sasakii Matsumura, 1900. Traditional dissection, paraffin section, and scanning electron microscopy techniques were used to study the morphological structure and cytohistology of the digestive system in different developmental stages of C. sasakii by classical comparativemorphology study. In order to adapt to the change of feeding habits from solid in the larva stage to liquid in the adult stage, the digestive tract of C. sasakii reconstructed in the pupal stage. The crop of the foregut transformed from a spherical shape in the larval stage to an enlarged lateral, accessory, bag-like structure beyond middle of pupal stage and in the adult stage. The hindgut transformed from a columnar structure in the larval stage to a dilated rectal sac at the end of the hindgut in the adult stage. The morphological changes of the digestive tract provided the basis for theC. sasakii to adapt to the changes of food habits and environment. In addition, the present study provides a basis for better understanding of pupal reconstruction of digestive tract. It also lays the foundation for the nutritional physiology and co-evolution between C. sasakii at different stages and its host plant, while providing morphological data for the toxicological and pathological research of this significant agricultural pest.

Neptosternus haibini sp. nov. is described from Guangdong Province, China. The new species is very similar to N. wewalkai Balke, Hendrich & Yang, 1997, from which it can be recognised only by the shape of the male genitalia. The habitus and genitalia of both species are illustrated. Neptosternus pocsi Sato, 1972 is recorded from China (Yunnan province), and the Palaearctic region, for the first time. Currently, eight species of Neptosternus are known from China; a key to Chinese Neptosternus is provided.