Acta Entomologica Sinica ›› 2020, Vol. 63 ›› Issue (4): 421-432.doi: 10.16380/j.kcxb.2020.04.005

• RESEARCH PAPERS • Previous Articles     Next Articles

Morphology, histology and ultrastructure of the alimentary canal of the adult mute cicada, Karenia caelatata (Hemiptera: Cicadidae) (In English)

ZHONG Hai-Ying1, 2, ZHANG Ya-Lin1, WEI Cong1,*   

  1.  (1. Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, Entomological Museum, Northwest A&F University, Yangling, Shaanxi 712100, China; 2. Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China)
  • Online:2020-04-20 Published:2020-05-08

Abstract: 【Aim】In order to better understand the morphology and function of alimentary canal of insects in Cicadidae, the alimentary canal of the mute cicada, Karenia caelatata, was investigated at the morphological, histological and ultrastructural levels. 【Methods】 The gross morphology of alimentary canal, ultrastructure of associated organs including oesophagus, filter chamber (including anterior and posterior extremities of the midgut, internal proximal extremity of the ileum, and internal proximal extremities of the Malpighian tubules), conical segment, a midgut loop, and hindgut (ileum and rectum), and histology of filter chamber of male adult of K. caelatata were observed using light and transmission electron microscopy. 【Results】 The results showed that the alimentary canal of K. caelatata consists of the oesophagus, filter chamber, external midgut section and hindgut. The elongated oesophagus is lined with a cuticle containing an epicuticle and an endocuticle. The filter chamber is enveloped by a thin filter chamber sheath, which contains the anterior and posterior extremities of the midgut, internal proximal extremity of the ileum and internal proximal extremities of the Malpighian tubules. Cells of the anterior and posterior extremities of the midgut possess well-developed basal infoldings and densely-packed apical microvilli. Numerous mitochondria and electron-dense secretory granules were observed in the posterior extremity of the midgut. The external midgut section contains a conical segment and a midgut loop. The conical segment is dilated, and consists of two types of cells: the first is featured by the well-developed basal infoldings, and the second lacks basal infoldings. The midgut loop is divided into three distinct regions, i.e., the anterior segment containing numerous secretory granules, mitochondria, rough endoplasmic reticulum and lysosomes in the cytoplasm, the mid-segment containing secretory granules in the cytoplasm, and the posterior segment with cells possessing numerous electron-lucent secretory granules and smooth endoplasmic reticulum. Ferritin-like granules scatter in the cells of the anterior segment and mid-segment of the midgut loop. Filamentous materials coat the microvilli of the cells of the conical and anterior segments of the midgut loop. The hindgut is lined by a layer of cuticle. Microorganisms reside in the oesophagus, mid-segment of the midgut loop and rectum cells. 【Conclusion】 Findings of the morphological, histological  and ultrastructural characteristics of the gut alimentary canal of K. caelatata  in this study improve our understanding of the functional differentiation of alimentary canal in this species. The discovery of microorganisms in the alimentary canal is formative to future study of coevolution between the Cicadoidea and related bacteria.

Key words: Auchenorrhyncha, Cicadidae, Karenia caelatata, digestive tract, morphology; histology, light microscopy, transmission electron microscopy