%A LAN Ying, WEI Cong %T Morphology, histology and ultrastructure of the compound eyes of the last instar nymphs and adults of Meimuna mongolica(Hemiptera: Cicadidae) %0 Journal Article %D 2020 %J Acta Entomologica Sinica %R 10.16380/j.kcxb.2020.12.002 %P 1441-1451 %V 63 %N 12 %U {http://www.insect.org.cn/CN/abstract/article_6617.shtml} %8 2020-12-20 %X 【Aim】 This study aims to clarify the differences in the compound eyes of the last instar (5th instar) nymphs and adults of the cicada Meimuna mongolica, so as to ascertain the changes in the morphological structure and functions of compound eyes of nymphs and adults of Cicadidae in the process of ecological niche shift. 【Methods】 The compound eyes of the last instar nymphs and adults of M. mongolicawere observed and compared at the morphological, histological and ultrastructural levels using light microscopy, scanning electron microscopy and transmission electron microscopy. 【Results】 The compound eyes of M. mongolica are of apposition type. The color of the compound eyes of the last instar nymphs change from white to red and dark brown gradually before adult emergence, whereas the compound eyes of the adults are light brown. Sensilla basiconica, sensilla trichoid and sensilla chaetica were observed on the surface of the compound eyes of the last instar nymphs, but no sensillum was found on the surface of the compound eyes of adults. The surface of the white compound eyes of the last instar nymphs has a complete cornea, and no ommatidial facet was observed. The red and dark brown compound eyes of the last instar nymphs are composed of many irregular, hexagonal or pentagonal ommatidia, whereas the compound eyes of adults are composed of equilateral hexagonal ommatidia. The white compound eyes of the last instar nymphs are composed of a large amount of clustered cells, and no ommatidium was observed. In each ommatidium of the dark brown compound eyes of the last instar nymphs, the nuclei of secondary pigment cells are distributed between the rhabdom and the crystalline cone. In the compound eyes of adults, the nuclei of secondary pigment cells are distributed around the proximal center of crystalline cone. In the dark brown compound eyes of the last instar nymphs, the pigment granules of the primary pigment cells and retinula cells are evenly distributed, whereas those in the compound eyes of adults are mainly distributed around the rhabdoms.【Conclusion】 The compound eyes of the last instar nymphs and adults of M. mongolica show significant differences in the development of ommatidia, the distribution of pigment cells, and the presence or absence of sensilla. The major developmental period of compound eyes of cicadas is during the last instar nymphal stage when the compound eyes are red in color. The results suggest that the compound eyes of cicada nymphs during the earlier developmental stage of the last instar as well as the earlier instars do not have visual ability, but can function to sense mechanical pressure or other environmental signals underground. This should be an adaptation to the niche shift during the ontogeny of cicadas which live underground for a very long time in the nymphal stage and have a short adult lifespan above ground. The findings of morphological, ultrastructural and functional characteristics of compound eyes of the last instar nymphs and adults of this species improve our understanding of the changes in the development and function of compound eyes of insects and their association with habitats, and provide new information for further exploring the phylogenetic relationship between Cicadoidea and allies in Hemiptera.