关键词: 西沙大眼长蝽, 形态, 生物学, 发育历期, 行为

Abstract: 【Aim】 The morphological and biological characteristics of Geocoris xishaensis were clarified to provide a scientific basis for its taxonomic identification and propagation.【Methods】 At the constant temperature of (26±1) ℃, the eggs of Corcyra cephalonica were used as the food to feed G. xishaensis. The main morphological characteristics, the individual development from egg to adult, survival and fecundity of G. xishaensis were recorded by the individual rearing method, and the behaviors such as feeding, predation, mating and oviposition, eclosion and cannibalism were observed and described. 【Results】 The development of G. xishaensis includes egg, 1st-5th instar nymphs and adult. Eggs are milky white and turn to pink with obvious eyespots before hatching. There are white markings on the dorsal side of abdomen of the 2nd-5th instar nymphs. The wing bud appears in the 5th instar nymph. The body length, eye width and abdominal width increase with the increase of developmental stage. The head of the adult is wide and in yellowish brown. The pronotum is in yellowish-brown, with a dark spot in the mid-region. The scutellum has black markings. G. xishaensis usually lifts its preys in the air for sucking. The mating postures of female and male adults are tail to tail in a straight line. The upper body of G. xishaensis is raised upward while the abdomen is facing down during the oviposition. When the nymphs molt, the head and neck are separated from the exuvium first, and then sequentially detach the leg and body. The cannibalism behavior appears in the same and different developmental stages of G. xishaensis. But the early instar nymphs are easier to be killed by the adults and late instar nymphs. The egg duration, nymphal duration, pre-oviposition period, generation time and adult longevity of G. xishaensis were 9.24, 26.63, 4.80, 40.45 and 46.53 d, respectively. 【Conclusion】 In this study, the main morphological characteristics, developmental duration and fecundity of G. xishaensis have been clarified, and the behaviors of predation, mating, oviposition and eclosion, and the cannibalism behavior of adults and nymphs have been preliminarily revealed. Based on the current studies, the white markings on the dorsal side of abdomen and the wing bud development can be used as the main morphological characteristics to identify the instar of nymphs.

Key words: Geocoris xishaensis; morphology, biology, developmental duration, behavior