Abstract:  【Aim】 As carnivorous insects preying on spiders, different species of Trypoxylon possess obviously different nesting strategies. This study aims to clarify the morphological characteristics and nesting behavior of T. melanocorne, so as to reveal the nesting and survival strategies of Trypoxylon. 【Methods】Man-made nest-trap boxes were set up by choosing different habitats in the Yugong Forest Farm and Nanshan Forest Farm in Jiyuan City, Henan Province, Central China from 2019 to 2020, and then the trap-nests that were nested by T. melanocorne adults were regularly collected. The internal structure data of the trap-nests were measured by dissecting trap-nests, and the development of offspring was observed and the parasitic enemies were collected in the laboratory. 【Results】 A total of 111 trap-nests nested by T. melanocorne adults were collected in the Yugong Forest Farm and Nanshan Forest Farm in Jiyuan City, Henan Province during 2019-2020, and 511 brood cells were dissected. The average number of eggs laid by females in a single trap-nest was 4.60±2.39 grains, and the majority of offspring was female (female to male ratio=2∶1). The average length of nests and length of brood cells were (123.38±46.45) and (16.01±5.57) mm, respectively. The numbers of intercalary cells and nests with vestibular cells accounted for 5.04% and 6.09%, respectively, of the total number of cells. The number of brood cells was significantly affected by the length of nests, and the length of cells of females was significantly longer than that of males. Two parasitic enemies of T. melanocorne, Trichrysis pellucida (Chrysidoidae) and Amobia quatei (Sarcophagidae) were found, with the parasitism rates of 196% and 1.57%, respectively. 【Conclusion】 The results of this study suggest that the population size of T. melanocorne distributed in the two forest farms in the southern Taihang Mountains, Henan Province is small, female progeny are more numerous than males, and one of the reasons for the small population size probably is low adult eclosion rate and sex ratio imbalance.

Key words: Trypoxylon melanocorne, trap-nests, morphological characteristics, nesting architecture, brood cells, parasitic enemies