Aging can cause immune-senescence in insect by increasing cell apoptosis and decreasing cellular immune response. We report that the micro-aggregation reaction of adult Jamaican field cricket, Gryllus assimilis, decreased 21 days after molting (F=20.12; df=4, 10; P=0.0001) while nodulation decreased 28 days after molting (F=21.39; df=4, 10; P=0.0001) when challenged by LPS (400ug/2ul). Total hemocyte counts declined after 21 days. The ratio of granularocytes increased on 28 days-old adults and after. However, the difference in water content was not significant in hemocoel (F=2.39; df=4, 20; P=0.0847). Our result shows that immune-senescence relate with cellular immune response in adult male cricket.