Larval crickets develop a big body and high aggressiveness under isolated conditions, but develop a small body and low aggression under crowded conditions. Furthermore, their ensemble variance increases. It is known that the heavier cricket tends to win. Therefore, the two growth processes affect competition. We constructed a mathematical model for intraspecific competition based on the Bonabeau model, showing bodyweight effects on the winning rate. Results show that the population mean of body weight decreases under the condition of specific memory enhancement that places more emphasis on losing than winning. Furthermore, hierarchical effects in foraging efficiency increase the ensemble variance.