A laboratory model of circulation of the malaria causative agent P. gallinaceum 
has been used to show that the effect of precocene (antijuvenoid) leads to a 
statistically significant reduction in the proportion of infected females 
developing eggs after blood suction. The females failing to develop eggs are not 
infected. Trichopol (antiexdisone) inhibits vitellogenesis The females 
undeveloping eggs become susceptible to the causative agent though to a lesser 
degree than those developing them. The findings suggest that there is an 
association of the mosquito susceptibility to the malaria causative agent with 
the balance of hormones in the body of disease the carrier.