A population of 420 snails Biomphalaria straminea, an intermediate host of
Schistosoma mansoni, received gamma-rays obtained from a ^60Co source in
low-doses (0/2,5/5/7,5/10/15/20 and 25 Gy); half population was kept in
colonies (allowing cross fertilization) and the other half was mantained in
sexual isolation (allowing self fertilization). Results showed that 15 Gy
stimulates the fertility of both groups but the colonies were more
sensitive and at this dose its fertility overpasses the control group dose.
The possible hormonal role played in the observed phenomena is under