Effect of trypsin modulating oostatic factor (TMOF) on trypsin and chymotrypsin in Glyphodes pyloalis Walker (Lep.: Pyralidae) and Hyphantria cunea Drury (Lep.: Arctiidae)

In the present study, the effect of three concentrations of TMOF (7.5, 15 and 30 μg dissolved in water) on trypsin and chymotrypsin biosynthesis in 4th instar larvae of Glyphodes pyloalis walker and Hyphantria cunea Drury were studied 24 h and 48 h after injecting. Our results indicated that in G. pyloalis, lower concentrations (7.5 and 15 μg) inhibited trypsin biosynthesis at 24 h after injection. (P < 0.0001). TMOF, however, did not significantly affect trypsin biosynthesis at 48 h. In H. cunea, at 48 h after the injection, all concentrations (7.5, 15 and 30 μg per larvae) significantly inhibited trypsin biosynthesis (P < 0.05). Injections of TMOF did not significantly affect chymotrypsin in both insects. Although, in G. pyloalis, chymotrypsin activity decreased about 25% at 48 h after injection.