El Gusano Rosado Colombiano (Sacadodes Pyralis): Observaciones Preliminares Sobre Fecundidad,Fototropismo Y Dormancia 1

The objective of the present study was to make observations on the fecundity, phototropism and dormancy of the "gusano rosado colombiano" Sacadodes pyralis Dyar (Lepidoptera: Noctuidae). Eggs were collected in the field and also obtained from females captured at light sources; the fluctuation of the number of males and females caught at light sources was related to precipitation and moon phases, and the length of the pupal stage of individuals collected at different dates was measured. All studies were carried out at the ICA Experimental Station "Motilonia" and in the cotton region of Codazzi-Valledupar during the 1975-76 growing season.

The results indicate that the percent hatch of eggs obtained from females collected at light sources and kept under laboratory conditions is higher than that of eggs collected in the fields, being the average in the first case 86.29 % and in the second 57.37 %. Only eggs collected at the end of the season were parasitized by Trichogramma sp. (Hymenoptera: Trichogrammatidae). As the embryonic development of the eggs advances their initial turquois-blue color changes to white and then to grey. Turquois-blue eggs presented a lower percent of eclosion than the white ones.

The light sources used in this study attracted a higher number of males than females and the latter ones were already fertilized, but apparently had not oviposited. The variation in flight activity of the adults could be related to the moon phases, observing an increasing activity towards crescent moon and a decreasing one towards full moon. Another important factor influencing adult emergency is precipitation.

It was confirmed that pupae of S. pyralis are capable of entering an inactive state which allows the insect to survive from season to season.

Based on the results of the duration of the pupal stage and additional observations, the hypothesis that this inactive state is dormancy, induced by environmental factors like precipitation and food availability, and that the same factors once again favourable finish the inactivity, was established.