THERMAL REQUIREMENTS OF Thyrinteina arnobia (Stoll, 1782) AND EFFECTS OF THE TEMPERATURE IN ITS BIOLOGY

Abstract

This paper deals with  the thermal requirements of Thyrinteina arnobia (Stoll, 1782) and the  effect of temperature in its biology. The experiments were set at the Laboratory of Forest Entomology, “College of Agriculture Luiz de Queiroz”, University of São Paulo, Piracicaba, State of São Paulo. The thermal requirement of Thyrinteina arnobia were determined by using climatic chambers regulated at the following temperatures: 18, 22, 25, 30 and 32ºC. The relative humidity inside of the chambers was 60±10% and the photophase of 14 hours. The caterpillars were fed with leaves of Eucalyptus grandis, changed daily. The viability and the duration of the incubation period as well as the mortality in the larval phase (first instar, post first instar and larval total), prepupa and pupa phases and the malformation in the pupae and in the adults were determined. The duration of the larva, prepupa, pupa and adult phases were obtained for both sexes and also separately, in all the temperatures. The periods of preoviposition, oviposition, and postoviposition; number of egg masses/female; total number of eggs/female and viability of the oviposition/female were only observed at the temperatures of 22º, 25º, and 32ºC. The results indicated that mortality, duration of the developmental phases and the weight of pupae are affected by the threshold temperatures are: 9,0ºC for the egg phase; 11.72ºC (♂) and 11.40ºC (♀) for the larval phase; 8.10ºC (♂) and 10.89ºC (♀) for the prepupal phase; 11.73ºC (♂) and 11.74ºC (♀) for the pupal phase; 10.07ºC (♂) and 11.91ºC (♀) for the postembryonic development period; the thermal constants are 156.123 GD for the egg phase; 413.750 GD (♂) and 496.236 GD (♀) for the larval phase; 26.368 GD (♂) and 22.156 GD (♀) for the prepupal phase; 146.266 GD (♂) and 133.164 GD (♀) for the pupal phase; 855.120 GD (♂) and 637.479 GD (♀) for the postembryonic development period.