Impacto da temperatura no desenvolvimento, fecundidade e longevidade de Corythucha gossypii fabricius, 1794 (HEMIPTERA: TINGIDAE) em mamoneira

Abstract

The castor bean (Ricinus communis) is attacked by several species of insects and mites that can cause damage to your plant tissues and may limit productivity. Among these, deserve attention Corythucha gossypii (Hemiptera: Tingidae) responsible for causing severe damage to several plant species, including the castor bean. Insects, in particular, are quite vulnerable to climatic changes, since most of these organisms are ectothermic. The objective of this research was to study the impact of temperature on the development, fecundity and longevity of C. gossypii in castor beans. The study was conducted at the laboratory of Pathology and Molecular Biology of Insects from Embrapa Cotton, municipality of Campina Grande, Paraíba, Brazil in climatic chambers, adjusted to temperatures 20, 23, 25 and 28 ° C, Relative Humidity of 60 ± 10% and photoperiod of 12 hours. The following biological variables were quantified: the egg stage (duration and viability), nymph (total duration, duration of each instar, number of instars and survival); egg period the emergence of adult males and females who were sexed according to the genitalia. In adult phase were evaluated periods of pre-oviposition, oviposition, post-oviposition, longevity and fecundity. The thermal constant (K) and temperature-base (Tb) was estimated for each of the immature stages and egg to adult emergence (males and females) according Réamur Law and the X intercept method, respectively. The duration of the stages of egg, nymph and egg to adult of C. gossypii with castor bean leaves temperatures ranged between 20 ° C and 28 ° C from 17.2 to 7.6 days; From 28.5 to 10.3 days and 45.7 to 17.9 days, respectively. The duration of nymphal stages of C. gossypii with castor leaves varied within each instar, between instars and sexes according to the temperature. The development stages of the egg, nymph and egg to adult of the C. gossypii requires 86.8; 123.5 and 208.3 degree-day, respectively, above the lower thermal limit of 15.1 ° C; 15.4 ° C and 15.4 ° C. The fertility was inversely proportional to the temperature increase. The biggest longevity of C. gossypii adults with castor leaves was observed at 25 °C and the minor at 20 °C.