Laboratory experiments were conducted to test the influence of temperature on several aspects of the female reproductive biology of the imported field bindweed moth, Tyta luctuosa. Results showed that some females emerge with partially developed ovarioles. However, temperatures (20 or 27.5°C) experienced during the pupal and preemerged adult period had no apparent influence on the degree of oocyte development at emergence. When held under constant temperatures before and after emergence, oocyte development in T. luctuosa was slightly retarded at 20°C within the first 24 hours as compared to 27.5°C. Thereafter, maturation was similar. When females experienced an increase in temperature (20 to 27.5°C) at emergence, oocytes developed faster than those held at a constant 27.5°C. A temperature decrease (27.5 to 20°C) delayed oocyte development. The preoviposition period was consistent over a wide range of temperatures (22.5 to 35°C), but it was inversely temperature-dependent between 15 and 20°C. The mean realized fecundity was the greatest (495 eggs) at 27.5°C and it was generally high between 20 and 32.5°C. The mean percentage of viable eggs was greatest between 22.5 and 27.5°C, and decreased above and below those temperatures. Very few viable eggs were observed at the extreme temperatures (15 and 35°C). Holding females under a thermoperiod of 35/30°C (avg.=32.5°C) resulted in a higher percentage of viable eggs than those held under a constant 32.5°C. Females lived the longest (mean=50 days) at 15°C. The shortest longevities (17-22 days) were observed at temperatures above 22.5°C. Our results contribute to improved rearing efficiency and population predictions of this weed biological control agent.
Species 1: Lepidoptera Noctuidae Tyta luctuosa
Keywords: Biological control, Weeds
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