The influence of temperature and humidity on the life-cycle of Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae)

Abstract

The development of a stock of Corcyra cephalonica (Stnt.) from Burma was followed carefully on a diet of wheatfeed, glycerol and yeast at constant temperatures ranging from 15 to 37°C and humidities from 15 to 90% RH. Two other stocks, from Nigeria and Malawi, were also studied under a few conditions. Limits for complete development from egg hatch to adult emergence were about 17 and 35°C at 70% RH. At 15°C, all larvae died early in development, but at 37 -5°C a few managed to pupate. Highest survival and most rapid development occurred at 30-3 2-5 °C and 70% RH. Development was completed in the range 15-80% RH, but few adults emerged at 15% RH and none at 90% RH unless a mouldinhibitor was present in the food. No second-generation larvae were obtained from adults reared and kept at 20°C and 70% RH. Egg period was influenced by temperature but not by humidity in the range 20-80% ,RH. Eggs hatched at temperatures from 175 to 325 C C. Hatch was adversely affected by low humidity, and very few hatched at 20% RH. Considerable variation in the rate of egg hatch between the three stocks may have been due to differences in the length of time each stock had been reared in the laboratory. Cold tolerance of eggs of the Nigerian stock was low. All eggs died at 10°C after a seven-day exposure, and at 15°C, although a few 0-1-day-old eggs exposed for 14 days hatched, none completed development to the adult stage. Although older eggs were slightly more cold-tolerant than younger ones at 10°C, they were less so at 15°C. Adult males tended to emerge earlier and live longer than unmated females. Adults of the recently collected Malawi stock were heavier and lived longer than those of the Burma stock that had been reared in the laboratory for many generations.

Impact of Abiotic Factors on the Growth and Development of Corcyra cephalonica Stainton in Stored Maize

“…The effect of both factors on longevity of male and female adults showed that the longevity of adult was maximum at 20°C and 40 per cent relative humidity combinations, and it was minimum at 40°C and 60 per cent relative humidity. This finding is in close conformity with the findings of Cox et al, (1981) reported that the life span of C. cephalonica increased with decreasing temperature between 20 and 35°C. Cheema et al, 1988.…”

Comparison of artificial diets for rearing Corcyra cephalonica (Stainton, 1865) (Lep., Pyralidae) for Trichogramma mass production

“…Comparison of diets for Corcyra cephalonica (Stainton, 1865) With regard to the duration of the egg-adult period, diets E (wheat germ and yeast) and F (rice bran, sugar and yeast) proved to be the most adequate for the insect, as they provided a reduction in that period, although they did not statistically differ from diets B (ground rice and sugar) and D (whole wheat flour and yeast). Based on Singh (1983), who recommended 75% of total viability as the minimum percentage for an artificial diet to be considered adequate for insect rearing, the diets under study are close to that value, specially diets B and E. The total viability results (Table 2) observed in this study are within the range reported by Cox et al (1981), Osman (1986), and Shazali & Smith (1986), even though they differ from those reported by Russell et al (1980) and Cadapan (1988). In statistical terms, the mortality in the egg-adult period was similar on the 6 diets studied.…”

The Importance of Relative Humidity for Telenomus remus (Hymenoptera: Platygastridae) Parasitism and Development on Corcyra cephalonica (Lepidoptera: Pyralidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) Eggs

“…The difference in the effect of humidity on parasitism in the two hosts may be because of the physiological differences between them; as the factitious host is able to develop in a low humidity environment (15%; Cox et al 1981), the eggs have a low water content, and an increase in humidity in this environment might be required for the proper development of the parasitoid. However, features like host egg volume, chorion thickness, nutritional content, age, and the shape of the host egg masses can affect the ability of the host egg to maintain its humidity, which affects parasitism and the sex ratio (Hoffmann et al 2001, Roriz et al 2006, Rukmowati-Brotodjojo and Walter 2006.…”