Effect of temperature and relative humidity on the development and fecundity of Chilo partellus (Swinhoe) (Lepidoptera: Crambidae)

Abstract

The spotted stemborer, Chilo partellus (Swinhoe) (Lepidoptera: Crambidae), is one of the most important insect pests attacking maize and sorghum in Ethiopia. Recent studies have indicated that the pest is spreading to new locations where it was not reported before. In the current study, laboratory investigations were carried out to determine the combined effect of different levels of relative humidity and temperature regimes on the development and fecundity of C. partellus, as these physical factors are known to play an important role in the life cycle of insects and adaptability to local climate. Developmental time, longevity, potential fecundity and realized fecundity of C. partellus were measured under controlled conditions. Three temperature regimes (22°C, 26°C and 30°C) and three relative humidity levels (40%, 60% and 80%) were tested. It was found that temperature, relative humidity (RH) and their interaction significantly affected the developmental time, adult longevity, potential fecundity and realized fecundity of the pest. Developmental time was inversely related to temperature. Mean duration of C. partellus life cycle was 70.2 days at 22°C and 80% RH, whereas it took only 26.5 days to complete its life cycle at 30°C and 40% RH. Male and female longevity were similar in most cases. The adult life span ranged between 6.9-11.1 days at 22°C and 3.1-7.2 days at 30°C for different levels of relative humidity. The most suitable conditions for C. partellus development and fecundity were 26-30°C temperatures regimes and 60-80% RH levels.

Effect of rearing season, host plants and their interaction on economical traits of tropical tasar silkworm, Antheraea mylitta Drury- an overview

“…Temperature regimes and different levels of relative humidity are known to play an important role in the life cycle of insect and its adaptability to the local climate (Tamiru et al, 2012). Some researchers believe that the effect of temperature on insects largely overwhelms the effects of other environmental factors (Bale et al.…”

“…It has been reported that the temperature has highly significant effects on all developmental parameter of insect than humidity and rainfall (Bhat and Bhattacharya, 1978). Developmental time of an insect is inversely related to temperature (Tamiru et al, 2012). Among plants and their interactions (Venugopal and Krishnaswami, 1987).…”

“…Insects are cold-blooded (Poikilothermic) organisms, so their body temperature is more or less same as that of their surrounding microenvironment. Temperature influences everything that an organism does (Clarke, 2003), humidity affects embryonic development (Tamiru et al, 2012), and rainfall affects both.Environmental temperature, being the major abiotic factor, regulates the body temperature of caterpillar that determines the rates of feeding, fecundity, and mortality (Casey, 1981;Wellington et al, 1999). Temperature is probably the single most important environmental factor that influences behaviour, development, survival, reproduction, and geographical distribution of insects (Benchamin and Jolly, 1986;Shiva Kumar et al, 1997;Petzoldt and Seaman, 2013).…”

“…Temperature is probably the single most important environmental factor that influences behaviour, development, survival, reproduction, and geographical distribution of insects (Benchamin and Jolly, 1986;Shiva Kumar et al, 1997;Petzoldt and Seaman, 2013). All the insect species has their own choice of temperatures for usual growth and very high temperature slows down the growth that may leads to developmental malfunction, such as larval ecdysis and adult emergence (Chapman, 2002).Temperature regimes and different levels of relative humidity are known to play an important role in the life cycle of insect and its adaptability to the local climate (Tamiru et al, 2012). Some researchers believe that the effect of temperature on insects largely overwhelms the effects of other environmental factors (Bale et al.…”

“…If humidity falls below 70% during incubation, it affects hatching . Studies have also indicated the combined effects of temperature and relative humidity (Getu, 2007;Tamiru et al, 2012).Rainfall alters the functioning of microhabitat, which along with soil and other environmental factors affects foliage and water levels, which consequently affect on performance of insect (Mattson and Haack, 1987). Chemically the variation from succulent leaves to mature is so large that it may halve the growth rate of Lepidopteran larvae (Rausher, 1981).…”