Biological And Ecological Characteristics Of Callosobruchus Maculatus Fabricius

As one kind of target insect in plant quarantine, Callosobruchus maculatus Fabricius has been often captured at border checkpoints in China. Lots of studies on the control of C. maculatus have been carried out to date and there were few researches about biological and ecological characteristics of C. maculatus, however, a comprehensive and systematical study on biological and ecological characteristics of C. maculatus has not been reported yet. In this paper, the biological and ecological characteristics of C. maculatus were systematically studied to provide some valuable information for the food sections and plant quarantine departments and meanwhile provide theoretical knowledge for the integrated control of C. maculatus.1 Biological characteristics of C. maculatusTwenty couples of newly emerged C. maculatus feeding on Vigna radiatus were mated in laboratory condition. The development periods of following eggs layed were observed and the biological characteristics of different stages of C. maculatus were also recorded. The results showed that 6 or 7 generations of C. maculatus occurred every year in Beibei, Chongqing. They overwintered in beans in stages of larvae, pupae and adults and there was a phenomenon of overlapping generations. Every adult could mate many times. When there was a low population density of C. maculatus and lots of beans existed, female adults were inclined to spawn on smooth and plump beans and only one egg would be laid on every bean. In contrast, one to four or more eggs would be laid on every bean if the population density of C. maculatus was large and thus limited beans could be found.2 Effects of temperature on growth and development and reproduction of C. maculatusEffects of temperature (20℃, 25℃, 28℃, 32℃, 35℃and 37℃) on growth and development and reproduction of C. maculatus feeding on mung bean were systematically studied in laboratory under a relative humidity of 75%. The results suggested that the corresponding development periods from eggs to adults amounted to 63.9, 30.8, 25.3, 19.5, 19.3 and 21.0 d, respectively, and the development zero temperatures of egg, larvae and immature periods were 12.67℃, 13.86℃and 13.53℃, respectively. There was a parabola relationship between temperature and development period. According to the corresponding parabola functions, the highest of generation survival rate of 86.53% expressed at 32℃and lowest of 34.01% at 20℃. There were significant effects of temperatures on ovipostion amount. At the temperatures range from 20 to 35℃, higher temperature, higher oviposition amount, however, there was a significant decrease for oviposition amount at 37℃. There was a parabola relationship between temperature and intrinsic increase rate and the optimum temperature for population growth was 32.5℃.3. Effects of food on the development and reproduction of C. maculatusThe development and reproduction of Callosobruchus maculatus Fabricius feeding on the seeds of Vigna radiata, Glycine max (L) Merr, V. angularis, Pisum sativum and V. umbellata were studied under the condition of 32℃with a relative humidity of 75%. C. maculatus feeding on the above six kinds of beans were able to develope and reproduce normally, but the development rates were different because of different kinds of beans. The development periods of larvae feeding on V. radiate and P. sativum were shorter than larvae on other beans from egg to adult. Higher survivorship rate, higher intrinsic increase rate were recorded for V. radiate and P. sativum and thus the two kinds of beans were considered to be the optimum hosts of C. maculatus.