| The cabbage beetle, Colaphellus bowringi Baly (Coleoptera: Chrysomelidae) is a serious pest of crucifers (Brassica chinensis and Raphanus sativus) and is widely distributed in China, undergoing an imaginal diapause in the soil. The experimental animals were collected from Harbin city (HB,45°8’N,126°6’E) in Heilongjiang Province, Taian city(TA,36°2’N,117°1’E) in Shandong Province, Xiu Shui county (XS,29°1’N,114°4’E) in Jiangxi Province and Longnan county(LN,24°9’N,114°8’E) in Jiangxi Province. The HB population only has one generation per year in Harbin city and has only one distinct infestation peaks per year in summer, hiberating as adults in the soil. The HB population is lack of photoperiodic response, and all individuals enter diapause at temperatures≤28℃, only few individuals can develop without diapause at30℃. The TA population has two distinct infestation peaks per year in the field, one in spring and the other in autumn, hiberating and aestivating as adults in the soil. The TA population is also lack of photoperiodic response, and all individuals enter diapause at temperatures≤25℃, only few individuals can develop without diapause at25℃. The XS population and LN population both have four generations per year, one generation in spring, aestivating as adults in the soil, the other in autumn, hiberating as adults in the soil. The two populations both show a short-day response. The short-day can induce development, but long-day can induce diapause. However, the photoperiodic responses for the two populations highly depend on temperature. All individuals of XS population enter diapause at≤20℃regardless of photoperiod, non-diapause individuals can be produced at temperatures>20℃. All individuals of LN population enter diapause at≤18℃regardless of photoperiod, non-diapause individuals can be produced at temperatures>18℃.In this study, the four different populations (HB, TA, XS and LN) were crossed, and their biology, photoperiodic response of diapause induction and diapause termination were investigated.1. Biology of the crosses between TA and XS populations of C. bowringiThe number of egg production and longevity of hybrids and selfings of XS and TA populations in C. bowringi were systematically investigated at22℃under LD12:12, and the body weight for their diapause progeny and diapause termination were compared at25℃,28℃and30℃. The result shows that, the number of egg production of XS population was significantly higher than TA and the hybrid populations. The mean total egg production per female of TA population was higher than the hybrid populations, but not significantly. The number of egg production of the hybrids of♀XS×♂TA was higher than the hybrids of♀TA×♂XS. The female longevity of XS population was significantly higher than TA and the hybrid populations, but there were no significantly difference in male longevity. The body weight of male and female of XS population was significantly higher than TA population, and the body weight of hybrids of♀XS×♂TA and♀TA×♂XS population were between XS and TA populations, and the body weights of progeny in♀XS×♂TA were higher than those in♀TA×♂XS, indicating that maternal effects on diapause induction are stronger than paternal effects. The body weight of XS、 TA、♀XS×♂TA and♀TA×♂XS populations decreased with increasing temperature. The experiment of diapause termination shows that, the percent of adult emergence of XS、TA、♀XS×♂TA and♀TA×♂XS populations from the soil in autumn of XS、 TA、♀XS×♂TA and♀TA×♂XS populations were lower than those in spring. The percent of adult emergence from the soil of♀XS×♂TA population was similar with XS population. The♀TA×♂XS population was similar with TA population.2. Biology of the crosses between HB and TA populations of C. bowringiThe number of egg production and longevity of hybrids and selfings of HB and TA populations in C. bowringi were systematically investigated at22℃under LD12:12, and the body weight for their diapause progeny and diapause termination were compared at25℃,28℃and30℃. The result shows that, the mean total egg productions in♀HB×♂TA and♀TA×♂HB were significantly lower than TA and HB population. The male and female longevity of♀TA×♂HB was shorter than that of♀HB×♂TA. The body weights of progeny of♀HB×♂TA and♀TA×♂HB were between HB and TA populations, and the body weight of progeny of♀TA×♂HB was higher than the progeny of♀HB×♂TA, showing that maternal effects on the body weight are stronger than paternal effects. The body weight of TA, HB, and♀TA×♂HB and♀HB×♂TA populations decreased with increasing temperature. The hatching rate of eggs produced by♀TA×♂HB and♀HB×♂TA were higher than those produced TA and HB population, but not significantly different. The experiment of diapause termination showed that most individuals of TA、♀TA×♂HB and♀HB×♂TA populations emerged from the soil in spring, a few individuals emerged from the soil in autumn, however, all hiberating individuals of HB emerged from the soil in spring.3The photoperiodic responses of diapause induction for the crosses between the different geographic populations of C. bowringiThe photoperiodic responses of XSxXS, TA×TA,♀XS×♂TA and♀TA×♂XS populations in C. bowringi were observed at25℃and28℃. The results showed that the photoperiodic responses in♀XS×♂TA showed a short photoperiodic response, similar to the XSxXS, whereas the incidences of diapause inTAxTA and♀TA×♂XS populations were similar under different photoperiods, without showing a short-day photoperiodic response. This result suggests that the inheritance of photoperiodic response is controlled by maternal. There were no photoperiodic response in TA and HB populations at25℃and28℃, almost all individuals entered diapause regardless of photoperiod. However, the progeny of♀HB×♂TA show a short-day photoperiodic response, and the rate of diapause under short photoperiods was obviously lower than their parents. It was rare phenomenon that two high rate of diapause hybridization populations can produce low rate of diapause offspring, and it needed to be further confirmed.4Biology of the crosses between LN and HB populations of C. bowringiThe number of eggs production and longevity of LN×LN, HBxHB,♀LN×♂HB and♀HB×♂LN in C. bowringi were systematically investigated at22℃under LD12:12, and the body weight for their diapause progeny were compared at25℃and28℃. The result showed that the mean total egg production of♀LN×♂HB and♀HB×♂LN populations were significantly lower than LN and HB populations. The hatching rate of eggs of the♀LN×♂HB was similar to LN population, and the♀HB×♂LN was similar to HB population, but not significantly different. The female longevity of the♀LN×♂HB was similar to LN population, and the♀HB×♂LN was similar to HB population. The body weights of the♀HB×♂LN and♀LN×♂HB population were between HB and LN populations, suggesting that the inheritance of body weight is contolled under polygene. The body weight of the♀LN×♂HB was higher than the♀HB×♂LN, suggesting that maternal effects on body weight are stronger than paternal effects. |
PDF Full Text Request