豚草条纹叶的生态学特性

在一定空间(7238厘米~3)的养虫器内,豚草条纹叶(虫甲)成虫的生殖力随密度的增加而下降。单对饲养的生殖力最高,平均产卵386.7粒;当密度为18和25头时,产卵仅157.6和50.4粒。幼虫期以及蛹期的死亡率,在不同空间中均随密度的增加而增加,随空间的增大,各密度下的死亡率相应减少。食料质量是影响幼虫存活的重要因素之一,用豚草上、中、下部叶片饲养幼虫,其死亡率分别为10％、70.3％和97.6％。幼虫期累计食叶量可达90.58毫克鲜重,随着日龄增加,近似消化力逐渐下降,摄入物质转换为体物质的效率和消化食物转换为体物质的效率随日龄的增加而增加。成熟成虫的取食量基本恒定,平均每48小时食叶28.01毫克鲜重,其近似消化力为64.2％。刚羽化出土的成虫,达到成熟进入生殖生长所需的食叶量约为213.22毫克鲜重。

LABORATORY BIONOMICAL STUDIES ON ZYGOGRAMMA SUTURALIS [COL.: CHRYSOMELIDAE]

Laboratory studies on some biological and ecological characteristics of Z. suturalis were conducted during 1987-1989. The total number of eggs laid by the experimental population of Z, suturalis was influenced by the rearing density in a parabolical pattern. The average fecundity of the females declined as the adult density increased in the containers of a fixed volume. A maximum of 386.7 eggs was obtained when only one pair of adults were reared in a container of 7238cm3 volume. When 18 and 25 adults were reared in the containers of the same size, each female laid 157.6 and 50.4 eggs, respectively. The mortalities of the larval and larva-pupal stages increased as the rearing density increased. Yet the mortalities in each density treatment decreased in larger containers. Food quality was found to be one of the important factors affecting larval survival. When the larvae were fed with the leaves fiom upper, middle and lower parts of ragweed plants, the average mortalities were 10%, 70.8% and 97.6%, respectively. Results of the larval consumption rate analysis showed that the accumulative consumption was 90.58 mg (fresh weight) per larva. Larvae of 10 days old had the highest consumption. The approximate digestibility (A.D.) declined and the efficiencies of conversion for ingested and digested food (E.C.I, and E.C.D.) increased as the larvae developed older.The daily food consumption by new-lyemerged adults was significantly greater than that by mature adults.Each adult consumed an average of 213.22 mg of fresh leaves before oviposition.