Laboratoire d'Entomologie Appliquée, Faculté des Sciences, Université de Lomé BP 1515, Lomé Togo.
J Insect Sci. 2010;10:129. doi: 10.1673/031.010.12901.
The reproductive capacities and development of the seed beetle Acanthoscelides macrophthalmus (Schaeffer) (Coleoptera: Bruchidae), found in Togo, were determined under natural conditions in a Guinean zone for its use as a substitute host for the mass rearing of the parasitoid Dinarmus basalts Rond (Hymenoptera: Pteromalidae), a biological agent for the control of beetles that are pests of cowpea, Vigna unguiculata (L.) Walpers (Fabales: Fabaceae). Population dynamics at the field level; and survival, fecundity and offspring production by A. macrophthalmus under laboratory conditions were measured when fed on its natural plant-host Leucaena leucocephala (Lamark) deWit (Fabales: Mimosaceae). The data resulting from the laboratory study were used to calculate the demographic parameters of A. macrophthalmus by establishing its fertility and life tables. Contrary to cultivated leguminous food plants, L. leucocephala is a perennial sub-spontaneous leguminous plant whose pods are available year round. Although A. macrophthalmus was present in nature throughout the year, its infestation rate of the pods fluctuated according to the phenology of the plant. The maximum infestation of L. leucocephala pods was observed between August and December. Four larval stages and one pupal stage of A. macrophthalmus were identified in the laboratory. The total mean development time varied on average 33.75 ± 2.87 days on the mature pods and 33.39 ± 2.02 days on seeds. The adult female lived from one to two weeks. During its life time, the female laid an average of 62.3 ± 19 and 43.1 ± 13 eggs on the mature pods and seeds respectively and produced an average of 36.7 ± 11.3 offspring on the mature pods and 21.8 ± 8.4 offspring on seeds. On seeds, the net reproduction rate was 5.88 females per female and the intrinsic rate of population increase 0.051 per day. The generation time was 34.59 days and the doubling time 13.59 days. The demographic parameters of A. macrophthalmus in this study are close to those of Callobruchus maculatus F. (Bruchidae), the natural host of D. basalts in a previous study. A. macrophthalmus could therefore be used as substitute host for the mass rearing of D. basalts and subsequently its release in farmers' storage containers. The data presented in this study provide some baseline information regarding the reproductive capacities of A. macrophthalmus that may be useful for its promotion as a substitute host for mass rearing of D. basalts.
在为替代寄主大规模饲养寄生蜂巴氏金小蜂（Dinarmus basalts Rond）（膜翅目：金小蜂科）而对其在自然条件下进行研究时，确定了在多哥发现的种象甲（Acanthoscelides macrophthalmus）（鞘翅目：豆象科）的生殖能力和发育情况。巴氏金小蜂是豇豆象（Callosobruchus maculatus F.）（鞘翅目：豆象科）的一种生物防治剂，也是豇豆的害虫。在野外水平上对种群动态进行了测量；并在实验室条件下，以其天然植物寄主勒氏银合欢（Leucaena leucocephala）（Fabales：含羞草科）为食时，对种象甲的存活率、繁殖力和后代产量进行了测量。通过建立其生殖力和生命表，利用实验室研究得出的数据计算了种象甲的人口统计学参数。与栽培豆类食物植物相反，勒氏银合欢是一种多年生半野生豆科植物，其豆荚全年都有。尽管种象甲全年都存在于自然界中，但它对豆荚的侵染率随植物的物候而波动。勒氏银合欢荚果的最大侵染发生在 8 月至 12 月之间。在实验室中鉴定出种象甲的四个幼虫阶段和一个蛹阶段。在成熟豆荚上，总平均发育时间平均为 33.75 ± 2.87 天，在种子上为 33.39 ± 2.02 天。雌性成虫的寿命为一到两周。在其生命周期中，雌性在成熟的豆荚上平均产卵 62.3 ± 19 枚，在种子上产卵 43.1 ± 13 枚，在成熟的豆荚上平均产生 36.7 ± 11.3 只后代，在种子上产生 21.8 ± 8.4 只后代。在种子上，净生殖率为每只雌虫 5.88 只，种群内增长率为每天 0.051。世代时间为 34.59 天，倍增时间为 13.59 天。种象甲的人口统计学参数与巴氏金小蜂的自然寄主豇豆象（Callobruchus maculatus F.）（鞘翅目：豆象科）的参数相近。因此，种象甲可用作巴氏金小蜂的大量饲养替代寄主，随后可将其释放到农民的储存容器中。本研究提供了有关种象甲生殖能力的一些基线信息，这可能对其作为巴氏金小蜂大量饲养的替代寄主的推广有用。
