Abstract The flour beetles Tribolium castaneum (Herbst) and Tribolium confusum (du Val) are model organisms for studying the effects of intra- and interspecific competition. Both species are known to compete directly through egg cannibalism and indirectly through the density-dependent release of allelopathic chemicals.To better characterize these indirect interactions, recent work has focused on quantifying the per-capita effects of intraspecific chemical competition. However, the effects of interspecific chemical competition in this system have not previously been estimated. We used experimental microcosms to examine how interspecific chemical secretions affected the reproductive activity and development time of laboratory populations of T. castaneum and T. confusum. We created replicated habitats containing flour medium that had been occupied and chemically ‘conditioned’ by one of the two beetle species across a range of densities, then examined how beetles of the other species responded in terms of the number of eggs laid by females and, separately, the development time of offspring. We found that T. castaneum fecundity was reduced when beetles experienced flour conditioned by T. confusum. In contrast, fecundity of T. confusum was largely unaffected by flour conditioned by T. castaneum. Additionally, we found that interspecific conditioning decreased development times for beetles of both species, particularly the development of larvae to pupae. Our results indicate that interspecific chemical competition impacts the life history of Tribolium species and suggests that models incorporating chemical competition may more accurately describe the biology of flour beetle communities.

中文翻译：

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Tribolium castaneum 和 Tribolium confusum（鞘翅目：Tenebrionidae）之间的种间化学竞争降低繁殖力并加快发育时间

摘要 面粉甲虫 Tribolium castaneum (Herbst) 和 Tribolium confusum (du Val) 是研究种内和种间竞争影响的模式生物。已知这两个物种通过卵子同类相食直接竞争，并通过化感化学物质的密度依赖性释放间接竞争。为了更好地表征这些间接相互作用，最近的工作重点是量化种内化学竞争的人均效应。然而，以前尚未估计该系统中种间化学竞争的影响。我们使用实验微观世界来检查种间化学分泌物如何影响 T. castaneum 和 T. confusum 实验室种群的繁殖活动和发育时间。我们创建了包含面粉培养基的复制栖息地，这些培养基已被两种甲虫物种中的一种占据并进行化学“调节”，具有一定的密度，然后检查了其他物种的甲虫如何根据雌性产卵的数量做出反应，并且，分别，后代的发育时间。我们发现当甲虫经历由 T. confusum 调节的面粉时，T. castaneum 的繁殖力会降低。相比之下，T. confusum 的繁殖力在很大程度上不受由 T. castaneum 调节的面粉的影响。此外，我们发现种间调节减少了两种甲虫的发育时间，特别是幼虫到蛹的发育。