Athanassiou Christos G, Kavallieratos Nickolas G, Campbell James F
Laboratory of Entomology and Agricultural Zoology, Department of Agriculture Crop Production and Rural Development, University of Thessaly, Nea Ionia, Magnissia, Greece.
United States Department of Agriculture (USDA), Agricultural Research Service (ARS), Center for Grain and Animal Health Research (CGAHR), Manhattan Kansas, United States of America.
PLoS One. 2017 Mar 6;12(3):e0173377. doi: 10.1371/journal.pone.0173377. eCollection 2017.
Laboratory tests were carried out in order to examine competition among three congeneric species on rice and maize: the granary weevil, Sitophilus granarius, the rice weevil, Sitophilus oryzae and the maize weevil, Sitophilus zeamais. For this purpose, a total of 30 adults were placed in vials that contained 50 g or either rice or maize: 30 adults of S. granarius, 30 adults of S. oryzae, 30 adults of S. zeamais, 15 adults of S. granarius+15 adults of S. oryzae, 15 adults of S. granarius+15 adults of S. zeamais, 15 adults of S. oryzae +15 adults of S. zeamais, and 10 adults of S. granarius+10 adults of S. oryzae+10 adults of S. zeamais. After 62 days at 30°C and 65% relative humidity the number of individuals of each species were counted. Insect damaged kernels (IDK), weight of frass and grain weight were measured. When each species was alone, S. granarius had the lowest numbers of adults in both grains, which did not exceed 34 adults/vial, and S. oryzae numbers were always higher than other species. For S. oryzae and S. zeamais, the numbers of adults were considerably higher on rice than on maize. On rice, S. oryzae numbers ranged between 281 and 563 adults per vial, while for S. zeamais between 137 and 372 adults per vial. At the same time, for both species on maize, adult numbers did not exceed 54 adults per vial. The number of S. oryzae adults were constantly higher than the other species in all combinations tested. Moreover, for rice, IDK in the vials that contained S. oryzae, either alone or in combination with other species, was higher than all the other combinations. Similarly, grain weight was lower in the vials that contained S. oryzae compared to the other species combinations. In general, for S. oryzae and S. zeamais progeny production was increased with the increase of the number of the initial adults that had been placed inside the vials. At the same time, progeny production of all three species was not affected by the presence of another species inside the vial. Given that the coexistence of congeneric species in the same stored product ecosystem is often reported, our results highlight some of the inferences that are necessary in order to predict the potential outcome of competition patterns. Apart from its ecological significance, the prediction of the superior species in mixed species communities, can guide and time any control measures, on a more species-targeted basis.
为研究三种近缘象甲在水稻和玉米上的竞争情况，进行了实验室试验。这三种象甲分别是谷象（Sitophilus granarius）、米象（Sitophilus oryzae）和玉米象（Sitophilus zeamais）。为此，将总共30只成虫放入装有50克水稻或玉米的小瓶中：30只谷象成虫、30只米象成虫、30只玉米象成虫、15只谷象成虫 + 15只米象成虫、15只谷象成虫 + 15只玉米象成虫、15只米象成虫 + 15只玉米象成虫，以及10只谷象成虫 + 10只米象成虫 + 10只玉米象成虫。在30°C和65%相对湿度条件下放置62天后，统计每种象甲的个体数量，并测量昆虫损伤粒（IDK）、粪便重量和谷物重量。当每种象甲单独存在时，谷象在两种谷物中的成虫数量最少，每个小瓶不超过34只，米象的数量始终高于其他象甲。对于米象和玉米象，在水稻上的成虫数量明显高于在玉米上的。在水稻上，每个小瓶中米象的数量在281至563只成虫之间，而玉米象在137至372只成虫之间。同时，对于这两种象甲在玉米上的情况，每个小瓶中的成虫数量不超过54只。在所有测试组合中，米象成虫的数量始终高于其他象甲。此外，对于水稻，装有米象的小瓶，无论单独存在还是与其他象甲组合，其昆虫损伤粒都高于所有其他组合。同样，装有米象的小瓶中的谷物重量比其他象甲组合的要低。总体而言，对于米象和玉米象，随着放入小瓶中初始成虫数量的增加，后代数量增加。同时，小瓶中存在其他象甲不会影响这三种象甲的后代数量。鉴于在同一储藏产品生态系统中经常报道近缘象甲的共存情况，我们的结果突出了一些为预测竞争模式潜在结果所必需的推断。除了其生态意义外，预测混合物种群落中的优势物种，可以在更具针对性的物种基础上指导并适时采取任何控制措施。
