González-Tokman Daniel, Martínez M Imelda, Villalobos-Ávalos Yesenia, Munguía-Steyer Roberto, Ortiz-Zayas María Del Rosario, Cruz-Rosales Magdalena, Lumaret Jean-Pierre
CONACYT, Mexico; Instituto de Ecología, A. C. Carretera Antigua a Coatepec 351, El Haya, Xalapa, Veracruz 91070, Mexico.
Instituto de Ecología, A. C. Carretera Antigua a Coatepec 351, El Haya, Xalapa, Veracruz 91070, Mexico.
Chemosphere. 2017 Jul;178:129-135. doi: 10.1016/j.chemosphere.2017.03.013. Epub 2017 Mar 16.
Ivermectin is a very common parasiticide used in livestock. It is excreted in the dung and has negative effects on survival and reproduction of dung-degrading organisms, including dung beetles. Here we exposed the dung beetle Euoniticellus intermedius to different concentrations of ivermectin in the food and evaluated reproductive success and the expression of traits associated with survival and reproduction under laboratory conditions. It is the first time the effects of ivermectin were evaluated on offspring physiological condition and the expression of a secondary sexual trait. We also registered the number of emerged beetles, sex ratio and body size of emerged adult beetles. Besides reducing the number of emerged beetles and body size, as found in the same and other insects, ivermectin at high doses reduced muscle mass while at intermediate doses it increased lipid mass. Ivermectin changed offspring sex ratio and at high doses increased the size of male horn, which is an important trait defining the male mating success. Our results highlight the importance of regulating parasiticide usage in livestock in order to maintain ecosystem services provided by dung beetles and confirm that contaminants impose new environmental conditions that not only impact on wild animal survival, but also on evolutionary processes such as sexual selection.
伊维菌素是一种在牲畜中常用的驱虫剂。它会随粪便排出，对包括蜣螂在内的粪便降解生物的生存和繁殖产生负面影响。在此，我们让中间真蜣螂（Euoniticellus intermedius）在食物中接触不同浓度的伊维菌素，并在实验室条件下评估其繁殖成功率以及与生存和繁殖相关的性状表达。这是首次评估伊维菌素对后代生理状况和第二性征表达的影响。我们还记录了羽化出的甲虫数量、性别比例以及羽化出的成年甲虫的体型大小。除了像在同种及其他昆虫中所发现的那样减少羽化出的甲虫数量和体型大小外，高剂量的伊维菌素会减少肌肉量，而中等剂量则会增加脂质含量。伊维菌素改变了后代的性别比例，高剂量时会增大雄性角的尺寸，而雄性角是决定雄性交配成功率的一个重要性状。我们的研究结果凸显了规范牲畜驱虫剂使用对于维持蜣螂所提供的生态系统服务的重要性，并证实污染物会带来新的环境条件，这不仅会影响野生动物的生存，还会影响诸如性选择等进化过程。
