Miño Carolina Isabel, de Souza Elaine Dantas, Moralez-Silva Emmanuel, Valdes Talita Alvarenga, Cortiço Corrêa Rodrigues Vera Lúcia, Del Lama Sílvia Nassif
Instituto de Biología Subtropical (IBS), Nodo Iguazú, Universidad Nacional de Misiones (UNaM)-CONICET, Puerto Iguazú, Misiones, Argentina.
Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos-SP, Brazil.
PLoS One. 2017 Aug 30;12(8):e0183153. doi: 10.1371/journal.pone.0183153. eCollection 2017.
Colonial waterbirds such as herons, egrets and spoonbills exhibit ecological characteristics that could have promoted the evolution of conspecific brood parasitism and extra-pair copulation. However, an adequate characterization of the genetic mating systems of this avian group has been hindered by the lack of samples of elusive candidate parents which precluded conducting conventional parentage allocation tests. Here, we investigate the genetic mating system of the invasive cattle egret using hematophagous insects contained in fake eggs to collect blood from incubating adults in a wild breeding colony. We tested a protocol with a previously unused Neotropical Triatominae, Panstrongylus megistus, obtained blood samples from males and females in 31 nests built on trees, drew blood from 89 nestlings at those nests, and genotyped all samples at 14 microsatellite loci, including six new species-specific loci. We comparatively addressed the performance of parentage allocation versus kinship classification of nestlings to infer the genetic mating system of cattle egrets. In line with previous behavioral observations, we found evidence in support of a non-monogamous genetic mating system, including extra-pair paternity (EPP) and conspecific brood parasitism (CBP). Parentage allocation tests detected a higher percentage of nests with alternative reproductive tactics (EPP: 61.7%; CBP: 64.5%) than the kinship classification method (EPP: 50.0%; CBP: 43.3%). Overall, these results indicate that rates of alternative reproductive tactics inferred in the absence of parental genetic information could be underestimated and should be interpreted with caution. This study highlights the importance of incorporating samples from candidate parents to adequately determine the genetic mating system of a species. We expand knowledge on the reproductive tactics of colonial waterbirds, contributing novel data on the genetic mating system of the cattle egret, valuable for the design of management strategies for this invasive bird.
诸如苍鹭、白鹭和琵鹭等群居水鸟表现出的生态特征，可能促进了同种巢寄生和配偶外交配的进化。然而，由于难以获得难以捉摸的候选亲本样本，这妨碍了进行常规的亲子关系分配测试，从而阻碍了对这一鸟类群体遗传交配系统的充分表征。在这里，我们利用假蛋中所含的吸血昆虫从野生繁殖群体中正在孵蛋的成年鸟身上采集血液，来研究入侵性牛背鹭的遗传交配系统。我们测试了一种方案，使用一种此前未使用过的新热带地区锥蝽，即巨蝽，从树上建造的31个鸟巢中的雄性和雌性鸟身上获取血液样本，从这些鸟巢中的89只雏鸟身上采血，并在14个微卫星位点对所有样本进行基因分型，其中包括6个新的物种特异性位点。我们比较了雏鸟亲子关系分配与亲属关系分类的表现，以推断牛背鹭的遗传交配系统。与之前的行为观察结果一致，我们发现了支持非一夫一妻制遗传交配系统的证据，包括配偶外交配（EPP）和同种巢寄生（CBP）。亲子关系分配测试检测到采用替代繁殖策略的鸟巢比例（EPP：61.7%；CBP：64.5%）高于亲属关系分类方法（EPP：50.0%；CBP：43.3%）。总体而言，这些结果表明，在没有亲本遗传信息的情况下推断出的替代繁殖策略发生率可能被低估，应该谨慎解释。这项研究强调了纳入候选亲本样本以充分确定一个物种遗传交配系统的重要性。我们扩展了对群居水鸟繁殖策略的认识，为牛背鹭的遗传交配系统提供了新的数据，这对于设计针对这种入侵鸟类的管理策略具有重要价值。
