Data from: The unexpected genetic mating system of the red-backed toadlet (Pseudophryne coriacea); a species with prolonged terrestrial breeding and cryptic reproductive behaviour

Molecular technologies have revolutionised our classification of animal-mating systems, yet we still know very little about the genetic-mating systems of many vertebrate groups. It is widely believed that anuran amphibians have the highest reproductive diversity of all vertebrates, yet genetic mating systems have been studied in less than one percent of all described species. Here, we use SNPs to quantify the genetic-mating system of the terrestrial breeding red-backed toadlet Pseudophryne coriacea. In this species, breeding is prolonged (approximately 5 months), and males construct subterranean nests in which females deposit eggs. We predicted that females would display extreme sequential polyandry because this mating system has been reported in a closely-related species (P. bibronii). Parentage analysis revealed that mating success was heavily skewed towards a subset of males (30.6% of potential sires), and that nearly all females (92.6%) mated with one male. In a high percentage of occupied nests (37.1%) the resident male was not the genetic sire, and very few nests (4.3%) contained clutches with multiple paternity. Unexpectedly, these results show that sequential polyandry is rare. They also show that there is a high frequency of nest takeover and extreme competition between males for nest sites, but that males rarely sneak matings. Genetic analysis also revealed introgressive hybridisation between P. coriacea and the red-crowned toadlet (P. australis). Our study demonstrates a high level of mating system complexity and it shows that closely-related anurans can vary dramatically in their genetic-mating system.

分子技术彻底革新了我们对动物交配系统的分类认知，但目前我们对多数脊椎动物类群的遗传交配系统仍知之甚少。学界普遍认为，无尾两栖类（Anura）是所有脊椎动物中生殖多样性最高的类群，但目前已开展遗传交配系统研究的物种尚不足已描述物种总数的1%。本研究借助单核苷酸多态性（Single Nucleotide Polymorphisms, SNPs）标记，对陆栖繁殖的红背丛蟾（Pseudophryne coriacea）的遗传交配系统进行定量分析。该物种的繁殖周期较长（约5个月），雄性会构筑地下巢穴供雌性产卵。我们曾预测雌性会表现出极端的连续一妻多夫制，因为该交配模式已在其近缘物种P. bibronii中被报道。亲子鉴定分析显示，交配成功率高度偏向少数雄性——仅30.6%的潜在父本成功获得交配机会，且几乎所有雌性（92.6%）仅与1只雄性交配。在占比达37.1%的已占用巢穴中，定居雄性并非子代的遗传父本；且仅有4.3%的极少量巢穴的卵团存在多父本现象。出乎意料的是，本研究结果表明连续一妻多夫制极为罕见。同时结果还显示，雄性间对巢穴位点的竞争极为激烈，巢穴被接管的频率较高，但雄性极少通过盗配获得交配机会。遗传分析还发现，红背丛蟾（P. coriacea）与红冠丛蟾（P. australis）之间存在渐渗杂交现象。本研究揭示了该物种极高的交配系统复杂性，同时也表明近缘无尾两栖类的遗传交配系统可能存在显著差异。