Abstract：
Hybridization induced by human activities, such as crossbreeding between invasive and native species, can adversely affect the natural biodiversity of an ecosystem. In Japan, the endemic turtle species Mauremys japonica is known to hybridize with the alien species Mauremys reevesii, and putative hybrids have been encountered in the wild. If M. japonica × M. reevesii hybrids can readily crossbreed with M. japonica, the hybridization with M. reevesii could lead to the extinction of pure M. japonica populations. However, information on the reproductive ability of M. japonica × M. reevesii hybrids is limited. In this study, we collected wild-caught hybrids from across western Japan to assess their reproductive ability. We investigated the nesting season timing, clutch size, embryonic development, hatching success, and sperm viability. The results showed that female hybrids nested during the same months as the parental species and had similar clutch sizes and hatching success. No embryonic development abnormalities were detected, and viable sperm were observed in all hybrid male semen samples. In conclusion, the fertility of M. japonica × M. reevesii hybrids appears to be similar to the fertilities of the parental species, posing a potential challenge for M. japonica conservation.
摘要：
人类活动诱导的杂交，例如入侵物种和本地物种之间的杂交，会对生态系统的自然生物多样性产生不利影响。在日本,已知特有的海龟物种Mauremysjaponica与外来物种Mauremysreevesii杂交，在野外遇到了推定的杂种。如果M.japonica×M.reevesii杂种可以很容易地与M.japonica杂交，与reevesiiM.杂交可能导致纯种的灭绝。然而,有关M.japonica×M.reevesii杂种繁殖能力的信息有限。在这项研究中,我们从日本西部收集了野生捕获的杂种，以评估其繁殖能力。我们调查了筑巢季节的时间，离合器尺寸，胚胎发育,孵化成功，和精子活力。结果表明，雌性杂种在与亲本物种相同的月份嵌套，并且具有相似的离合器大小和孵化成功率。未检测到胚胎发育异常，在所有杂种男性精液样本中均观察到有活力的精子。总之,M.japonica×M.reevesii杂种的繁殖力似乎与亲本物种的受精相似，对粳稻的保护构成了潜在的挑战。
