Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-8528, Japan.
Fukushima Prefectural Research Institute of Fisheries Resources, Soma, Fukushima, 976-0005, Japan.
Sci Rep. 2022 May 12;12(1):7911. doi: 10.1038/s41598-022-12144-1.
The naticid snail Laguncula pulchella is an invasive species that preys on clams in tidal flats and has serious impacts on clam fisheries in Japan. Laguncula pulchella burrow in sand, but often crawl on sediment surfaces during low tide. We investigated seasonal changes in the abundance and sex ratio of crawling L. pulchella during the daytime at Matsukawaura Lagoon, Japan, from March to October from 2015 to 2019. The density of crawling individuals peaked in July. The sex ratio of crawling individuals varied with months and years but was significantly biased towards males during the main copulation period (July-August); males accounted for 77-98% of the mature crawling individuals (≥ 25 mm shell height). The somatic condition of mature males declined from June to August, whereas that of females was constant during this period. These results indicate that mature males actively come to the sand surface during low tide to search for females for copulation from July to August. Fishermen make efforts to remove crawling individuals in summer, but the male-biased sex ratio must also be considered for effective population control of this species.
豆荚螺是一种入侵物种，以潮间带的贻贝类为食，对日本的贻贝渔业造成了严重影响。豆荚螺在沙中挖洞，但在退潮时经常在沉积物表面爬行。本研究于 2015 年至 2019 年 3 月至 10 月在日本松川浦泻湖，对豆荚螺白天在沙滩上的爬行密度和性别比例的季节性变化进行了调查。爬行个体的密度在 7 月达到峰值。爬行个体的性别比例随月份和年份而变化，但在主要交配期（7-8 月）明显偏向雄性；成熟的爬行个体（壳高≥25mm）中，雄性占 77-98%。成熟雄性个体的体况从 6 月到 8 月下降，而雌性个体在这段时间内保持不变。这些结果表明，成熟的雄性个体在 7 月至 8 月期间会在退潮时主动来到沙滩表面寻找雌性进行交配。渔民在夏季努力清除爬行个体，但为了有效控制该物种的种群数量，还必须考虑雄性偏多的性别比例。
