Researchers Test the Prediction of Life History Theory about the Island Rule

Animals on islands often show distinctive differences in life-history traits, such as the gigantic or dwarf body size, when compared with neighboring mainland populations; this is known as the island rule. Until recently, there has not been a good explanation for the island rule, except for the life-history theory. Although the theory provides an ideal explanation for the trait differences on the island, the evolutionary consequences of these changes on offspring fitness has seldom been tested.

To test the life history theory's prediction about the island rule, researchers from Xinjiang Institute of Ecology and Geography of Chinese Academy of Sciences compared the difference of egg size and offspring fitness of the frog among 20 islands and two nearby mainland sites.

Research results showed that frogs on most of the islands did produce enlarged eggs and their larvae evolved from enlarged eggs had increased offspring fitness. The results of this study indicate that, for the first time, the life-history theory predictions concerning egg size and offspring fitness are supported.

The study is supported by China's Biodiversity Observation Network (Sino-BON). And the results, entitled “Enlarged egg size increases offspring fitness of a frog species on the Zhoushan Archipelago of China” were published in Scientific Reports.

Article link: https://www.nature.com/articles/s41598-019-48147-8

Contact: LIU Jie, Xinjiang Institute of Ecology and Geography

E-mail: liujie@ms.xjb.ac.cn