Latitudinal pattern in body size in a cockroach,Eupolyphaga sinensis |
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Authors: | Yuwei Hu Fen Zhu Xiaoping Wang Chuxiong Guan Yuxing An Chaoliang Lei |
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Institution: | 1. Bioengineering Institute of Guangdong, General Research Institute for Industrial Technology, , Guangzhou, 510316 Guangdong, China;2. Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science & Technology, Huazhong Agricultural University, , Wuhan, 430070 Hubei, China |
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Abstract: | Body size of insects with flexible life cycles is expected to conform to the saw‐tooth model, a model in which the relationship between size and developmental time depends on length of the growing season. In species with high variability in terms of voltinism, however, more complex patterns can be expected. Few empirical studies have demonstrated the existence of such relationships, or whether climatic factors contribute to these relationships. In this study, we investigated the geographic variation in body size of the Chinese cockroach, Eupolyphaga sinensis Walker (Blattaria: Polyphagidae), which has a variable life cycle length. The sizes of adults – collected from 14 localities ranging from temperate to subtropical zones in China – were measured, using body length, body width, and pronotum width as parameters. The relationship between size, latitude, and climate factors (encompassing 10 variables) was then investigated. We found that the body size of E. sinensis varied considerably with latitude: cockroaches were larger at low and high latitudes, but smaller at intermediate latitudes. Thus, the relationship between climate and body size conformed to a saw‐tooth pattern. Results indicate that two factors were significantly associated with body size clines: season length and variability in life cycle length. Our results also demonstrated that climatic factors contribute to latitudinal clines in body size, which has important ecological and evolutionary implications. It can be expected that global climate change may alter latitudinal clines in body size of E. sinensis. |
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Keywords: | climate climate change saw‐tooth model season length voltinism latitude Blattaria Polyphagidae |
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