Egg trait variation in a large hawk‐cuckoo (Hierococcyx sparverioides) host population of Chinese babax (Babax lanceolatus) |
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| Authors: | Canchao YANG Yang LIU Wei LIANG |
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| Institution: | 1. Ministry of Education Key Laboratory for Tropical Animal and Plant Ecology, College of Life Sciences, Hainan Normal University, Haikou, China;2. State Key Laboratory of Biocontrol and College of Ecology and Evolution, Sun Yat‐sen University, Guangzhou, China |
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| Abstract: | Mutual interaction between brood parasites and their hosts is a well‐known model system for studying host–parasite coevolution. Both parties have acted reciprocally, resembling an evolutionary arms race, in which adaptations and counter‐adaptations have evolved as a result of host–parasite dynamics, such as the classical cuckoo–host system. Discrimination among parasite and cuckoo eggs and rejection of foreign eggs is regarded as an important anti‐parasitism strategy. The Chinese babax (Babax lanceolatus) is a large hawk‐cuckoo (Hierococcyx sparverioides) host distributed in southwest China. A previous study shows that the babax is an intermediate egg rejector, and most cuckoo eggs are accepted by the Chinese babax, although a small proportion of hosts reject cuckoo eggs. Interestingly, the large hawk‐cuckoo lays non‐mimetic eggs in contrast to the uniform blue eggs of babaxes. Because egg coloration is a critical cue used by host species in favor of the recognition of parasitic eggs by hosts, we used a spectrometer to quantify egg color variation to understand the differentiation in discrimination ability between the egg rejectors and acceptors. We found that the chroma of intra‐clutch variation of babax eggs was more consistent in egg rejectors than in acceptors. However, no statistical significance was found in inter‐clutch variation between these two types of hosts. Our results suggest that hosts lay eggs with a low level of intra‐clutch variation without the necessity of a high level of inter‐clutch variation simultaneously as predicted by the egg signature hypothesis. This study may further indicate that selection pressures from evolutionarily recent parasites can drive individual‐based differences in an anti‐parasitism strategy. |
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| Keywords: | brood parasitism coevolution egg rejection inter‐clutch variation intra‐clutch variation |
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