<b>L</b><b>inear markings on eggs as important </b><b>egg </b><b>recognition cues for bunting hosts</b>

This study was conducted in the Liuzhi area (22°13′ N, 106°42′ E), Guizhou, southwest China, from March to August during 2018–2022. The study area is situated in the north temperate monsoon climate zone at altitudes of 1070–1657 m. The study area mainly consists of a karst landscape, with a mosaic of villages, farmland, shrubland, and barren slopes. The preservation of traditional agricultural practices may play an important role in the distribution and reproduction of birds in the area (Zhong et al., 2023).Field experiments were conducted to verify whether the hosts could use these linear markings to recognize parasitic eggs. In these experiments, two sympatric hosts of the common cuckoo, namely the south rock bunting <i>(Emberiza yunnanensis</i>) (which lays eggs with linear markings) and the yellow-throated bunting (<i>Emberiza elegans</i>) (which lays eggs with spot markings), were studied. The results demonstrated that both species of bunting hosts show high rejection rates for plain egg budgerigar (<i>Melopsittacus undulatus</i>) eggs and moderate recognition and rejection abilities for swapped eggs (spot versus linear markings), suggesting that linear markings can serve as a cue for egg recognition in the anti-parasitism of these two hosts. This implied that linear markings, an egg trait of south rock buntings, has an anti-parasitism adaptation function against mimicry by parasites. It was experimentally demonstrated for the first time that the evolution of linear markings on eggs of the hosts of common cuckoos may be an egg-characteristic adaptation against parasitism. Nevertheless, additional research is necessary to verify its generality across different systems.