Coevolution between the large hawk-cuckoo (Cuculus sparverioides) and its two sympatric Leiothrichidae hosts: evidence for recent expansion and switch in host use?

Abstract

Obligate brood parasites only account for 1% of birds in the world, but utilize a great variety of avian species as hosts. Host switch theory predicts that parasites should shift from one host to another during the long‐term arms race with hosts whenever such a shift would be facilitated by similarity in ecology and distribution. However, few studies have been conducted to address this puzzle because it is extremely difficult for humans to witness such host shifts during the long‐lasting process of evolution. Here we adopted an alternative way to understand host switch behaviour of brood parasites by comparing egg colour variation, cuckoo egg mimicry and egg recognition capacity between two sympatric hosts, the Chinese babax (Babax lanceolatus) and the white‐browed laughing thrush (Garrulax sannio), which are both parasitized by the large hawk‐cuckoo (Cuculus sparverioides). The babax lays dark blue eggs whilst the laughing thrush lays white to pale blue eggs, and the large hawk‐cuckoo parasitizes them by laying eggs that optimally match laughing thrush eggs according to avian vision. The laughing thrush possesses a greater capacity of egg recognition than the babax because it rejected all non‐mimetic eggs while the babax is an intermediate rejecter. Furthermore, all the nest characteristics measured were similar in these two host species with no statistical significant differences. These results are consistent with the hypothesis that the white‐browed laughing thrush is the original and main host species that has a longer coevolutionary interaction with the large hawk‐cuckoo than the Chinese babax, which is a recent host acquired through a host switch by the hawk‐cuckoo. We discuss the possible outcome of the interaction between the large hawk‐cuckoo and these two host species, and emphasize that host switch behaviour in brood parasites is more likely an adaptation to expand the range of host species rather than a change in host species favoring an increase in reproductive output. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, ●●, ●●–●●.

Potential cuckoo hosts have similar egg rejection rates to parasitized host species

“…1 in Yang et al 2015a). This shows that parasitism selection pressures can drive differences in anti-parasitism strategies (Yang et al 2015b). In our study area, the Whitebellied Redstart is a host of the Common Cuckoo, with an actual parasitism rate of 16.4% (Hu et al 2013b).…”

Do common cuckoos (Cuculus canorus) possess an optimal laying behaviour to match their own egg phenotype to that of their Oriental reed warbler (Acrocephalus orientalis) hosts?

“…Furthermore, the reed parrotbill ( Paradoxornis heudei ), which is sympatrically distributed with the Oriental reed warbler but lays eggs significantly differing from those of cuckoo eggs, was also parasitized by the common cuckoo (Yang et al ., ), implying that cuckoos do not select host nests with better matched eggs. Finally, optimal laying behaviour of cuckoos may not evolve because some studies have argued that evolution primarily produces inept designs as a result of selection not producing perfectly optimal phenotypes (Lewontin & Cohen, ; Gould & Lewontin, ; Yang et al ., ).…”

Do swallows (Hirundo daurica) use the visual cue of hatchling down‐feathers to discriminate parasite alien nestlings?

“…Many brood parasite host species possess egg recognition capacities as a defense to counter brood parasitism (Davies 2000(Davies , 2011Soler et al 2014). These host species recognize not only non-mimetic or intermediate mimetic parasite eggs (Yang et al 2014(Yang et al , 2015a but also mimetic or highly mimetic parasite eggs (de la Colina et al 2012;Yang et al 2016;Hanley et al 2017). However, once the parasite nestlings hatch, the host generally does not reject them, even though they look very different than the nestlings of the host (Davies & Brooke 1989).…”