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?

Abstract

Optimality theory suggests that parasitic cuckoos should evolve an optimal laying behaviour aiming to positively select host nests in which the eggs match the phenotype of their own eggs, thus minimizing the rejection risk from hosts and, in turn, maximizing the cuckoos' fitness. We tested this hypothesis by investigating cuckoo-egg matching between parasitized and nonparasitized nests in a common cuckoo (Cuculus canorus) host, the Oriental reed warbler (Acrocephalus orientalis), by use of Vorobyev-Osorio and Nature-Pattern-Match models to quantify the matching of egg colour and pattern from avian vision, respectively. The results of our study indicated that cuckoo-egg matching in parasitized nests was no better than that in nonparasitized nests, and thus we found no support for the optimal laying hypothesis in cuckoos. The mixed conclusions from all previous studies, including the present study, may be explained by (1) the parallel coevolution in different cuckoo-host systems; (2) the inappropriate methodology; and (3) the deficiency of the assumption itself. We suggest that a better methodology should be developed to solve the puzzle of whether cuckoos choose to lay eggs matching those of the host.

A computer vision for animal ecology

“…Compared to human review, computer vision provides a more consistent way to score animal appearance across images by using non-RBG colour spaces, such as HSV or YChCr, which are less sensitive to changes in illumination and other image artefacts (Kühl & Burghardt, 2013;Troscianko, Skelhorn, & Stevens, 2017). By comparing image features, computer vision can be used to study animal camouflage (Tankus & Yeshurun, 2009) and biomimicry (Yang, Wang, Liang, & Møller, 2016). For example, Stoddard et al (2016) developed edge detection algorithms to evaluate the relative camouflage of nesting shorebird species as compared to their nesting substrate ( Figure 3b).…”

How can distinct egg polymorphism be maintained in the rufescent prinia (Prinia rufescens)–plaintive cuckoo (Cacomantis merulinus) interaction—a modeling approach

“…In order to ensure egg acceptance, cuckoo females should parasitize only host nests where egg phenotype matches. Although this “phenotype matching” parasitic behavior is intuitively appealing, previous empirical studies have shown conflicting results (Antonov et al., ; Cherry et al., ; Honza et al., ; Liang et al., ; Yang et al., ; Yang, Huang et al., ); Yang, Wang, Liang, Møller, ). In this model, we have assumed that parasites choose host nests randomly, irrespective of egg phenotype.…”

“…We assume that a proportion P of host nests are parasitized (0 < P < 1) and that nests are parasitized randomly, independent of phenotype (Antonov et al., ; Yang, Takasu, Liang, & Møller, ; Liang, Yang, & Takasu, ; Yang, Wang, Liang, & Møller, ; Yang, Huang, et al., ; but see Cherry, Bennett, & Moskát, ; Honza, Sulc, Jelínek, Pozgayová, & Procházka, ). Multiple parasitism is ignored as we implicitly assume a low parasitism rate P (but see Moskát & Honza, ; Takasu & Moskát, ).…”

Heterospecific alarm-call recognition in two warbler hosts of common cuckoos

“…This study was performed in Zhalong National Nature Reserve (46°48ʹ‒47°31ʹN, 123°51ʹ‒124°37ʹE) located on the northern Songnen Plain in Heilongjiang Province, northeast China during the breeding seasons (June–August) 2016–2017. We searched for nests of the two species every 3–5 days and monitored the activities of parents to confirm their reproductive stage (Li et al 2015; Yang et al 2015).…”

“…The function of a control stimulus is to act as a criterion of behavioral responses in target birds. We have studied ORWs and BRWs in our study area for many years (from 2012 to date, e.g., Yang et al 2015, 2016, 2017), and conducted several dummy experiments (common cuckoo, sparrowhawk, Oriental turtle dove Streptopelia orientalis , etc., unpublished data). We can exclude the possibility that target ORWs and BRWs responded similarly to all birds near the nest.…”