A Failure to Demonstrate Host Imprinting in the Cuckoo (Cuculus canorus) and Alternative Hypotheses for the Maintenance of Egg Mimicry

Abstract

The cuckoo Cuculus canorus is divided into various gentes, each laying a distinctive egg and favouring a different species as host. It has long been assumed that the gentes remain distinct because female cuckoos lay the same egg‐type as their mother and prefer the same host, developing this preference by imprinting on their foster parents. We tested whether imprinting occurred by laboratory experiments with 7 cuckoos originating from reed warbler Acrocephalus scirpaceus nests. Two were transferred soon after hatching to robin Erithacus rubecula nests and were raised by robins, while the other five were raised by reed warblers. When about 12 d old, the nestling cuckoos and their foster parents were transferred from the wild to aviaries, where the fosterers continued to raise the cuckoos to independence. The fosterers were then released and the cuckoos retained and presented, at one and two years of age, with a behavioural choice between robins and reed warblers. None of the cuckoos (five females and two males) displayed a consistent preference for the host that reared them even, in the case of females, after oestradiol implantation. We discuss the inadequacies of our experiment and present data on cuckoo egg types to test whether natal philopatry might be sufficient to maintain the gentes. We suggest that mitochondrial DNA studies, now underway, will help to resolve the issue.

No effect of larval experience on adult host preferences in Polygonia c‐album (Lepidoptera: Nymphalidae): on the persistence of Hopkins’ host selection principle

“…Recent studies, however, have questioned this 'common knowledge' and have revealed genetic differences in host preference among gentes ( Brooke & Davies, 1991;Gibbs et al , 2000 ). As with the HHSP, these gentes have commonly been assumed to be maintained by host imprinting in juvenile cuckoos.…”

Pattern mimicry of host eggs by the common cuckoo, as seen through a bird's eye

“…Interestingly, our analyses showed that the eggs of the different cuckoo gentes were significantly less variable than were the host eggs. A more general pattern could permit cuckoos to parasitize subsidiary hosts successfully when the primary host is unavailable (Brooke & Davies 1991;Moksnes & Røskaft 1995). Alternatively, the relative similarity of cuckoo eggs could result from genetic constraints on egg-patterning in cuckoos or from evolutionary lag (Davies 2000).…”

Egg-spot matching in common cuckoo parasitism of the oriental reed warbler: effects of host nest availability and egg rejection

“…Such interactions have led to the evolution of many amazing biological phenomena (Davies 2011;Spottiswoode and Stevens 2012;Soler 2014). Among these, the remarkable resemblance in egg appearance (color and spot patterns) between cuckoos and their hosts, termed "mimicry", has long attracted the attention of behavioral ecologists (Chance 1940;Brooke and Davies 1991;Davies 2000;Igic et al 2011). Although this phenomenon has been extensively studied, it has largely been explained as an evolutionary response to the strong egg rejection carried out by the host during their long co-evolutionary interaction Soler et al 2003;Stoddard and Stevens 2011;Avilés et al 2012).…”