Imperfect mimicry of host begging calls by a brood parasitic cuckoo: a cue for nestling rejection by hosts?

Coevolutionary interactions between avian brood parasites and their hosts often lead to the evolution of discrimination and rejection of parasite eggs or chicks by hosts based on visual cues, and the evolution of visual mimicry of host eggs or chicks by brood parasites. Hosts may also base rejection of brood parasite nestlings on vocal cues, which would in turn select for mimicry of host begging calls in brood parasite chicks. In cuckoos that exploit multiple hosts with different begging calls, call structure may be plastic, allowing nestlings to modify their calls to match those of their various hosts, or fixed, in which case we would predict either imperfect mimicry or divergence of the species into host-specific lineages. In our study of the little bronze-cuckoo Chalcites minutillus and its primary host, the large-billed gerygone Gerygone magnirostris, we tested whether: (a) hosts use nestling vocalisations as a cue to discriminate cuckoo chicks; (b) cuckoo nestlings mimic the host begging calls throughout the nestling period; and (c) the cuckoo begging calls are plastic, thereby facilitating mimicry of the calls of different hosts. We found that the begging calls of little bronze-cuckoos are most similar to their gerygone hosts shortly after hatching (when rejection by hosts typically occurs) but become less similar as cuckoo chicks get older. Begging call structure may be used as a cue for rejection by hosts, and these results are consistent with gerygone defences selecting for age-specific vocal mimicry in cuckoo chicks. We found no evidence that little bronze-cuckoo begging calls were plastic.

Mimicry in motion and morphology: do information limitation, trade-offs or compensation relax selection for mimetic accuracy?

Many animals mimic dangerous or undesirable prey as a defence from predators. We would expect predators to reliably avoid animals that closely resemble dangerous prey, yet imperfect mimics are common across a wide taxonomic range. There have been many hypotheses suggested to explain imperfect mimicry, but comparative tests across multiple mimicry systems are needed to determine which are applicable, and which—if any—represent general principles governing imperfect mimicry. We tested four hypotheses on Australian ant mimics and found support for only one of them: the information limitation hypothesis. A predator with incomplete information will be unable to discriminate some poor mimics from their models. We further present a simple model to show that predators are likely to operate with incomplete information because they forage and make decisions while they are learning, so might never learn to properly discriminate poor mimics from their models. We found no evidence that one accurate mimetic trait can compensate for, or constrain, another, or that rapid movement reduces selection pressure for good mimicry. We argue that information limitation may be a general principle behind imperfect mimicry of complex traits, while interactions between components of mimicry are unlikely to provide a general explanation for imperfect mimicry.

The limits of evolutionary convergence in sympatry: reproductive interference and developmental constraints leading to local diversity in aposematic signals

ABSTRACTMutualistic interaction between defended species is a striking case of evolutionary convergence in sympatry, driven by the increased protection against predators brought by mimicry. However, such convergence is often limited: sympatric defended species frequently display different or imperfectly similar warning traits. The phylogenetic distance between sympatric species may indeed prevent evolution towards the exact same signal. Moreover, warning traits are also implied in mate recognition, so that trait convergence might result in heterospecific courtship and mating. Here, we investigate the strength and direction of convergence in warning trait in defended species with different ancestral traits, using a mathematical model. We specifically determine the effect of phenotypic distances among ancestral traits of converging species, and costs of heterospecific sexual interactions on imperfect mimicry and trait divergence. Our analytical results confirm that reproductive interference limits the convergence of warning trait, leading to either imperfect mimicry or complete divergence. More surprisingly, our model pinpoints that reproductive interference can change the direction of convergence depending on the relative species densities. We also show that reproductive interference can generate imperfect mimicry only between species with different ancestral traits. Our model therefore highlights that convergence triggered by Müllerian mimicry not only depends on relative defence levels, but that relative species densities, heterospecific sexual interactions and ancestral traits interfere in the direction and strength of convergence between species.

How the Easter Egg Weevils Got Their Spots: Phylogenomics reveals Müllerian Mimicry in Pachyrhynchus (Coleoptera, Curculionidae)

ABSTRACTThe evolutionary origins of mimicry in the Easter Egg weevil, Pachyrhynchus, have fascinated researchers since first noted more than a century ago by Alfred Russel Wallace. Müllerian mimicry, or mimicry in which two or more distasteful species look similar, is widespread throughout the animal kingdom. Given the varied but discrete color patterns in Pachyrhynchus, this genus presents one of the best opportunities to study the evolution of both perfect and imperfect mimicry. We analyzed more than 10,000 UCE loci using a novel partitioning strategy to resolve the relationships of closely related species in the genus. Our results indicate that many of the mimetic color patterns observed in sympatric species are due to convergent evolution. We suggest that this convergence is driven by frequency-dependent selection.

Bacteria use structural imperfect mimicry to hijack the host interactome

Bacteria use protein-protein interactions to infect their hosts and hijack fundamental pathways, which ensures their survival and proliferation. Hence, the infectious capacity of the pathogen is closely related to its ability to interact with host proteins. Here, we show that hubs in the host-pathogen interactome are isolated in the pathogen network by adapting the geometry of the interacting interfaces. An imperfect mimicry of the eukaryotic interfaces allows pathogen proteins to actively bind to the host’s target while preventing deleterious effects on the pathogen interactome. Understanding how bacteria recognize eukaryotic proteins may pave the way for the rational design of new antibiotic molecules.

Bacteria Use Structural Imperfect Mimicry To Hijack The Host Interactome

ABSTRACTBacteria use protein-protein interactions to infect their hosts and hijack fundamental pathways, which ensures their survival and proliferation. Hence, the infectious capacity of the pathogen is closely related to its ability to interact with host proteins. Here, we show that hubs in the host-pathogen interactome are isolated in the pathogen network by adapting the geometry of the interacting interfaces. An imperfect mimicry of the eukaryotic interfaces allows pathogen proteins to actively bind to the host’s target while preventing deleterious effects on the pathogen interactome. Understanding how bacteria recognize eukaryotic proteins may pave the way for the rational design of new antibiotic molecules.

Católico a mi manera

This chapter discusses Manzano’s early identity formation from a religious and racial standpoint prior to his 1836 manumission.Instead of reading Manzano’s Catholicism as imperfect mimicry–as Homi Bhabha might suggest–this chapter explores the mulatto-Catholic identity as a persona that garnered social capital and as a political statement that rendered Manzano inoffensive when questioned by the Military Commission under suspicion of conspiracy.The racial self-image that Manzano created in his slave narrative, poetry, and letters to his patron Domingo Del Monte manifest double-consciousness because the poet reads himself through the prism of the white gaze.But unlike in previous studies, Pettway demonstrates that Manzano’s Autobiografíaand poetry demonstrate that the Catholic redemption narrative was insufficient to emancipate the enslaved person.