Evidence for aggressive mimicry in an adult brood parasitic bird, and generalized defences in its host.

Mimicry of a harmless model (aggressive mimicry) is used by egg, chick and fledgling brood parasites that resemble the host's own eggs, chicks and fledglings. However, aggressive mimicry may also evolve in adult brood parasites, to avoid attack from hosts and/or manipulate their perception of parasitism risk. We tested the hypothesis that female cuckoo finches (Anomalospiza imberbis) are aggressive mimics of female Euplectes weavers, such as the harmless, abundant and sympatric southern red bishop (Euplectes orix). We show that female cuckoo finch plumage colour and pattern more closely resembled those of Euplectes weavers (putative models) than Vidua finches (closest relatives); that their tawny-flanked prinia (Prinia subflava) hosts were equally aggressive towards female cuckoo finches and southern red bishops, and more aggressive to both than to their male counterparts; and that prinias were equally likely to reject an egg after seeing a female cuckoo finch or bishop, and more likely to do so than after seeing a male bishop near their nest. This is, to our knowledge, the first quantitative evidence for aggressive mimicry in an adult bird, and suggests that host-parasite coevolution can select for aggressive mimicry by avian brood parasites, and counter-defences by hosts, at all stages of the reproductive cycle.W.E.F. was funded by the Australian National University Research School of Biology studentship, and an Endeavour Research Fellowship; C.N.S. was funded by a Royal Society Dorothy Hodgkin Fellowship, a BBSRC David Phillips Research Fellowship (BB/J014109/1) and the DST-NRF Centre of Excellence at the Percy FitzPatrick Institute; and N.E.L. was funded by the Australian Research Council.This is the final version of the article. It first appeared from Royal Society Publishing via http://dx.doi.org/10.1098/rspb.2015.07

Chase-away evolution maintains imperfect mimicry in a brood parasite-host system despite rapid evolution of mimics.

We studied a brood parasite-host system (the cuckoo finch Anomalospiza imberbis and its host, the tawny-flanked prinia Prinia subflava) to test (1) the fundamental hypothesis that deceptive mimics evolve to resemble models, selecting in turn for models to evolve away from mimics ('chase-away evolution') and (2) whether such reciprocal evolution maintains imperfect mimicry over time. Over only 50 years, parasites evolved towards hosts and hosts evolved away from parasites, resulting in no detectible increase in mimetic fidelity. Our results reflect rapid adaptive evolution in wild populations of models and mimics and show that chase-away evolution in models can counteract even rapid evolution of mimics, resulting in the persistence of imperfect mimicry. [Abstract copyright: © 2023. The Author(s).

A Daedalic Sampler

"In the seventh century B.C., Greek art passed through a phase between Geometric and Archaic, a phase first defined by R. Jenkins and named by him the "Dedalic style," a style which is best understood by the modeling of the human face. Jenkins was able to identify four great centers of Rroduction: Corinth, Rhodes, Crete, and Sparta. It is now recognized that the style was not confined to Dorian communities, but rather was widely spread throughout the Greek world during the seventh century. The Museum of Art and Archaeology, University of Missouri-Columbia, is fortunate in having several examples of Daedalic art which illustrate not only developments in the treatment of the human face but also a diversity of objects made in the Daedalic style."--First paragraph.Includes bibliographical reference

How to evade a coevolving brood parasite: egg discrimination versus egg variability as host defences

Arms races between avian brood parasites and their hosts often result in parasitic mimicry of host eggs, to evade rejection. Once egg mimicry has evolved, host defences could escalate in two ways: (i) hosts could improve their level of egg discrimination; and (ii) negative frequency-dependent selection could generate increased variation in egg appearance (polymorphism) among individuals. Proficiency in one defence might reduce selection on the other, while a combination of the two should enable successful rejection of parasitic eggs. We compared three highly variable host species of the Afrotropical cuckoo finch Anomalospiza imberbis, using egg rejection experiments and modelling of avian colour and pattern vision. We show that each differed in their level of polymorphism, in the visual cues they used to reject foreign eggs, and in their degree of discrimination. The most polymorphic host had the crudest discrimination, whereas the least polymorphic was most discriminating. The third species, not currently parasitized, was intermediate for both defences. A model simulating parasitic laying and host rejection behaviour based on the field experiments showed that the two host strategies result in approximately the same fitness advantage to hosts. Thus, neither strategy is superior, but rather they reflect alternative potential evolutionary trajectories

Cultural biographies of Cretan storage jars (<i>pithoi</i>):From antiquity to postmodernity

In a short story entitled The Jar (La Giara, 1909), Luigi Pirandello narrates the cultural biography (making, breaking and mending) of a huge storage jar and the way it represents socio-political and economic realities in a traditional Sicilian village. Inspired by La Giara, and integrating material culture theory with ethnoarchaeological, art-historical and science-based approaches, this thesis treats the cultural biographies of Cretan pithoi from antiquity to postmodernity to reveal the intertwined lives of people and artefacts and the dynamics of a very powerful relationship, hinting at the many possibilities and stories which lie behind these vessels.The body of material discussed includes published and unpublished Cretan pithoi and fragments thereof, which date from the second and the first millennia BC, especially ca. 800-500 BC. This material is examined primarily in the form of case-studies which contextualize the production, distribution and consumption of these vessels in their ancient and modern socio-cultural settings.In viewing ancient Cretan pithoi as the protagonists in the various episodes of their lives as well as of the lives of the people who interacted with them, this study illustrates the shifting meanings and symbolism of objects and highlights the fluid and ever-changing agency of archaeological artefacts as they move through different contexts. Ultimately, this work hopes to encourage future investigations on other types of durable archaeological objects and to centre discussions on the socially-constituted processes that create meaning in the material world of people

Host-Parasite Arms Races and Rapid Changes in Bird Egg Appearance

Abstract Coevolutionary arms races are a powerful force driving evolution, adaptation, and diversification. They can generate phenotypic polymorphisms that render it harder for a coevolving parasite or predator to exploit any one individual of a given species. In birds, egg polymorphisms should be an effective defense against mimetic brood parasites and are extreme in the African tawny-flanked prinia (Prinia subflava) and its parasite, the cuckoo finch (Anomalospiza imberbis). Here we use models of avian visual perception to analyze the appearance of prinia and cuckoo finch eggs from the same location over 40 years. We show that the two interacting populations have experienced rapid changes in egg traits. Egg colors of both species have diversified over time, expanding into avian color space as expected under negative frequency-dependent selection. Egg pattern showed signatures of both frequency-dependent and directional selection in different traits, which appeared to be evolving independently of one ano..