Micro-evolutionary change in host response to a brood parasite

1994 ◽  
Vol 35 (4) ◽  
pp. 295-301 ◽  
Author(s):  
M. Soler ◽  
J. J. Soler ◽  
J. G. Martinez ◽  
A. P. M�ller
1994 ◽  
Vol 35 (4) ◽  
pp. 295-301 ◽  
Author(s):  
M. Soler ◽  
J. G. Martinez ◽  
J. J. Soler ◽  
A. P. Møller

Oecologia ◽  
1998 ◽  
Vol 117 (3) ◽  
pp. 381-390 ◽  
Author(s):  
Manuel Soler ◽  
Juan J. Soler ◽  
Juan G. Martinez ◽  
Tomás Pérez-Contreras ◽  
Anders P. Møller

2006 ◽  
Vol 274 (1608) ◽  
pp. 373-381 ◽  
Author(s):  
Tomáš Grim

Recognition is considered a critical basis for discriminatory behaviours in animals. Theoretically, recognition and discrimination of parasitic chicks are not predicted to evolve in hosts of brood parasitic birds that evict nest-mates. Yet, an earlier study showed that host reed warblers ( Acrocephalus scirpaceus ) of an evicting parasite, the common cuckoo ( Cuculus canorus ), can avoid the costs of prolonged care for unrelated young by deserting the cuckoo chick before it fledges. Desertion was not based on specific recognition of the parasite because hosts accept any chick cross-fostered into their nests. Thus, the mechanism of this adaptive host response remains enigmatic. Here, I show experimentally that the cue triggering this ‘discrimination without recognition’ behaviour is the duration of parental care. Neither the intensity of brood care nor the presence of a single-chick in the nest could explain desertions. Hosts responded similarly to foreign chicks, whether heterospecific or experimental conspecifics. The proposed mechanism of discrimination strikingly differs from those found in other parasite–host systems because hosts do not need an internal recognition template of the parasite's appearance to effectively discriminate. Thus, host defences against parasitic chicks may be based upon mechanisms qualitatively different from those operating against parasitic eggs. I also demonstrate that this discriminatory mechanism is non-costly in terms of recognition errors. Comparative data strongly suggest that parasites cannot counter-evolve any adaptation to mitigate effects of this host defence. These findings have crucial implications for the process and end-result of host–parasite arms races and our understanding of the cognitive basis of discriminatory mechanisms in general.


Author(s):  
J. Richtsmeier ◽  
K.M. Lesciotto

Traditionally, anthropologists study evolutionary change throughmorphological analysis of fossils and comparative primate data. For the analysis of the genotypephenotype continuum, the current emphasis on genes is misplaced because genes don’t make structure. Developmental processes make structure through the activity of cells that use instructions specified by genes. A critical mechanism underlying any phenotypic trait is the genetically guided change in developmental events that produce the trait. But even when a developmental mechanism is identified, the links between genetically guided instructions and phenotypic outcome are lengthy, complicated, flexible, and sensitive to physical forces of functioning organs. We use the study of craniofacial phenotypes of craniosynostosis (premature closure of sutures) to demonstrate how patterns produced by the covariation of cranial traits cannot always reveal mechanism. Next we turn to encephalization, a critical feature of human evolution that covaries with cranial phenotypes, and show how experimental approaches can be used to analyze mechanism underlying this well-documented pattern in human evolution. With the realization that no single line of evidence can explain the dramatic changes in cranial morphology that characterize human evolution come fundamental changes in the way we conduct anthropological inquiry - collaborative efforts from scientists with diverse expertise will continue to push the field forward.


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