eprintid: 1431198 rev_number: 27 eprint_status: archive userid: 608 dir: disk0/01/43/11/98 datestamp: 2014-06-02 19:05:03 lastmod: 2021-11-15 02:00:15 status_changed: 2014-06-02 19:05:03 type: article metadata_visibility: show item_issues_count: 0 creators_name: Tazzyman, SJ creators_name: Iwasa, Y creators_name: Pomiankowski, A title: THE HANDICAP PROCESS FAVOURS EXAGGERATED, RATHER THAN REDUCED, SEXUAL ORNAMENTS. ispublished: pub divisions: UCL divisions: B02 divisions: C08 divisions: D09 divisions: F99 keywords: Handicap process, Selection - Sexual, Signaling/Courtship, mate choice, mate preference, sexual dimorphism note: © 2014 The Authors. Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. abstract: Why are traits that function as secondary sexual ornaments generally exaggerated in size compared to the naturally selected optimum, and not reduced? Since they deviate from the naturally selected optimum, traits that are reduced in size will handicap their bearer, and could thus provide an honest signal of quality to a potential mate. Thus if secondary sexual ornaments evolve via the handicap process, current theory suggests that reduced ornamentation should be as frequent as exaggerated ornamentation, but this is not the case. To try to explain this discrepancy, we analyse a simple model of the handicap process. Our analysis shows that asymmetries in costs of preference or ornament with regard to exaggeration and reduction cannot fully explain the imbalance. Rather, the bias towards exaggeration can be best explained if either the signalling efficacy or the condition dependence of a trait increases with size. Under these circumstances, evolution always leads to more extreme exaggeration than reduction: though the two should occur just as frequently, exaggerated secondary sexual ornaments are likely to be further removed from the naturally selected optimum than reduced ornaments. This article is protected by copyright. All rights reserved. date: 2014-09 official_url: http://dx.doi.org/10.1111/evo.12450 vfaculties: VFLS oa_status: green full_text_type: pub primo: open primo_central: open_green article_type_text: JOURNAL ARTICLE verified: verified_manual elements_source: PubMed elements_id: 949632 doi: 10.1111/evo.12450 language_elements: ENG lyricists_name: Pomiankowski, Andrew lyricists_id: APOMI03 full_text_status: public publication: Evolution volume: 68 number: 9 pagerange: 2534-2549 citation: Tazzyman, SJ; Iwasa, Y; Pomiankowski, A; (2014) THE HANDICAP PROCESS FAVOURS EXAGGERATED, RATHER THAN REDUCED, SEXUAL ORNAMENTS. Evolution , 68 (9) pp. 2534-2549. 10.1111/evo.12450 <https://doi.org/10.1111/evo.12450>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1431198/1/evo12450.pdf