Allometry of a sexual trait in relation to diet experience and alternative mating tactics in two rubyspot damselflies (Calopterygidae: Hetaerina) HUGO A. ÁLVAREZ 1 , MARTÍN ALEJANDRO SERRANO-MENESES 2 *, ISIDORA REYES-MÁRQUEZ 2 , JESÚS GUILLERMO JIMÉNEZ-CORTÉS 3 and ALEX CÓRDOBA-AGUILAR 3 1 Laboratorio de Ecología de Poblaciones, Escuela de Biología, Benemérita Universidad Autónoma de Puebla, Blvd. Valsequillo y Av. San Claudio, Edificio 112-A, Col. Jardines de San Manuel, Ciudad Universitaria, CP 72570 Puebla, México 2 Laboratorio de Biología Evolutiva, Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Carretera Tlaxcala-Puebla Km. 1.5, 90062 Tlaxcala, México 3 Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apdo. Postal 70-275, Ciudad Universitaria, 04510 México DF, México Received 1 August 2012; revised 11 September 2012; accepted for publication 12 September 2012 Several arguments have been put forward to explain how sexual selection drives the evolution of sexual trait allometry, especially hyperallometry. The ‘positive allometry theory’ suggests that hyperallometry is a rule in all-secondary sexual traits, whereas the ‘display hypothesis’ suggests that only males in good condition will exhibit hyperallometric sexual display traits. In the present study, we investigated: (1) the condition-dependence nature (by using two diet treatments that varied in the amount of food provided to the larvae) of a sexually selected trait (wing pigmentation; WP) in recently-emerged adults of the American rubyspot damselfly, Hetaerina americana, and (2) the scaling relationship between WP and body size (wing and body length) in the rubyspot damselflies H. americana and Hetaerina vulnerata, according to alternative reproductive tactics (ARTs; territorial and nonterritorial males). First, we found support that indicated that diet positively affected WP length, although there was no significant WP allometric pattern in relation to diet regimes. Second, WP was hyperallometric in both Hetaerina species. WP size was similar between ARTs and, in H. americana (but not H. vulnerata), nonterritorial males showed steeper slopes than territorial males when wing length was used. The results obtained support the notion that sexual traits are hyperallometric, although there is no clear pattern in relation to ARTs. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 108, 521–533. ADDITIONAL KEYWORDS: reproductive tactics – hyperallometry – secondary sexual traits – sexual selection – display hypothesis. INTRODUCTION Allometry refers to the scaling relationship between a given trait and body size, given the equation y =bx a , where y is the size of the trait of interest and x refers to body size (Gould, 1974). Three types of allometric scaling relationships are recognized: hyperallometry (b > 1), a relationship in which large individuals have proportionally larger traits than small individuals; hypoallometry (b < 1), in which large individuals have proportionally smaller traits than small indi- viduals; and isometry (b= 1), a relation in which trait size increases at proportionally the same rate as body size in large and small animals (Bonduriansky, 2007). To date, much has been debated regarding the allometry of sexual traits (Green, 1992; Bonduriansky & Day, 2003; Kodric-Brown, Sibly & Brown, 2006; Bonduriansky, 2007) given that some sexual traits *Corresponding author. E-mail: serrano.meneses@gmail.com Biological Journal of the Linnean Society, 2013, 108, 521–533. With 5 figures © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 108, 521–533 521 Downloaded from https://academic.oup.com/biolinnean/article/108/3/521/2415582 by guest on 22 February 2023