Author's personal copy Original article Flower size and longevity influence florivory in the large-flowered shrub Cistus ladanifer Alberto L. Teixido a, * , Marcos Méndez a , Fernando Valladares a, b a Área de Biodiversidad y Conservación, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Tulipán s/n, Móstoles, E-28933 Madrid, Spain b Museo Nacional de Ciencias Naturales, Consejo Superior de Investigaciones Científicas, MNCN-CSIC, Serrano 115 dpdo, E-28006 Madrid, Spain article info Article history: Received 20 December 2010 Accepted 13 May 2011 Available online 8 June 2011 Keywords: Floral longevity Florivores Flower size Number of flowers Variation within-populations abstract Plants with larger and longer-lived flowers receive more pollinator visits and increase reproductive success, though may also suffer more from antagonistic interactions with animals. Florivores can reduce fruit and seed production, so selection on flower size, floral longevity and/or number of flowers may thus be determined by the relative effects of both pollinators and florivores. In this study flowers of Cistus ladanifer, a large-flowered Mediterranean shrub, were monitored to evaluate the effects of flower size, floral longevity and number of flowers on levels of florivory in four populations. Number of flowers was variable but did not differ among populations. Both flower size and floral longevity of C. ladanifer showed broad variation and significantly differed among populations. Overall, 7% of flowers suffered attack by florivores, which were mainly ants picking the stamens and beetles consuming petals and pollen. Within-populations, larger and longer-lived flowers tended to be affected by florivores more frequently. The low overall incidence of florivores and its lack of between-population variation suggest that florivory may not influence intraspecific variation of these floral traits. However, moderate florivory levels on the largest and longest-lived flowers open the possibility of exerting selection towards smaller and shorter-lived flowers in some of the populations studied. Ó 2011 Elsevier Masson SAS. All rights reserved. 1. Introduction Attractiveness to pollinators plays a decisive role in the repro- ductive ecology of entomophilous plants. The importance of the number of displayed flowers for pollinator visitation rates and fruit production has been broadly reported (Brody and Mitchell, 1997; Thompson, 2001; Harder and Johnson, 2005). Larger flowers have also been associated with higher pollinator attraction and, as a result, an increase in cross-pollination and reproductive success (Galen, 1989; Kudoh and Whigham, 1998; Arista and Ortiz, 2007). In the same way, floral longevity (the length of time that flowers remain open and functional) involves both a greater amount of pollen removal, and higher amount and quality of pollen deposition, on the flower (Primack, 1985; Ashman and Schoen, 1994, 1996). As a conse- quence, longer-lived flowers may also increase reproductive success. Despite its benefits, floral attractiveness can also be related with greater planteanimal antagonist interactions. For example, floral herbivores (i.e. florivores) cause damage to open flowers, including damage to bracts, sepals, petals, androecium and/or gynoecium (McCall and Irwin, 2006). Thus, florivores may reduce fruit and seed production by degrading the attractive properties of flowers for pollinator service or by direct consumption of viable gametes (Schemske and Horvitz, 1988; Krupnick et al., 1999; Irwin, 2006; Cardel and Koptur, 2010). In this way, florivores can exert negative selective pressures on the same floral traits positively selected for pollinators (Galen, 1999; Irwin et al., 2001; Irwin, 2006). There is evidence that florivory increases with increasing components of plant attractiveness to pollinators such as the number of flowers displayed and flower size (Galen, 1999; Mosleh Arany et al., 2009). Longer floral longevity should also increase the risk of florivory, as documented for other antagonistic interactions (e.g., fungal infection: Shykoff et al., 1996; Kaltz and Shykoff, 2001). However, the effects of floral longevity on the incidence of florivory seem to have been only scarcely studied and are not even mentioned in reviews of non-pollinator influences on floral traits (Strauss and Whittall, 2006). The strength of agents of selection can vary geographically and lead to contrasting selective pressures at different locations (Thompson, 1982, 2005). Several studies have reported that individuals in those populations with a higher incidence of florivores display fewer, smaller flowers (Galen, 1999; Mosleh Arany et al., 2009). Thus, documenting spatial variation in incidence of flo- rivory is important to understand differences in floral display related traits among populations. * Corresponding author. Tel.: þ34 91 488 82 90; fax: þ34 91 664 74 90. E-mail address: alberto.teixido@urjc.es (A.L. Teixido). Contents lists available at ScienceDirect Acta Oecologica journal homepage: www.elsevier.com/locate/actoec 1146-609X/$ e see front matter Ó 2011 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.actao.2011.05.007 Acta Oecologica 37 (2011) 418e421