Phylogenetic analysis of interspecific variation in nectar of hummingbird‐visited plants

Abstract

We tested whether phylogeny, flower size and/or altitude were significant predictors of interspecific variation in nectar production of hummingbird‐visited plants in an assembled database (289 species, in 22 orders, 56 families and 131 genera). Although the study is focused on hummingbird‐pollinated plants (241 plant species), plants with different pollinator syndromes (48 species) are also included in the analyses. Nectar volume secreted in a given time period (usually 24 h) by a given flower, its sugar concentration and corolla length were compiled mainly from the literature. Altitude was also obtained from the original references. Sugar production was computed basically as the product of nectar secretion and sugar concentration, and expressed on a per 24‐h basis. All nectar traits and corolla length (all log transformed), as well as altitude, showed statistically significant phylogenetic signal. Both nonphylogenetic and phylogenetically informed (independent contrasts) analyses indicated a highly significant positive correlation between corolla length and both nectar volume and sugar production. In addition, altitude (which is partially a surrogate for temperature) was significantly negatively correlated with both sugar concentration and production. Possible reasons for coadaptation of nectar production and sugar production with corolla length are discussed.

Asociación entre el robo de néctar y las características florales en una comunidad montana de los Andes colombianos

“…Al igual que en otros estudios, se registró una relación positiva entre la longitud total de la corola y la cantidad de néctar producido por las flores (Castro et al 2009, Navarro y Medel 2009. Se ha demostrado que las flores más largas tienen nectarios más grandes y por lo tanto contienen mayores cantidades de néctar (Ornelas et al 2007, Gómez et al 2008. A su vez, los robadores de néctar tienen la habilidad de asociar la longitud de las flores con las recompensas energéticas que contienen y prefieren visitar flores con mayores recompensas.…”

Evolutionary associations between nectar properties and specificity in bird pollination systems

“…This hypothesis can be rejected on account of the significant pairwise contrasts that control for effects of phylogeny (table 1). Although nectar traits do have phylogenetic signal (Ornelas et al 2007), they can also be highly labile within genera (Bruneau 1997;Johnson et al 1998;Dupont et al 2004;figure 1b,d,f ).…”

Polinización y producción de néctar de Psittacanthus schiedeanus (Loranthaceae) en el centro de Veracruz, México

“…For hummingbirds, P. schiedeanus represents a rich resource compared to other hummingbird-pollinated fl owers of the cloud forests in the region (e.g., Lara and Ornelas, 2003;Ornelas et al, 2004), other late summer fl owers in this region (Lara and Ornelas, 2002), fl owers from other Psittacanthus species (Azpeitia and Lara, 2006), or from other hummingbird-adapted species (Hernández-Conrique et al, 2007;Lara and Ornelas, 2008). Although Neotropical mistletoe fl owers are highly variable in terms of nectar production, values for P. schiedeanus are high to median for Neotropical mistletoe fl owers (Cruden et al, 1983;Opler, 1983;Stiles and Freeman, 1993;Tadey and Aizen, 2001;Ornelas et al, 2007). Thus, the high nectar production rates, the large fl oral display (number of fl owers open per day and number of infl orescences per plant), fl ower longevity, and the extended fl owering time (3 mo) suggest that allocation to pollinator attraction is large in P. schiedeanus.…”

“…Hence, the high production of nectar by P. schiedeanus fl owers (and the number of fl owers produced per plant) represents an important ecosystem resource that may mediate interactions with a wide variety of plant visitors, depending on seasonal and spatial availability. The sugar totals (3.6-7.2 mg sugar per fl ower per day) are high compared to values of other hummingbird-visited species (reviewed in Ornelas et al, 2007). For hummingbirds, P. schiedeanus represents a rich resource compared to other hummingbird-pollinated fl owers of the cloud forests in the region (e.g., Lara and Ornelas, 2003;Ornelas et al, 2004), other late summer fl owers in this region (Lara and Ornelas, 2002), fl owers from other Psittacanthus species (Azpeitia and Lara, 2006), or from other hummingbird-adapted species (Hernández-Conrique et al, 2007;Lara and Ornelas, 2008).…”