Biting the hand that feeds you: wedge-billed hummingbird is a nectar robber of a sicklebill-adapted Andean bellflower

Abstract

I report on nectar robbing behavior of the wedge-billed hummingbird, Schistes geoffroyi (Trochilidae) on the Andean bellflower, Centropogon granulosus (Campanulaceae). Many species of Centropogon are characterized by an abruptly curved corolla tube which is likely specialized for pollination by sicklebill hummingbirds (Eutoxeres), as evident from the matching curvature of flower and bill. Nectar robbing has been documented for some Centropogon spp., but not for sicklebill pollinated C. granulosus. Given recent developments and interest in the Centropogon-sicklebill mutualism, it is pertinent to document any natural history observations that may underlie the ecology and evolution of this pollination system. The establishment of wedge-billed hummingbird as a nectar robber of C. granulosus calls for a new assessment of the ecology and evolution of the highly specialized Centropogon-sicklebill mutualism.

Nectar robbing in the trainbearers (Lesbia, Trochilidae)

“…Hummingbirds are generally thought to serve as legitimate flower visitors, and effect pollination in exchange for host plant nectar. There is, however, an increasing appreciation of the fact that nectar obtained during illegitimate visits-including both primary and secondary robbing, as well as thieving-may comprise a substantial portion of diets of many species (Lara & Ornelas, 2001;Irwin et al, 2010;Boehm, 2018). Presently, the frequency distribution of nectar larceny within and among bird individuals and species, and a variety of covariates (community composition, territoriality, seasonality, geography, etc.)…”

“…A growing list of bird species across several clades are known to forage for nectar on so-called "illegitimate" flower visits, in which flower rewards are taken without the requisite provision of pollination services. Also termed 'floral larceny,' this mode of foraging is correspondingly gaining a broader appreciation as an important factor shaping the ecology and evolution of plant-animal interactions (Lara & Ornelas, 2001;Irwin et al, 2010;Rojas-Nossa, Sánchez & Navarro, 2016;Boehm, 2018). Although species such as flower piercers (Diglossa, Passeriformes) are widely known to depend on nectar larceny, there are many reports of illegitimate visits by hummingbirds (Lara & Ornelas, 2001;Gonzalez & Loiselle, 2016).…”

Nectar larceny in the trainbearers (Lesbia, Trochilidae)

“…Hummingbirds are generally thought to serve as legitimate flower visitors, and effect pollination in exchange for host plant nectar. There is, however, an increasing appreciation of the fact that nectar obtained during illegitimate visits-including both primary and secondary robbing, as well as thievingmay comprise a substantial portion of diets of many species (Lara and Ornelas, 2001;Irwin et al, 2010;Boehm, 2018). Presently, the frequency distribution of nectar larceny within and among bird individuals and species, and a variety of covariates (community composition, territoriality, seasonality, geography, etc.)…”

“…An unpublished report (D. Boose, cited in Maloof and Inouye 2000) found that robbing may comprise up to 92% of all Stripe-tailed Hummingbird (Eupherusa exima) visits in Razisea spicata. Primary and secondary robbing are generally difficult to disentangle from casual observations (Vogt, 2006;Boehm, 2018). Confidently scoring the specific mode of robbing (primary vs. secondary) demands evidence bearing on the question whether 'breaking-and-entering' took place, which in turn requires careful experimental data collection that we could not directly collect.…”

“…A growing list of bird species across several clades are known to forage for nectar on so-called 'illegitimate' flower visits, in which flower rewards are taken without the requisite provision of pollination services. Also termed 'floral larceny,' this mode of foraging is correspondingly gaining a broader appreciation as an important factor shaping the ecology and evolution of plant-animal interactions (Lara and Ornelas, 2001; Irwin et al, 2010;Rojas-Nossa et al, 2016;Boehm, 2018). Although species such as flower piercers (Diglossa, Passeriformes) are widely known to depend on nectar larceny, there are many reports of illegitimate visits by hummingbirds (Lara and Ornelas, 2001;Gonzalez and Loiselle, 2016).…”