Novel nectar robbing negatively affects reproduction in Digitalis purpurea

Abstract

Many plant-pollinator interactions are undergoing change due to multiple anthropogenic influences (González-Varo et al., 2013;Goulson et al., 2015). At present, we have a limited understanding of how novel interactions affect plant reproductive success, for example, after plant invasion (Barrett et al., 2008;Chalcoff et al., 2019;Richardson et al., 2000). One interaction with consequences for plants is nectar robbing, where plants have their mutualism with pollinators bypassed by floral visitors (robbers) that consume nectar rewards without pollinating (Irwin et al., 2010). In the same way as pollination mutualisms, this interaction between

Nectar and floral morphology differ in evolutionary potential in novel pollination environments

“…Ideally, a reciprocal transplant would capture the environmental differences between native and introduced ranges, which may be wider than in our common garden. Other factors like nectar robbing, practically absent in native but widespread in introduced populations, might exert selection on flower traits affecting their adaptive potential (Mackin et al ., 2021a).…”

“…Nectar robbing is rare in native populations (but see Rojas‐Nossa et al ., 2016), but flowers in the American populations are frequently robbed by several species of flower piercers ( Diglossa spp.) with hummingbirds and bumblebees often acting as secondary robbers (Riveros et al ., 2006; Mackin et al ., 2021a).…”

Nectar robbing by bees affects the reproductive fitness of the distylous plant Tirpitzia sinensis (Linaceae)

“…Nectar robbing can directly damage floral reproductive structures (Traveset et al., 1998), decrease nectar volume (Hazlehurst & Karubian, 2016), influence female and/or male fitness, and reduce fruit and seed sets (Irwin & Brody, 1999). Indirectly, robbing may reduce the number of pollen grains deposited per visit, visit rates, or visit duration of the legitimate pollinator (Irwin et al., 2015; Mackin et al., 2021; Varma et al., 2020) and thus affect reproductive success. Neutral consequences have been inferred when nectar robbing had no significant effects on plant reproductive success because pollinator behavior was not modified by nectar robbing (Elena & Jaime, 2019; Rojas‐Nossa et al., 2016a; Souza et al., 2019; Ye et al., 2017).…”