Reproductive biology and nectar production of the Mexican endemic Psittacanthus auriculatus (Loranthaceae), a hummingbird‐pollinated mistletoe

Abstract

Many mistletoe species produce 'bird'-pollinated flowers; however, the reproductive biology of the majority of these species has not been studied. Psittacanthus auriculatus is a Mexican endemic mistletoe, most common in open, dry mesquite grassland. Knowledge of the reproductive biology of P. auriculatus is essential for understanding species formation and diversification of Psittacanthus mistletoes, but it is currently poorly understood. Thus, we studied floral biology and phenology, nectar production and breeding system and pollination of this species. The hermaphroditic red-pink flowers open from the middle to the tip and petals are curly, but remain partially fused forming a floral tube of ca. 20-mm long. Flowers are partially protandrous, produce large amounts of nectar, last 2 days, and stigma receptivity is highest during the second day. We recorded hummingbirds (Cynanthus latirostris, Hylocharis leucotis, Amazilia beryllina, A. violiceps, Calothorax lucifer, Archilochus colubris) and less commonly butterflies (Agraulis vanillae, Anteos clorinde, Papilio multicaudatus, Phocides urania, Phoebis sennae) as floral visitors. P. auriculatus flowers are self-compatible. However, this mistletoe is an obligate animal-pollinated species, as the sensitive stigma avoids self-pollination. Under natural conditions, reproductive success was higher than in manually selfed or cross-pollinated flowers, likely due to the traplining foraging behaviour of hummingbirds. We suggest that the apparent efficient foraging behaviour of hummingbirds maintains gene flow among P. auriculatus, promoting outcrossing.

The cascade impacts of climate change could threaten key ecological interactions

“…, Perez‐Crespo et al. ). In this context, mistletoes are particularly interesting for two reasons: (1) They establish complex plant–plant interactions with their hosts, relying on them to obtain water and nutrients.…”

“…Due to their parasitic life form and life-history strategy, mistletoes constitute a good study model to gain insight into the potential consequences of climate change on ecological interactions. These parasitic plants are strongly dependent on pollinator and seed disperser animals to ensure reproductive success (Weston et al 2012, Perez-Crespo et al 2016b. In this context, mistletoes are particularly interesting for two reasons: (1) They establish complex plantplant interactions with their hosts, relying on them to obtain water and nutrients.…”

Reproductive ecology and isolation ofPsittacanthus calyculatusandP. auriculatusmistletoes (Loranthaceae)

“…Although Psittacanthus is the most diverse genus of the family in the Neotropics ( Kuijt, 2009 ), knowledge on floral biology and breeding systems is limited to single populations of few species ( Azpeitia & Lara, 2006 ; Leal, Lopes & Machado, 2006 ; Ramírez & Ornelas, 2010 ; Arruda et al, 2012 ; Guerra, Galetto & Silva, 2014 ; Pérez-Crespo et al, 2016 ). Psittacanthus species possess flowers with a great variety of colors, sizes and shapes, but typically species of this genus possess large, brilliant and tubular flowers with inflorescences forming triads or sometimes dyads ( Kuijt, 2009 ; Arruda et al, 2012 ).…”

“…Psittacanthus species possess flowers with a great variety of colors, sizes and shapes, but typically species of this genus possess large, brilliant and tubular flowers with inflorescences forming triads or sometimes dyads ( Kuijt, 2009 ; Arruda et al, 2012 ). This variety of flowers attracts a diverse array of floral visitors, including butterflies, bumble bees, hummingbirds, several species of parrots and passerine birds, and nectar-feeding bats ( Ramírez & Ornelas, 2010 ; Arruda et al, 2012 ; Guerra, Galetto & Silva, 2014 ; Pérez-Crespo et al, 2016 ).…”

Pollination biology from micro‐morphological adaptations to community ecology of plant–pollinator interactions

“…In this Special Issue Pérez‐Crespo et al . () studied the reproductive biology of several mistletoes of the genus Psittacanthus (Loranthaceae) in relation to floral speciation and diversification as an example of this poorly described genus. The floral traits of P. auriculatus exemplify a typical suite of characters associated with bird pollination in this family: odourless flowers, diurnal pollination, tubular shape of flowers, with colours ranging from red to orange with robust corollas and sexual organs.…”