Reproductive biology of Pedicularis (Scrophulariaceae) in the Sichuan Himalaya

Abstract

In 1997-1998, the reproductive biology of Pedicularis bidentata, Pedicularis cranolopha, Pedicularis davidii, Pedicularis longiflora var. hongyuanensis, Pedicularis longiflora ssp. tubiformis, Pedicularis plicata, Pedicularis polyodonta, Pedicularis rhinanthoides ssp. labellata, Pedicularis roylei, Pedicularis semitorta, Pedicularis spicata and Pedicularis verticillata was studied in the subalpine-alpine zone of the Chinese Himalaya in western Sichuan Province. Except for Apis pollinators on P. polyodonta and P. spicata, only workers and queens of Bombus filchnerae, Bombus patagiatus, Bombus potanini, Bombus sichelii and Bombus waltoni pollinated Pedicularis. Nectariferous, erostrate flowers were pollinated nototribically and sternotribically, during foraging for nectar and pollen, respectively, whereas nectarless, rostrate (including very long-tubed) flowers were pollinated sternotribically during foraging for pollen only. Insect exclusion from flowers revealed that P. longiflora ssp. tubiformis, P. roylei and P. verticillata are insectpollinator dependent. Analysis of the corbicular pollen loads of pollinators revealed a moderate degree of pollen-foraging fidelity. Pollinator frequency on Pedicularis did not exceed three insects per hour, but Bombus pollinators were more common on other plant genera. No evidence of lepidopteran pollination on long-tubed Pedicularis species was found, nor was there any evidence of species-species specificity between Bombus pollinators and Pedicularis flowers.

Primary floral allocation per flower in 12 Pedicularis (Orobanchaceae) species: significant effect of two distinct rewarding types for pollinators

“…Some studies have shown that nectar secretion is in cost of decreased female reproductive success (Pyke 1991;Ornelas and Lara 2009). Pollination biology studies in the genus reported that frequency and duration of visitation of bumblebees are higher and longer for nectar rewarding plants than for nectarless rewarding plants (Macior et al 2001;Tang and Xie 2006;Huang and Fenster 2007). The activities of pollinators may benefit pollen export and increase male fitness for nectar rewarding plants ( Thomson and Plowright 1980;Harder and Thomson 1989;Biernaskie and Cartar 2004).…”

“…For the pollination biology of the genus in China, the previous studies have shown that export and receipt of pollen of Pedicularis species are simultaneous and almost exclusively dependent upon bumblebees (Macior and Tang 1997;Macior et al 2001;Tang and Xie 2006;Huang and Fenster 2007). Pedicularis species may be divided into two groups according to rewarding type for pollinators.…”

The pollination ecology of Pedicularis rex subsp. lipkyana and P. rex subsp. rex (Orobanchaceae) from Sichuan, southwestern China

“…The pollination process was studied by direct observation of pollinators on flowers and by recording their behavior on 35 mm color photographic films and videotapes. Observation period and number of bumblebee visits to each plant was recorded on an hourly basis, based on which visit frequency of pollinators was calculated, following Macior et al (2001). Pollinators were observed and collected whenever possible from both Pedicularis and from other sympatric blossoming plants.…”

“…This does not support speculations that pollinators of Pedicularis species would be as diverse as the floral morphology implies or that species with extremely elongated corolla tubes might require specific pollinators of lepidoptera or other insects with very long proboscides (Pennell, 1948;Li, 1948Li, , 1951. There are only few Pedicularis species that are also pollinated by honeybees, hummingbirds, or hawk moths besides the principal bumblebee pollinators (Macior, 1968b, c;Macior et al, 2001;Tang et al, unpublished observation). Only one species (P. hirsuta) that is distributed outside of the natural distributional area of bumblebees is pollinated by flies (Aiken et al, 1999).…”

“…It is one of the plant genera that have attracted extensive pollination studies. So far these studies have shown the only effective pollinators to be bumblebees (Sprague, 1962;Macior 1968aMacior , b, 1969Macior , 1970Macior , 1973Macior , 1975Macior , 1977Macior , 1978Macior , 1982Macior , 1983Macior , 1986aMacior -c, 1988Macior , 1990Macior , 1993Macior , 1995aMacior , b, 1996KoemanKwak, 1973KoemanKwak, , 1977KoemanKwak, , 1979Williams and Batzlli, 1982;Aluri and Robart, 1991;Eriksen et al, 1993;Macior and Sood, 1991;Philipp et al, 1996;Macior and Tang, 1997;Wang, 1998;Wang andLi, 1998, 2005;Macior et al, 2001;Tang and Xie, 2006). This does not support speculations that pollinators of Pedicularis species would be as diverse as the floral morphology implies or that species with extremely elongated corolla tubes might require specific pollinators of lepidoptera or other insects with very long proboscides (Pennell, 1948;Li, 1948Li, , 1951.…”