Pollination efficiencies of flower‐visiting insects as determined by direct genetic analysis of pollen origin

Abstract

The amount and genetic composition of pollen grains that are transported to flowers influence the reproduction and fitness of plants. Despite the importance of insect-pollination systems, an understanding of those systems is still lacking due to the absence of a genetic analysis of pollen grains that are transported to flowers. We evaluated the pollination efficiencies of bumblebees (Apidae, Bombus spp.), flower beetles (Scarabaeidae, subfamily Cetoniinae, Protaetia and Eucetonia sp.), and small beetles (Lagriidae, Arthromacra sp.) that visited the flowers of Magnolia obovata (Magnoliaceae) using quantitative (flower visitation frequency, amount of adherent pollen per insect) and qualitative (origin and genetic diversity of adherent pollen per insect) criteria. Most of the pollen adhering to bumblebees and small beetles was self-pollen. This result suggests that visitation by these insects may cause geitonogamous pollen flow and negatively affect the reproduction of M. obovata, causing inbreeding depression. In contrast, flower beetles transported large amounts of genetically diverse outcross pollen. Our results suggest that certain beetle species contribute quantitatively and qualitatively to the pollination of M. obovata. Direct genetic analysis of pollen grains will advance our understanding of plant mating systems and may shed light on the mutualism and coevolution of plants and flower visitors.

Pollination Efficiencies of Insects Visiting Magnolia obovata, as Determined by Single-Pollen Genotyping

“…For bumblebees, the pollen loads packed onto the bumblebee's hindleg pollen transport structure were not included in the counting, because such packed pollen was no longer available for pollination as a result of the addition of nectar and oil by the bumblebee (Thorp 1979(Thorp , 2000. The average numbers of pollen grains adhering to flower beetles (n = 38), small beetles (n = 118), and bumblebees (n = 41) were 27,761 ± 20,770 (range, 1,267-79,400), 916 ± 2,099 (range, 0-16,167), and 16,354 ± 12,227 (range, 0-54,867), respectively (Matsuki et al 2008). The number of pollen grains adhering to each insect differed among insect groups (F = 100.5, df = 2, P < 0.001).…”

“…): 1.55; small beetles (Lagriidae and Elateridae): 2.30; bumblebees (Apidae, Bombus spp. ): 2.05; other bees (Andrenidae and Halictidae): 0.56; and flies (Syrphidae): 0.29 (Matsuki et al 2008). Among the obovata that adhered to leg of the beetle and a pipette tip which was stretched and cut off to obtain a sharp end insects, flower beetles (Scarabaeidae, subfamily Cetoniinae: P. cataphracta), small beetles (Lagriidae: Arthromacra sumptuosa), and bumblebees (Apidae: Bombus ardens and Bombus diversus) were used for later analysis.…”

“…Here, we show the latest approach, which directly determines the genotypes of pollen grains transported by insects and evaluates the pollination efficiencies of each flower-visiting insect (Matsuki et al 2007(Matsuki et al , 2008.…”

Habitat and conservation status of molinillo (Magnolia sambuensis) and laurel arenillo (Magnolia katiorum), two endangered species from the lowland, Colombia

“…Although it is known that individual flowers of temperate species can last from two to four days, the stigmatic receptivity and the pollen maturity and viability for several Magnolia species remain unknown (Dieringer & Espinosa, 1994;Matsuki, Tateno, Shibata, & Isagi, 2008;Thien et al, 1998).…”

Assessment of Flower Visiting Insects Diversity as Pollinators in Two Parks, Kolkata, India

“…According to Turner et al (2004), biodiversity study has been shown to be inequitably distributed across cities, potentially due to micro level variation in vegetation and other biological resources. Pollination efficiency is an important part for pollinators that help to know mutualism between flowers and insect visitors (Matsuki, 2008).…”