Browsing by Author "Nuttman, Clive"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Pollination Ecology of Desmodium Setigerum (Fabaceae) in Uganda; Do Big Bees Do It Better?
    (2016-08) Stanley, Dara A.; Otieno, Mark; Steijven, Karin; Berlin, Emma Sandler; Piironen, Tiina; Willmer, Pat; Nuttman, Clive
    Explosive pollen release is documented in many plant families, including the Fabaceae. Desmodium setigerum E. Mey (Fabaceae) is a perennial herb with single trip explosive pollen release found in eastern Africa, and the unique ability to reverse floral colour change if insufficient pollination has occurred. However, little else is known about the pollination ecology of this species, what visitors can trigger explosive pollen release, and whether bee body size is related to pollination efficiency. We investigated: 1) the breeding system of D. setigerum, and whether it is pollen limited; 2) whether flowers are visited early in the day allowing sufficient time for a second opportunity for pollination; and 3) what insect species visit D. setigerum and the relative efficacy of different flower visitors in relation to visitor size and pollination success. We found that although self-compatible, D. setigerum requires insect visitation to set seed as explosive pollen release is needed even for selfing. Most flowers are initially visited before 1400h, and by 1800h nearly all flowers have been tripped. Flowers were not pollen limited in this study, and were visited primarily by bees. We observed 16 visiting species, and there was a wide variation (0-404 grains) in the amount of pollen deposited on stigmas. Although almost all bees deposited some pollen, the mean number of pollen grains deposited in a single visit per species was negatively related to body size. However, one particular megachilid species deposited significantly more pollen grains than any other visitor and so is likely an important pollinator of this species. This provides insights into the pollination biology of this unique plant species, and adds to increasing literature on the relationships between bee body size, explosive pollen release and pollination effectiveness.
  • Thumbnail Image
    Item
    Tea breaks: how flower visitors can benefit from unplanned floral buffer strips in a Tanzanian tea plantation
    (Blackwell Publishing Ltd, 2013) Norfolk, Olivia; Sadiki, Lotha Laisser; Broughton, Brittanie; Otieno, Mark; Nuttman, Clive
  • Thumbnail Image
    Item
    The Utility of Aerial Pan-Trapping for Assessing Insect Pollinators Across Vertical Strata
    (2011) Nuttman, Clive; Otieno, Mark; Kwapong, Peter K.; Combey, Rofela; Willmer, Pat; Potts, Simon G.
    Insect pollinators provide a critical ecosystem service by pollinating many wild flowers and crops. It is therefore essential to be able to effectively survey and monitor pollinator communities across a range of habitats, and in particular, sample the often stratified parts of the habitats where insects are found. To date, a wide array of sampling methods have been used to collect insect pollinators, but no single method has been used effectively to sample across habitat types and throughout the spatial structure of habitats. Here we present a method of ‘aerial pan-trapping’ that allows insect pollinators to be sampled across the vertical strata from the canopy of forests to agro-ecosystems. We surveyed and compared the species richness and abundance of a wide range of insect pollinators in agricultural, secondary regenerating forest and primary forest habitats in Ghana to evaluate the usefulness of this approach. In addition to confirming the efficacy of the method at heights of up to 30 metres and the effects of trap color on catch, we found greatest insect abundance in agricultural land and higher bee abundance and species richness in undisturbed forest compared to secondary forest.