The contribution of plant species with a steady-state flowering phenology to native bee conservation and bee pollination services

Authors


Valerie E. Peters, Smithsonian Conservation Biology Institute, National Zoological Park, 3001 Connecticut Ave. NW, Washington, DC 20008, USA. E-mail: cazamosca@gmail.com

Abstract

Abstract.  1. Neotropical organisms have evolved in an environment of relatively low temporal variation in food availability, but when neotropical forests are converted to agriculture, the temporal patchiness of food resources is increased. Plant species with a continuous (i.e. steady-state) flowering/fruiting phenology are unique to the tropics and may more evenly distribute food resources temporally in agroecosystems.

2. Here, we test the effects of an experimentally planted supplemental steady-state floral resource, Hamelia patens Jacq., on bee diversity and pollination services in coffee agroforests. In addition, we evaluate effects of the steady-state resource during low-density and mass coffee blooms.

3. Malaise trap data indicated that bee species density was significantly higher in coffee agroforests with the supplemental steady-state floral resources [11.89 ± 1.62 (SE)] compared to those without (8.88 ± 1.10).

4. The steady-state floral resource had a negative impact on native bee visits to coffee flowers and a positive impact on Apis mellifera visits to coffee flowers (e.g. during low-density blooms agroforests with steady-state resources had 76% fewer native bee and 130% more A. mellifera visits to coffee flowers). Although coffee initial fruit set rates were higher across all agroforests during low-density blooms (0.74 ± 0.03) compared to the mass bloom (0.59 ± 0.03), steady-state floral resources did not affect initial fruit set rates (= −1.05, = 0.29).

5. Our results suggest that plants with a steady-state phenology can provide more reliable resources for bees, supporting the conservation of wild bees in agroforests. However, steady-state flowering may draw native bees away from the focal crop, especially during low-density flowering.

Ancillary