- C D Eardley and M W Mansell
- Biosystematics Division, Plant Protection Institute, Private Bag X134, Pretoria 0001, South Africa
- 1996
The farm Carpe Diem, near Ofcolaco, South Africa, which is surrounded by indigenous vegetation, has a large complement of insects (38 species) that visit the litchi blossoms. Although most of these insects are ineffectual as pollinators, several species of indigenous bees, including the honey bee, and some flies apparently contribute significantly to pollination in the orchard. This was different from a similar study near Tzaneen in which there was an abundance of honey bees and very few other insects at the litchi flowers.
Summary:
The study was conducted on a litchi farm “Carpe Diem” near Ofcolaco, South Africa, surrounded by indigenous vegetation and with no nearby honeybee hives.
Over three years, 38 insect species were recorded visiting litchi flowers, including various bees and flies.
Most insect species were ineffective as pollinators, but indigenous bees like honeybees, mopani bees, and small carpenter bees, along with some flies, contributed significantly to pollination.
In contrast to a study near Tzaneen with abundant honeybees but few other insects, this orchard had more diverse pollinators.
Honeybees are the most common visitors but are considered poor pollinators because they carry pollen mainly on their hind legs and groom themselves.
Mopani bees and small carpenter bees are likely more effective pollinators due to smaller size and pollen-carrying habits.
Hover flies, which hover while feeding on nectar, are almost ineffectual pollinators.
Temperature and wind influenced insect activity: flies were more active in mornings and late afternoons, and bees and wasps during the hottest part of the day.
The number and diversity of insect visitors declined sharply in 1994, likely due to a cold winter.
Pollination in litchi relies heavily on honeybees, but dependence on a single species is risky in case of disease or parasites.
Alternative pollinators could include mopani bees, small carpenter bees, and calliphorid flies, though further study is needed for the flies.
The biologies of mopani and small carpenter bees are well known, and their populations can be increased via artificial nesting sites; different species prefer different nesting habitats.
Sweat bees nest in the ground with intricate burrows, but encouraging them to artificial sites is more challenging.
Further research is recommended on litchi pollination in different climatic regions and on the influence of surrounding vegetation on pollinator diversity.