Using Molecular Barcodes to Investigate Pollinator-Plant Interactions in Long-Tongued Bees

Pollination is a crucial ecosystem service that is required to maintain and diversify plant populations. Worldwide, bees are the most important invertebrate group that provides pollination services. South Africa has a high level of bee and plant species endemism and diversity, especially in the succulent Karoo Region in the western part of the Country. There is some evidence to suggest that many bee species in the succulent Karoo are oligolectic as opposed to mainly polylectic bee species found in the savannah region of the eastern part of South Africa. Bee plant foraging habits can be studied using morphology to identify pollen collected, but palynological identifications are complicated and time-consuming, and seldom enable species identifications. DNA barcoding technologies can provide fast and accurate species-level delimitation.  This study aimed to non-destructively sample and DNA barcode pollen loads from bees housed in a national collection at the Agricultural Research Council’s Biosystematics unit, in South Africa. Illumina next generation sequencing (NGS) was used to target two genomic (ITS1 and ITS2) and one chloroplast (rbcL) region, of mixed pollen loads, from bee specimens. Sample collections which date back to the early 1900’s were successfully identified. This technique will be used to give a historic perspective of how floral choice in indigenous bees has changed over time to understand the effects of land use and climate change on plant-bee relations in a area with a high proportion of oligolectic bees.