Harmala Alkaloids as Bee Signaling Chemicals

Abstract

Harmala alkaloids are pharmaceutically active molecules that can be found in various plants. These alkaloids are fluorescent molecules in the range of 300-700nm. Coincidently, bees have a similar visible range of 300-600nm.  This study takes these observations and interweaves them into a hypothesis: since bees use their sight to find flowers to pollinate, then these flowers contain harmala alkaloids that would be visible to bees. It can then be inferred harmala alkaloids attract bees. In other words, harmala alkaloids are functional components of plants. In order to determine harmala alkaloids content, standard solutions of harmine, harmaline, harmane, harmol, and harmalol will be compared with extractions from plant samples using high performance liquid chromatography and fluorescence.

A variety of plants were chosen to represent three categories. The first is plants that are found to be insect pollinated, these include lemon balm (Melissa officinali), common rue (Ruta graveolens), meadow rue (Thalictrum aquilegifolium), hydrangea (Hydrangea arborescens), spirea (Spirea japonica), forget-me-not (Myosotis scorpioides), blue star grass (Sisyrinchium augustifolium), common rue (Ruta graveolens) and meadow rue (Thalictrum aquilegifolium). The second category represents wind pollinated plants, including sugar maple (Acer saccharum), white velvet (Tradescantia sillamontana), meadow rue (Thalictrum ichangense), rhoeo (Rhoeo spathacea). Finally, a control was also analyzed. The lady fern (Athyrium felix-femina) was chosen because it is not genetically related to the plants in categories one or two and is not insect or wind pollinated.

Following chemical analysis, each of the insect pollinated plants was found to contain harmala alkaloids. The lady fern (Athyrium felix-femina) contained no harmala alkaloids, as well as the wind pollinated plants. Due to these results as well as a study of bee behavior, we were able to conclude that harmala alkaloids are present in plants that attract bees. This study both contributes to an understanding of factors involved in pollination and can be used as a guide for further investigation into a natural source of harmala alkaloids.