Synergistic effects of floral phytochemicals against a bumble bee parasite.
Floral landscapes comprise diverse phytochemical combinations. Individual phytochemicals in floral nectar and pollen can reduce infection in bees and directly inhibit trypanosome parasites. However, gut parasites of generalist pollinators, which consume nectar and pollen from many plant species, are exposed to phytochemical combinations. Interactions between phytochemicals could augment or decrease effects of single compounds on parasites. Using a matrix of 36 phytochemical treatment combinations, we assessed the combined effects of two floral phytochemicals, eugenol and thymol, against four strains of the bumblebee gut trypanosomeCrithidia bombi. Eugenol and thymol had synergistic effects againstC. bombigrowth across seven independent experiments, showing that the phytochemical combination can disproportionately inhibit parasites. The strength of synergistic effects varied across strains and experiments. Thus, the antiparasitic effects of individual compounds will depend on both the presence of other phytochemicals and parasite strain identity. The presence of synergistic phytochemical combinations could augment the antiparasitic activity of individual compounds for pollinators in diverse floral landscapes.
Department of Biology University of Massachusetts at Amherst Amherst MA USA.
Evan C
0000-0002-9258-2073
EC
Palmer-Young
School of Biological Sciences Illinois State University Normal IL USA.
Ben M
BM
Sadd
Department of Applied Ecology North Carolina State University Raleigh NC USA.
Rebecca E
RE
Irwin
Department of Biology University of Massachusetts at Amherst Amherst MA USA.
Lynn S
LS
Adler
Crithidia bombi; antimicrobial synergy; bumblebee; plant secondary metabolites; pollinator–parasite interactions; trypanosome