Abstract Detail

Life after Arabidopsis thaliana: Using non-model organisms to understand species interactions

Sipes, Sedonia D. [1], Messinger, Olivia J. [2], Simpson, Melissa [3].

Emphorine bees and their host plant as an ideal system for studying specialized bee-plant relationships.

Unlike the intensively-studied European honeybee, most wild bees are solitary and may have specialized relationships with their host plants. Unfortunately, basic biological information is lacking for many of these species. We have used a tribe of specialist bees (Emphorini) and their host plants as an ideal system to elucidate ecological and evolutionary aspects of bee/plant interactions. Emphorini are New World specialist bees, with each species utilizing 1-2 host plant genera in six distantly-related families (Malvaceae, Cactaceae, Asteraceae, Convolvulaceae, Onagraceae, and Pontederiaceae). We have described phylogenetic relationships, quantified host preferences using scopal pollen, reconstructed host switching patterns, elucidated the role of chemical and visual floral cues in host recognition, and are exploring interactions of these bees and plants with herbivores. Analyses of scopal pollen revealed that, though emphorines are all specialists, they vary in host choice breadth, with some being strict specialists some being eclectic specialists. A robust phylogeny suggested Convolvulaceae was the ancestral host family, with multiple independent switches to the other host families. The floral characters potentially important for host selection are not yet fully understood but show some intriguing patterns: most but not all hosts have very large pollen grains, most but not all have open, bowl-shaped flowers, most but not all have flowers that reflect in the bee blue-green and bee-UV portions of the spectrum. Analysis of host floral scents did not reveal a single chemical or suite of chemicals shared by all emphorine hosts. Rather, it seems the absence of repellant compounds may play a role in host choice: comparisons to abundant, sympatric non-hosts indicated that host plants have scents with fewer chemicals than non-hosts. Electroantennography showed mallow- and cactus-feeding species responded to some of the same floral chemicals, but varied for others; in general responses were to chemicals commonly found across a wide variety of plant taxa, not to rare or unusual compounds. Choice tests revealed that supplementing host flowers scent constituents did not increase bee visitation, but addition of non-host compounds reduced visitation. To date, most of our studies have focused on the genera Diadasia and Ptilothrix, but other Emphorini are promising systems for future study.

1 - Southern Illinois University, 1125 Lincoln Drive, Mail Code 6509, Carbondale, IL, 62901, USA
2 - Southern Illinios University Carbondale, Plant Biology, 1125 Lincoln Dr., Carbondale, IL, 62901, USA
3 - U.S. Forest Service, Chequamegon-Nicolet National Forest, 500 Hanson Lake Road, Rhinelander, WI, 54501, USA

Keywords:
bees
pollination
Evolution
chemical ecology
Evolutionary ecology
phytochemistry.

Presentation Type: Symposium or Colloquium Presentation
Session: SY10
Location: Pines North/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 4:45 PM
Number: SY10008
Abstract ID:819
Candidate for Awards:None