Abstract Detail

Recent Topics Posters

Cane, James [2], Weber, Melissa [1], Yost, Morgan [1], Gardner, Dale [3].

Alkaloids and old lace: Pollen toxins exclude generalist pollinators from death camas (Toxicoscordion [=Zigadenus] paniculatum) (Melanthiaceae).

Many plants produce toxins to which specialist herbivores – typically insects – have evolved counter-adaptations, sometimes spawning a co-evolutionary arms race. Although many non-social bee species are likewise taxonomic host specialists, pollination guilds at the specialists’ floral hosts frequently include diverse floral generalists as well, even o­n plants that are otherwise chemically defended. In this study, we show that pollen and nectar of foothills death camas contains zygacine, the alkaloid responsible for this plant’s notorious mammalian toxicity. Adults of the generalist solitary bee, Osmia lignaria (Megachilidae), were paralyzed and soon after died when fed biologically relevant doses of zygacine; larval progeny eating dosed provision masses likewise expired. Such lethality probably explains the absence of this and 50+ other native bee species from this potential host. The sole pollinating bee, Andrena astragali, is known to use o­nly death camas pollen to feed itself and its progeny. Thus, pollen and nectar toxins exclude generalist pollinators from foraging at death camas, despite demonstrated necessity of pollinators for seed set.

1 - Utah State University, Department of Biology, College of Science, 5305 Old Main Hill, Logan, Utah, 84322-0305, United States
2 - USDA-ARS, Bee Biology and Systematics Laboratory, Utah State University, Logan, Utah, 84322-5310, USA
3 - USDA – ARS, Poisonous Plant Research Lab, Utah State University, Logan, UT, 84322

Keywords:
Melanthiaceae
pollinators
pollination
pollen
adaptation
alkaloids
bees
herbivory
Floral biology
Liliales.

Presentation Type: Poster
Session: 32-167
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM
Abstract ID:1128