Lamphere Cameron C, McCormick Elyse C, Adler Lynn S
Department of Biology and Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA, USA.
J Econ Entomol. 2025 Jun 13;118(3):1431-1435. doi: 10.1093/jee/toaf051.
Widespread decline of pollinator populations is of concern for both natural and agricultural ecosystems. Pathogens have been identified as a major contributor to the decline of some bee species, making understanding host-pathogen dynamics a crucial area of research. Sunflower pollen (Helianthus annuus L.; Asterales: Asteraceae) dramatically and consistently reduces infection by a prevalent gut pathogen, Crithidia bombi Lipa & Triggiani 1988 (Kinetoplastida: Trypanosomatidae), in the common eastern bumble bee (Bombus impatiens Cresson 1863; Hymenoptera: Apidae), when consumed by bees post-infection, but we do not know if sunflower can confer protection when consumed before exposure. We asked whether feeding bumble bees sunflower pollen diets prior to pathogen exposure decreases Crithidia infection compared to buckwheat pollen (Fagopyrum esculentum Moench; Polygonales: Polygonaceae). Buckwheat pollen was used as a comparison since it has a similar protein concentration as sunflower pollen, but results in higher Crithidia counts more comparable to typical wildflower pollen when consumed post-infection. Bumble bees were fed sunflower or buckwheat pollen for 7 d, inoculated with Crithidia, and then fed a wildflower pollen control diet for seven more days before assessing infection. We found that consuming a sunflower pollen diet before inoculation did not reduce Crithidia cell counts compared to buckwheat pollen. Furthermore, bumble bee survival and consumption of sucrose solution and pollen did not differ between these diets. The results show no evidence of sunflower pollen providing prophylactic resistance against Crithidia bombi infection, indicating that the timing at which sunflower pollen is consumed relative to exposure has important consequences for infection.
传粉者种群的广泛减少引起了自然生态系统和农业生态系统的关注。病原体已被确认为一些蜜蜂物种数量下降的主要原因，因此了解宿主与病原体之间的动态关系成为一个关键的研究领域。向日葵花粉（Helianthus annuus L.；菊目：菊科）能显著且持续地降低常见东部熊蜂（Bombus impatiens Cresson 1863；膜翅目：蜜蜂科）感染一种常见肠道病原体——克氏锥虫（Crithidia bombi Lipa & Triggiani 1988，动基体目：锥虫科）的几率，前提是蜜蜂在感染后食用。但我们尚不清楚在接触病原体之前食用向日葵花粉是否能提供保护。我们研究了与荞麦花粉（Fagopyrum esculentum Moench；蓼目：蓼科）相比，在病原体暴露之前给熊蜂喂食向日葵花粉日粮是否会减少克氏锥虫感染。选择荞麦花粉作为对照是因为它的蛋白质浓度与向日葵花粉相似，但在感染后食用时，其克氏锥虫数量更高，更接近典型野花花粉。给熊蜂喂食向日葵或荞麦花粉7天，接种克氏锥虫，然后再喂食野花花粉对照日粮7天，之后评估感染情况。我们发现，与荞麦花粉相比，接种前食用向日葵花粉日粮并没有减少克氏锥虫细胞数量。此外，这些日粮之间，熊蜂的存活率、蔗糖溶液和花粉的消耗量没有差异。结果表明，没有证据表明向日葵花粉能对克氏锥虫感染提供预防性抗性，这表明相对于暴露时间，食用向日葵花粉的时间对感染有重要影响。
