Sunflower pollen induces rapid excretion in bumble bees: Implications for host-pathogen interactions. (February 2022)

• Record Type: Journal Article
• Authors: Giacomini, Jonathan J.; Moore, Nicholas; Adler, Lynn S.; Irwin, Rebecca E.
• Is Part Of: Journal of insect physiology. Volume 137(2022)
• Publication Date: 2022-02
• Subjects: Host physiology -- Host-pathogen interactions -- Insect excretory system -- Protozoan pathogens -- Rapid excretion; Insects -- Physiology -- Periodicals; Insectes -- Physiologie -- Périodiques; Insects -- Physiology; Periodicals; 571.157
• DOI: 10.1016/j.jinsphys.2022.104356
• Languages: English
• ISSNs: 0022-1910

Abstract

Graphical abstract: Highlights: Sunflower pollen reduced gut transit time in bumble bees. Sunflower pollen increased the number and volume of excretions in bumble bees. Infected and healthy bumble bees responded to sunflower pollen similarly. Infected bumble bees had higher excretion rates compared to healthy bumble bees. In infected bees, higher infection associated with lower excretion rate and volume. Abstract: Host diet can have a profound effect on host-pathogen interactions, including indirect effects on pathogens mediated through host physiology. In bumble bees ( Bombus impatiens ), the consumption of sunflower ( Helianthus annuus ) pollen dramatically reduces infection by the gut protozoan pathogen Crithidia bombi. One hypothesis for the medicinal effect of sunflower pollen is that consumption changes host gut physiological function, causing rapid excretion that flushes C. bombi from the system. We tested the effect of pollen diet and C. bombi infection on gut transit properties using a 2x2 factorial experiment in which bees were infected with C. bombi or not and fed sunflower or wildflower pollen diet. We measured several non-mutually exclusive physiological processes that underlie the insect excretory system, including gut transit time, bi-hourly excretion rate, the total number of excretion events and the total volume of excrement. Sunflower pollen significantly reduced gut transit time in uninfected bees, and increased the total number of excretion events and volume of excrement by 66 % and 68 %, respectively, in both infected and uninfected bees. Here we show that a sunflower pollen diet can affect host physiology gut function, causing more rapid and greater excretion. These results provide important insight into a mechanism that could underlie the medicinal effect of sunflower pollen for bumble bees.