Gut retention time of liquid and large particle digesta phases in small mammals
Abstract
Animals are important dispersers of plant seeds and other propagules. Gut retention time is a crucial component of dispersal because it influences the range and number of times propagules can be dispersed by animals after consumption. Yet, how factors such as particle morphology and gut morphology may affect gut retention times in small mammals is unknown. The goal of this project was to determine both the mean retention time (MRT) of different phases of digesta (liquid and large particle) through the digestive tract and also how gut morphology of small mammals impacts MRT. We hypothesized that large particles would pass through the gut slower than the liquid phase of digesta and that longer gut lengths will increase the time it takes for particles to complete the passage. To test these hypotheses, we fed three small mammal species: shrew (Blarina brevicauda), mouse (Peromyscus leucopus), and vole (Myodes gapperi), which differ in gut length, a liquid tracer (CrEDTA) and two solid tracers (glitter and beads) that represent the range of propagule morphologies that they disperse. We collected scat at intervals over a 5-day period and used spectrometry to assess CrEDTA concentrations and microscopy to assess glitter and bead abundance in the scat. In support of our hypothesis, we found that large particles have longer MRTs than the liquid phase of digesta, although particle shape altered gut retention time. Gut length had a strong influence on MRT with shorter guts (shrew) having significantly shorter retention times than mice or voles. Our findings provide valuable information on how small mammal species can disperse propagules, with large particles dispersed over longer time intervals than liquid phases in all species and mice and voles being able to disperse propagules over longer time intervals than shrews because of their gut morphology.
Start Time
16-4-2025 9:00 AM
End Time
16-4-2025 11:30 AM
Presentation Type
Poster
Presentation Category
Science, Technology and Engineering
Student Type
Undergraduate Student
Faculty Mentor
Ryan Stephens
Faculty Department
Biological Sciences
Gut retention time of liquid and large particle digesta phases in small mammals
Animals are important dispersers of plant seeds and other propagules. Gut retention time is a crucial component of dispersal because it influences the range and number of times propagules can be dispersed by animals after consumption. Yet, how factors such as particle morphology and gut morphology may affect gut retention times in small mammals is unknown. The goal of this project was to determine both the mean retention time (MRT) of different phases of digesta (liquid and large particle) through the digestive tract and also how gut morphology of small mammals impacts MRT. We hypothesized that large particles would pass through the gut slower than the liquid phase of digesta and that longer gut lengths will increase the time it takes for particles to complete the passage. To test these hypotheses, we fed three small mammal species: shrew (Blarina brevicauda), mouse (Peromyscus leucopus), and vole (Myodes gapperi), which differ in gut length, a liquid tracer (CrEDTA) and two solid tracers (glitter and beads) that represent the range of propagule morphologies that they disperse. We collected scat at intervals over a 5-day period and used spectrometry to assess CrEDTA concentrations and microscopy to assess glitter and bead abundance in the scat. In support of our hypothesis, we found that large particles have longer MRTs than the liquid phase of digesta, although particle shape altered gut retention time. Gut length had a strong influence on MRT with shorter guts (shrew) having significantly shorter retention times than mice or voles. Our findings provide valuable information on how small mammal species can disperse propagules, with large particles dispersed over longer time intervals than liquid phases in all species and mice and voles being able to disperse propagules over longer time intervals than shrews because of their gut morphology.