DOI: 10.5061/dryad.1g1jwsv22
title: Pelomedusa subrufa dry faecal mass and egg densities

description: Marsh helmeted terrapins (Pelomedusa subrufa) potentially facilitate
 zoochory of fairy shrimp dormant eggs between temporary wetland
 environments. Dominance hierarchies are known to establish in freshwater
 testudine populations, with larger-sized or older individuals being
 dominant over smaller or younger individuals. We assessed for zoochory
 potential between large- and small-sized turtles by assessing P. subrufa
 faecal samples from a temporary pan which was observed to hold high
 densities of both the terrapin and fairy shrimp. Small-sized terrapin dry
 faecal mass was similar to large-sized terrapin dry faecal mass. However,
 potential egg densities were much higher in small-sized
 terrapin. 
description: We opportunistically tested
 for the potential of size-related dominance hierarchy in <em>P.
 subrufa</em> to contribute to dispersal of large branchiopod
 dormant eggs in a southern
 African temporary wetland complex. On 12 January 2022, while sampling a
 wetland site as part of a larger investigation of temporary pan ecology,
 it was evident that high numbers of testudines were present. Dozens of
 <em>P. subrufa</em> were seen breaching the water surface with
 their heads at any one time. Sampling of the pan also revealed high
 densities of fairy shrimp. As such, we collected terrapins of two discrete
 size classes (small and large) and obtained faecal samples to assess for
 the presence of large branchiopod dormant eggs, their viability through hatching experiments,
 and size-related differences in zoochorous
 potential.  A total of 61 terrapins were sampled from the
 single seine net haul, all identified as <em>P. subrufa</em>.
 Two size classes were evident, with 36 individuals categorized as small
 (65 mm–115 mm carapace length) and 25 individuals (190 mm–220 mm carapace
 length) as large. No <em>P. subrufa</em> individuals between
 115 mm and 190 mm were sampled, suggesting that the two size classes
 represented discrete age groups. It was observed that while taking size
 measurements upon handling, some <em>P. subrufa</em> would
 defaecate. The faeces were carefully and opportunistically collected by
 placing a clean, inverted ziplock bag under the cloaca to catch the
 defaecant as it was extruded, being careful not to allow contact with any
 sediment or the animal’s body. Each individual was held for no longer than
 60 seconds before being gently released back into the wetland. Faecal
 matter was attained from 14 individuals in total: 8 individuals of the
 smaller size class and 6 individuals of the larger size class. Ziplock
 bags with faecal samples were then placed in a large polystyrene cooling
 container and allowed to air dry for 7 days prior to laboratory
 processing. The dried
 faecal samples were gently crushed in the Ziplock bags, with the contents
 then gently transferred into a weighing boat and weighed to the nearest
 0.1 mg, using an Ohaus Adventurer Balance, model AR2140. Samples were then
 carefully transferred to a zooplankton counting tray for processing using
 a dissecting microscope (Olympus SZ61) at 20 × magnification to assess for
 potential dormant eggs. Items with external morphological features that
 looked like dormant eggs were counted and expressed as the density of
 items per unit dry faecal mass. 
description: Microsoft Excel