A Periphyton-Based Diet Results in an Increased Growth Rate Compared to a Detritus-Based Diet in the Invasive New Zealand Mud Snail (Potamopyrgus antipodarum).

Periphyton growth on allochthonous input in streams may lead to higher individual growth rates of the invasive New Zealand mud snail (<em>Potamopyrgus antipodarum</em>)

“…This suggests that allochthonous substrates may provide a better biofilm diet than periphyton grown on rock surfaces. Previous work has demonstrated that NZMS grow at a faster rate when consuming periphyton on rock compared to detritus or a Spirulina powder control (Bilka and Levri, 2013;Levri et al, 2017a). In this experiment, we did not find a difference between the control and the periphyton on rock treatment.…”

“…species (Hansen et al, 2016) resulting in a greater impact on the periphyton community (Krist and Charles 2012). The diet of the NZMS has been demonstrated to influence its individual growth rate with diets of epilithic periphyton resulting in higher growth rates than detritus-based diets (Bilka and Levri, 2013;Levri et al, 2017a). However, periphyton communities colonize both autochthonous (materials found in the stream such as rocks and sediment) and allochthonous material (material found in the stream that came from outside sources such as leaf litter and woody debris).…”

“…We provided oxygen using aeration for five seconds per cup three times per week for all treatments, and we maintained the experiment for 59 days before the snails were removed from the cups and measured for length a second time. The length of approximately 59 days was chosen based on previous experiments where that amount of time was found to be sufficient for the snails to at least double in size while they are juveniles (Levri et al, 2017a;Levri et al, 2020). We calculated the change in length of each snail in millimeters, and we used SPSS statistical software to perform a univariate analysis of variance to test for the effects of treatment on the log of change in length.…”