Biology subjects

Traugott, M.

Publications and source records attributed to Traugott, M..

2 recordsLinked to original sources

bioRxiv2017

Combining molecular gut content analysis and functional response models shows how body size affects prey choice in soil predators

O_LIPredator-prey interactions are a core concept of animal ecology and functional response models provide a powerful tool to predict the strength of trophic links and assess motives for prey choice. However, due to their reductionist set-up, these models may not display field conditions, possibly leading to skewed results.\nC_LIO_LIWe tested the validity of functional response models for multiple prey by comparing them with empirical data from DNA-based molecular gut content analysis of two abundant and widespread macrofauna soil predators, lithobiid and geophilomorph centipedes.\nC_LIO_LIWe collected soil and litter dwelling centipedes, screened their gut contents for DNA of nine abundant decomposer and intraguild prey using specific primers and tested for different prey and predator traits explaining prey choice. In order to calculate the functional response of same predators, we used natural prey abundances and functional response parameters from published experiments and compared both approaches.\nC_LIO_LIMolecular gut content results showed that prey choice of centipedes is driven by predator body size and prey identity. Results of functional response models significantly correlated with results from molecular gut content analysis for the majority of prey species.\nC_LIO_LIOverall, the results suggest that functional response models are a powerful tool to predict trophic interactions in soil, however, species-specific traits have to be taken into account to improve predictions.\nC_LI

ecology↗

bioRxiv2017

Comparing three types of dietary samples for prey DNA decay in an insect generalist predator

The rapidly growing field of molecular diet analysis is becoming increasingly popular among ecologists, especially when investigating methodologically challenging groups such as invertebrate generalist predators. Prey DNA detection success is known to be affected by multiple factors, however the type of dietary sample has rarely been considered. Here, we address this knowledge gap by comparing prey DNA detection success from three types of dietary samples. In a controlled feeding experiment, using the carabid beetle Pterostichus melanarius as a model predator, we collected regurgitates, feces and whole consumers (including their gut contents) at different time points post-feeding. All dietary samples were analyzed using multiplex PCR targeting three different length DNA fragments (128 bp, 332 bp and 612 bp). Our results show that both the type of dietary sample and the size of the DNA fragment contribute to a significant part of the variation found in the detectability of prey DNA. Specifically, we observed that in both regurgitates and whole consumers prey DNA was detectable significantly longer for all fragment sizes than for feces. Based on these observations, we conclude that prey DNA detected from regurgitates and whole consumers DNA extracts are comparable, whereas prey DNA detected from feces, though still sufficiently reliable for ecological studies, will not be directly comparable to the former. Therefore, regurgitates and feces constitute an interesting, non-lethal source for dietary information that could be applied to field studies in situations when invertebrate predators should not be killed.

ecology↗