Biology subjects

Eitzinger, B.

Publications and source records attributed to Eitzinger, B..

3 recordsLinked to original sources

bioRxiv2026

Assessing RNA as a tool to detect scavenging in a riparian invertebrate predator

Riparian environments are characterised by a high diversity of arthropod species, linking the aquatic with the terrestrial ecosystem. One of the dominant arthropod predators in this ecotone, carabid beetles are of particular interest as they may also act as facultative scavengers, feeding on carrion deposited along the shoreline. To test whether carabids feed on carrion, we examined the feeding preferences of the abundant riparian carabid Bembidion elongatum in a laboratory feeding trial, offering freshly killed and 24 hours post mortem Drosophila melanogaster. We subsequently assessed the detection probability of ribosomal prey RNA and DNA in predator gut contents using Drosophila-specific RT-PCR and PCR assays, and quantified nucleotide abundance by quantitative real-time PCR at 0, 3, 6, and 12 hours post-feeding. In the feeding experiment, B. elongatum showed a significant preference for fresh over carrion prey. Following consumption, the quantities of prey DNA and RNA in the predators gut declined over a 12-hour post-feeding period. However, no differences were detected in prey DNA or RNA quantities between individuals fed fresh prey and those fed carrion. Only immediately after consumption was the DNA:RNA ratio significantly lower in individuals fed fresh prey compared to those fed carrion while this difference was not observed at later time points. Overall, our results indicate that ingested ribosomal prey RNA in predators is present in high quantities, and that the DNA:RNA ratio is not a suitable indicator for distinguishing between consumption of carrion and fresh prey.

ecology↗

bioRxiv2021

Long-term monitoring reveals topographical features and vegetation explain winter habitat use of an Arctic rodent

Collapsing lemming cycles have been observed across the Arctic, presumably due to global warming creating less favorable winter conditions. The quality of wintering habitats, such as depth of snow cover, plays a key role in sustaining population dynamics of arctic lemmings. However, few studies so far investigated habitat use during the arctic winter. Here, we used a unique long-term time series to test whether lemmings are associated with topographical and vegetational habitat features for their winter refugi. We examined yearly numbers and distribution of 22,769 winter nests of the collared lemming Dicrostonyx groenlandicus from an ongoing long-term research on Traill Island, Northeast Greenland, collected between 1989 and 2019, and correlated this information with data on dominant vegetation types, elevation and slope. We specifically asked if lemming nests were more frequent at sites with preferred food plants such as Dryas octopetala x integrifolia and at sites with increased snow cover. We found that the number of lemming nests was highest in areas with a high proportion of Dryas heath, but also correlated with other vegetation types which suggest some flexibility in resource use of wintering lemmings. Conversely, they showed a distinct preference for sloped terrain, probably as it enhances the formation of deep snow drifts which increases the insulative characteristics of the snowpack and protection from predators. With global warming, prime lemming winter habitats may become scarce through alteration of snow physical properties, potentially resulting in negative consequence for the whole community of terrestrial vertebrates.

ecology↗

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↗