Stella F. Uiterwaal

Arina's paper is out in Food Webs! While much research on predation rates and temperature is focused on warmer temperatures, Arina's work shows that cold temperatures are important too! Specifically, intraguild foraging rates of wolf spiders on ladybeetle larvae decrease during unseasonably cold temperatures, which are becoming more common in a changing climate. Because both wolf spiders and ladybeetles are biocontrol agents, these findings can help inform biocontrol programs. Arina performed this experiment as an undergrad taking the Predator Ecology field course at Cedar Point Biological Station. Nice work, Arina!

Photo of a Hogna carolinensis at CPBS, taken by Arina Martin. This is the largest wolf spider species in North America!

A three-toed box turtle with a VHF tracking tag. Our paper in Journal of Thermal Biology shows that urban box turtles experience colder winter temperatures than rural box turtles. This is likely due to habitat fragmentation and degradation, which limit the ability of turtles to find suitable microhabitats. We also show that turtles that experience colder temperatures face increased mortality risk, highlighting the importance of overwinter thermoregulatory ability for the abundance and fitness of urban ectotherms.

"Astrid", one of the Great Horned Owls in Forest Park, St. Louis. As the Senior Scientist for the Forest Park Living Lab, I conducted research on the movement, diet, and health of St. Louis' urban wildlife, including raccoons, coyotes, waterbirds, hawks, and turtles. This work was in collaboration with Washington University in St. Louis, Saint Louis University, Saint Louis Zoo, National Great Rivers Research and Education Center, and the World Bird Sanctuary. Astrid was the first Forest Park raptor to be fitted with a GPS transmitter, and we since tagged many more! Read more about the project here.

Our paper on prey diversity in raptor diets is out in Proc B. We find that, unexpectedly, many raptors have close to the maximum possible diet entropy. This suggests that raptors play key roles in food webs and help maintain biodiversity. This is the first paper using our new OS-Prey (Omnibus Study of Prey) database of raptor diets from around the world!

Photo: A Cooper's Hawk in St. Louis, Missouri.

Amputee felids with GPS collars. Our study in Ecology and Evolution uses movement data from bobcat, snow leopard, and Iberian lynx to show that amputee felids in the wild move similarly to four-legged individuals. We further find that these felids can successfully hunt and reproduce in the wild, showing that severely injured felids can go on to live healthy lives in the wild and contribute to local populations. This is especially great news for the Iberian lynx, a threatened species.

As part of my research with the Forest Park Living Lab, we deployed GPS tags on three diurnal and two nocturnal raptor species, as well as eight other species of reptiles, mammals, and birds.

Photo shows a Red-tailed Hawk with a solar GPS tag. This hawk has traveled from St. Louis to Canada and back multiple times, stopping at various towns along the way. Photo by Jamie Palmer.

Fitting one of St. Louis' coyotes with a GPS collar to understand how these resilient predators use urban green spaces and surrounding residential areas. This research was featured in the St. Louis Post-Dispatch as a Sunday paper cover story.

Photo by Stephen Blake

Banding nestling Barn Owls in Nebraska. We are putting GPS tags on breeding owls and dissecting pellets to examine how owls use the landscape to their advantage when hunting prey for their offspring. We are also collecting data from live-trapped small mammals to understand barn owl prey selection.

A close up of a nestling barn owl's face. The owl is covered in down and is being held in front of a blue sky and green prairie background

The last big chunk of my dissertation! This paper published in Ecology Letters shows how the functional responses of wild arthropods can be estimated by combining dietary metabarcoding data, DNA detection half-lives, and prey density data. These field functional responses are considerably lower than lab-estimated functional responses, suggesting that we need to be careful about how we use foraging experiments in the lab to draw conclusions about what happens in nature.

A male Tree Swallow with food provisioned for his nestlings at Cedar Point Biological Station. In 2022, we built a Motus tower at CPBS, connecting the station to an international, collaborative network designed to study the movement patterns of aerial animals.

An iridescent blue and white Tree Swallow with prey in its beak being held while banding

A wolf spider eating a metamorph toad. A natural history note on this observation is published in Herpetelogical Review.

Gut content samples ready for DNA extraction and metabarcoding to determine what prey the predators consumed. To quantify this type of data, half-lives can be used to describe how long prey DNA is detectable in the predator, but these half-lives are typically found using resource-intensive feeding trials. We show how these half-lives can be predicted and present a new method for improved metabarcoding quantification in our paper in Molecular Ecology Resources.

Epi tubes with pink numbers arranged in a tray, viewed from above.

A scatter plot of consumer mass and handling time, showing that handling time decreases with mass

FoRAGE is our publicly-available, ever-expanding database of functional responses. Our meta-analysis of FoRAGE in Ecology confirmed known effects of predator and prey mass, revealed optimum foraging temperatures, and showed that dimensionality and taxonomic identity can profoundly influence functional responses. We are always adding to FoRAGE, so please do contact me with new functional responses!

Paramecium caudatum, an approximately 0.15 mm long protist and the subject of our study in Ecology and Evolution. We exposed replicate populations to either a constant temperature or temperature fluctuations and to either predation or no predation. Our study revealed that these challenges produce conflicting selective pressures and that responses to these pressures are constrained by trade-offs between cell morphology and thermal performance.

Photo by Miranda Salsbery.

A photograph of Paramecium caudatum, a long, oval protist that appears greenish in this picture

A brown wolf spider in a glass respirometry tube being held in front of a grey background

Hogna wolf spider in a respirometry vial as part of our study in Ecological Entomology. As the spider respires, the oxygen concentration in the air-tight vial decreases. The sensor spot at the bottom of the vial detects these changes over time when the vial is placed in a respirometer. Our study shows that spiders with bigger opisthosoma (abdomens) - indicative of recent foraging success - have higher respiration rates for their size.

Still from a video of Drosophila melanogaster walking in arenas of different sizes. Using tracking software, we followed individuals' paths and found that the flies - and their predators - preferentially stayed near arena edges. Our study in Behavioral Ecology describes how this behavior, called thigmotaxis, causes arena size to have a pervasive effect on predation rates.

A still from a black and white video showing the location of flies in circular arenas

An close up photograph of ladybugs, spiders, and other arthropods on green vegetation with pink flowers

Lady beetles from an alfalfa field, including the native Hippodamia convergens (upper right) and the invasive Harmonia axyridis (lower right). Because they are a common biocontrol agent, there is an abundance of predation literature focused on lady beetles. A meta-analysis of this literature reveals that arena size has a large impact on the outcomes of predation experiments with lady beetles. This critical finding suggests that pest management decisions can be misinformed if laboratory experiments do not take arena size into account. Published in the Journal of Applied Ecology.

A Bold Jumping Spider (Phidippus audax ) with its prey, a Salt Marsh Moth (Estigmene acrea) on a window at Cedar Point Biological Station in western Nebraska. See the iNaturalist observation for this photo here and here.

A black jumping spider with green chelicera, holding an orange and white moth with black spots, clinging to a window that reflects the blue sky and green trees behind.

An overhead view of a lime green damselfly nymph sitting in shallow water in a Petri dish, with the number 49 written in pencil on the paper below.

Damselfly nymph from research published in Oecologia. Damselflies are voracious generalist predators, and in our experiment we fed them Daphnia, copepods, and Chydorus. We found that, across all three prey types, nymphs forage best at an intermediate predator:prey size ratio. This was also our first study where we found evidence that experimental arena size (in our case, Petri dish size) plays an important role in determining predation rates.

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