Annie Krueger

Ph.D in entomology

Completed field conservation project:

We set out to quantify detoxification enzyme activity and expression in monarch caterpillars raised on different milkweed species with and without insecticide exposure. Originally, we set out to compare three different milkweed species however due to pest pressures and difficulty cultivating one of the species we were left with only two milkweed species to work with. Caterpillars were reared on either the highly defended (i.e., high cardenolide) tropical milkweed species (Asclepias curassavica) or the less defended (i.e., low cardenolide) swamp milkweed species (Asclepias incarnata). 

We raised caterpillars from hatching through the fifth and final larval instar on either species. At the fifth instar, half of the caterpillars on each species were treated with a pyrethroid insecticide (bifenthrin) and the other half were treated with acetone as a control group. Originally, we set out to apply a formulated insecticide product to plants and then place caterpillars on treated plants. However, we decided to topically treat individuals to ensure a more uniform insecticide exposure across all caterpillars. 

Survival was recorded 24 hours after topical treatment and caterpillars were frozen for further analysis. We quantified activity of key detoxification enzymes and expanded the research to also look at the gene expression of several of these enzymes.  By looking at gene expression we could also see if caterpillars were producing more of these enzymes when feeding on one milkweed species over the other.

The impact of your field conservation work: 

We identified key physiological differences in monarch caterpillars developing on different milkweed species, suggesting milkweed species with higher defense chemicals may improve the health of monarch caterpillars. This project will be submitted for full publication by the end of 2021 providing researchers the opportunity to further explore milkweed species selection in conservation and implications for insecticide tolerance.

Samuel Eliades 

Ph.D. student from Oklahoma University 

Completed field conservation project:

This Texas horned lizard headstart and reintroduction program is a collaborative effort originally developed by the Sam Noble Museum at the University of Oklahoma, Tinker Air Force Base, and the Oklahoma City Zoo in 2019 but has since expanded to include partners such as the Oklahoma Department of Wildlife Conservation and the Friends of Sunset Zoo. In June of 2021, 34 Texas horned lizards originally raised at the Oklahoma City Zoo were transported from the “Lizard Lab” to enclosed pens on Tinker Air Force Base in Oklahoma City, Oklahoma. These headstart lizards were from two distinct age classes, 15 animals that hatched in 2019 and 19 animals that hatched in 2020. All lizards spent five weeks in pens on Tinker for observation and to adjust to wild conditions before complete reintroduction.

On July 9, 20 lizards were removed from their pens and released with tracking diodes attached that enabled me and other researchers to monitor their activity throughout the summer. As many as 16 headstart lizards may still be on Tinker as of late October, though most of these individuals have shed or dropped their tracking diodes making it difficult to assess their status. Interestingly, two headstart lizards were observed dug underground in preparation for winter on October 19, emulating a natural behavior that was not exhibited in human care.

 Throughout the release process, we collected roughly 100 fecal samples from wild and headstart horned lizards on Tinker to better understand gut bacteria in these lizards pre- and post-release. These samples are now expected to be processed and sequenced in November 2021 for publication of results in spring 2022.

The impact of your field conservation work: 

This program resulted in the release of 34 Texas horned lizards onto a native managed prairie habitat in Oklahoma City, Oklahoma. We estimate that as many as 16 lizards still remain at their introduced field site and two lizards have been observed buried underground for brumation through the winter.

Keely Rodriguez

Ph.D. student in the Voyles' Lab at the University of Nevada Reno

Completed field conservation project:

Although the pandemic prevented me from travelling abroad to Panama to perform field work since receiving this scholarship, my work has continued in the laboratory. My laboratory work has involved in vitro challenge assays using the blood serum of the American bullfrog (Lithobates catesbeianus). My work focuses on the complement system, which is a biochemical system of proteins that work together to prevent some diseases. This work is challenging because there are no non-aquatic amphibian model species to reference. Specifically, I am using a complement depletion molecule called Cobra Venom Factor, to deplete complement proteins in frog serum and assess the efficacy of the complement system against pathogens. Because field conditions vary greatly from laboratory conditions, these assays will incorporate environmental chambers to mimic environmentally stochastic conditions such as temperature and humidity. Because amphibians are ectotherms, and protein efficiency can be altered with varying temperatures, I will assess how the efficacy of the complement system on infections with chytridiomycosis may or may not change based on varying temperatures. Once I am able to return to the field I will perform the same assays to see if the patterns observed in the laboratory can be observed in other amphibian species in the field. Additionally, I have been working in a chemistry lab to characterize activated complement proteins using top-down mass spectrometry, the ultimate goal being to transfer these methods from human complement to amphibian complement proteins. 

 Impact of your field conservation work: 

Due to the pandemic, my fieldwork has been postponed. However, my laboratory work has validated immune mechanisms of an amphibian species. I was also a co-author on a publication about a computer program that can identify frog calls. We used this program to find the critically endangered Panamanian Golden frog in a location thought to be void of this species.