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DIY EPG

26Aug

We received good news that Manjari requires more space for her EPG work, so the group made another Faraday cage.

Modeling thermoregulators

18May

Working with Aaron Tarone of Texas A&M Entomology and members of his group, we have been developing insect phenology models that account for thermoregulatory behavior. These models are intended for use in predicting vector and pest dynamics, and in retrodicting events of forensic importance that can be indicated by insect development.

We’re happy to have some of this work recently published in Frontiers in Ecology and Evolution: https://static.frontiersin.org/articles/10.3389/fevo.2022.837732/full

The rationale of this work has been that organisms capable of behavior will behave in ways that are on average beneficial. Insects have been shown to “have” what we call “preferred temperatures.” The mechanisms related to this are complex, but they don’t need to be clarified before we can improve predictions by implicitly incorporating behavior into models. Our improvement transforms distributions of environmental temperature into distributions of insect temperatures, through a function that involves environmental temperature and its variance, and insect preferred temperature. It is a simple convolution, wherein development rate is a function of insect body temperature, which is a function of environmental temperatures and insect behavior.

Here’s how it looks:

The graph shows temperatures through time: ambient air (which is what many phenology models use as input), colonized flesh (because this work was done on necrophagous fly larvae), and predicted insect temperature using our model. I’ve arbitrarily chosen 27 °C as a preferred temperature. Blue bands around the ambient temperature trace are to suggest temperature variation across space.  Predicted larval temperatures lie between ambient and preferred, determined jointly by the difference between ambient and preferred and the variance around ambient.

 

Roy graduates

7May

Roy L. Davis II becomes Graduate I,

Roy is hooded at spring 2022 commencement

and departs from the department.

Roy departs; colleagues support

Later, Dr. Davis looks back and reflects.

Roy looks back

Roy’s soilborne inoculum work

5May

Roy spent plenty of time in the laboratory quantifying Fusarium oxysporum f. sp. vasinfectum (Fov) DNA from field soil, and some of his work is now reported in a Plant Disease publication: https://doi.org/10.1094/PDIS-08-21-1664-RE

The work’s objective was to describe spatial variability in Fov inoculum density in the field, because that variation is hypothesized to affect risk of cotton plants expressing Fusarium wilt disease. Much of Roy’s report concerns development of the quantification method, which targets the Fov race affecting the selected field sites. Roy discovered that inoculum density varies across the field space by orders of magnitude (shown in the figure below, where “inoculum level” is a relative logarithmic scale), and by observing it at multiple time points he noticed a temporal pattern: inoculum density trajectory depends on growth resource type and availability, which depends on prior inoculum density.  Roy is now finishing documentation of that cycle in this system.

Learning About EPG

29Apr

Manjari explaining the basic principles of EPG to Maggie.

2022 Graduate Research Showcase

26Apr

Roy, Jensen, Manjari, and Tim all presented posters of their research at the 2022 PLPM Graduate Research Showcase.

Horizontal Movement of Inoculum

12Apr

Jensen and Maggie in the process of running a horizontal column.

Maggie at Work

12Apr

Maggie is hard at work using aseptic techniques for plating effluent from a horizontal column run.

Timothy Martin

12Apr

About Me

I am a first year PhD student at Texas A&M University.  I graduated from St. Olaf College in Northfield, MN in 2017 with a B.A. in Biology.  I then went to Illinois State University where I completed a M.S. in plant ecology in 2021 under the direction of Dr. Victoria Borowicz with a thesis titled “In Defense of Plants: Salicylic Acid in a Host-Parasite-Pathogen System.”  During which time I completed a graduate certificate in geographic information systems.

I am interested in the ecological factors impacting pathogenesis,  especially as it relates to spatial patterns of pathogen interaction in both agricultural and natural settings.  In the Chappell lab, I have been working on characterizing the environment around cotton fleahopper collection sites to determine if the land use in areas surrounding fleahopper populations impacts the abundance of fleahoppers.

2022 Conference on Soilborne Plant Pathogens

24Mar

Roy was invited to present his work at the Conference on Soilborne Plant Pathogens held virtually on March 22 and 23, 2022. He presented research related to his work with the spatial and temporal variation of FOV4. Roy was also one of four recipients of the Martin Stoner Memorial Fellowship.

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