RESEARCH
AN AGENT-BASED MODEL TO SIMULATE MONARCH BUTTERFLY MOVEMENT AND EGG-LAYING
My agent-based model advances movement modeling by allowing monarch agents to respond to habitat within their perceptual range when making movement decisions. This model also incorporates spatial memory of monarch butterflies. This model will be used to simulate effectiveness of conservation scenarios, conduct a risk assessment for pesticide drift on a landscape scale, and provide hypotheses for empirical research.
A paper describing this model and implications of behavior at a landscape scale is published in Ecological Modelling: Grant, T.J., Parry, H.R., Zalucki, M.P. and Bradbury, S.P., 2018. Predicting monarch butterfly (Danaus plexippus) movement and egg-laying with a spatially-explicit agent-based model: The role of monarch perceptual range and spatial memory. Ecological Modelling 374:37-50.
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See a video demonstrating a simple test of habitat changes in a small area in Iowa.
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A BAYESIAN STATE-SPACE MODEL TO ESTIMATE SURVIVAL PROBABILITIES IN ARTHROPODS
Estimating survival probabilities for insects and other arthropods has been a long-standing statistical problem. Available methods typically involve marking individuals, but arthropods molt between developmental stages, rendering marking ineffective. I developed a Bayesian state-space model to estimate arthropod survival probabilities from field counts. This model uses ambient temperature to predict stage duration of monarch larvae and models the latent cohort structure of field counts. Daily, stage, and cumulative survival probability can then be estimated, though cumulative survival probability is least sensitive to potential sources of bias such as individual variation in stage duration.
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A manuscript describing this model and its application to monarch butterfly survival probability from oviposition to pupation has been submitted for publication.
MULTIPLE LIFE STAGE OCCUPANCY DESIGN
In multi-season occupancy studies, "seasons" typically refer to temporal divisions. However, life stages can also be treated as "seasons." In amphibian species with very different aquatic and terrestrial life stages, treating life stages as seasons can provide insight into life stages most critical to population growth.
A paper describing this approach was published in the Journal of Herpetology in December of 2018.