Johanna E. Elsensohn

Measuring insect size with automated smartphone imaging

Calipers are the standard for measuring insect size - their length, width, height, etc. This measurement method is time consuming and prone to human error. I worked with agricultural engineer Amy Tabb to develop a automated method for calculating the length and width of an insect, starting with the brown marmorated stink bug, Halyomorpha halts. I did the hand measurements with the calipers, and Amy used her program to measure the insect from a smartphone image. We had about 0.88 correlation, which is pretty good, but we’ll work to improve that number. Although we don’t know for sure, I’m guessing the variance is due to both my measurements being off a bit and the program’s partitioning of the image.

The potential for this program is huge. Imagine trying to compare insects from different populations, quantifying wing size, body length, thorax width, etc. How long that would take to do sufficient replication? All Amy did was place the (albeit dead) insect on a piece of paper and snapped a photo. Caliper measurements of 166 specimens took 4 hours, the total for the image-based approach was 33 minutes. One fourth of the time! Snapping a photo of a live insect is a lot easier than trying to wrangle it to stay still for caliper adjustments!

I’m excited to work with Amy more to develop this program so it can be released to a wide audience for entomological use. Stay tuned for further developments!

Citation: Tabb, A., Elsensohn, J.E. and Leskey, T.C., 2022. Automated size measurements of Halyomorpha halys (Stål)(Heteroptera: Pentatomidae) with simple image-based methodology. Florida Entomologist, pp.262-264. Link to article

Spotted Lanternfly - 2021

A good deal of my current research involves Lycorma delicatula, the spotted lanternfly (SLF), a new invasive insect in the United States that is a large threat to wine grape growers across the country. I’m trying to understand their movement patterns and risks to vineyards in the Mid-Atlantic region.

Human-assisted movement

Like many insects, SLF can and do end up traveling on vehicles. But how far can they travel before being blown off? What speeds dislodge them? These are important questions to answer if we want to prevent this human-assisted travel. I worked with our engineering department to build a wind machine and test SLF on actual cars in different conditions.

Interactions with non crop hosts

 While invasive pests by definition are a problem for economic and aesthetic interests, insects can also play large roles in non-crop areas, like parks and forests. Will a crop pest be just as likely to infest non-agricultural areas near or far from crop hosts?

I investigated the federal wilderness areas of North Carolina in summer 2017. My research says that yes, SWD are everywhere, so what does that mean? And do these insects that reproduce in forests part of the same population that infest local crops? Hopefully, we will have those answers soon!

Anticipating the impacts from new pest control technologies

The spotted wing drosophila (SWD), Drosophila suzukii, is an important, dangerous pest for many fruit growers worldwide. Unless controlled, these flies infest (and thus make unsalable) ripening fruit before it is ready to be sold at market. This is a serious pest for farmers and households that grow strawberries, blueberries, cherries, raspberries, and blackberries (there are other affected fruit too, but these are the main ones). Many scientists are trying to develop new pest management strategies that don't rely as heavily on insecticides (current practice). Today's technological capabilities can allow scientists to alter the food they eat or the pests themselves to help control them. Many of these technologies are being researched in laboratories but have never been field tested - what sort of impacts might they have? What kinds of information do we need to know before we think about releasing them? I'm asking a bunch of different people involved in research, government and food production (i.e., an expert elicitation) their thoughts about what the impacts might be and how important they are. 

Factors impacting non-crop host use and population dynamics of an invasive fly

While working as a research technician for Cornell University, I investigated the potential impact from the infestation of wild-growing plants nearby berry crop plantings on spotted wing drosophila population levels. Over two years, we collected berries from all species growing nearby commercial berry farms beginning in the spring and continuing until late November to get a better sense of how SWD use these non-crop hosts and how that might influence local population dynamics. By studying host plants that were unmanaged, we were able to determine how seasonal temperature and host availability affect SWD populations. 

Citation: Elsensohn, J.E. and G.M. Loeb. 2018. Non-crop host sampling yields insights into small-scale population dynamics of Drosophila suzukii (Matsumura). Insects. 9(1), 5

Usage analysis of species richness estimator software

In 2011, I was dead set against getting a PhD so I decided to go for a non-thesis MS degree. As part of my time at the University of Connecticut, my advisor Dr. Robert Colwell asked me to help him evaluate the impact and usage patterns of one of his signature packages, EstimateS, a software program that helps people estimate species richness on the basis of the number of single and double occurrences within a sample. 

Citation: Colwell, R.K., and J.E. Elsensohn. 2014. EstimateS turns 20: statistical estimation of species richness and shared species from samples, with non-parametric extrapolation. Ecography. 37(6), 609-613. DOI: 10.1111/ecog.00814.