Vector Biology Class

Did you ever want to understand something really complex, but you aren’t very good at math? Yea, me too. Join the club. This short article captions how I use lecture and games so that beekeepers can internalize and understand parameters of vectorial capacity models that influence their honey bee health.

A bee with crippled wings and a mite. But how would a vector biologist describe this photo? Well, that was the goal of my workshop, to re-imagine *Varroa* and the honey bee not as beekeepers, but as vector biologists.

The field of vector biology studies how pathogens can be spread through the bites of infectious arthropods. Most people immediately think of the mosquito, which can transit a myriad of pathogens to people through their blood feedings. But numerous other “vectors” can transmit pathogens and cause disease. These include non-insect species of ticks, lice, and mites. Heck, even cope-pods can transmit viruses through their bites. But if you’re reading this page you’re probably a beekeeper, and more familiar with Varroa destructor, the parasitic mite that vectors (transmits) viruses to honey bees when it feeds upon them. Why then would we want to talk about mosquitoes?

Well, there is an immense amount of study in mosquitoes due to their huge influence on human health. We don’t need to recreate the wheel as beekeepers, but rather can look at the amazing wealth of knowledge about disease transmission in the mosquito world and apply it to Varroa and the honey bee. In short, what we did was we looked at this complex equation called vectorial capacity (C=ma^2p^n/−ln(p)) and then looked at which parts of a bee’s and mite’s biology aligned with the model.

To save us all some time here, this is the boring lecture part of the class. We talked about the major parts of that equation like the biting rate of the mite, or the proportion to host, the vector competence which is a way of saying, “how good is something at spreading disease when it takes a bite out of a host”. Then we re-imagined our beekeeping world not as beekeepers, but as vector biologist trying to describe the mite and the bee for the first time.

Next we headed to the field to put our new skills to the test. We no longer wanted to ask questions as a beekeeper, but rather from a vector biologists’ perspective.

Beekeeper questions would sound like: Does this colony have mites? How do I treat these mites?

Whereas a vector biologist asks: What proportion of newly emerged hosts are infested? Is this an asymptomatic or symptomatic host?

We are in the field putting our new skills as vector biologist to the test. And yes, in my class we pet our bees, and that is a dino nuggie hat. (*photo credit Benton Kastman)*

Back in the classroom we had an amazing Q and A session to bring together our lecture and field component. We also had lunch. Lots of lunch. Because this was a long day. And then we did one more thing. We played a game.

The lecture wasn’t all lecture. I spent weeks wondering how can we play to internalize these concepts about vectorial capacity. Every class member had a series of dice, and would roll to see what their biting rate would be, or whether they would be a competent vector or a susceptible host. This all culminated in a game between Host versus Parasites and Pathogens. Parasites had to toss bean bags through small hoops. When they did, this represented them competently vectoring a pathogen. Hosts then had to roll a dice to stop infection, while a Pathogen simultaneously was rolling a dice to start infection. In a way, each component of the game represented a parameter on that complex vectorial capacity equation. But there was a twist, we would change some of the parameters between each round. For example, the biting rate (number of bags a Parasite could throw) was determined by rolling a ten sided dice before the start of the game. The biting rate was random, it was just based on a dice roll. But the coolest part for me was seeing the Host team’s physical response during the last round when all the dice rolls were high for the biting rate. The biting rate is the most influential component of vectorial capacity, without having to do all the math in the model, everyone got it. They internalized the understanding through the game. And that was cool.

At the end of the day we used a game where each component of the game represented a parameter of the vectorial capacity model. Parasites and Pathogens attempted to cause infection through their bites, while Team Hosts attempted to prevent infection through an immune response. (*photo credit Benton Kastman)*

Thank you to the Texas Beekeeping Association for inviting me to speak. Huge thanks to the members who wanted to take this all day course, and thank you Benton Kastman for taking the photos.