Entomology Today

A Place for Engineering in Entomology

Meghan Bennett engineered a device to detect the emergence of alfalfa leafcutting bees from their nest cells. Her device is composed of a microcontroller, infared detectors, metal BBs, and Eppendorf tubes, among other components.

Meghan Bennett, a Ph.D., student studying the alfalfa leafcutting bee (Megachile rotundata), was interested in how the bees time their emergence from their nest cells. She needed to record exactly what time the bees emerge in relation to different environmental cues. But collecting this kind of data requires watching nest cells (or videos of nest cells) and carefully noting time of emergence. It’s tedious and time-consuming, and one person can only watch so many cells at a time. She had a problem—an engineering problem.

Engineering is an extremely broad discipline, but the etymology of the word illustrates its essence. The word “engineering” is derived from the Latin ingeniare, meaning to contrive or devise. Bennett needed to devise a device that would allow her to record bee emergence more efficiently. She soon waded into the world of 3D printing, infrared detectors, and microcontrollers. Along with collaborators, she built a device (pictured above) that allows her to record the exact emergence times of 1,000 bees in a single experiment without the need to sit and watch them crawl out of their cells. The entomologist had completed an engineering project.

This is exactly the kind of scenario Barukh Ben Rohde of the University of Florida had in mind when he organized the Entomology 2017 Section Symposium “Entomological Engineering: Tracking, Stimulation, and Detection of Insects.” Rohde is an electrical engineer interested in teaching engineers how to work on biological problems. He used his engineering skills to solve an entomological problem: the need for a low-cost device, with low electrical power requirements, to trap biologically modified male mosquitoes.

What happens when an electrical engineer tackles mosquito trapping? A sound trap for male Aedes aegypti, as shown in this figure from Barukh Ben Rohde’s presentation.

The symposium showcased the need for engineering in entomology. Richard Mankin, Ph.D., of the U.S. Department of Agriculture-Agricultural Research Service is an entomologist who studies the Asian longhorned beetle, an invasive, destructive tree pest. Mankin shared his work on a low cost, easy-to-use device that detects the presence of beetles in living trees or lumber using sound. Perry Jetter of the University of Florida presented low-cost techniques to detect when honey bee queens have died using tiny radio frequency identification (RFID) chips or magnets. Quick detection of queen death allows beekeepers to replace the queen before the colony fails.

James Snyder of the Florida Department of Agriculture and Consumer Services demonstrated his work using 3D printing to produce and rapidly redesign traps for the Asian citrus psyllid (Diaphorina citri). The psyllid spreads huanglongbing (HLB), or citrus greening disease, which has devastated the citrus industry in Florida. Snyder’s traps have advantages over the traditional sticky traps because they prevent deterioration of trapped insects and allow managers to test the psyllids for HLB disease onsite using a handheld PCR device. These tools may prove crucial in rapid detection and containment of this devastating tree disease.

This is not a giant Christmas tree ornament; rather, it’s a trap for Asian citrus psyllids. James Snyder created this device using a 3D printer to effectively catch the insects so they can be screened for huanglongbing disease.

Kan Li, Ph.D., of the University of Florida is an engineer who works with machine learning. He joked that his last biology course was AP Biology in high school. Li is using a complex mathematical model called a “finite state machine” to automatically recognize insects like mosquitoes and house flies based on their flight dynamics.

In order to control mosquitoes and prevent mosquito-borne diseases, we need more field observations of mosquitoes—lots more. But detecting mosquitoes in the field can be costly and laborious. You can identify mosquitoes by the whining sound their wings make, but a rugged, inexpensive device that can filter out background noise is needed. Rather than designing such a device, Haripriya Mukundarajan, a Ph.D. student at Stanford, realized that most of us are already carrying it in our pockets: a cell phone. Mukundarajan presented her work verifying that cell phones could record mosquito whines effectively. She and her colleagues then created software that could distinguish mosquito species using these recordings and trained citizen scientists in Madagascar to use their phones to record mosquitoes. They are now working on developing an app to facilitate recording and submitting data to their “ABUZZ” citizen science project.

So, is Mukundarajan an entomologist or an engineer? She jokes that “no field would claim her.” She started out working in robotics, then got into space technology, is currently working in biophysics, but is also starting to get into genomics. Mukundarajan says she “prefers to let the problem dictate the field.” Her work, and the research presented in this symposium, clearly demonstrates the power of combining disciplines like engineering and entomology to solve important scientific problems.

Meredith Swett Walker

Meredith Swett Walker is a former avian endocrinologist who now studies the development and behavior of two juvenile humans in the high desert of western Colorado. When she is not handling her research subjects, she writes about science and nature. You can read her work on her blogs Pica Hudsonia and The Citizen Biologist or follow her on Twitter at @mswettwalker.