Texas A&M Entomology Assistant Professor Gabe Hamer is working to make it easier for training the next generation of medical entomologists by mounting arthropods in resin.
In a paper that was recently published in the Journal of Insect Science featured with the journal’s cover image and on Entomology Today, Hamer’s lab created protocols for encapsulating medically important arthropods in resin for educators to use in educating the public on various arthropods that can vector dangerous diseases, such as Chagas disease, Lyme disease, and Rickettsiosis. The work was led by graduate student Justin Bejcek, who earned his BS in Entomology and will graduate with his MS in Veterinary Public Health this Spring.
The idea for the project came after Hamer was looking for a way to make it easier to have quality teaching specimens of arthropods available as a training tool for veterinary and medical entomology students that are entering the workforce to help them to properly identify these arthropods.
Hamer said that most common tools used in training for identifying include photographs, illustrations, and specimens pinned or in vials preserved with ethanol. According to the paper, the photos and illustrations are limited in what they can show in relation to size and proportion and that pinned and ethanol preserved specimens can become damaged and degrade due to time and excessive handling.
“It is great to be able to hand someone a real insect embedded in resin,” he said. “This is especially important when we are trying to educate students or the public on what insects look like that feed on blood, and are thus important disease vectors, compared to look-a-like insects that do not feed on blood. Even with the best macro-photography pictures available, this just isn’t the same as having the real specimens in your hand.”
The objective of the project was to develop a resin embedding protocol to help maximize the quality while reducing the cost of making each of the castings. For the past 4 years, the team has experimented with polyester and polypropylene casting molds and used triatomines, ticks, mosquitoes, spiders, fleas and true fly adults and larvae.
The result of the experiments done on different resin types culminated in a protocol that includes having the insects stored in ethanol and dried for a specified amount of time before resin casting. Then they used a two layer resin process using Petri dishes for the molds.
The insects in resin were then cut, sanded, and polished to make sure that the surfaces were flat and optically clear to allow for better viewing of the specimens inside.
Hamer said several of the specimens have been in use in the Veterinary Entomology, Medical and Urban Entomology courses to help the students better identify vector insects and has been asked by people outside the university to provide insects for them.
“The extension groups certainly appreciate the resin bugs,” he said. “We occasionally receive requests for the resin insects, but the demand exceeds our ability to supply.”
Hamer said the best part about making the specimens is that it helps to teach people about medically important arthropods and the diseases they vector.
“The best thing about producing our resin bugs is that it enhances our outreach and extension abilities with regard to arthropods of medical importance,” he said.
He said that the hardest insects that they had mounted were mosquitoes, but that they will be working to improve the process.
“We have attempted to mount mosquitoes in resin which didn’t work well. We still don’t have a great mounting approach for the long-term preservation of mosquitoes while allowing close scrutiny for the identification of morphological characteristics,” Hamer said. “We need to keep brainstorming and working on innovative ways to resolve the mosquito mounting challenge.”