University of Minnesota
October 17, 2011
Brazilian graduate student Renata Borba poses with bees and the sticky substance propolis, which the insects smear inside their natural hives.
Photo: Patrick O'Leary
A Brazilian graduate student blossoms as a bee researcher
By Deane Morrison
Growing up in a coastal Brazilian town, Renata Borba loved to surf year-round. And as a student at the University of Ceara, she came to love honeybees.
But that university requires students to spend their final semester in an internship outside its walls. So Borba applied to study bees through the Minnesota Agricultural Student Trainee (MAST) program, which could have sent her anywhere in the United States.
"A Brazilian professor gave a talk about it and said people who work with honeybees will probably go to Florida or Hawaii," Borba recalls. Since she was a surfer and had two sisters living in Florida, either one sounded good. She crossed her fingers and hoped for Hawaii—but when the papers came they said "Minnesota."
Since the only waves in Minnesota are of amber grain, that ruled out her favorite sport. But you won't hear Borba complain, because it also led to her meeting Marla Spivak, a University of Minnesota entomology professor and internationally recognized honeybee authority. She is now a graduate student of Spivak's, en route to a career researching ways to help her favorite insects.
A quick study
Arriving in Minnesota in April 2008, Borba—who knew no English when she applied to MAST—went to a honeybee farm in Watertown, in the southwestern part of the state.
"The farmer introduced me to Marla," says Borba. "At first I wasn't thinking about taking classes, but when I talked to her I asked if she could give me a part-time job while I took classes. I took the fall 2009 academic semester and did 10 hours a week of work."
"I wasn't sure she was ready for graduate school, so I hired her to help me and my graduate students with field research," Spivak says. "We were all very impressed with her. She is not afraid of hard work, and she is extremely persistent and resourceful, and she tolerates bee stings very well.
"On her own initiative, she applied for a Regent's Scholarship so she could take some graduate level courses, and she did very well. I really enjoy mentoring students like Renata, who are highly driven, creative, smart and fun to have around."
"I took her class in honeybees and other social insects," notes Borba. "She compared the social systems in general, then the social insects in general. It was interesting to see how some characteristics of honeybees were found in other insects, like ants, termites, and paper wasps. Even some spiders are social."
Honeybees today are under attack from a variety of agents, including pathogenic fungi and bacteria. One defense they have is propolis, a concoction of tree resins with a little water, beeswax, and bee secretions mixed in. Bees living in tree holes smear it on the rough surfaces inside their dwellings, where it has an antiseptic effect. But bees living in artificial bee boxes don't, because the insides of the boxes are smooth.
The bees from Brazil
In her doctoral research, Borba is investigating whether different types and formulations of propolis can improve the health of bees in commerical hives. She's beginning by comparing the immune systems of European honeybees to those of Africanized—commonly called killer—bees from Brazil.
"The Africanized bees collect more propolis. But does propolis affect the two kinds of bees differently?" she wants to know.
The big question now is whether propolis leads to changes in the functioning of genes important to the immune response. For example, if propolis kills fungi and bacteria that would otherwise provoke an immune response, then bees from propolis-treated colonies should have less activity in those genes than bees from untreated colonies.
In previous work on European honeybees by former Spivak graduate student Mike Simone, bees from treated and untreated colonies showed significant differences across treatments in three of six immune genes he examined. The tests showed whether or not the genes were expressed; that is, whether the products of their activity—RNA that was made by the genes—was present. Borba is testing the same three genes in Africanized bees to see if they are expressed differently with different propolis treatments.
"Then I will be able to compare the immune systems of African- and European-derived colonies that have been enriched or deprived of a propolis envelope in the nest," she explains.
Borba traveled to Brazil and collected samples of RNA from Africanized bees in treated and untreated colonies. Back at the University, she will test the samples for the presence of RNA made by genes important to the immune system; if she finds it, that's an indication that the gene is active--that is, expressed--in the bee.
If proposlis does seem to improve bee immune function and health, Borba's research may next turn to experiments such as roughening the insides of bee boxes to see if this will stimulate "propolizing" behavior and improve the odds for the bees.
"I want to do more research on this and one day maybe find a way to treat bees without drugs," says Borba. "I'm really glad I ended up being sent to Minnesota and met Marla and had the opportunity to do a Ph.D. here. She's more than an adviser--she's a good friend."
And how is this denizen of the tropics adjusting to life in the frozen north?
"This is the first time I've had the four seasons," she observes. "I'm learning how to enjoy winter. I made my first snowman last year."
Published in 2011