American Scientist

Suzanne W. T. Batra worked as an entomologist with the U.S. Department of Agriculture (USDA) from 1974 to 1999. More than 20 years after her retirement, she continues her work of keeping and observing bees. Her research continues to inform agricultural policy, and in 2019 her former USDA colleagues organized a research symposium called Batrafest in her honor. Batra received her PhD in entomology in 1964 from the University of Kansas, then spent a year as a visiting researcher at Punjab Agricultural University with her husband, the late Lekh R. Batra, a mycologist. Both of them later joined the USDA, and they traveled extensively, gathering examples of both fungi and insects. Batra made numerous seminal contributions to the study of bee behavior, as well as to practical agricultural extension—and she has long argued that there are far better pollinator bees than the honeybee. As a doctoral student, Batra received a Sigma Xi GIAR grant that she used to study sweat bees in India, where she was able to identify several new species. Batra spoke about her career highlights and her experiences as a woman in science with American Scientist editor-in-chief Fenella Saunders. This interview has been edited for length and clarity.

Why did you decide to study insects?

I grew up in the 1940s and 1950s, when women didn’t become scientists; girls didn’t even have jobs then. But I was a pretty unusual girl. I grew up first in Vermont, and I loved all the outdoors things. I learned to catch trout by the time I was three or so, using the net bags oranges come in. Anything that moved, I’d catch it. One day I was taking a bath, and I dumped a jar of Japanese beetles in the bathtub with me, because they could swim and they were very pretty. My parents were very tolerant, they just thought I was hilarious. Later I found in my dad’s letters that he had taken me to be mentally evaluated, but I tested fine. So they let me continue playing with bugs, and here I am, still playing with bugs.

What do you think remains the most common misconception about bees?

People are hung up on honeybees, and there are only seven species of honeybee in the world, most of which live in India. I studied five species of honeybee. But most bees are not social and don’t live like honeybees. We have 20,000 species of bee in the world, and about 85 percent of them are solitary bees.

Honeybees aren’t particularly good pollinators compared with other bees. They pack down the pollen they collect onto their hind legs and use nectar to compress it. The pollen doesn’t fall off on the next flower it goes to. They also fly very slowly. You can use them as pollinators if you have a lot of them. They’ll get the job done. When the Pilgrims brought their honeybees over from Europe, along with their other livestock, nobody knew anything about pollination. They brought them over for honey and wax. But if you want to use bees on a farm, there are better pollinator bees.

Most solitary bees come out only once a year for about six weeks, coordinated with the blooming of their favorite flowers. If you’re a farmer who specializes in apples, you want a bee that’s going to pollinate your apples, coming out at that time. You don’t want to mess with managing honeybees all year if you don’t have to. We had a get-together of bee scientists, and the term pollen bees was suggested by another scientist to refer to bees used for pollination, which I think is a good term.

Your study of sweat bees led you to develop the term eusocial. What did you intend that term to mean, and how has it morphed over time?

In the summertime, go outside, work up some sweat, and you’ll attract some sweat bees. They’ll come around and start licking your skin. They’re small, mostly black bees. Nobody knows why, but probably they’re getting some kind of nutrients. They gather nectar the same way. They’re quite abundant.

I was studying the social behavior of one sweat bee species, Lasioglossum zephyrum, for my thesis, and at the time everybody used the term “primitively social” for the societies of bees that weren’t honeybees. You have to remember, I came up when people were still discriminating against women quite a lot. I was a little touchy. I was just generally alert to words. I could see these bees doing their thing, and I didn’t think they were primitive. So I was thinking, “Well, honeybees aren’t so great. The queen can’t even live on her own. She can’t start a nest by herself. She’s dependent on workers.” I later coined the term hypersocial for honeybees: They’re so social that the queen is never on her own. A solitary bee has to do it all, start a nest by herself and everything. I came up with eusocial to mean “truly social.”

A eusocial sweat bee has a solitary phase in the life cycle, when the female mates, starts a nest, makes the cells, collects the pollen, does everything like a solitary bee would do. But then, when the daughter bees come out, they stay instead of going away, and help their mother. Then she becomes a queen. She stays with the young ones. The young ones don’t mate normally. They become workers. There can be several generations of young. Some of these eusocial nests can get quite large, more than 100 bees. In the fall, the one who becomes a queen will start producing male eggs. At that time, only the fertilized young females go out, and they become the next year’s queens. Then the cycle runs again.

But people wildly misuse the term now; it’s applied to all kinds of things, even people, when you might as well just say “social.”

How were you able to see and study the behavior of ground-dwelling bees?

When I was a kid, I had ant farms. I devised, essentially, a bee farm. It was the same clear-sided structure, but I had a landing platform on top. I was able to get these bees to nest in the bee farm. Then I could observe their behavior in the nest. I used these for many kinds of bees to observe their social interactions. You could study the interaction between the queen and the workers, how they made their cells, how they lined their cells, what stuff the liner was made of.

How did this setup help you research what are now known as polyester bees?

Oh, they’re fascinating. That was my favorite scientific discovery moment. With the bee farm, I could see exactly how genus Colletes bees build their nests. Many bees nest in the ground, and many bees nest in the springtime when it rains a lot. So what do they put inside their nests? They put in nectar and pollen. Nectar is sweet and it absorbs moisture, so fungi like to grow on it. Then that destroys the nectar and kills the larvae of the bees. The bees have to protect themselves from this danger. The bees that nest in the ground have to line the cells with something impervious.

These bees have what’s called a Dufour’s gland in the abdomen, and it makes a chemical, which can be different for other species. A mama Colletes flies out all day getting nectar and pollen, and each night she digs a cell. They have a special plate on their rear end, these underground bees, called a pygidial plate. The bees use this plate to tamp the ground down so it’s firm. When it’s all tight, the bee will start licking. She alternately licks the wall, and then she’ll lick her abdomen. That’s when she’s picking up this clear chemical from the Dufour’s gland. It’s a liquid, but when it’s exposed to the air, it hardens.

Most bees’ tongues are narrow. This Colletes bee has a wide, flat tongue with hairs all over it, much like a paintbrush. She starts rotating in the cell, making a loop, going around and around with her tongue, one streak exactly next to the rest. When she’s gone one way, then she’ll turn around and add another layer facing the other way, crisscross. She’s covering it layer by layer with the secretion. Then she’ll turn again toward the opening of the cell and do a third layer. She’ll do that for a long, slow time. She adds a lip at the end when she’s done with it, just like a sandwich bag, which she can close later, when she’s done building. The next day she makes a ball out of her pollen and nectar and then lays an egg on it. Then she seals it. But it has to be porous to air, because the larva has to grow into an adult. Oxygen can get in through the seal. But not moisture. Isn’t that nifty?

“We were doing bootleg science. It’s science you do just because you like it. It’s not your regular job. We were all doing it on the side. All the most interesting research I’ve done has been on the side.”

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I was itching to know what the heck is this stuff. It took me until the late 1970s before I was able to answer the question, 20 long years of wanting to find out. There was a chemist who was working on the pheromones with me, which are produced mostly from the bee’s mouth. Then he got another colleague at the National Heart, Lung, and Blood Institute interested. We were doing, all of us, what’s called bootleg science. It’s science you do just because you like it. It’s not your regular job. It wasn’t my job. It wasn’t their job. We were all doing this on the side. All the most interesting research I’ve done has been on the side. But when these chemists analyzed what the liner was, it turned out to be plastic, a polyester. These bees have invented plastic. I thought I’d died and gone to heaven when we found that. Scientists don’t often get a eureka moment. And the plastic is degradable in five years. I buried some bee cells in a sand pile and checked them every year for five years until they fell apart. This plastic was something you couldn’t make commercially.

You have said that you prefer fieldwork and are not a computer person, but have you had some times when automation has aided your work?

Part of my job, when I started working at the USDA, was working with APHIS [Animal and Plant Health Inspection Service]. I worked to identify the bugs that are caught by customs officials at the airports and so on, to see what kind of invasive bees were coming into our country. That included killer bees, for instance, which are properly called Africanized bees. One thing that I did pioneer was the use of “facial” recognition to identify bees. It didn’t recognize the bees’ faces, but their wings. I worked with the Smithsonian and USDA to identify insects based on their insect collection. The first year, I spent most of my time at the Smithsonian because a lot of bees in the collection had not been identified. They gave me this job to identify the so-called killer bees. They are very similar to the European honeybee. They’re African honeybees that have hybridized with European honeybees here.

The African honeybee is the same species as the European honeybee, but a different subspecies. Mostly they’re okay, except there are some from Tanzania that get disturbed if you bother the hive and they come out to sting a lot; they tend to be vicious. A few were shipped to Brazil. Somehow these bees got out of the hives and started breeding with the local European honeybees that were there already. Being tropical gave them a survival advantage, of course. That developed a really antsy, easily upset honeybee, which attacked people and livestock. They were easily disturbed if anything bothered their nests. They’d sting and they’d chase you.

I was asked to identify them, tell them apart from regular honeybees. The bees were heading north, coming to the United States through Mexico. The thing is, these are only slightly smaller than the European honeybee. They look the same, superficially, but they’re just a bit smaller. I knew another scientist who had developed a method to measure the bees. Insect wings have veins in them. For lots of kinds of bees, you measure the veins and the angles in the veins where they meet each other, and you can find out what kind of bee it is using the vein pattern. You’d get 10 wings from 10 bees in a colony, put them on a slide, and do it by hand. That’s pretty tedious. It would take me nearly half a day. They wanted me to do that for the rest of my career? No. That’s for automation.

I’m not computer-minded, but you needed a computer to do something automated. I got in touch with a computer guy at the USDA and got hold of various computer companies in different countries, asking, how can we mechanize this? There was a company in England called Cambridge Instruments. You could have a computer, attach it to a microscope, and run your slides under the microscope. The computer would automatically take measurements. And it worked. The only other people who had done it before and published a paper were in geology, where they used computers to scan pebbles and rocks for their sizes and shapes. So this project started the automatic image analysis of objects.

Can you talk about your research on the relationship between insects and fungi?

It’s a great story about how science works. Some flowers, like blueberries or tomatoes, won’t release their pollen from their anthers unless they’re vibrating. Honeybees can’t pollinate this way. Bumblebees can, and some others can. So blueberry flowers have to be buzz pollinated, and one of the species of Colletes specializes in blueberry flowers.

When you buy blueberries in the store, sometimes some of them are white and dried up. What that is, the blueberry is infected by a fungus. My husband studied plant diseases for the USDA. He wrote a monograph on fruit diseases caused by several species of the fungus Monilinia. Blueberry blooms and the fungus come out for about a week a year. If it’s raining that week, nothing happens, because the pollinators don’t fly, and you miss the fungus for that year. It takes a long time. You have to be very patient to do this kind of research.

The fungus has two parts to its life cycle. Usually a rotten, white berry falls off the plant and goes through the winter on the ground. In the spring it grows this little cup fungus that comes to the surface when it warms up, and blueberries start to bloom at the same time. The leaves start to come out. The cup-shaped fungus shoots up spores. The spores land on the blueberry leaves and infect them. The leaves get round, brown spots.

And then my husband noticed that insects were coming and licking the brown spots on these leaves. He asked me, “Why are they doing this?” Of course my curiosity got going. Luckily, during this particular time I’d been using a filter on my camera so I could take pictures in ultraviolet. A lot of flowers reflect UV light, which insects can see. I’d done research on mimicry before, early in my career—I was always interested in mimicry in nature. The pictures showed that the brown spots were reflecting like a flower. I said, “Hey, let’s test these things for sugar.” I got a strip for sugar testing, and yes, the brown spots were secreting sugar.

“It took about eight years to do all that research, because of the weather. It’s not like you’re working in a lab under controlled conditions. We couldn’t manipulate anything. This was all observational science.”

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It was secreting sugar, reflecting like a flower, and of course it has spores on it. See, this fungus has a double cycle. A lot of fungi do that. It has one set of spores that hits the leaves, and then it has to get its spores from the leaves into the flowers. Blueberry flowers are really deep flowers. The spores have to get into the flower. So who’s going to do that? The bugs. We took electron microscope pictures with the spores clinging to the bees. The next thing they’ll do is go from the leaf to the flower to get nectar. There go the spores into the flower.

It took about eight years to do all that research, because of the weather. It’s not like you’re working in a lab under controlled conditions. We couldn’t manipulate anything. This was all observational science.

You had imported some bees from Japan and other places. Did you work with matching particular bees to specific farming needs?

About 75 percent of my time was spent on basic science, and about 25 percent was what’s called extension for farmers and the general public. I always think of it as, you have basic research, and then extension in agriculture is like nurses and medical doctors working with patients. Farmers are really smart.

Many solitary bees come out in the springtime, but some only come out in certain months during the summer, and some only in the fall. That behavior is why I got interested in them. I worked with George E. Bohart, who was director of the USDA Bee Biology and Systematics Lab in Utah, and out there they grow a lot of alfalfa, which is a major feed stock for cattle, horses, and other livestock. I worked with him and learned how to manage the leafcutter bee, which is a good pollinator for alfalfa.

The crops we grow here in America are mostly imported from Eurasia. There’s very little that’s native here. Most of these things were imported by the settlers from Europe, and some from Asia later. My yard is full of Japanese plants like azaleas, to feed my Japanese bees. A good thing to do is to try to find out where a crop came from and which pollinators time their activity with it there.

The first bee I brought over was the horn-faced bee, Osmia cornifrons. In Japan it was already being used for pollination of apple trees and other spring-blooming crops. I met a farmer when I went over in 1981. He had a little apple orchard. He noticed the bees were nesting in the straw thatch of his roof and going to his apple trees. He put on more thatch and drilled some holes in the wood of his house and they nested there too. Then he devised special nesting tubes for the bees, set up little bee shelters. Later on, a university in northern Japan started working with the bees.

I had already brought back some horn-faced bees in about 1979. I started with a small number of them. You don’t know how they will do, because the climates are not typically the same. The climate is the overriding factor. The bee lab in Utah had tried several times to get the horn-faced bees to live there, but the bees died. It’s cold and dry in Utah. Japan has a more mild, moist climate, more like the East Coast. The head of the lab in Utah asked if I would like to try using the horn-faced bees in Maryland. I said I’d give it a try, and they worked.

I got permits from the states where I thought they would live. On the West Coast, Washington is moist. I tried a couple places in Canada, but they didn’t work there, at least in eastern Canada. I tried them all along the East Coast, except in tropical areas like Florida. I sent them out for free, while the bees were dormant in the winter. I sent them instructions, illustrations of how to set up the nest, and a questionnaire to send back to me about how the bees did. I got a pretty good response. I know in Pennsylvania they’ve gone commercial now, big time. I heard from people that they’re doing quite well.

A podcast interview with Suzanne Batra: