ASU Research E-Magazine: Low Tech Science Down Under--Or in the Back Yard

Much of humanity’s fundamental scientific knowledge is the result of research done with little or no assistance from advanced technology.

For example, during the 1880s, an Austrian monk named Gregor Mendel prepared the soil for the field of genetics when he argued that genes form the basis for inherited traits such as height and eye color. Mendel did his groundbreaking work simply by breeding pea plants in his garden. Of course, Mendel never actually saw genes—he deduced that they existed by observing how his pea plants generated offspring of different types.

Many early breakthroughs depended heavily on logic, intellect, and carefully planned experiments. Certainly, new technology and more sophisticated research methods are now available. But are they necessary for scientific progress?

ASU biologist John Alcock doesn’t think so. He makes do without much high-tech assistance. Alcock uses an insect net, binoculars, and some vials of acrylic paint to study insect mating behavior.

Alcock argues the advantages of keeping things simple. For example, he can easily take his research on the road. In fact, during the past seven years, Alcock has set up shop five times in Western Australia, where he studies the mating behavior of Dawson’s burrowing bees (Amegilla dawsoni).

Male burrowing bees come in two distinct varieties: large and small. Much like Arizona’s small male tarantula hawk wasps, little male bees have a rough time competing with the bigger guys. Alcock wants to know how small males manage to find mates.

The ASU scientist travels down under during Australia’s winter months—that’s mating season for Dawson’s burrowing bees. On location, Alcock sets up camp near a dry lakebed the bees use as a mating arena.

Thousands of underground nests exist along the lake’s edge. Months before, female bees filled the nests with nectar and pollen before laying eggs on the packets of food. Mating season starts when the next generation of bees emerges from the underground cells.

Alcock uses binoculars to scan the emergence site. Male bees pop out of the ground and immediately set about the task of searching for a mate. After locating a female’s cell, a male stands guard until she emerges.

A male bee’s business is complicated by dozens of rivals buzzing about. While guarding a female, males are frequently forced to fend off intruders. They are likely to lose to larger opponents. A small male in the thick of mating season is sure to suffer defeat many times.

Among Dawson’s burrowing bees, being big is the ticket to reproductive success. So why are there so many small males?

Alcock has his own hypothesis. Perhaps the small males have an alternative-mating tactic that sidesteps head-to-head competition with stronger rivals.

To test the idea, he first must formulate a logical prediction based on the hypothesis: Alcock thinks that as the number of bees competing in the arena grows, an increasing number of small males should shift their mate-searching elsewhere. As a result, the proportion of small males inside the emergence site should go down.

Next, Alcock must collect the relevant data to prove or disprove the idea.

First, he has to measure the level of competition. He makes an hourly census of the number of males in the mating arena. Binoculars are the tool of choice. The census total will serve as an indicator of competition intensity.

Alcock deploys the insect net for the next task. Males found mating are caught and categorized by size. Each bee is marked with a harmless dot of paint, and then released.

Next, Alcock gathers information about where small males perform their mate searches. He predicts that little guys will be found in the shrubs surrounding the barren arena. The bees also use these plants as a food source.

This fact adds another dimension to the experiment. To gather accurate information, Alcock must discriminate between males searching for mates and males searching for a meal.

A female bee decoy helps Alcock tell the difference. He pins the decoy to the bushes, and waits to see if she lures potential mates. Sure enough, some small males make straight for the decoy and even attempt to mate with it. Finding food, he concludes, is not these males’ primary objective.

Alcock evaluates his hypothesis by analyzing the number and behavior of males of different sizes found in the different areas.

The findings are clear. When lots of competitors crowd the mating arena, small male burrowing bees take note and step back. They seem to be able to assess an increase in the density of their rivals. When things look crowded, they are more likely to move their operations to the nearby bushes, out of harm’s way. Here, they have a chance to mate with living females that have slipped past the big males back at the emergence site.

Hypothesis confirmed: Small males can reproduce in a social environment that at first glance appears severely stacked against them.

Alcock applies these simple techniques to research in his own back yard. He noticed that the bushes in his yard were occupied nightly by sleeping bees, a local Sonoran Desert species. The bees seemed to prefer certain bushes and even certain twigs on those bushes. He wanted to know what attracted the bees to individual stems?

A stem-switching experiment suggested that a scent, or other chemical, could be the source of the bees’ preferences. Alcock cut some of the bees’ best-loved branches and swapped them with other ordinary branches, securing them with masking tape.

The bees were not fooled. Most of the time, they refused to accept an impostor roost. Many found and perched on the relocated favorite twig.

“It’s a little natural history project that kept me entertained,” Alcock notes. Other backyard bugs have found their way into Alcock’s research notebooks. The eggplants in his garden attracted mating wasps, and another species of bee patrolled the tomatoes.

Equipped with the most powerful tool—a creative and curious mind — Alcock knows that all the world’s a laboratory.—Danika Painter