Somewhere along the evolutionary history of these bees, juvenile hormone stopped doing one job, and started doing a different job.
By JUDY SIEGEL-ITZKOVICHHoney bees in Israel 370(photo credit: Reuters/Amir Cohen)
The honey bee is very common, highly social and important to humanity because it makes honey and pollinates our food crops. Without this important bee, many people would go hungry. Young honey bee “workers” spend much of their time in the colony taking care of baby bees. Older bees work outside on jobs such as collecting food. In these worker honey bees, a substance called juvenile hormone is not involved in egg laying. Instead, it determines when the bees stop working inside and start working outside.Somewhere along the evolutionary history of these bees, juvenile hormone stopped doing one job, and started doing a different job, says Dr. Adam Siegel, a Fulbright postdoctoral research fellow in the Hebrew University lab of Dr.Guy Bloch. Fulbright is the US government's most prestigious and widely-known academic exchange program. The US–Israel Educational Foundation is responsible for the management of Israeli participation in the program.Scientists are interested in juvenile hormone.One way to work on this question is to study the hormone in a bee that demonstrates some characteristics of solitary bees and some characteristics of highly social bees.The bumble bee is a perfect bee for this type of study, as they live in groups and have an egg-laying queen bee and worker bees. But the groups are small compared to honey bee groups, and worker bees have very similar bodies to the queen bee. The workers will also start laying eggs as the colony gets old. Additionally, the worker bees have a much less organized system of division of labor. Worker bees will switch from inside jobs to outside jobs and back again throughout their lives.Like the honey bee, the bumble bee is also a very important pollinator of food crops. Very little is known about what juvenile hormone does in these bees, which demonstrate an intermediate level of social behavior. The Bloch lab team are working to figure out what some of the functions of the hormone are in the bumble bee. “This will help us to understand how this important hormone has taken on new functions in social systems,” said Siegel. In addition, this work has very important implications for people.Many pest insects also use the hormone to produce eggs.Because the hormone has to be present at very specific concentrations to work correctly, farmers can spray pesticides on plants that include chemicals that work in the same way as the hormone. These pesticides overload the hormone system in the pest insects and stop them from laying eggs.In honey bees, these hormone-like chemicals will not stop the bees from pollinating crops. However, says Siegel, “we do not know what effects juvenile hormone has on bumble bee pollination. Like honey bees, bumble bees are a very important crop pollinator. They are especially useful in greenhouses, because unlike honey bees, bumble bees can work in an enclosed space.”
Israel has a strong agricultural tradition, but limited land available for growing crops, he says. “Many Israeli farmers use greenhouses to maximize the use of limited available agricultural land. Our experiments on juvenile hormone effects on bumble bee behavior will tell us if these pesticides are safe to use with bumble bee pollinators, or if they will hurt the foraging bumble bees. This will help farmers in israel and around the world,” the Fulbright scholar concludes.VATERITE MYSTERY SOLVED Technion-Israel Institute of Technology scientists have solved a century-old mystery involving an unstable atomic arrangement of the chemical compound calcium carbonate.Called “vaterite,” the compound forms crystals that are composed of two different atomic structures, they discovered and wrote in a recent issue of the prestigious journal Science.Boaz Pokroy, an assistant professor in the materials science and engineering department, and his doctoral student Lee Kabalah-Amitai, explain that the compound of calcium carbonate and oxygen is the most abundant mineral in nature and appears in different forms that vary in their spatial atomic positioning. Vaterite is a specific atomic arrangement of calcium carbonate and in relation to other atomic arrangements is extremely rare in nature.Although it is not very uncommon, vaterites are present in many aspects of our lives, from gallbladder stones and an essential material in the paper industry to and cement and certain geological structures. It is found even in meteorites from space.The Haifa scientists are studying the development and formation of vaterites in the important biological process known as biomineralization. In this process, living organisms control the production of different minerals on its atomic level. For example, when a mollusk shell receives a blow that cracks its shell it uses “vaterite” to repair the damage, a pearl usually has a deep shine (resulting from a collection of different calcium carbonate) but occasionally (as a result of a growth error). vaterite forms in the pearl and eliminates its shine, and fish such as salmon grow vaterite in their ears to aid them with their balance.For over 100 years, scientists have failed to reach a clearcut explanation for the atomic arrangement of vaterite.Kabalah-Amitai and Pokroy examined crystals found on and within the bodies of small marine animals known as sea squirts. “This small organism produces a bundle of crystals from vaterite that are very sharp and relatively large, making them relatively easy to work with”, the team explained.“This is why we examined these crystals; and this is the first time they have ever been studied on the atomic level. Until now, different scientists tried to find a unified atomic arrangement for vaterites or determine which of its original structures were the most accurate. We found that vaterites actually consisted of two different atomic arrangements that exist in harmony with one another. The second atomic arrangement was found in a microscopic area (nano-metric – around 40,000 times smaller than a human hair) and this is the reason it eluded the eyes of scientists who believed this was a singular structure rather than a dual structure.”The Technion scientists expect their discovery will facilitate future understanding of the formation mechanisms and stabilization of vaterite.
