The honey bee Apis mellifera has experienced recent unexplained die-offs around the world. Although catastrophic losses of honey bee colonies have occurred in the past, the magnitude and speed of recent hive losses appear unprecedented. So far, the main causal suspects have been parasitic mites, fungal parasites, viral diseases and interactions amongst them.

In this paper, the authors provide the first documentation that the phorid fly Apocephalus borealis, previously known to only parasitize bumble bees, also infects and eventually kills honey bees - by leading them to abandon their hives at night.

Brown is a world authority on phorid flies, and blogs about the weird creatures at http://flyobsession.net. He has received reports of nighttime bee activity in Los Angeles. "It seems to be concentrated near the coast," he said, "which is where our collecting has also encountered the flies."

The authors prove that parasitized honey bees show hive abandonment behavior, leaving their hives at night and dying shortly thereafter. On average, seven days later, up to 13 phorid larvae emerge from each dead bee and pupate away from the bee. Using DNA barcoding, the authors confirmed that phorids that emerged from honey bees and bumble bees were the same species.

Understanding details of phorid infection may shed light on similar hive abandonment behaviors seen in CCD. Further, knowledge of this parasite could help prevent its spread into regions of the world where naive hosts may be easily susceptible to attack.

In addition to Brown, the paper's authors include Andrew Core, Charles Runckel, Jonathan Ivers, Christopher Quock, Travis Siapno, Seraphina DeNault, Joseph DeRisi, and John Hafernik from the San Francisco State University.

]]> Wed, 08 FEB 2012 08:56:25 AEST Toronto, Canada (SPX) Sep 07, 2010 - Widespread reports of a decline in the population of bees and other flower-visiting animals have aroused fear and speculation that pollination is also likely on the decline. A recent University of Toronto study provides the first long-term evidence of a downward trend in pollination, while also pointing to climate change as a possible contributor.

"Bee numbers may have declined at our research site, but we suspect that a climate-driven mismatch between the times when flowers open and when bees emerge from hibernation is a more important factor," says James Thomson, a scientist with U of T's Department of Ecology and Evolutionary Biology.

Thomson's 17-year examination of the wild lily in the Rocky Mountains of Colorado is one of the longest-term studies of pollination ever done. It reveals a progressive decline in pollination over the years, with particularly noteworthy pollination deficits early in the season. The study will be published in Philosophical Transactions of the Royal Society B: Biological Sciences on September 6.

Three times each year, Thomson compared the fruiting rate of unmanipulated flowers to that of flowers that are supplementally pollinated by hand.

"Early in the year, when bumble bee queens are still hibernating, the fruiting rates are especially low," he says. "This is sobering because it suggests that pollination is vulnerable even in a relatively pristine environment that is free of pesticides and human disturbance but still subject to climate change."

Thomson began his long-term studies in the late 1980s after purchasing a remote plot of land and building a log cabin in the middle of a meadow full of glacier lilies. His work has been supported by the U.S. National Science Foundation and the Natural Sciences and Engineering Research Council of Canada.

]]> Wed, 08 FEB 2012 08:56:25 AEST London, UK (SPX) Aug 13, 2010 - Despite their tiny brains, bees have remarkable navigation capabilities based on their vision. Now scientists have recreated a light-weight imaging system mimicking a honeybee's field of view, which could change the way we build mobile robots and small flying vehicles.

New research published in IOP Publishing's Bioinspiration and Biomimetics, describes how the researchers from the Center of Excellence 'Cognitive Interaction Technology' at Bielefeld University, Germany, have built an artificial bee eye, complete with fully functional camera, to shed light on the insects' complex sensing, processing and navigational skills.

Consisting of a light-weight mirror-lens combination attached to a USB video camera, the artificial eye manages to achieve a field of vision comparable to that of a bee.

In combining a curved reflective surface that is built into acrylic glass with lenses covering the frontal field, the bee eye camera has allowed the researchers to take unique images showing the world from an insect's viewpoint.

In the future, the researchers hope to include UV to fully reflect a bee's colour vision, which is important to honeybees for flower recognition and discrimination and also polarisation vision, which bees use for orientation. They also hope to incorporate models of the subsequent neural processing stages.

As the researchers write, "Despite the discussed limitations of our model of the spatial resolution of the honeybees compound eyes, we are confident that it is useful for many purposes, e.g. for the simulation of bee-like agents in virtual environments and, in combination with presented imaging system, for testing bee-inspired visual navigation strategies on mobile robots."

]]> Wed, 08 FEB 2012 08:56:25 AEST Ann Arbor MI (SPX) Jul 28, 2010 - Shade-grown coffee farms support native bees that help maintain the health of some of the world's most biodiverse tropical regions, according to a study by a University of Michigan biologist and a colleague at the University of California, Berkeley.

The study suggests that by pollinating native trees on shade-coffee farms and adjacent patches of forest, the bees help preserve the genetic diversity of remnant native-tree populations. The study was published online Monday in the Proceedings of the National Academy of Sciences.

"A concern in tropical agriculture areas is that increasingly fragmented landscapes isolate native plant populations, eventually leading to lower genetic diversity," said Christopher Dick, a U-M assistant professor of ecology and evolutionary biology.

"But this study shows that specialized native bees help enhance the fecundity and the genetic diversity of remnant native trees, which could serve as reservoirs for future forest regeneration."

An estimated 32.1 million acres of tropical forest are destroyed each year by the expansion of cropland, pasture and logging. Often grown adjacent to remnant forest patches, coffee crops cover more than 27 million acres of land in many of the world's most biodiverse regions.

Over the last three decades, many Latin American coffee farmers have abandoned traditional shade-growing techniques, in which plants are grown beneath a diverse canopy of trees. In an effort to increase production, much of the acreage has been converted to "sun coffee," which involves thinning or removing the canopy.

Previous studies have demonstrated that shade-grown farms boost biodiversity by providing a haven for migratory birds, nonmigratory bats and other beneficial creatures. Shade-coffee farms also require far less synthetic fertilizer, pesticides and herbicides than sun-coffee plantations.

In the latest study, U-M's Dick and UC-Berkeley's Shalene Jha investigated the role of native bees that pollinate native trees in and around shade-grown coffee farms in the highlands of southern Chiapas, Mexico. In their study area, tropical forest now represents less than 10 percent of the land cover.

Jha and Dick wanted to determine the degree to which native bees, which forage for pollen and nectar and pollinate trees in the process, facilitate gene flow between the remnant forest and adjacent shade-coffee farms.

They focused on Miconia affinis, a small, native understory tree that many farmers allow to invade shade-coffee farms because the trees help control soil erosion.

M. affinis, commonly known as the saquiyac tree, is pollinated by an unusual method known as buzz pollination. In order to release pollen from the tree's flowers, bees grab hold and vibrate their flight muscles, shaking the pollen free. Non-native Africanized honeybees don't perform buzz pollination, but many native bees do.

"Our focus on a buzz-pollinated tree allowed us to exclude Africanized honeybees and highlight the role of native bees as both pollinators and vectors of gene flow in the shade-coffee landscape mosaic," said Jha, a postdoctoral fellow at UC-Berkeley who conducted the research while earning her doctorate at U-M.

Jha and Dick combined field observations with seed-parentage genetic analysis of Miconia affinis. They found that trees growing on shade-coffee farms received bee-delivered pollen from twice as many donor trees as M. affinis trees growing in the adjacent remnant forest. The higher number of pollen donors translates into greater genetic diversity among the offspring of the shade-farm trees.

Seed parentage analysis revealed that pollen from forest trees sired 65.1 percent of the seeds sampled from M. affinis trees growing in a shade-coffee habitat.

That finding demonstrates that native bees are promoting gene flow between the remnant forest and the coffee farms-bridging the two habitat types-and that the shade-farm trees serve as a repository of local M. affinis genetic diversity, according to the authors.

In addition, Jha and Dick found that native bees carried pollen twice as far in a shade-coffee habitat than they did in the forest. They documented shade-farm pollination trips of nearly a mile, which are among the longest precisely recorded pollination trips by native tropical bees.

Jha and Dick said their results likely apply to other buzz-pollinated plants, which represent about 8 percent of the world's flowering plant species, as well as to other native plants whose limited pollen and nectar rewards don't attract honeybees.

The enhanced genetic diversity of the shade-farm trees could provide a reservoir for future forest regeneration, as the coffee farms typically fall out of production in less than a century.

Given that potential, along with the shade farm's previously identified roles in connecting habitat patches and sheltering native wildlife, it is important to encourage this traditional style of agriculture, Jha and Dick said.

The project was supported by the Helen Olson Brower Fellowship at the University of Michigan and by the National Science Foundation.

]]> Wed, 08 FEB 2012 08:56:25 AEST Tempe AZ (SPX) Jul 16, 2010 - What makes a bee grow up to be a queen? Scientists have long pondered this mystery. Now, researchers in the School of Life Sciences at Arizona State University have fit a new piece into the puzzle of bee development. Their work not only adds to understanding about bees, but also adds insights into our own development and aging.

The study, which appeared in the June 30 online edition of Biology Letters, shows that a key protein in the insulin signaling pathway plays a strong role in caste development among bees.

A female bee can become either a worker or a queen. Queen bees are larger and live longer than workers. Queen bees are also fertile while workers are essentially sterile. A queen has only one role-to lay eggs-while workers tend the hive, care for the queen and larvae, and forage for food.

"The incredible thing is that both of these types of female honeybees emerge from the same genome," says Florian Wolschin, an assistant research professor in the School of Life Sciences in ASU's College of Liberal Arts and Sciences, is the lead author of the study. "So how does that happen?"

Workers determine the fate of the larvae by what they feed them. The amount and composition of food that the larvae receive determine whether they become workers or queens. People have known this for many years, but exactly what happens inside the cells to create this split isn't completely clear.

Wolschin, Gro Amdam, an associate professor, and Navdeep S. Mutti, a postdoctoral research associate, found that the insulin signaling pathway plays a role in caste development. Insulin is a hormone found in humans and many other animals, and insulin-like peptides have been discovered in bees. Insulin moves glucose-sugar-from the bloodstream into the body's cells where it can be used.

The researchers suppressed one of the key proteins in this pathway in honeybee larvae. The protein, called the insulin receptor substrate (IRS), has been linked to growth, development and reproduction in mice. The researchers fed the altered larvae a queen's diet, but they developed into workers, not queens.

IRS is only one component of the process that decides a bee's ultimate fate. Wolschin says several other molecules are known to play a role, including DNA methyltransferase, juvenile hormone and a protein called TOR.

"Those are all very important and fundamental mechanisms," says Wolschin. "One single part cannot alone be responsible. It has to be the interplay between different mechanisms that finally results in the divergence of queens and workers."

The researchers are now looking at the interconnections between several of these factors. "We want to see if maybe there's a hierarchy involved. Several of the components are probably 'upstream' of other processes. So they serve as mass regulators and switches," says Wolschin.

Honeybees are vitally important to our economy through pollination of crops as well as production of honey, wax and royal jelly. Understanding bee biology is crucial to maintaining this industry in the face of problems like colony collapse disorder.

Wolschin adds that bees also provide an important model system that can help us understand our own biology. For example, scientists have successfully reversed many signs of aging in worker bees.

"That is pretty unique," says Wolschin. "You don't have other model organisms in aging research that can do that."

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