Altering Agricultural Practices Improves Honey Bee Populations

Buri, P., Humbert, J. Y., & Arlettaz, R.  2014.  Promoting Pollinating Insects in Intensive AgriculturalMatrices: Field-Scale Experimental Manipulation of Hay-Meadow Mowing Regimes and Its Effects on Bees.  Public Library of Science ONE 9(1):  1-12.

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0085635

Honey bees (Apis mellifera) provide a crucial ecosystem service by pollinating flowering plants.  This service is mutually beneficial to agricultural professionals and the ecosystem within the range of the bees.  However, honey bees do not only provide a service, but they require ample stores of pollen in order to survive.  If these stores are greatly altered over the course of an agricultural season, the honey bees suffer the consequence.  Farmers need to clear cut hay meadows in order to create bales and harvest a crop.  When this occurs, the entire field of hay honey bees feed upon is removed, and the bees are required to find an alternate food source within their range.  In order to quantify the effect of hay-meadow mowing techniques, Buri et al. 2014 performed a study.  Buri et al. 2014 hypothesized that honey bee numbers would decline sharply if their immediate food source, accessible to the hive, had suddenly been removed.  Contrarily, they hypothesized that honey bees would survive if an uncut hay refuge persisted after a mowing.

In order to test their hypotheses, Buri et al. 2014 implemented a study with three treatment methods on thirty-six hay fields on the Swiss Plateau (near European Alps).  A majority of the land in this region, upwards of 90 percent, serves agricultural purposes.  The control hay meadow was clear-cut after June 15 according to regulations.  The first experimental group was also cut after June 15, but 10-20 percent of the meadow was left as a refuge for bees. The other experimental group was delayed in mowing until after July 15, 2011.  Bees from hives adjacent to each experimental section were collected during the summer of 2011 and also in the subsequent year.  Buri et al. 2014 intended to determine both short and long term effects of agricultural techniques on the health of the bees.  Control groups showed a decline in bee numbers after the June 15 mowing.  Delayed mowing demonstrated a positive effect on honey bee health and numbers in the short term, but had similar long term effects to the control.  The optimal treatment for maintenance of honey bees was incomplete mowing.  The refuges allowed bees to persist both short and long term increasing hive health and therefore pollination output.

With this information, farmers around the world with any crop that relies on bee pollination can better manage their cropland.  By reserving refuges of plants for the honey bees, the bees are able to persist and maintain a healthy hive.  In return, the honey bees are capable of more adequately providing the farmers with the pollination ecosystem service.  This mutual relationship can allow farming to improve while also maintaining biodiversity by promoting pollinator species.

Occupying a Pollination Niche: To Bee or not to Bee

Brittain, C., Williams, N., Kremen, C., & Klein, A. M.  2013.  Synergistic effects of non-Apis bees and honey bees for pollination services.  Proceedings of the Royal Society B.  280:  20122767. 

 

http://www.ncbi.nlm.nih.gov/pubmed/20559562

Insect pollination is an effective and prolific method of augmenting agricultural output without overexerting the land or providing additional input.  Because of their typical roles, honey bees (Apis mellifera) are optimal pollinators for agricultural and non-agricultural plants.  However, honey bees are not the only insect that occupies the pollination functional group.  There are many non-Apis bees that coexist with honey bees within pollination systems.  Because they fill very similar roles, the specific plants of which honey bees feed and pollinate vary as bee biodiversity also varies.  Despite the seemingly inherent need for competition, different bee species may complement each other.  Brittain et al.  2013 specifically address these issues in their study.  The researchers hypothesize that biodiversity enhances the amount and effectiveness of pollination by bee species.

                Brittain et al. 2013 conducted their study in 2008 to 2011 on 25 almond orchards in northern California.  The researchers studied the movement of honey bees among trees, single pollination visit effectiveness, fruit development, and an extensive cage experiment; all of which carried a variable of honey bee, non-honey bee, none, or multiple species.  The cage experiment demonstrated that Apis mellifera is the stronger, more dominant pollinator of the bee species, but with the addition of the weaker, Osmia lignaria.  The researchers demonstrated that the presence of non-Apis species enhanced fruit setting, pollen tube development, successful pollination, and movement amongst rows for honey bees.  Brittain et al. 2013 achieved results that demonstrated a positive relationship between biodiversity and successful pollination.  The researchers also found that with multiple species present, honey bees traveled among more trees and promoted better pollen deposition and pollen tube growth within the pistil. 

Brittain et al. 2013 successfully demonstrated a positive correlation between biodiversity of pollinator species and pollination services such as pollen tube growth, fertilization, and fruit development.  With the use of honey bees and non-Apis species, pollination services can be augmented.  Biodiversity which includes species that occupy the same functional group often leads to competition.  However, the biodiversity in this experiment has clearly demonstrated that there can be a positive correlation between ecosystem production and biodiversity.  This critical information could be relevant for farmers of orchards and production crops that could enhance their output and augment pollination services.  Honey bees and other species of pollinators could also be useful for non-agricultural species of plants in need of a boost in fertilizations.  Honey bees and other species of bees are not necessary for successful plant species, however, they can enhance plant production.

Bacterial Entrapment by Honey Bees through Foraging

Anderson, K. E., Sheehan, T. H., Mott, B. M., Maes, P., Snyder, L., Schwan, M. R., Walton, A., Jones, B. M., & Corby-Harris, V.  2013.  Microbial Ecology of the Hive and Pollination Landscape:  Bacterial Associates from Floral Nectar, the Alimentary Tract and Stored Food of Honey Bees (Apis mellifera).  Public Library of Science ONE.  8(12):  1-16.

http://www.ncbi.nlm.nih.gov/pubmed/24358254

Many bacteria are associated with the honey bee alimentary tract.  These bacteria can be absorbed from the environment through the consumption of nectar from flowers.  Bacteria play an important role in regulating honey bee gut health, and they are not all detrimental to the welfare of the hive.  Worker bees deposit their honey and packed pollen within the honey comb of the hive.  The packed pollen is referred to as “bee-bread.”  Both of these sources can be cultured by researchers to determine the bacterial content.  Another indicator of bacterial consistency within individuals of a hive is the content of bacteria within each region of the honey bee gut:  foregut or crop, midgut, and hindgut.  Honey bees within the hive can be infected with bacteria from source of honey and bee-bread.  For these reasons, Anderson et al. 2013 have cultured bacterial samples from honey bee colonies in order to understand the bacterial associations honey bees make and their implications to individual and overall hive health.

                The honey bee hive as a whole can be labeled as a macro-organism made up of many individuals, honey, honey comb, and bee bread.  All of these elements have diverse temperature gradients, pH fluctuations, and other homeostatic elements.  This inconsistency provides variation in the bacterial diversity of the hive as well.  Anderson et al. 2013 studied nine different honey bee colonies in the Carl Hayden Bee Research Center in Tucson AZ.  They focused on the transient nature of bacteria in the honey bee crop and midgut with an emphasis on the differences among nectar sources.  Newly emergent bees were compared based on their exposure to honey and bee-bread, their exposure to older bees within the hive, neither, or both.  These emergent bees’ crops were sampled for bacterial consistency and compared with the bacteria found within pollen, bee-bread, honey, and older bee samples.  Bacterial were cultured on various media and their DNA signatures were determined using PCR (polymerase chain reaction).  The outcome of these experiments demonstrated that the emergent bees exposed to food sources (honey and bee-bread) were infected with a more diverse range of bacteria than random in-hive bees.  This indicated that the food sources had a greater effect than the individual to individual transmission of bacteria.

                Anderson et al. 2013 were able to refute their hypothesis of the importance of peer to peer transmission of disease and confirm the importance of environmental contribution of bacterial vectors.  Depending on the presence of proper bacteria in the nectar food sources of honey bees, bacteria could become associated with the macro-organism of the honey bee hive.  These sources could contribute to the alimentary health and therefore overall health of the hive.  Because honey bees are generalist consumers, farmers and cultivars can place strategically located nectar sources near hives to contribute to healthy hives.  These hives are mutually beneficial as they pollinate crops, native plants, and other plant species.  Healthy honey bee gut health can contribute to the functionality and diversity of the overall ecosystem.