During lecture, Professor Allan highlighted colony collapse disorder (CCD) as an example of change in population dynamics. There is news that lends further insight into this phenomenon. In late September in a PNAS paper, USDA researchers and University of Indiana scientists including May Berenbaum identified a single molecular marker of CCD. The finding stemmed from a honey bee genome project that employed the microarray to search for differences in gene expression in the guts of healthy honey bees and honey bees from hives with CCD.
The study's microarray analyses unusually turned up large quantities of fragmented rNA in bees affected by CCD; normally the analyses identify only active genes, or genes that have been transcribed into messenger RNA in the first stage of protein construction. The doctoral student and first author, Reed Johnson, first observed this "polyadenylation," which is thought to be a symptom of ribosome degradation. Polyadenylation is present in other animals but significantly overrepresented in CCD bees of the investigation. The CCD bees were found to have suffered "more than their fair share" of attacks from "picorna-like" viruses that attack the ribosome, overtake the cell and cause it to solely manufacture viral proteins.
Quoted in a press release, Berenbaum said, "“If your ribosome is compromised, then you can’t respond to pesticides, you can’t respond to fungal infections or bacteria or inadequate nutrition because the ribosome is central to the survival of any organism. You need proteins to survive.”
The varroa mite that is suspected to have killed off many honey bees upon its invasion in 1986 likely carries picorna-like viruses and may be a significant contributor to the high viral pathogen load that afflicts U.S. bees. The mite may be a tipping factor in the process of ribosome breakdown, concluded the researchers.
The paper: "Changes in transcript abundance relating to colony collapse disorder in honey bees (Apis mellifera)" By Reed M. Johnsona, Jay D. Evans, Gene E. Robinsona and
May R. Berenbaum. http://www.pnas.org/content/106/35/14790.abstract?sid=9cfcd335-f132-45f3-be21-e406f9b73092