Despite a recent abundance of research on honeybees, bumblebees and the diseases and circumstances that are threatening the world's vital pollinators, there is remarkably little research on the flowers that act as hubs for fungal, bacterial and viral diseases that are transmitted to bees, according to a new study.

"As major hubs of plant-animal interactions throughout the world, flowers are ideal venues for the transmission of microbes among plants and animals," University of Massachusetts Amherst researchers Scott McArt and Lynn Adler said in a joint statement, yet "almost nothing is known regarding how pathogens of pollinators are transmitted at flowers."

Writing in the journal Ecology Letters, McArt, Adler and their colleagues report that there are numerous areas where more research is needed in order to better understand how flowers transmit disease to pollinators.

"Given recent concerns about pollinator declines caused in part by pathogens, the role of floral traits in mediating pathogen transmission is a key area for further research," the study authors said.

The research involved a synthesis of 187 studies pertaining to plant pathogens published between 1947 and 2013. An additional 618 relevant animal pathogen studies were also included in the analysis.

The researchers found eight major animal pathogens that are potentially transmitted at flowers, including fungi, bacteria, RNA viruses and a trypanosomatid.

"Our intent with this paper is to stimulate interest in the fascinating yet poorly understood microbial world of flowers," McArt said. "We found several generalities in how plant pathogens are transmitted at flowers, yet the major take-home from our paper may be in pointing out that this is an important gap in our knowledge."