Another Bee Study Finds CCD is Likely Due to Combination of Factors Including Pesticides
Posted on August 10, 2013 Comments (2)
Abstract of open access science paper funded by the United States Department of Agriculture (USDA) Crop Pollination Exposes Honey Bees to Pesticides Which Alters Their Susceptibility to the Gut Pathogen Nosema ceranae:
We collected pollen from bee hives in seven major crops to determine 1) what types of pesticides bees are exposed to when rented for pollination of various crops and 2) how field-relevant pesticide blends affect bees’ susceptibility to the gut parasite Nosema ceranae. Our samples represent pollen collected by foragers for use by the colony, and do not necessarily indicate foragers’ roles as pollinators. In blueberry, cranberry, cucumber, pumpkin and watermelon bees collected pollen almost exclusively from weeds and wildflowers during our sampling.
Thus more attention must be paid to how honey bees are exposed to pesticides outside of the field in which they are placed. We detected 35 different pesticides in the sampled pollen, and found high fungicide loads. The insecticides esfenvalerate and phosmet were at a concentration higher than their median lethal dose in at least one pollen sample. While fungicides are typically seen as fairly safe for honey bees, we found an increased probability of Nosema infection in bees that consumed pollen with a higher fungicide load.
Our results highlight a need for research on sub-lethal effects of fungicides and other chemicals that bees placed in an agricultural setting are exposed to.
The attempts to discover the main causes of bee colony deaths and find solutions continues to prove difficult years after the problems became major. The complex interaction of many variables makes it difficult. And special interest groups pushing pesticides and the like, which have seemed to be major contributors to the problem for years, make it even more difficult (by preventing restrictions on potentially damaging pesticide use).
The challenges in determining what is killing bees are similar to the challenges of discovering what practices are damaging human health. The success of studying complex biological interactions (to discover threats to human health) is extremely limited. I am concerned we are far too caviler about using large numbers of interventions (drugs, pesticides, massive antibiotics use in factory farms, pollution…).
Related: Europe Bans Certain Pesticides, USA Just Keeps Looking, Bees Keep Dying – Germany Bans Chemicals Linked to Bee Deaths (2008) – Virus Found to be One Likely Factor in Bee Colony Colapse Disorder (2007) – Study of the Colony Collapse Disorder Continues as Bee Colonies Continue to Disappear