Investigating the importance of altitude and weather conditions for the production of toxic honey in New Zealand

Abstract

Toxic honey is produced in New Zealand when honey bees (Apis mellifera) forage on honeydew containing the phytotoxin tutin that is produced by the passion vine hopper (Scolypopa australis) when feeding on the poisonous plant tutu (Coriaria arborea). Observational studies suggest that there are a set of conditions required for the production of toxic honey, but these factors have not been well studied. This research aims to investigate the importance of altitude and weather conditions for the production of toxic honey in New Zealand and makes some recommendations for a review of the New Zealand Food Safety Authority (NZFSA) Food (tutin in honey) Standard 2008 that was introduced after a toxic honey outbreak in 2008. Transects were established in parts of the North Island during the summer of 2009 and were visited weekly for 6 consecutive weeks. Variables recorded were elevation, S. australis density, honeydew abundance, honey bee and wasp (Vespula spp.) presence and temperature and rainfall data. Weather conditions present during the 2008 outbreak were compared with those from 1999 to 2009. S. australis were not present at altitudes of 375 m and above; with more research, some higher areas of New Zealand may be able to be reclassified as 'low risk'. Honeydew was available in a wide range of temperature and rainfall conditions. Rainfall appeared to wash honeydew from tutu bushes; however, it quickly reappeared in densely populated sites. Honey bee and wasp presence was positively affected by the presence of honeydew, nevertheless 30Á50% of the time they were observed foraging in the absence of honeydew, indicating they may feed on small amounts of dew. As the absence of honeydew is an option given by the NZFSA to demonstrate honey safety, this requires investigation. Weather conditions leading up to the 2008 toxic honey outbreak were warm and dry but were not significantly different from other years. Therefore, inadequate management practices, rather than more favourable environmental conditions were probably responsible for the 2008 toxic honey outbreak. Future research should focus on determining the conditions required for toxic levels of honeydew to be incorporated into hives, and regions that have not produced toxic honey historically should be closely studied to determine whether any fit the low-risk criteria.

Population Growth and Insecticide Residues of Honey Bees in Tropical Agricultural Landscapes

“…This might be related to the foraging range of bees as well as the food source, which is not only pollen but also honeydew. Honey bee presence was positively affected by the presence of honeydew and source of insecticide residue that affected honey quality [30]. Neonicotinoid (imidacloprid), which was found in our study, was also detected in 11% samples of honey from apiaries located in Poland [31].…”

Sugar concentration influences decision making in <i>Apis mellifera</i> L. workers during early-stage honey storage behaviour

“…[63] also suggests that honeybees store pollen with high levels of chlorothalonil separately in entombed cells which might be a phenomenon similar to the honey storage pattern behaviour shown in this experiment. In addition, there are plants in several genera from at least 11 families [64,65] that naturally produce nectars which contain constituents that have varying degrees of toxicity to bees (and humans) and there are plants that produce toxic pollen [66,67]. Foragers bring these naturally occurring nectars and pollens back to the hive.…”

Diagnostic Radioentomology

“…We should also consider that there are plants in several genera from at least 11 families [61,62] that naturally produce nectar which contain constituents that have varying degrees of toxicity to bees and humans. There are also plants that produce toxic pollen [63,64].…”

“…This would be an effective way to prevent up to 38% of bees [68] receiving toxins/pathogens and it would reduce widespread contamination in the hive and thus help prevent bee losses. In addition, there are plants in several genera from at least 11 families [61,62] that naturally produce nectar which contain constituents that have varying degrees of toxicity to bees. Foragers bring these naturally occurring nectars back to the hive.…”