Fatal sting of winter
An ongoing problem with bee death on the Poverty Bay Flats has struck again.
Wintering hives in parts of the Poverty Bay Flats have suffered bee losses since 2005, says Apiculture NZ research focus group chairman Barry Foster.
A Gisborne beekeeper with an apiary in the Te Karaka area expects about 80 percent of his 40 hives are likely to perish over winter.
Mr Foster, an experienced beekeeper, says this appears to be symptomatic of chemical poisoning.
He has not yet heard of other recently-affected hives in the area but he would be surprised if there were not other cases.
The number of bees in the affected hives have dwindled since the owner last checked them about two weeks ago.
More than 30 of the 40 hives are too weak to survive the winter. This sort of impact on hives in parts of the Poverty Bay Flats during autumn and winter is well known to experienced beekeepers.
“This has been an ongoing problem with wintering hives on the Poverty Bay Flats since 2005,” says Mr Foster.
“We know it occurs between March and June and we know if we move the hives from the flats into the hills we don’t get this.
“We call it Flats disease. My hives have suffered these sorts of things in the past. You tend to move away from risky areas.”
Bee loss on the Flats is unlikely to be symptomatic of colony collapse disorder, which has decimated bee populations overseas, says Mr Foster.
Beekeepers have previously suspected neonicotinoids in insecticides impacted their hives. However, past tests on affected bees and honey from Gisborne, East Coast, Bay of Plenty and Waikato have not proved chemicals are responsible.
Mr Foster suspects chemicals in sprays have an indirect role in the diminished hive populations.
“They could be getting sub-lethal doses of a chemical that affects their immune-systems so that pathogens take over and kill them.
“The hives still have plenty of honey, nectar and pollen, and have been treated for varroa mite, so it can’t be that.”
The decline in a hive’s bee population means there are too few bees in the hive to keep it warm.
“The brood — the eggs, larvae and pupae — will chill and die,” says Mr Foster. “When you lose too many adult bees in a hive there are insufficient numbers to keep all of the brood at around 36 degrees.
“The hive goes into a spiral of death of adult bees that in turn leaves large patches of brood to chill and die. This leads to the death of the hive.”
Samples from affected hives and bees have been collected to be sent for testing at Hill Laboratories in Hamilton, and possibly another lab with sensitive equipment.