Beekeepers have reported losing around 10 per cent of their hives last year – with wasps and suspected weather-driven starvation among the reasons.
More than 3,600 beekeepers – making up nearly half of those registered beekeepers and colonies in New Zealand – reported another year of falls in the 2018 Colony Loss Survey.
It showed an overall hive loss of 10.2 per cent for the year, and compared with losses of 8.4 per cent in 2015, 9.6 per cent in 2017 and 9.7 per cent in 2017.
The most commonly reported causes of colony losses in 2018, accounting for about 80 per cent of them, were varying problems with queens, suspected varroa mite infestations, suspected starvation of bees from weather and other factors, and wasps, which are known to kill bees, eat pupae and steal honey.
To a small extent, losses were also caused by American foulbrood disease, theft and vandalism, toxicity, accidents, and Argentine ants.
Dr Michael Taylor of Biosecurity New Zealand, for which Manaaki Whenua – Landcare Research carried out the survey, said the loss rate was still relatively low compared with many other countries.
However, he said, it highlighted the importance of ensuring good biosecurity, colony health and beekeeping practice.
The data showed some interesting variation in loss rates, he said, and some clues as to the causes of those losses, across different regions.
"For example, there has been an increase in annual winter colony losses reported for the South Island and the top of the North Island," Taylor said.
"However, I am pleased to see that beekeepers in the middle and south of the North Island on the other hand are bucking the national trend, reporting decreased rates of colony losses since 2016.
"The 2018 loss figures for these areas are 9.9 per cent and 8.1 per cent respectively, the lowest results in the country."
Beekeepers made up colony losses every year with new colonies that they split from existing colonies.
Queens were either created by the beekeeper or introduced as new queens from a queen breeder.
The Bee Colony Loss Survey was designed to give baseline information for monitoring managed honey bee colony loss and survival over time.