A four-decade profile of apicultural demographics and production in New Zealand, 1980-2020.

The demand for honey and pollination services has continued to grow in many countries worldwide, including New Zealand. This has influenced changes in the demographics of the managed population of honey bees (Apis mellifera). We examined historical data to describe how the apicultural demographics in New Zealand have changed temporally and geographically in the four decades to 2020. We also describe trends in honey production and the economic value of pure honey exported from New Zealand between 2000 and 2020. Our findings suggest that commercial apiculture has been key to the intensification of beekeeping in New Zealand during the study period. This is supported by evidence showing pronounced expansion of beekeeping operations among those with more than 1,000 colonies. The intensification has resulted in the density of apiaries increasing threefold across New Zealand during the four decades. While higher numbers of colonies per area produced higher volumes of honey, there was no corresponding improvement in production efficiency. Honey yields per apiary or colony, as indicators of production efficiency, appear to decline from the mid-2000s. The volume of pure honey export increased over 40-fold, a magnitude approximately ten times higher than that of production increase. This reflects a substantial increase in returns from honey exports, mostly driven by the price of manuka honey. Our findings add to a pool of information to support evidence-based decision making to enhance honey bee health and develop the apicultural industry in New Zealand.

Genomic analysis of the population structure of Paenibacillus larvae in New Zealand.

New Zealand is a remote country in the South Pacific Ocean. The isolation and relatively late arrival of humans into New Zealand has meant there is a recorded history of the introduction of domestic species. Honey bees (Apis mellifera) were introduced to New Zealand in 1839, and the disease American foulbrood was subsequently found in the 1870s. Paenibacillus larvae, the causative agent of American foulbrood, has been genome sequenced in other countries. We sequenced the genomes of P. larvae obtained from 164 New Zealand apiaries where American foulbrood was identified in symptomatic hives during visual inspection. Multi-locus sequencing typing (MLST) revealed the dominant sequence type to be ST18, with this clonal cluster accounting for 90.2% of isolates. Only two other sequence types (with variants) were identified, ST5 and ST23. ST23 was only observed in the Otago area, whereas ST5 was limited to two geographically non-contiguous areas. The sequence types are all from the enterobacterial repetitive intergenic consensus I (ERIC I) genogroup. The ST18 and ST5 from New Zealand and international P. larvae all clustered by sequence type. Based on core genome MLST and SNP analysis, localized regional clusters were observed within New Zealand, but some closely related genomes were also geographically dispersed, presumably due to hive movements by beekeepers.

Varroa Appears to Drive Persistent Increases in New Zealand Colony Losses.

New Zealand's temperate climate and bountiful flora are well suited to managed honey bees, and its geographic isolation and strict biosecurity laws have made sure that some pests and diseases affecting bees elsewhere are not present. Nevertheless, given the importance of pollination and high-value export honey to the economy, New Zealand began systematically measuring winter colony losses in 2015. The New Zealand Colony Loss Survey is modelled on the COLOSS survey but has been adapted to the New Zealand apicultural context. Some 49% of New Zealand beekeepers completed the winter 2021 survey. Between 2015 and 2021, overall colony loss rates increased monotonically from 8.37% [95% CI: 7.66%, 9.15%] to 13.59% [95% CI: 13.21%, 13.99%]. Whereas beekeepers most commonly attributed losses to queen problems between 2015 and 2020, attributions to varroa have escalated year-on-year to become the largest attributed cause of colony loss. Losses to varroa are perhaps amplified by the 23.4% of respondents who did not monitor mite loads and the 4.4% of beekeepers who did not treat varroa during the 2020/21 season. Indeed, most beekeepers consider their treatment to be effective and note that treating at the wrong time and reinvasion were major drivers of losses to varroa.