Japanese Honeybees (Apis cerana japonica Radoszkowski, 1877) May Be Resilient to Land Use Change

Pollinators are being threatened globally by urbanisation and agricultural intensification, driven by a growing human population. Understanding these impacts on landscapes and pollinators is critical to ensuring a robust pollination system. Remote sensing data on land use attributes have previously linked honeybee nutrition to land use in the Western Honeybee (Apis mellifera L.). Here, we instead focus on the less commonly studied Apis cerana japonica—the Japanese Honeybee. Our study presents preliminary data comparing forage (honey and pollen) with land use across a rural-urban gradient from 22 sites in Kyushu, southern Japan. Honey samples were collected from hives between June 2018 and August 2019. Pollen were collected and biotyped from hives in urban and rural locations (n = 4). Previous studies of honey show substantial variation in monosaccharide content. Our analysis of A. cerana japonica honey found very little variation in glucose and fructose (which accounted for 97% of monosaccharides), despite substantial differences in surrounding forage composition. As expected, we observed temporal variation in pollen foraged by A. cerana japonica, likely dependent on flowering phenology. These preliminary results suggest that the forage and nutrition of A. cerana japonica may not be negatively affected by urban land use. This highlights the need for further comparative studies between A. cerana japonica and A. mellifera as it could suggest a resilience in pollinators foraging in their native range.

Japanese Honeybees (Apis Cerana Japonica Radoszkowski, 1877) May Be Resilient to Land Use Change

Pollinators are being threatened globally by urbanisation and agricultural intensification, driv-en by a growing human population. Understanding these impacts on landscapes and pollinators is critical to ensuring a robust pollination system. Remote sensing data on land use attributes have previously linked honeybee nutrition to land use in the Western Honeybee (Apis mellifera L.). Here, we instead focus on the less commonly studied Apis cerana japonica – the Japanese Honeybee. Our study presents preliminary data comparing forage (honey and pollen) with land use across a rural-urban gradient from 22 sites in Kyushu, southern Japan. Honey samples were collected from hives between June 2018 and August 2019. Pollen were collected and biotyped from hives in urban and rural locations (n = 4). Previous studies of honey show substantial vari-ation in monosaccharide content. Our analysis of A. cerana japonica honey found very little varia-tion in glucose and fructose (which accounted for 97% of monosaccharides), despite substantial differences in surrounding forage composition. As expected, we observed temporal variation in pollen foraged by A. cerana japonica, likely dependent on flowering phenology. These prelimi-nary results suggest that the forage and nutrition of A. cerana japonica may not be negatively af-fected by urban land use. This highlights the need for further comparative studies between A. cerana japonica and A. mellifera as it could suggest a resilience in pollinators foraging in their na-tive range.

Japanese Honeybees (Apis Cerana Japonica Radoszkowski, 1877) May Be Resilient to Land Use Change

Pollinators are being threatened globally by urbanisation and agricultural intensification, driven by a growing human population. Honeybees are part of a wide suite of insect pollinators with a global distribution. Understanding the impacts of landscape change and other influencing factors on pollinators is critical to ensuring food security and ecological stability. Remote sensing data on land use attributes have previously linked honeybee nutrition to land use in the Western Honeybee (Apis mellifera L.). Our study presents preliminary data comparing forage (honey and pollen) with land use across a rural-urban gradient from 22 sites in Kyushu, Southern Japan. Honey samples were collected from managed hives between June 2018 and August 2019. Pollen were collected and biotyped from hives in urban and rural locations (n = 5). Previous studies of western honeybee honey shows substantial variation in monosaccharide content. Our analysis of A. cerana japonica honey found very little variation in glucose and fructose (which accounted for 97% of monosaccharides), despite substantial differences in surrounding forage composition. As expected, we observed temporal variation in pollen foraged by A. cerana japonica, likely dependent on flowering phenology. These results suggest that A. cerana japonica may be resilient previously observed negative effects of urban land use on pollinator nutrition. We suggest this effect could be due to differences in urban green infrastructure in Japan, or due to an adaptation by A. cerana japonica to their surroundings, meaning landscape change may not be as detrimental to A. cerana japonica as has been observed elsewhere in the world.

Differential autogrooming response to the tracheal mite Acarapis woodi by the honey bees Apis cerana and Apis mellifera

The infestation of honey bees by the endoparasitic tracheal mite Acarapis woodi was first discovered in Apis mellifera on the Isle of Wight, England, and the mite has since spread to all continents except Australia. Since 2010, this tracheal mite has spread rapidly in the Japanese honey bee, Apis cerana japonica, of mainland Japan, causing considerable colony mortality. In contrast, infestations by the mites in the imported and managed European honey bee, A. mellifera, have rarely been observed in Japan. A previous laboratory experiment revealed a difference in susceptibility by demonstrating that the tracheal mite more frequently enters tracheae of A. cerana than those of A. mellifera. In this study, we compared autogrooming responses of A. cerana and A. mellifera by depositing a mite on each honey bee’s mesoscutum, and we then assessed the efficacy of autogrooming to remove the mite. The bees that received mites more frequently showed an autogrooming response compared to unchallenged bees in both bee species. However, a significantly greater proportion of A. mellifera individuals autogroomed compared to A. cerana. In addition, when bees autogroomed, A. mellifera removed the tracheal mite more effectively than A. cerana. When considering all bees in the mite-deposited group, the proportion of mite removal in A. mellifera was almost twice as high as that in A. cerana. Thus, the difference in susceptibility to the tracheal mite between these two bee species is attributed to the difference in the behavioral response threshold to mites and the effectiveness of mite removal by grooming.