Genetic Structure and Potential Environmental Determinants of Local Genetic Diversity in Japanese Honeybees (Apis cerana japonica)

Abstract

Declines in honeybee populations have been a recent concern. Although causes of the declines remain unclear, environmental factors may be responsible. We focused on the potential environmental determinants of local populations of wild honeybees, Apis cerana japonica, in Japan. This subspecies has little genetic variation in terms of its mitochondrial DNA sequences, and genetic variations at nuclear loci are as yet unknown. We estimated the genetic structure and environmental determinants of local genetic diversity in nuclear microsatellite genotypes of fathers and mothers, inferred from workers collected at 139 sites. The genotypes of fathers and mothers showed weak isolation by distance and negligible genetic structure. The local genetic diversity was high in central Japan, decreasing toward the peripheries, and depended on the climate and land use characteristics of the sites. The local genetic diversity decreased as the annual precipitation increased, and increased as the proportion of urban and paddy field areas increased. Positive effects of natural forest area, which have also been observed in terms of forager abundance in farms, were not detected with respect to the local genetic diversity. The findings suggest that A. cerana japonica forms a single population connected by gene flow in its main distributional range, and that climate and landscape properties potentially affect its local genetic diversity.

Evolution of life in urban environments

“…The evolutionary effects of this fragmentation are evident from declines in genome-wide diversity along a 142-km urbanization gradient from forested and rural areas to the urban core ( Fig. 3B) (42). Two rodent species in Warsaw, Poland (43), and Dundee, Scotland (44), that are ecologically similar to white-footed mice also exhibited lower genetic diversity within urban populations and greater differentiation between them, when compared with that of rural populations.…”

New insights into the genetic structure of the outbreak-prone migratory locust

“…It was reported in other species that climatic variables play an important role in the formation of genetic structure (e.g., Ding et al, 2018). Climate variables affected the genetic structure of Aedes aegypti (Mendonça et al, 2014;Gao et al, 2021), Apis cerana japonica (Nagamitsu et al, 2016), and Trialeurodes vaporariorum (Ovčarenko et al, 2014). Thus, seasonality of climatic variables is an important factor affecting genetic structure.…”

Application of Environmental DNA: Honey Bee behavior and Ecosystems for Sustainable Beekeeping

“…Urban beekeeping became one of the main ways of beekeeping in different regions of the world [3]. Urban environment can contribute to maintenance of diversity of honeybee species including native species [4]. Alternatively, the issues of pesticides are becoming serious in some countries [5], although the honeybee colony declines can be caused by complex factors including pesticides and global honey trade [6].…”

“…The size of urban areas is relatively small as compared with farmland and other habitats of honeybee. However, the roles of urban areas to maintain the genetic diversity of organisms and to enhance the environmental awareness of citizens are suggested by the existing studies [4,7], and urban beekeeping is expected as a main way of beekeeping. In the promotion of urban beekeeping, rack of scientific evidence of behavior of urban honeybee is a serious issue.…”