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Osmia solitary bees are important pollinators of various crops worldwide. Refrigeration has been widely used to synchronize the emergence time of Osmia species from cocoons with the blooming time of different crops, but the fitness of Osmia after refrigeration remains unknown. Here, the effects of long‐term refrigeration at 0 °C on the vitality, flight ability, and metabolism of Osmia excavata, which is known as the "king of pollination" in China, were studied. The survival rate (>90% before 120 d), weight loss rate (<15% after 170 d), and mean flight speed of O. excavata were not greatly affected after long‐term refrigeration. The content of fats, which have antifreeze and energy storage properties, was not significantly altered in O. excavata before 130 d of refrigeration, which might explain why the survival rates and flight speed of O. excavata remained high after long‐term refrigeration. However, the flight duration and distance decreased significantly (P < 0.05), and both were positively correlated with the reduced trehalose levels in O. excavata (r = [+0.69] – [+0.71]; P < 0.05). Overall, these findings indicate that the pollination potential of O. excavata for various crops with different flowering periods is high after long‐term refrigeration; however, long‐term refrigeration may decrease pollination efficiency. Our findings highlight new research directions that could improve the ecological service function of refrigerated O. excavata. [ABSTRACT FROM AUTHOR]

Crop expansion often leads to high pest pressure. These pests may have fitness trade‐offs related to host use, and some host‐associated genotypes may benefit and increase in frequency. However, evidence concerning the effect of host availability on spatial distribution and frequency of mitochondrial haplotypes is scarce. We studied genetic variation of the Asian corn borer, Ostrinia furnacalis (Guenée), across a large area during 2 years (2016 and 2017). Mitochondrial sequence data were obtained from 530 individuals collected from 79 locations in Shandong Province, China. In total, 155 haplotypes were found based on the combined cytochrome oxidase subunit 1 (COI) and COII genes. Three haplotypes (H2, H12, and H23) were dominant, whereas most of the other haplotypes occurred in low frequency. A haplotype network showed that the 155 haplotypes can be grouped into three clusters. Haplotype clusters seemed to be randomly distributed. The frequency of H12 (in Cluster 1) was positively correlated with maize crop proportion, but negatively correlated with other crops (primarily vegetables, oilseed crops, and cotton) at all spatial scales (1‐, 3‐, and 5‐km radius). Cluster 2 had haplotype H23, and this cluster was negatively correlated with semi‐natural habitats. Cluster 3 had no dominant haplotype and was not affected by landscape factors. We conclude that H12 may be a maize‐associated haplotype. Further study is needed to verify the possibility that the carriers of this haplotype may possess some fitness trade‐offs. Our study highlights the importance of host availability in O. furnacalis haplotype distribution and frequency. [ABSTRACT FROM AUTHOR]