Agricultural landscape composition affects the development and life expectancy of colonies of Bombus impatiens

On-farm wildflower plantings generate opposing reproductive outcomes for solitary and bumble bee species

Pollinator habitat can be planted on farms to enhance floral and nesting resources, and subsequently, pollinator populations. There is ample evidence linking such plantings to greater pollinator abundance on farms, but less is known about their effects on pollinator reproduction. We placed Bombus impatiens Cresson (Hymenoptera: Apidae) and Megachile rotundata (F.) (Hymenoptera: Megachilidae) nests out on 19 Mid-Atlantic farms in 2018, where half (n = 10) the farms had established wildflower plantings and half (n = 9) did not. Bombus impatiens nests were placed at each farm in spring and mid-summer and repeatedly weighed to capture colony growth. We quantified the relative production of reproductive castes and assessed parasitism rates by screening for conopid fly parasitism and Nosema spores within female workers. We also released M. rotundata cocoons at each farm in spring and collected new nests and emergent adult offspring over the next year, recording female weight as an indicator of reproductive potential and quantifying Nosema parasitism and parasitoid infection rates. Bombus impatiens nests gained less weight and contained female workers with Nosema spore loads over 150 times greater on farms with wildflower plantings. In contrast, M. rotundata female offspring weighed more on farms with wildflower plantings and marginally less on farms with honey bee hives. We conclude that wildflower plantings likely enhance reproduction in some species, but that they could also enhance microsporidian parasitism rates in susceptible bee species. It will be important to determine how wildflower planting benefits can be harnessed while minimizing parasitism in wild and managed bee species.

New genomic resources inform transcriptomic responses to heavy metal toxins in the common Eastern bumble bee Bombus impatiens

BACKGROUND

The common Eastern bumble bee Bombus impatiens is native to North America and is the main commercially reared pollinator in the Americas. There has been extensive research on this species related to its social biology, applied pollination, and genetics. The genome of this species was previously sequenced using short-read technology, but recent technological advances provide an opportunity for substantial improvements. This species is common in agricultural and urban environments, and heavy metal contaminants produced by industrial processes can negatively impact it. To begin to identify possible mechanisms underlying responses to these toxins, we used RNA-sequencing to examine how exposure to a cocktail of four heavy metals at field-realistic levels from industrial areas affected B. impatiens worker gene expression.

RESULTS

PacBio long-read sequencing resulted in 544x coverage of the genome, and HiC technology was used to map chromatin contacts. Using Juicer and manual curation, the genome was scaffolded into 18 main pseudomolecules, representing a high quality, chromosome-level assembly. The sequenced genome size is 266.6 Mb and BRAKER3 annotation produced 13,938 annotated genes. The genome and annotation show high completeness, with ≥ 96% of conserved Eukaryota and Hymenoptera genes present in both the assembly and annotated genes. RNA sequencing of heavy metal exposed workers revealed 603 brain and 34 fat body differentially expressed genes. In the brain, differentially expressed genes had biological functions related to chaperone activity and protein folding.

CONCLUSIONS

Our data represent a large improvement in genomic resources for this important model species-with 10% more genome coverage than previously available, and a high-quality assembly into 18 chromosomes, the expected karyotype for this species. The new gene annotation added 777 new genes. Altered gene expression in response to heavy metal exposure suggests a possible mechanism for how these urban toxins are negatively impacting bee health, specifically by altering protein folding in the brain. Overall, these data are useful as a general high quality genomic resource for this species, and provide insight into mechanisms underlying tissue-specific toxicological responses of bumble bees to heavy metals.

Application of Big Data Technology to Promote Agricultural Structure Adjustment and High-Quality Development of Modern Agriculture

The implementation of the strategy of rural revitalization is a major ministerial work made by the Nineteenth National Congress of the Communist Party of China and is the general grasp of contemporary agriculture, peasants, and rural work. In recent years, with the rapid development of remote sensing technology and deep learning technology, the demand for the technology for the classification of crops on satellite remote sensing images based on deep learning technology has increased in agricultural insurance and land survey. Therefore, this paper trains one, which is 85.9%-92.8%, the accuracy of corn classification is 77%-93%, and the accuracy of forest classification is 77%-87.6%. Subsequently, the overall accuracy of classifying all directories through the multi-temporal validation data set between May 2017 and October 2017 reached 92.6%. Such a multi-time combination method can be used for monthly, timely, and efficient iteration of agricultural insurance and crop yield estimation, which will be more accurate each time. These methods can also be further applied to the growth and change monitoring of large agricultural planting areas, adding bricks and tiles to China's agricultural remote sensing. If the countryside is to be revitalized, agriculture must develop rapidly at the same time, industries must flourish, ecology must be livable, rural customs must be civilized, and life must be prosperous. Modern agriculture is a comprehensive circulation system with high yield, high quality, low consumption, ecology, environmental protection, and high efficiency. The development of modern agriculture is inseparable from the industrialization of agriculture, the globalization of agriculture, the digitization of agriculture, the integration of agriculture, the adjustment of agricultural structure, and agricultural innovation. Only the continuous development of modern agriculture can make rural revitalization enter a new journey.