How population structure and nest membership shape pathogen patterns in bumble bees?

Host density, genetic diversity, and social groups are key factors influencing pathogen transmission in wildlife populations, but their interactions remain poorly understood in insects. Islands can provide natural laboratories with distinct populations that vary in density and genetic diversity, whereby dense, genetically homogenous populations are expected to facilitate pathogen transmission. We used bumble bees to test these predictions, assessing the population structure of the two common species Bombus pascuorum and B. terrestris across island and mainland sites in the British Isles and France, and testing bees for five micro-parasitic and four viral pathogens. B. pascuorum formed distinct genetic clusters on islands, with varying levels of heterozygosity, and only the Isle of Arran clustered with mainland populations. B. terrestris populations were less structured, but populations on the Isle of Man and the Scilly Isles were genetically separated from other island and mainland popu..., 216 Bombus pascuorum and 573 B. terrestris were collected from flowers from mid June to late August in 2021 across seven islands in the Irish Sea, the English Channel, and off the coast of Brittany in France, and four coastal sites in England and France in 2021. From late June to early August 2022, islands (except for the Scilly Isles) were sampled again using five sampling sites on large islands (Arran, Isle of Man, Guernsey, Belle-Ile) or collecting across the whole island on smaller islands (< 15 km2, Alderney and Ouessant). A total of 988 B. pascuorum and 1,163 B. terrestris were obtained in 2022.
DNA was extracted from bees using a single hind leg. Bees were genotyped at 12 loci, and fragments were run on a Thermo Fisher Scientific Genetic Analyzer 3130 Series. Alleles were scored in Geneious Prime® v2023.0.1. Sibship reconstruction was performed in COLONY v2.0.6,7, and population structure was assessed using DAPC (discriminant analysis of principal components) and the..., , # How population structure and nest membership shape pathogen patterns in bumble bees?

[https://doi.org/10.5061/dryad.prr4xgxws](https://doi.org/10.5061/dryad.prr4xgxws)

## Description of the data and file structure

This file is the primary dataset utilized for the various analyses described in our article, \"How population structure and sociality shape pathogen patterns in bumble bees\". In this article, we investigate the population structure of two bumble bee species and link this structure to disease patterns. Microsatellite data were used to calculate genetic diversity in bee populations and in sibship reconstructions. Inferred nest membership then allowed us to estimate the bumble bee density using mark recapture models and to further look into the similarity in pathogen infections within and between nests.

### Files and variables

#### File: data_table_bb_pop_patho.csv

**Description:** Individual genotype data (allele sizes) and pathogen prevalence for *Bombus pascuorum* and *...,