Martin Hasselmann

University of Hohenheim · Institute of Animal Science

Deciphering the evolutionary processes driving nucleotide variation in multi-allelic genes is limited by the number of genetic systems in which such genes occur. The complementary sex determiner (csd) gene in the honey bee Apis mellifera is an informative example for studying allelic diversity and the underlying evolutionary forces in a well-descri...

All hymenopteran species, such as bees, wasps and ants, are characterized by the common principle of haplodiploid sex determination in which haploid males arise from unfertilized eggs and females from fertilized eggs. The underlying molecular mechanism has been studied in detail in the western honey bee Apis mellifera, in which the gene complementa...

The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some spe...

Understanding the genetic basis of adaption is a central task in biology. Populations of the honey bee Apis mellifera that inhabit the mountain forests of East Africa differ in behavior and morphology from those inhabiting the surrounding lowland savannahs, which likely reflects adaptation to these habitats. We performed whole genome sequencing on...

Bumblebees are a diverse group of globally important pollinators in natural ecosystems and for agricultural food production. With both eusocial and solitary life-cycle phases, and some social parasite species, they are especially interesting models to understand social evolution, behavior, and ecology. Reports of many species in decline point to pa...

The honey bee ectoparasite Varroa destructor is the main cause of honey bee colony losses worldwide. Over the last decades, several projects have focused on improving the robustness of Apis mellifera against this parasitic mite. Selection traits, such as mite non-reproduction (MNR) and Varroa sensitive hygiene (VSH), are favored selection factors i...

A sustainable solution to the global threat of the Varroa destructor mite is the selection of varroa‐resistant honey bee (Apis mellifera) colonies. Both “mite non‐reproduction” (MNR) and “varroa sensitive hygiene” (VSH) appear to be promising selection traits for achieving the goal of a resistant honey bee. MNR describes colonies that have a high n...

Anthropogenic activities like trade facilitate increasing rates of biological invasions. Asian long-horned beetle (ALB), which is naturally distributed in eastern Asia (China, Korean peninsula), was introduced via wood packing materials (WPM) used in trade to North America (1996) and Europe (2001). We used 7810 single nucleotide polymorphisms (SNPs...

Final report of the EIP project SETBie in Baden- Württemberg. The intention of the project was the selection and etablation of varroa tolerant honey bee colonies (SETBie) in Baden-Württemberg, Germany (2019-2022). View: https://setbie.uni-hohenheim.de/

Since the inception of the term sustainable development at the end of the 20th century as a reconciliation between the needs for socio-economic development and environmental protection, various concepts and production systems have been initiated to address demands for food and other products. These include organic agriculture and sustainable intens...

1. Bee parasites are the main threat to apiculture and since many parasite taxa can spill over from honeybees (Apis mellifera) to other bee species, honeybee disease management is important for pollinator conservation in general. It is unknown whether honeybees that escaped from apiaries (i.e. feral colonies) benefit from natural parasite-reducing...

Wild honeybees (Apis mellifera) are considered extinct in most parts of Europe. The likely causes of their decline include increased parasite burden, lack of high-quality nesting sites and associated depredation pressure, and food scarcity. In Germany, feral honeybees still colonize managed forests, but their survival rate is too low to maintain vi...

The honey bee, Apis mellifera differs from all other social bees in its gonad phenotype and mating strategy. Honey bee queens and drones have tremendously enlarged gonads, and virgin queens mate with several males. In contrast, in all the other bees, the male and female gonads are small, and the females mate with only one or very few males, thus, s...

The taxonomy and evolutionary relationships of populations of Apis mellifera have been studied worldwide using morphological and molecular methods. In this study, we used integrated methods to classify and characterize the highly debated Ethiopian honey bee lineages and subspecies. Firstly, forewing geometric morphometric analyses separated Ethiopi...

It presented beekeeping progress, the status of colony marketing and honey bee population differentiation using official annual reports of 16 years, colony market surveys, and sequence data of a nuclear gene fragment associated with adaptation to habitat elevation, respectively.

Subsistent beekeeping has been an established tradition in Tigray, northern Ethiopia. In the last two decades, extension efforts tried to transform it into improved apiculture, which led to development of colony marketing. Here, we assessed the progress in beekeeping, colony marketing, and population differentiation with a hypothesis that the exten...

Parasites are the main threat for managed honeybee ( Apis mellifera ) colonies. It is unknown whether feral colonies that escaped from apiaries benefit from parasite-reducing mechanisms like swarming or suffer from high parasite pressure due to the lack of disease management. We compared the occurrence of 18 microparasites among managed (N=74) and...

Mitochondria and the energy metabolism are linked to both, the availability of Ca and P to provide the eukaryotic cell with energy. Both minerals are commonly used supplements in the feed of laying hens but little is known about the relationship between the feed content, energy metabolism and genetic background. In this study, we provide a large-sc...

The gonads of honey bee, Apis mellifera, queens and drones are each composed of hundreds of serial units, the ovarioles and testioles, while the ovaries of the adult subfertile workers consist of only few ovarioles. We performed a comparative RNA‐seq analysis on early fifth‐instar (L5F1) larval gonads, which is a critical stage in gonad development...

Traditional beekeeping is an important part of rural livelihood in Ethiopia. In northern Ethiopia, development initiatives recently tried to transform it into improved apiculture, which led to colony marketing development. We assessed the progress in beekeeping, colony marketing and gene flow with a hypothesis that the extension might have supporte...

Cytoplasmic incompatibility (CI) is a form of reproductive manipulation caused by maternally inherited endosymbionts infecting arthropods, like Wolbachia, whereby matings between infected males and uninfected females produce few or no offspring. We report the discovery of a new CI symbiont, a strain of Spiroplasma causing CI in the parasitoid wasp...

The cellular energy metabolism is one of the most conserved processes, as it is present in all living organisms. Mitochondria are providing the eukaryotic cell with energy and thus their genome and gene expression has been of broad interest for a long time. Mitochondrial gene expression changes under different conditions and is regulated by genes e...

Suppressed mite reproduction (SMR) is an important trait for the selection of Varroa resistant honey bee colonies. It has repeatedly been assumed that SMR is an effect of varroa sensitive hygiene (VSH) when hygienic bees preferably remove those brood cells where the mite has reproduced. We here compare the VSH behaviour of honey bees toward brood c...

Analysis of plant pollen can provide valuable insights into the existing spectrum of microorganisms in the environment. When harvesting bee-collected pollen as a dietary supplement for human consumption, timely preservation of the freshly collected pollen is fundamental for product quality. Environmental microorganisms contained in freshly collecte...

Honeydew honey belongs to the main honey sorts produced in European countries. Phloem sap feeding insects of the order Hemiptera excrete honeydew and honey bees process it into honey. In the case of high osmolality in the phloem sap, hemipteran species counteract osmotic pressure by producing oligosaccharides such as melezitose. Melezitose is a poo...

The incorrect Associate Editor was listed. The correct Associate Editor is Fuwen Wei. This error has been corrected online.

Background: The black soldier fly (Hermetia illucens) is the most promising insect candidate for nutrient-recycling through bioconversion of organic waste into biomass, thereby improving sustainability of protein supplies for animal feed and facilitating transition to a circular economy. Contrary to conventional livestock, genetic resources of farm...

Background The black soldier fly (Hermetia illucens) is the most promising insect candidate for nutrient-recycling through bioconversion of organic waste into biomass, thereby improving sustainability of protein supplies for animal feed and facilitating transition to a circular economy. Contrary to conventional livestock, genetic resources of farme...

Mitochondria are essential components of eukaryotes as they are involved in several organismic key processes such as energy production, apoptosis and cell growth. Despite their importance for the metabolism and physiology of all eukaryotic organisms, the impact of mitochondrial haplotype variation has only been studied for very few species. In this...

The diversity and local differentiation of honey bees are subjects of broad general interest. In particular, the classification of Ethiopian honey bees has been a subject of debate for decades. Here, we conducted an integrated analysis based on classical morphometrics and a putative nuclear marker (denoted r7-frag) for elevational adaptation to cla...

The objective of this study was to compare 2 laying hen strains in 5 production periods regarding phytase activity, phytate (InsP6) degradation, and myo-inositol (MI) release in the digestive tract and phosphorus (P) and calcium (Ca) utilization. One offspring of 10 nonrelated roosters per strain (Lohmann Brown-classic (LB) or Lohmann LSL-classic (...

The project SETBie honey bee colonies of Apis mellifera with a varroa-sensitive hygiene (VSH) trait were raised. VSH lead to an increased removal of Varroa destructor (Varroa) mite infested brood cells. Thereby leading to mite reduction within the honey bee colony by interruption of the Varroa reproduction cycle. The goal for the project is the red...

Laying hens require less phosphorus (P) but markedly more calcium (Ca) in their diet than broilers. These differences may cause more distinct interactions with phytate degradation and utilization of minerals in laying hens than those in broilers. The objective of the study was to characterize intestinal phytate degradation, ileal transcript copy nu...

Traditional beekeeping has been playing important socio-economic roles in Ethiopia for millennia. The country is situated in northeast Africa, where ranges of major evolutionary lineages of Apis mellifera adjoin. However, studies on the classification and distribution of subspecies and lineages of honey bees in the country are partly inconsistent,...

When selection favours rare alleles over common ones (balancing selection in the form of negative frequency-dependent selection), a locus may maintain a large number of alleles, each at similar frequency. To better understand how allelic richness is generated and maintained at such loci, we assessed 201 sequences of the complementary sex determiner...

Bumblebees are a diverse group of globally important pollinators in natural ecosystems and for agricultural food production. With both eusocial and solitary life-cycle phases, and some social parasite species, they are especially interesting models to understand social evolution, behavior, and ecology. Reports of many species in decline point to pa...

In general, honey bees (Apis mellifera L.) feed on honey produced from collected nectar. In the absence of nectar, during certain times of the year or in monocultural landscapes, honey bees forage on honeydew. Honeydew is excreted by different herbivores of the order Hemiptera that consume phloem sap of plant species. In comparison to nectar, honey...

Due to the combined effects of global warming and eutrophication, the frequency of deleterious cyanobacterial blooms in freshwater ecosystems has increased. In line with this, local adaptation of the aquatic keystone herbivore Daphnia to cyanobacteria has received major attention. Besides microcystins, the most frequent cyanobacterial secondary met...

The Na⁺ - ion translocating NADH:quinone oxidoreductase (NQR) from Vibrio cholerae is a membrane bound respiratory enzyme which harbors flavins and Fe-S clusters as redox centers. The NQR is the main producer of sodium motive force (SMF) and drives energy-dissipating processes such as flagellar rotation, substrate uptake, ATP synthesis and cation-p...

Abstract The health of the honey bee Apis mellifera is challenged by introduced parasites that interact with its inherent pathogens and cause elevated rates of colony losses. To elucidate co‐occurrence, population dynamics, and synergistic interactions of honey bee pathogens, we established an array of diagnostic assays for a high‐throughput qPCR p...

Abstract Modern-day dairy cows express great variation in metabolic capacity to adapt to the onset of lactation. Although breeding programs increased the breeding value for longevity and robustness in the sires, a respective phenotype in female offspring has not been improving as predicted. Fundamental energy generating pathways such as mitochondri...

Social insects have gained many novel morphological and behavioral traits relative to their solitary ancestors. One remarkable behavior of the western honey bee Apis mellifera is the cannibalism of diploid drone larvae at early developmental stages. Quantitative differences of larval cuticular substances are proposed to be recognized by worker bees...

The intestinal microbiota of honey bees consists of only few bacterial species and may have effects on health and pathogen resilience. Honey is usually harvested and replaced by sugar syrup. We hypothesized that replacing honey may change the composition of the intestinal microbiota, and therefore compromise pathogen resilience. Fifteen colonies we...

Eusociality represents a major transition in evolution and is typified by cooperative brood care and reproductive division of labor between generations. In bees, this division of labor allows queens and workers to phenotypically specialize. Worker traits associated with helping are thought to be crucial to the fitness of a eusocial lineage, and rec...

Quantile-quantile plot of a genome-wide association study between SNPs and highland and lowland habitats. SNP p-values associated with the observed (y-axis) and the expected (x-axis) distribution of allele frequency differences between highland bees (n = 20) and lowland bees (n = 19). Blue line indicates the distribution where observed data equals...

Possible locations of unplaced scaffolds with outlier SNPs. (XLSX)

Divergence and substitutions across genes in highland and lowland haplotypes. (XLSX)

PCA clustering of samples using PLINK multidimensional scaling. (A) Clustering based on all SNPs outside of the r7 and r9 regions. (B) Clustering in the r7 region on chromosome 7. Yellow circle indicates samples that are homozygous for the lowland haplotype. Grey circle indicates samples that are homozygous for the highland haplotype. Pink circle i...

FST distribution produced by coalescent simulations of a population split. 1 million simulated SNPs were binned according to 0.01 intervals. Blue area represents SNP FST distribution (y1-axis). Red line is the cumulate proportion of SNPs (y2-axis). Black dots indicate the proportion (p) of SNPs above an FST threshold (p = 0.05 is the top 50,000 SNP...

Worldwide distribution of highland and lowland haplotypes. (A) Haplotypes detected for the 11 samples sequenced by Fuller et al. Color codes and bottom panels as in Fig 4. Sample order as in S1B Table. (B) A global sample of honey bees from [25]. Symbols as in Fig 4. Sample order as in S1C Table. (C) The r9 region for the African samples and subdiv...

Abdominal pigmentation in monticola forest highland bees and scutellata savannah lowland bees. Stars indicate samples with contrasting haplotypes for r7 (blue) or r9 (green) from the common haplotype in either habitat (see Fig 4). Black bars indicate individuals with back/dark pigmentation across all tergites of the abdomen. (TIF)

Allele frequency differences between population pairs. (A) Genome-wide plot of allele frequency differences (FST) of every nuclear SNP segregating between Mount Kenya highland bees (n = 10) and lowland bees (n = 9). Divergent regions r7 (chromosome 7; blue) and r9 (chromosome 9; green). Black line indicates overall FST across 10 kbp non-overlapping...

Distribution of haplotypes as inferred from divergent SNP genotypes (n) across r7i, r7ii and the unplaced scaffolds. (A) Genotype and haplotype distributions on r7i and r7ii at SNPs that diverge between highland and lowland populations. At every genotype, a sample can be homozygous for the reference allele (0/0), homozygous for the non-reference al...

r7 haplotype breakpoints. (A) Tablet visualization of read mapping across the putative breakpoint at the start of the r7 haplotype using. Reads from bees with r7 lowland haplotypes are yellow. Reads from bees with r7 highland haplotypes are grey. Reads from heterozygous samples are pink. Light blue box indicates spuriously mapped region in highland...

Sample locations and sequence information. (XLSX)

Extended filtering and quality control. (A) Proportion of retained sites across the genome or divergent regions r7 and r9 after stringent filtering for mapping depth and sample coverage (see Results section for filters; r7h = r7 highland haplogroup; r7l = r7 lowland haplogroup; r9h = r9 highland haplogroup; r9l = r9 lowland haplogroup). (B) Average...

Studying the fate of duplicated genes provides informative insight into the evolutionary plasticity of biological pathways to which they belong. In the paralogous sex-determining genes complementary sex determiner (csd) and feminizer (fem) of honey bee species (genus Apis), only heterozygous csd initiates female development. Here, the full-length c...

For bees, many roads lead to social harmony Eusociality, where workers sacrifice their reproductive rights to support the colony, has evolved repeatedly and represents the most evolved form of social evolution in insects. Kapheim et al. looked across the genomes of 10 bee species with varying degrees of sociality to determine the underlying genomic...