Biology subjects

Gabel, M.

Publications and source records attributed to Gabel, M..

4 recordsLinked to original sources

bioRxiv2026

Conserved task-specific profiles outweigh seasonal shifts in cuticular hydrocarbons of European honey bee subspecies

Cuticular hydrocarbons (CHCs) are essential for insect waterproofing, yet how they change seasonally in social insects remains poorly understood. Due to its distinct seasonal worker phenotypes (summer and winter bees) and diverse subspecies, the western honey bee (Apis mellifera) is an ideal model to study seasonal CHC plasticity across populations with distinct local adaptations. We performed a common garden experiment to investigate the seasonal plasticity in CHC profiles across five European subspecies (A. m. carnica, A. m. iberiensis, A. m. ligustica, A. m. macedonica, A. m. ruttneri). We compared the CHC composition of workers performing tasks inside ("in-hive") or outside ("out-hive") the colony during summer and winter. Notably, out-hive workers consistently exhibited more waterproofing CHC profiles compared to in-hive workers, regardless of season or subspecies. The persistence of this stereotypical task-related differentiation in long-lived winter bees, which largely lack an age-based division of labor, indicates a robust, age-independent regulatory mechanism linked to the environment faced by the workers rather than a simple response to seasonal desiccation pressure. Moreover, we demonstrate CHC seasonal plasticity for the first time in honey bees. However, these seasonal shifts in hydrocarbon classes and chain length were not uniform; they varied across subspecies and critically depended on the task the workers performed.

ecology↗

bioRxiv2026

A fast and easy mass sampling method for social bee crop content

Honey bees (Apis mellifera) are capable of foraging over large distances around their nest and can thus serve as ideal bioindicators for various research questions. While foraging for nectar, they collect a variety of pollutants such as environmental toxins and agrochemicals, which can be traced in their digestive tract. Likewise, naturally occurring compounds in a bees crop content (e.g., different sugars and pollen grains) can be analyzed to assess the foraging preferences of bees or to study the species composition of flowering plants in the respective environment. Regardless of the research question, a precise, reproducible, and efficient method for examining pollinators crop contents is needed to fully exploit the honey bees potential as a bioindicator. Existing methods are often insufficiently precise with respect to the recovered volume and content, too time-consuming or lack the opportunity to store samples flexibly. Consequently, they do not meet the requirements of large-scale sampling commonly needed in scientific field work. We present a novel, rapid and scalable method for fast and easy mass sampling of honey bee crop contents which holds potential for adaptation to other pollinator taxa such as bumblebees. With this method individuals can be collected in the field and stored prior to sample processing. Crop contents can be obtained later on by centrifuging the entire individual, thereby decoupling sample collection from further analysis. Afterwards, insect samples and extracted fluids can be stored again, enabling subsequent analysis in an efficient and time-saving manner. We demonstrate that crop contents of previously fed animals can be obtained precisely in terms of both volume and composition and present an example of application in honey bee foraging ecology as a proof of concept.

ecology↗

bioRxiv2024

Deciphering the variation in cuticular hydrocarbon profiles of five European honey bee subspecies

The Western honey bee (Apis mellifera) subspecies exhibit local adaptive traits that evolved in response to the different environments that characterize their native distribution ranges. An important trait is the cuticular hydrocarbon (CHC) profile, which helps preventing desiccation and mediating communication. We compared the CHC profiles of six European subspecies (A. m. mellifera, A. m. carnica, A. m. ligustica, A. m. macedonica, A. m. iberiensis, and A. m. ruttneri) and investigated potential factors shaping their composition. We did not find evidence of adaptation of the CHC profiles of the subspecies to the climatic conditions in their distribution range. Subspecies-specific differences in CHC composition might be explained by phylogenetic constraints or genetic drift. The CHC profiles of foragers were more subspecies-specific than those of nurse bees, while the latter showed more variation in their CHC profiles, likely due to the lower desiccation stress exerted by the controlled environment inside the hive. The strongest profile differences appeared between nurse bees and foragers among all subspecies, suggesting an adaptation to social task and a role in communication. Foragers also showed an increase in the relative amount of alkanes in their profiles compared to nurses, indicating adaptation to climatic conditions.

evolutionary biology↗

bioRxiv2021

Constant rate of Plasmodium falciparum sexual commitment promotes variable gametocyte proportions as infection progresses over time

Plasmodium falciparum infections persist through long dry seasons at low parasitaemia without causing malaria symptoms and thus remain untreated. In asymptomatic children, increased circulation of infected erythrocytes without adhering to the vascular endothelium is observed during the dry months, compared to febrile malaria in the wet season. However, alterations of parasite sexual commitment and gametocytogenesis have not been investigated. Here, we compared the expression of genes related to sexual commitment and gametocytogenesis, the proportion and density of P. falciparum gametocytes, and the blood concentration of phospholipids in dry season asymptomatic individuals versus symptomatic subjects in the wet season. Additionally, we adapted a within-host mathematical model considering asexual and sexually-committed parasites and gametocytes to understand the dynamics of gametocyte number and proportion as infections progress. Compared to clinical malaria cases, transcripts of late-stage gametocytes were predominantly upregulated in the dry season, associating with increased proportions of mature gametocytes; while transcription of genes related to parasite sexual commitment was unaltered throughout the year. Our data suggest that gametocyte density and proportion diverge as infections progress from recent transmission to chronic carriage, without alterations in the sexual commitment rate over time.

microbiology↗