Biology subjects

Weinhold, A.

Publications and source records attributed to Weinhold, A..

5 recordsLinked to original sources

bioRxiv2026

Climatic stress reshapes sex-specific multimodal floral phenotypes and interactions with a nursery pollinator across life stages

Background: Nursery pollination combines mutualistic and antagonistic interactions between plants and insects: adult insects provide pollination services, while their larvae consume plant reproductive tissues. Climatic stress may alter the benefits and costs for both partners by modifying plant phenotypes and their consequences for pollinator behaviour and offspring performance. These dynamics gain an additional layer of complexity in systems where both plants and insects have separate sexes, giving rise to sex-specific interactions and potentially divergent stress responses. Yet how climatic stress affects these specialized interactions remains unexplored. Methods: We addressed this gap in a nursery pollination system comprising the dioecious plant Silene latifolia and the moth Hadena bicruris. We exposed female and male plants from five populations to water limitation, assessing visual floral traits, scent, nectar chemistry and moth behaviour alongside seed production, seed chemistry, larval consumption and performance. Results: We identified previously unexplored chemical trait spaces potentially mediating mutualistic and antagonistic components of the interaction, encompassing nectar rewards and larval seed resources. Water limitation altered floral and seed phenotypes, with pronounced reductions in nectar metabolites in male plants eroding sexual dimorphism in nectar chemistry. This was accompanied by a loss of moth preference for ovipositing on female flowers, while oviposition declined overall under water limitation and feeding behaviour remained unaffected. Meanwhile, water limitation reduced several defence-associated seed metabolites, and larvae grew faster on seeds from water-limited plants despite consuming similar amounts of seeds. Synthesis: Against the broader backdrop of specialist species loss and shifts towards more generalized interaction networks under global change, our study provides the first comprehensive assessment of climatic stress effects on a nursery pollination system. By revealing opposing effects on adult oviposition and offspring performance, our findings highlight how climatic stress may redistribute benefits and costs within specialized species interactions through changes in multidimensional plant phenotypes and interconnected mutualistic and antagonistic processes.

ecology↗

bioRxiv2026

Host-specific and common core microbiota in adult butterflies across continents

1 Abstract The assembly of host-specific microbiota is critical for health and functioning of many insect pollinators. While social pollinators maintain core microbiota through social transmission, the factors driving microbiota assembly in solitary pollinators remain poorly understood. Lepidoptera are an important group of pollinators, but microbiome research has largely focused on their larval stage, while nectar-feeding adults have been widely ignored. Field-based studies of the adult butterfly microbiota are rare and geographically and taxonomically restricted. Here, we characterize the microbiota of adult butterflies from natural environments along elevational and seasonal gradients across two continents spanning the Neotropical and Palearctic realms. Microbiota diversity and composition were primarily explained by host taxonomic identity, whereas geographic location and temperature had little effect. We found high microbial titers and a common core microbiota across seven butterfly subfamilies from temperate and tropical regions. A comparison with sympatric wild bees revealed partial taxonomic overlap but marked distinctions in lactic acid bacteria between Lepidoptera and Hymenoptera. Together, our results demonstrate that host taxonomic identity, rather than environmental drivers, is the dominant force structuring the microbiota of adult butterflies. This highlights that the host-filtering capacity of solitary species has been largely underestimated, challenging previous assumptions that the microbiota of this important pollinator group is primarily environmentally driven and of limited functional significance.

ecology↗

bioRxiv2023

Bumble bee microbiota shows temporal succession and increase of lactic acid bacteria when exposed to outdoor environments

QuestionThe large earth bumble bee (Bombus terrestris) maintains a social core gut-microbiota, similar as known from the honey bee, which plays an important role for host health and resistance. Experiments under laboratory conditions with commercial hives are limited to these vertically transmitted microbes and neglect variability by environmental influences and external acquisition of microbes. Various environmental and landscape-level factors may have an impact on the gut-microbiota of pollinating insects, with consequences for pollinator health and fitness in agroecosystems. Still, it is not fully clear whether access to a higher vs lower flower diversity will have a significant influence on the bumble bee microbiota. Here, we tested in a semi-field experiment how strongly the bumble bee microbiota changes over time when exposed to different flower diversities within outdoor flight cages. We used commercial hives to distinguish between vertically and horizontally transmitted bacteria, respectively from the nest environment or the exposed outside environment. ResultThe sequential sampling of foraging workers over a period of 35 days indicated a temporal progression of the bumble bee microbiota when exposed to outside conditions. The microbiota became not only more diverse, but changed in composition and variability over time. We observed a major increase in relative abundance of the families Lactobacillaceae, Bifidobacteriaceae and Weeksellaceae. In contrast, major core taxa like Snodgrassella and Gilliamella declined in their relative abundance over time. The genus Lactobacillus showed a high diversity and strain specific turnover, so that only specific ASVs showed an increase over time, while others had a more erratic occurrence pattern. Exposure to different flower diversities had no significant influence on the bumble bee microbiota. ConclusionThe bumble bee microbiota showed a dynamic temporal progression with distinct compositional changes and diversification over time. The exposure of bumble bees to environmental conditions, or environmental microbes, increases dissimilarity and changes the gut-community composition compared to laboratory rearing conditions. This shows the importance of environmental influences on the temporal dynamic and progression of the bumble bee microbiota. Scope statementBumble bees (Bombus terrestris) are, next to the honey bee, commercially important pollinators and widely used to enhance crop pollination service within greenhouse environments. They host a similar, but characteristic, set of core-microbiota which are of known importance for bumble bee health. Despite this, bumble bees harbor their own specific set of symbionts, which do not occur within the honey bee and seem to be more easily influenced by colonization of environmental microbes. While experiments under controlled lab-based rearing conditions often lack the influence of environmental or landscape-level drivers, field-based observation can often not resolve the influence of a single factor. One major unresolved question is which environmental factor influences the microbiota of social pollinators by environmental microbes. Especially whether monocultures (low flower diversity) are per se rather detrimental to microbiota composition compared to more balanced and diverse pollen provisions (high flower diversity). Within this article, we investigated the influence of different flower diversities as potential drivers of the bumble bee gut-microbiota under semi-field conditions. We used outdoor cages which contained a flower diversity gradient to specifically test how a low and high diversity of flower resources could influence the bumble bee microbiota over time.

microbiology↗

bioRxiv2020

Plot diversity differentially affects the chemical composition of leaves, roots and root exudates in four subtropical tree species

O_LIPlants produce thousands of compounds, collectively called the metabolome, which mediate interactions with other organisms. The metabolome of an individual plant may change according to the number and nature of these interactions. We tested the hypothesis that tree diversity level affects the metabolome of four subtropical tree species in a biodiversity ecosystem-functioning experiment, BEF-China. We postulated that the chemical diversity of leaves, roots and root exudates increases with tree diversity. We expected the strength of this diversity effect to differ among leaf, root and root exudates samples. Considering their role in plant competition, we expected to find the strongest effects in root exudates. C_LIO_LIIn an ecometabolomics approach, roots, root exudates and leaves of four tree species (Cinnamomum camphora, Cyclobalanopsis glauca, Daphniphyllum oldhamii, Schima superba) were sampled from selected plots in BEF-China. Samples were extracted and analysed using Liquid Chromatography-Time of Flight-Mass Spectrometry. The exudate metabolomes were normalized over their non-purgeable organic carbon level. Multivariate analyses were applied to identify the effect of both neighbouring (local) trees and plot diversity on tree metabolomes. The species and sample specific metabolites were assigned to major compound classes using the ClassyFire tool, whereas m/z features related to diversity effects were annotated manually. C_LIO_LIIndividual tree species showed distinct leaf, root and root exudate metabolomes. The main compound class in leaves were the flavonoids, whereas carboxylic acids, prenol lipids and specific alkaloids were most prominent in root exudates and roots. Overall plot diversity had a stronger effect on metabolome profiles than the diversity of local, directly neighbouring trees. Leaf metabolomes responded more often to tree diversity level than exudates, whereas root metabolomes varied the least. We found not overall correlation between metabolite richness or diversity and tree diversity. C_LIO_LISynthesis: Classification of metabolites supported initial ecological interpretation of differences among species and organs. Particularly the metabolomes of leaves and root exudates respond to differences in tree diversity. These responses were neither linear nor uniform and individual metabolites showed different dynamics. More controlled interaction experiments are needed to dissect the causes and consequences of the observed shifts in plant metabolomes. C_LI

ecology↗

bioRxiv2020

The rhizosphere metabolome triggers species-specific and context-dependent root responses in later arriving plants

Soil legacies play an important role for the creation of priority effects. However, we still poorly understand to what extent the metabolome found in the soil solution of a plant community is conditioned by its species composition and whether soil chemical legacies affect subsequent species during assembly. To test these hypotheses, we collected soil solutions from forb or grass communities and evaluated how the metabolome of these soil solutions affected the growth, biomass allocation, and functional traits of a forb (Dianthus deltoides) and a grass species (Festuca rubra). Results showed that the metabolomes found in the soil solutions of forb and grass communities differed in composition and chemical diversity. While soil chemical legacies did not have any effect on F. rubra, root foraging by D. deltoides decreased when plants received the soil solution from a grass or a forb community. Structural equation modelling showed that reduced soil exploration by D. deltoides arose via either a root growth-dependent pathway (forb metabolome) or a root trait-dependent pathway (grass metabolome). Reduced root foraging was not connected to a decrease in total N uptake. Our findings reveal that soil chemical legacies can create belowground priority effects by affecting root foraging in later arriving plants.

ecology↗