Honeybee colony health
Honeybees (Apis mellifera) not only supply humanity with delicious honey but also deliver substantial pollination services in agricultural settings and natural ecosystems worldwide.
Around ~75 % of all crops need pollination by insects and the honey bee is the most important provider of this ecosystem service.
Due to a variety of natural and human made causes these insects are threatened.
Besides indirect stressors, like loss of foraging resources, individual bees and whole colonies are exposed to pesticides and several viral (e.g. Deformed wing virus), fungal (e.g. Nosema spp.), bacterial (e.g. Paenibacillus larvae causing American foulbrood), and mite (e.g. Varroa destructor) parasites.
With my colleagues Barbara Locke Grandér, Joachim de Miranda and Srinivas Thaduri I am investigating virus infections and Varroa mite-surviving honeybee populations. With my colleague Eva Forsgren and Sepideh Lamei I am studying the epidemiology of American foulbrood and Lactic acid bacterial symbionts.
Within all projects we aim to contribute to the understanding of the complex epidemiological, ecological and evolutionary processes among pathogens, their vectors and the honey bee colonies as superorganism. We therefore try to understand and predict the risk of honeybee colony disease and mortality in relation to alternative treatment and management options.
The blue willow leaf beetle lives in groups as adult and larvae and can be described as a communal species, which is the least complex form of sociality (e.g. ants/bees are eusocial which is the most complex form with overlapping generations, giving up sex of all individuals, and brood care).
This beetle is considered as the major insect pest within willow short rotation coppices that are grown as a second generation bio-fuel production system (`second generation´ because it’s not a food plant).
In this system I am interested in factors modulating aggregation, like food availability, the interaction with other beetle individuals, and the effect of predatory bugs on the beetle behaviour.
I have approached these questions mainly with controlled experiments in the lab that result in rather theoretical reflections on grouping of individuals.
Interactions among plants, insect herbivores, and pathogens can affect insect and plant pathogen dynamics and plant performance.
In this project I try to elucidate the spatial and temporal dynamics of the main herbivore (blue willow leaf beetle Phratora vulgatissima) and the main pathogen (leaf rust fungus Melampsora spp.) within willow short rotation plantations. Currently I am investigating the co-occurrence of both and the potential yield loss in a plantations. In the future I aim to investigate the changes in the insect community due to changes the plants undergo due to the attack by these species. The project aims to bridge the gap between controlled lab studies, which frequently showed that one species affects another via changes in the shared plant, and large-scale field patterns. The understanding gained in this project will enable predictions about insect and fungus outbreaks, possibly leading the better plant protections strategies.
As an accompanying project I am scoring leaf rust, beetle herbivory, and leaf gall infestation on natural willow plants in Europe where ever I go and hope to have a really nice data set after some years. I am a big fan of synergies and here I am merging my personal travels with reaching field sites in an eco-friendly manner.
About the Birds and the Bees
This project was triggered by my observation that honeybee colonies are visited frequently by birds that feed on the dead bees on the ground in the vicinity of honeybee colonies.
Especially at the beginning of the year dead bees are removed by younger workers (undertaker behavior). During the season the majority of old bees just do not return from their flight (self-removal behavior). This means there is a continuously “production” of dead bees that offer a rich source of many amino acids, are easy to excess, and are sparsely, but regularly distributed over many landscapes.
To quantify the anecdotally description of this behaviour I am currently using camera traps and event locking software. Questions I aim to address include the potential modulators of such behaviour (e.g. rural vs urban landscape) and the potential large scale ecosystem effect of human beekeeping on birds.