Projects with Maculinea and related butterflies, and other social parasites David Nash, Centre for Social Evolution, 2012

Life cycle of the Alcon blue butterfly:

larvae

pupa

adults

eggs

adoption

Caterpillars of M. alcon spend the winter and spring inside nests of Myrmica red ants, where they eat the ant brood, and are fed on regurgitated food by the worker ants. From around the beginning of June, some of the larvae pupate (still inside the nest), while others seem to wait for another 12 months before doing so. The pupal stage lasts around a month, after which the adult butterflies emerge from the ant nest (they are covered in very loose scales, which protect them against marauding ants on their way out of the nest, and do not expand their wings until they are out in the open air). The adults live a few days, feeding on flower nectar, and mate. The females lay their eggs on the unopened flower buds of the marsh gentian Gentiana pneumonanthe (klokkensian), and the first instar caterpillars hatch through the base of the eggs directly into the developing flowers, where they eat the ovaries. After about 2 weeks, and having gone though three moults, the fourth instar larva emerges from the flower bud and lets itself down to the ground on a silken thread. Here it waits to be discovered by a Myrmica ant, which will pick it up and take it back to the ant nest, where it will complete its development.

Fieldwork:

Lyngholt

Læsø

Nordmarkshus

Distribution

Most of our fieldwork is carried out on Læsø, where there are two field stations, Lygholt and Nordmarkshus conveniently situated quite close to the two major populations of M. alcon on the island. There are also several populations of M. alcon on Jutland, mostly on the west coast. In addition, there are populations of M. alcon in Skåne, just beyond Malmö and near to Göteborg. M. arion is only found on Møn in Denmark, but there are also some populations in central and western Skåne and on Öland and Gottland, as well as in other Baltic countries (Finland, Estonia)

Potential projects 2012

Our main research focuses on questions of the evolution of parasitism in Maculinea butterflies and their coevolution with their ant hosts, including the evolution of host specificity. All of these fields are highly relevant for conservation of Maculinea butterflies.

In 2012 we will carry out quite a bit of fieldwork, including carrying out our annual surveys of the butterfly populations on Læsø during the flight period and while eggs are visible on the food plants. Volunteers are welcome for such work. In addition there are several projects that we hope to carry out this year or in the near future which could form the basis of Bachelor or Speciale projects. While we have listed some potential projects and questions that we are interested in answering below, these are only for guidance, as we prefer to develop tailor-made projects for each student to combine his or her interests with what is feasible. This means that there will almost certainly be other projects available which will develop during the year. Please contact us and arrange to come and talk about particular project ideas.

If you are interested, please contact David Nash (DRNash@bio.ku.dk)

Conservation projects suitable for groups of students

Please see the attached PDF file for a summary (in Danish) of several possible projects (some of which are also summarized below).

Projects with Maculinea alcon butterflies on Aage V. Jensen's fond reserves

The alcon blue butterfly (Maculinea alcon) has a complex life cycle where it depends on a specific host plant, the marsh gentian (Gentiana pneumonanthe) for its early development, and then spends most of its life inside nests of red ants (Myrmica sp.). The alcon blue has declined considerably in Denmark over the last century, mostly due to habitat changes that affect its host plants and ants, and it is now listed as vulnerable on the Danish red list. Three Aage V. Jensen’s fund reserves used to support populations of the Alcon blue – Lille Vildmøse, Filsø and Råbjerg møse, but it disappeared from Lille Vildmøse in the 1950s, and its status on the other reserves is unknown. Several possible projects are available to:

1. Assess the current distribution and status of the alcon blue, its food plant and possible host ants on these reserves.
2. Compare populations of the alcon blue on these reserves with well-known populations on Læsø and in other parts of Jutland in terms of population genetics and host ant specificity.
3. Compare populations of Myrmica ants on the reserves with those elsewhere in terms of social structure and population genetics.
4. To assess changes in the host plant and ant populations, and their likely effect on possible reintroduction of the alcon blue as a result of reestablishment of wetlands in Lille Vildmøse and Filsø.

Time period for field work: Between May and September.

Monitoring of Maculinea alcon on Østerild plantage

As part of the experimental wind farm that is being set up in Østerild plantage in North-West jutland, some wetland areas are being restored where conifer plantations are currently found. A population of Maculinea alcon is already found on the site, and some basic monitoring was carried out in 2011, but we still need more information about this population - for example, which host ants is it using, how large is it, how genetically diverse is the population? We plan to follow the development of this population over the next decades as habitat is restored.

We may also coordinate the monitoing and identification of ants and other hymenoptera from the site, and there are lab-based project available to examine hymenopteran biodiversity.

This project is in conjunction with Dr. Toke Høye from the Danish Centre for Environment and Energy, Aarhus University - see also this link

Time period for field work: Between May and September. Lab work can be carried out at any time of year.

Monitoring of Maculinea alcon in the Thy National Park

One of the newly established Danish national parks in Thy, North-West Jutland, contains several recorded populations of Maculinea alcon. However, littl is known about these particular populations. We plan to collaborate with the park wardens to estabish monitoring schemes and to answer some basic questions about these populations (e.g. how large are they, do they function as a metapopulation, or are they to isolated from each other to exchange genes, which host ant species do they use.

Time period for field work: Between May and September.

The biodiversity of obligate myrmecophiles (projects in collaboration with Aage V. Jensen's fonmd reserves)

Larger colonies of many ant species have beetles, fly-larvae and spiders living in obligate symbiosis in the ant nests. Most of these are rare and little studied, so their distribution patterns in Denmark are very poorly known. We also normally do not know whether they are parasites, commensals or even mutualists. As we know from other insects that are obligatorily associated with ants (e.g. Maculinea butterflies), ant myrmecophiles tend to have very interesting forms of chemical mimicry or chemical ‘invisibility’ to avoid being recognized by the ants. Projects of this kind are suitable for BSc projects involving several students, and such projects could then be a starting platform for MSc work on cuticular hydrocarbon chemistry. Depending on the taxonomic groups, co-supervision by entomology curators at the Zoological Museum will be possible.

Can Myrmica ants detect the surface hydrocarbons of Maculinea alcon caterpillars?

In 2006, we used electroantennongraphy to show that Myrmica rubra antennae could detect extracts from the surface cuticle of Myrmica rubra larvae. We hope to expand this study to examine the detection of the surface hydrocarbon of Maculinea alcon, which are thought to mimic those of Myrmica larvae. Unfortunately our GC-MS lab is still not up-and-running yet following building work during 2011, but we hope that it will be available again in mod 2012.

Time period for lab work: Mid August - early September.

Effect of dispersal abilities on the population dynamics of Maculinea butterflies

This project would involve the development and running of mathematical models of the Maculinea life cycle with varying levels of dispersal, to examine the effect of dispersal distance on population stability. The starting point for this model would be models of Maculinea/Myrmica popualtion dynamics that have been previously developed, so it would not involve starting completely from scratch.

This is a computer based project that can be carried out at any time of year.

Effect of the life history of Maculinea butterflies on their population and conservation genetics

This project would involve the development and running of mathematical models of the Maculinea life cycle with explicit genetic structure, to examine the effect of potential bottlenecks caused by the unusual life history of Maculinea buttrflies on genetic diversity and genetic drift.

This is a computer based project that can be carried out at any time of year.

Genetics of Maculinea species (several projects)

We have major on-going projects involving the genetics of Maculinea alcon and Maculinea arion in Denmark and Sweden. These are based on an extensive set of microstellite markers developed over the last few years. There will almost certainly be small projects available related to this, for example, based around extracting DNA from egg-shells, to avoid harming the existing populations, and using genetic fingerprinting to examine the behavioural ecology of Maculinea alcon.

Particuar questions we would like to answer are:

• When we find several Maculinea caterpillars in one host nest, are they likely to be related? (using DNA fingerprinting)
• When we find several Maculinea eggs on one host plant, are they likely to be related? (using DNA fingerprinting)
• How is diversity at neutral genetic markers associated with diversity of cuticular hydrocarbons of Maculinea caterpillars?
• Are there any clear signs of inbreeding depression in Maculinea populations?
• How is dispersal ability of individuals and populations related to their gentype at neutral genetic markers?

These projects could involve both fieldwork and labwork based on previously collected samples

Why are some Myrmica ant colonies more susceptible to Maculinea social parasitism than others?

The goal of this project is to find out whether within colony relatedness of Myrmica ants affects adoption time of caterpillars of Maculinea alcon. It involves collection of ant colonies and Maculinea caterpillars on Læsø and adoption experiments and lab work at CSE.

Time period for field and lab work: August – September

Projects on Myrmica rubra microgynes

Eusocial insects like ants are characterized by having castes specialized on reproduction (queens) and a sterile caste (workers) in the same colonies. In a few ant species with multiple queens per nest so called microgynes occur. These look similar than normal queens but they are smaller. Microgynes are interesting study organisms because they are considered as potential precursors for the evolution of socially parasitic ants.  They sometimes invest more or only into reproductive offspring in contrast to their hosts (normal queens) which they exploit to produce the sterile workers. Examples of such pre-parasitic lineages are found in the ant Myrmica rubra. These are lineages because they show genetic differentiation from their host on a local but not on a sufficiently large geographic scale and therefore still belong to the species M. rubra.

Project 1: Measuring the fitness impact of microgynes on their host M. rubra
Genetic studies indicate that M. rubra microgynes are social parasites of M. rubra. Still unknown are the degree of virulence and how microgynes affect their host colonies. We managed to establish a relatively large amount of standardized experimental nests of M. rubra with and without microgynes under laboratory conditions. The goal of this project is to compare fitness of infected and non-infected nests. It is a laboratory based long term experiment with live ants and includes statistical analyses.

Project 2: Exploring the role of social colony structure for susceptibility of M. rubra nests for microgyne social parasitism
Queen number and social colony structure is highly variable in M. rubra. Some nests have only a single queen and therefore high relatedness of the worker ants. Other colonies consist of many queens and show very low relatedness of workers. Social parasites like for example larvae of the blue butterfly Maculinea alcon are often found in M. rubra nest with relatively low within colony relatedness, perhaps due to reduced kin recognition abilities of these colonies. The goal of this project is to shed light on the role of social colony structure on the susceptibility of M. rubra to microgynous social parasites. It includes microsatellite laboratory work and computational analysis of the data.