Group Menzel

Chemical Ecology and Biotic Interactions

Keywords: chemical ecology, evolution of cuticular hydrocarbon profiles, antipredator behaviour, interspecific interactions, ecosystem functions of ants, ant community ecology, division of labor, tropical rainforest, ants, spiders, aphids.

RESEARCH INTERESTS

Our group is interested in interspecific interactions between different ant species and between ants and other arthropods. Interactions between ant species can be competitive and aggressive, but also mutualistic, commensalistic or parasitic. We study these interactions from two perspectives: from a top-down perspective, we study community organization and ecosystem functions in ant communities in tropical rainforests. In this context we are also interested in biodiversity and ecosystem functions of ants and other arthropods in conventional agriculture and dynamic agroforestry.

From a bottom-up perspective, we investigate the mechanisms in specific interactions between few species. We study behavioural interactions and chemical cues that are involved in ant-ant and ant-aphid interactions, as well as predator-prey interactions between other arthropods.

These interactions are often driven by chemical cues – cues from the insects’ body surface (cuticular hydrocarbons) or indirect cues, such as chemical footprints. We recently showed that ants respond to chemical footprints of other colonies and species, which may have great effects on their foraging behaviour. In general, the most important intra- and interspecific communication signal in ants and other insects are cuticular hydrocarbons (CHC). Therefore, we do not only investigate their role in interactions, but also study the proximate and ultimate factors that shape their composition. CHC experience selection from multiple sides, since beside their communication function they also act as waterproofing agent. In our group, we study how CHC profiles evolve and diversify in response to selection pressures arising from their multiple functions. Furthermore, we study how individual ants can adjust their profiles in response to different climatic conditions. To understand the molecular basis of CHC biosynthesis and evolution, we analyse gene expression in ants from different climatic conditions and in closely related, but chemically different ants.

Current research questions include:

  • Climatic impacts on the CHC profile of ants, and their consequences for drought resistance, nestmate recognition and CHC material properties
  • Behavioural responses to chemical footprints in ants
  • Evolution and phylogenetic signal of cuticular hydrocarbon profiles in ants
  • CHC diversification in mutualistic ant-ant associations (parabioses) in tropical South America
  • Ecosystem functions and community structure in ants of tropical rainforests in South America and Southeast Asia.
  • Relations between ecological niches and body morphology in tropical and temperate ants
  • Antipredator behaviour and non-consumptive effects of spider predators on arthropod prey: behavioural interactions, chemical cues, and ecological consequences
  • The impact of agricultural regimes on biodiversity and ecosystem functions

Topics for research practicals, bachelor, diploma or master theses include:

  • How do ants respond to chemical footprints?
  • Can ants learn to respond to certain footprints?
  • How does individual personality influence ant behaviour?
  • Is there a left-right bias in ant behaviour?
  • How does gene expression change when an ant acclimates to different temperatures?
  • Mutualism or not? Costs and benefits in ant-aphid symbioses
  • What do ants eat? Dietary niche partitioning within and across ant species
  • Chemical diversification in ant species of tropical South America
  • How is chemical variation linked to nestmate recognition?
  • How do ants change their chemical profiles in response to a different climate?
  • How are chemical profiles and drought tolerance related across arthropod taxa?
  • How is CHC composition linked to the waterproofing ability of the CHC layer?
  • How is the chemical CHC composition linked to its physical properties?
  • How do CHCs influence the resistance of ants against pathogens?
  • How do biodiversity and ecosystem functions differ between conventional agriculture and dynamic agroforestry?

 Methods used:

  • Field experiments
  • Behavioural experiments in the lab
  • Chemical analyses of cuticular hydrocarbons and fatty acids using GC-MS
  • Microrheological measurements of viscosity (in collaboration with Bérengère Abou, Paris)
  • Transcriptome analyses (RNAseq)
  • Population genetics
  • microbial assays
  • Agent-based modelling

 

GROUP MEMBERS

The 'ant crew' during our field season in French Guiana, October 2018

Group leader

Post-doctorals

PhD students:

  • Vanessa Menges: The role of chemical footprints for foraging and competitive interactions in ants.
  • Lucas Jäger: The impact of cuticular chemistry and surface morphology of arthropods on adhesion forces in cribellate and ecribellate spider threads (co-supervisor Anna-Christin Joel)

Master students:

  • Ronja Krüsemer (Insect cuticular hydrocarbons as barriers against fungal infection)

Bachelor students:

  • Sophie Späth (Inter-colony variation in behavioural traits in the ant Lasius niger)
  • Theresa Immke (Comparison of cuticular hydrocarbons and the efficiency of their waterproofing in different Central European ants)
  • Leonie Polonyi (Associative learning of chemical footprints in the ant species Lasius niger)
  • Merle Rohovsky
  • Raul Rojas Feilke
  • Dominik Heidt

Former PhD students: