PhD Project - Arthur Hais

Title of the Project: Assessment of the indirect impacts of human activities on ant’s social communication through the modification of their microbiota

Name: Arthur

Surname: Hais

Tutor (surname): Barbero (dr. Luca Pietro Casacci, dr. Irene Stefanini, Prof. David Badía Villas)

Ants are ecosystem engineers and bioindicators that can be directly or indirectly impacted by human activities in agricultural landscapes. Their successful social organisation relies on several communication cues that enable the colony's proper functioning and the ability to discriminate between nestmates and strangers. The ant recognition system is based on mixtures of Cuticular HydroCarbons (CHCs) which form a chemical signature peculiar to each colony. Multiple factors influence the chemical profiles (e.g. climatic conditions), and I hypothesise that the variation of CHCs could also be an outcome of the association between ants and their microbiota.

My PhD project aims to understand the ant-microorganism relationship and how biotic and abiotic factors in agricultural environments could affect this association.

Specifically, I will assess:

- the role of microbiota on ant social behaviour and recognition abilities;

- how human activities alter the soil characteristics in agricultural environments.

I will then evaluate if human activities influence the ant behaviour directly by altering the soil characteristic or indirectly by modulating the microbial community associated with ants.

Ant nests and soil will be sampled in vineyards with different management (organic/ traditional) and in natural areas. A multidisciplinary approach, combining pedology, edaphology, metabarcoding, metagenomics, ethological assays and gas chromatography techniques, will be used to tackle my research questions.

The artificial modification of the ant microbiota and the following analysis of their CHC profiles will shed light on the potential contribution of microorganisms in developing the colony odour. If the microbiota plays a role in a fundamental mechanism fostering the colony structure, microorganisms should be regarded as a further pressure shaping the evolution of insect eusociality. The knowledge of how human activities, through the modification of the environment, could affect the biology of an essential component of the ecosystem is crucial to suggesting sustainable exploitation of our agricultural ecosystems.