Sienenviljelijätermiittien ravintostrategiat, ekosysteemivuorovaikutukset ja vanhojen termiittikekojen paleoekologinen potentiaali

Mound-building, fungus-growing termites of the genus Macrotermes play pivotal roles in African dry savannas. They improve soil
conditions, enhance biome productivity and diversity, and are major agents of litter decomposition and nutrient recycling. Despite these
essential contributions, many aspects of their functioning are not understood. The live in generally protein-limited and highly seasonal
environments causing significant fluctuation in diet quality. How exactly do Macrotermes colonies succeed to maintain a sufficient
supply of nutrients for homeostasis and reproduction? What kind of foraging strategies do they employ in different savanna types? How
are nutrients sourced, transmitted and partitioned within their nests involving e.g. large fungus gardens and a complex social hierarchy
and functional specialization? Generally, what are the key elements of their success in these harsh environments? This project aims to
understand the subsistence strategies of Macrotermes colonies including dietary inputs, the within-nest symbiotic/social food
processing, nutrient stoichiometry and balancing mechanisms, emitted/assimilated outputs, and their seasonal variability. We
particularly focus on nitrogen provisioning, exploring the hypothesized use of N2 fixation in fungus-growing termites. We employ
extensive field studies and laboratory experiments, natural abundance and labeling isotope studies, ‘bulk’ and amino acid stable isotope
methods and C/N content analysis, as well as traditional gut content analysis to track nutrient flows within the plant-fungus-termite food
web, define caste-specific diets and examine gut microbe contributions. We quantify nest internal levels and emitted fluxes of metabolic
gases, characterize them isotopically to understand their roles in colony C/N mass balance, and provide more accurate, field based
estimates of the significance of termite mounds as greenhouse gas sources. Finally, we aim to validate the biomolecular signals in
ancient termite hills, ubiquitous in dryland environments globally, as a novel source of paleoecological information on past vegetation
by combining stable isotope and dating approaches. Learning their past occurrence densities and associated vegetation history will lead
to a better grasp of the macroecological conditions conducive for their success. With a synthesis of the present-day subsistence
strategies and the insights gained from their past, we aim to elucidate how they will fare in the future.