Foitzik/Baumann/Barau

Scientific Background:
Many parasites, especially those with complex life cycles, manipulate life history traits and behaviour of their hosts to increase transmission. Alterations in host gene expression are often linked to these parasite-induced phenotypic changes - termed the parasites’ extended phenotype by Dawkins. We hypothesise that parasites manipulate host phenotypes by interfering with host gene regulation and test whether and how they do this on a molecular level. In particular, we want to elucidate which gene regulatory processes they interfere with. Infection of Temnothorax nylanderi ant larvae with the parasitic cestode Anomotaenia brevis strongly transforms the adult phenotype of these ants. Infected workers exhibit altered behaviour, morphology, chemical profile and an extreme lifespan extension (Beros et al. 2015, Beros et al. 2021). In a three-year study, the survival rates of infected workers matched those of queens, which can reach 20 years in this species (Beros et al. 2021). We could show associated changes in gene expression e.g. the upregulation of immunity and longevity genes (Feldmeyer et al. 2016, Stoldt et al. 2021), such as the silver gene carboxypeptidase Blike, linked to postponed senescence in D. melanogaster. Recent results show that infection intensity strongly affects fat body transcriptomes, with genes with telomerase maintenance, apoptosis and transposon activity functionalities being differentially expressed between highly infected ants (over 18 cestodes) and lowly infected (1 cestode) or uninfected ants. The cestode, residing in its cysticercoid stage in the haemolymph of the ants’ abdomen is transcriptionally active (Stoldt et al. 2021). In collaboration with Falk Butter, we compared the proteomes of the haemolymph of healthy workers + queens and infected workers and contrasted them with that of the cestode (N = 22 pooled samples from 8 colonies). The majority of proteins only found in infected workers originated from the cestode. Bioinformatic analyses reveal that the cestode is releasing proteins affecting lifespan (antioxidants e.g. superoxide dismutases or thioredoxin) and gene regulatory processes including histone acetylation and the piwi-pathway. The next steps are to investigate how epigenetic processes are altered in infected ants.