Traits of social immune memory in a fungus-growing superorganism

Author(s)

Aryel C. Goes

• Document type: Master's Dissertation
• Press: Rio Claro. 2023-05-26.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. Rio Claro
• Defense date: 2023-04-17
• Advisor: André Rodrigues; Pepijn Wilhelmus Kooij

Abstract

The immune system is crucial for organisms to defend against pathogens. Likewise, analogous immune mechanisms evolved to confront similar pressures at the superorganismal level. Retain information from previous infections and use it to upregulate hygiene are some of the convergent immune mechanisms found in social insects. Whether it extends to immunological memory is still elusive. Here we evaluate immune memory at the colonylevel by challenging the leaf-cutting ant Atta sexdens with homologous and heterologous exposures to the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana, and the mycoantagonistic fungi Fusarium oxysporum and Trichoderma spirale. By measuring ants’ behaviors, we bounce the capacity of A. sexdens to (i) enhance their collective hygiene, (ii) whether it occurs faster, (iii) how long this capacity lasts in the colonies, and (iv) the degree of specificity to increase responses. Sanitization was enhanced to the four challenged fungi, with unclear signs of velocity against all of them. The capacity to elicit upregulated hygienic actions lasted for up to 30 days when we exposed the same fungus for a third time, but not in colonies that received it after 60 days. Overall, colonies showed a degree of immune specificity by decreasing hygiene when exposed secondarily to a distinct fungus. Our results highlight that A. sexdens have some traits of immunological memory against fungi pathogens, based on the dynamics of their colony-level responses under secondary infections. (AU)

• FAPESP's process: 21/04112-4 - The superorganism immunology: detection, response, and memory in leaf-cutting ants
• Grantee: Aryel Camero Goes
• Support Opportunities: Scholarships in Brazil - Master