Effects of juvenile hormone on the division of labor and its relationship with cuticular hydrocarbon dynamics in Scaptotrigona aff. depilis (Hymenoptera, Apidae, Meliponini)

• Grant number: 22/01427-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: June 01, 2023
• End date: January 31, 2026
• Field of knowledge: Biological Sciences - Zoology - Animal Behavior
• Principal Investigator: Fábio Santos do Nascimento
• Grantee: Jéferson Pedrosa dos Santos
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated scholarship(s): 24/04588-7 - The reproductive groundplan hypothesis being tested in the progressive provisioner wasp Zethus miniatus (Vespidae, Eumeninae), BE.EP.DR

Abstract

The social communication of the insects is largely mediated by chemical compounds, which are found in various exocrine glands secretions and at the cuticle surface (e.g., cuticular hydrocarbons, or CHCs). These chemical compounds are also utilized to mediate tasks and have a direct relationship between the individuals age and the function performed by them at the colony (age polyethism). Furthermore, the juvenile hormone (JH) regulates this task division between workers, besides regulating both fertility and reproductive behavior of workers and gynes. There is also a relationship between the JH quantity and the chemical profile expressed by the individuals. These relationships are unknown for most social insects' species, including economically important taxa. The aim of this current project is to investigate if there is a relationship between JH and the regulation of reproduction, reproduction signaling, and task partitioning in the eusocial bee species Scaptotrigona aff. depilis. The specific objectives of this project are: 1 - verify variations in JH titres present in the hemolymph related to caste, reproductive status, and workers' tasks specialization, and correlate it with the variation of chemical compounds of workers and gynes; 2 - Describe the age of the workers involved in nest activities considering two distinct contexts (presence and absence of the physogastric queen) in S. aff. depilis nests; 3 - Experimentally test if there is regulation of fertility, reproductive behavior, gyne signaling and worker task partitioning mediated by JH titres. In order to do so, individuals treated with the synthetic compounds precocene (anti-JH) and methoprene (JH analogous) will be studied to avail possible changes in the cuticular profile; number of eggs laid by the queens; and workers age polyethism. It is expected that JH titres directly influences in reproduction and fertility in both gynes and workers, as well as task partitioning and chemical profiles. Since the queen does not control workers reproductive behavior in S. aff. depilis, it is possible that the role to regulate this process belongs to the JH.