Poster Presentation 11th Australian Peptide Conference 2015

Functional analysis of oxytocin-like signaling in ants (#144)

Zita Liutkeviciute 1 , Esther Gil-Mansilla 2 , Maria Giulia Di Giglio 2 , Sylvia Cremer 3 , Christian Gruber 1
  1. The University of Queensland, Brisbane, QLD, Australia
  2. Medical University of Vienna, Vienna, Austria
  3. Institute of Science and Technology Austria, Klosterneuburg, Austria

In recent years the genomes of different ant species have been sequenced and the putative inotocin precursor (homolog of oxytocin) and receptor were discovered [1]. It was the first evidence that oxytocin-like signalling system exists in social insects and possibly regulates individual physiology and social organization in ant colonies. Commonly in invertebrates – similar to the vertebrate system – oxytocin/vasopressin-like signalling appears to be important for water homeostasis, reproduction, learning, memory and behaviour [2]. To date its biological function in insects has only been studied in the beetle Tribolium castaneum where it has been implicated in water retention [3; 4]. Interestingly, honey bees lack the inotocin signalling system making ants a unique model system to study a role of inotocin in social insects. For our study we have chosen two ant species of the genus Lasius that are closely related genetically, but significantly differ in their ecology and colony structure [5].

Following pharmacological characterization of the ligand-receptor pair in vitro, our aim was to quantify expression levels of both the receptor and the inotocin peptide precursor in different parts of the body and developmental stages in ants using quantitative PCR. In contrast to beetles where both genes exhibit the highest expression in the larvae stage [3], the expression of the receptor and precursor in early broods (eggs and larvae) of ants is about an order of magnitude smaller compared to pupae or worker. Next we dissected organs of gaster of L. niger and L. neglectus worker, queens and males and showed that in most of the cases the highest expression of receptor exists in nervous system, crop, fat body and testis while it is very low in Malpighian tubules, ovaries, glands and midgut.

These findings indicate that the expression patterns of inotocin and its receptor are different in distinct insect species and provide further hints about diverse biological functions of this important neuropeptide signalling system. These preliminary outcomes will be important for further functional genomics studies to elucidate the role of inotocin signalling for individual and group level behaviour in ant societies.

  1. References: [1] Gruber CW, Muttenthaler M. PLoS One. 2012; 7(3):e32559. [2] Gruber CW. Exp Physiol. 2014; 99(1):55-61. [3] Aikins MJ et al., 2008; Insect Biochem Mol Biol. 38(7):740-8. [4] Stafflinger et al., 2008; Proc Natl Acad Sci USA. 105(9):3262-7 [5] Cremer S et al., 2008; PLoS One. 3(12):e3838.
  2. Acknowledgements: The authors would like to thank Markus Gold-Binder, Thomas Eder, Anna Grasse, Matthias Konrad and Christopher Pull for their help and discussions. The project has been funded by the Vienna Science and Technology Fund (WWTF) through project grant LS13-017.