Mutual Use of Trail-Following Chemical Cues by a Termite Host and Its Inquiline

Paulo Fellipe Cristaldo,Og Desouza,Anna Jirošová,Eraldo Rodrigues Lima,Jana Krasulová,Kateřina Kutalová,David Sillam-Dussès,Jan Šobotník,Judith Korb

doi:10.1371/journal.pone.0085315

Abstract

Termite nests are often secondarily inhabited by other termite species ( = inquilines) that cohabit with the host. To understand this association, we studied the trail-following behaviour in two Neotropical species, Constrictotermes cyphergaster (Termitidae: Nasutitermitinae) and its obligatory inquiline, Inquilinitermes microcerus (Termitidae: Termitinae). Using behavioural experiments and chemical analyses, we determined that the trail-following pheromone of C. cyphergaster is made of neocembrene and (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol. Although no specific compound was identified in I. microcerus, workers were able to follow the above compounds in behavioural bioassays. Interestingly, in choice tests, C. cyphergaster prefers conspecific over heterospecific trails while I. microcerus shows the converse behaviour. In no-choice tests with whole body extracts, C. cyphergaster showed no preference for, while I. microcerus clearly avoided heterospecific trails. This seems to agree with the hypothesis that trail-following pheromones may shape the cohabitation of C. cyphergaster and I. microcerus and reinforce the idea that their cohabitation is based on conflict-avoiding strategies.

Highlights

A wide variety of species adopt the strategy to live in close association to each other, establishing symbiotic interactions
The glands are ovoid in shape and of comparable size but the gland width is slightly larger in C. cyphergaster compared to I. microcerus (15067.07 mm vs. 12062.83 mm, respectively) which corresponds to a difference in body sizes: C. cyphergaster 4.3360.41 mm; I. microcerus 3.5060.43 mm
Trail-following pheromones and their activities Based on trail-following bioassays and chemical analyses, we confirmed that neocembrene and dodecatrienol are the major compounds of the trail-following pheromone of C. cyphergaster [27] and we estimated the quantity of both compounds in the sternal glands of workers to be approximately 1 ng and 0.02 ng, respectively

Summary

Introduction

A wide variety of species adopt the strategy to live in close association to each other, establishing symbiotic interactions (see e.g. [1,2,3,4]). Chances of occasional encounters are increased by the fact that cohabitation may take place in volumes as small as 13 litres [14], with inquilines inhabiting the ‘‘heart of the hive’’ and being outnumbered by their host [5]. All this would enhance selective pressures for defensive strategies on the part of the host with consequent development of deceiving strategies on the part of inquilines, establishing arms races likely similar to those observed for cuckoos versus hosts in birds and in other social insects [21]

Methods

Results

Conclusion