The interactions of ants with their biotic environment

Abstract

This special feature results from the symposium 'Ants 2016: ant interactions with their biotic environments' held in Munich in May 2016 and deals with the interactions between ants and other insects, plants, microbes and fungi, studied at micro- and macroevolutionary levels with a wide range of approaches, from field ecology to next-generation sequencing, chemical ecology and molecular genetics. In this paper, we review key aspects of these biotic interactions to provide background information for the papers of this special feature After listing the major types of biotic interactions that ants engage in, we present a brief overview of ant/ant communication, ant/plant interactions, ant/fungus symbioses, and recent insights about ants and their endosymbionts. Using a large molecular clock-dated Formicidae phylogeny, we map the evolutionary origins of different ant clades' interactions with plants, fungi and hemiptera. Ants' biotic interactions provide ideal systems to address fundamental ecological and evolutionary questions about mutualism, coevolution, adaptation and animal communication.

Keywords: ants; bacteria; fungi; insects; interactions; plants.

Figure 1.

The diversity of ant biotic interactions. (a,b) Ant/ant interactions. (a) Slavemaking ant Protomognathus americanus (black) and its host Temnothorax longispinosus. (b) Parabiosis between Crematogaster modiglianii (small, left) and Camponotus rufifemur (large, right). (c,d) Ant/other arthropod interactions. (c) ant/lycaenid interaction. (d) The rove beetle Diploeciton nevermanni is a social parasite of the army ant Neivamyrmex pilosus. (e–k) Ant/plant interactions. (e) Ant foraging on Senna scabriuscula extrafloral nectary. (f) Pheidole pallidula ant dispersing a Borderea chouardii seed. (g) Philidris nagasau ant farm of Squamellaria plants in Fiji. (h) Pseudomyrmex concolor living in Tachigali domatium and cultivating Chaetothyriales fungi inside the domatium (black patches). (i–k) Ant/pitcher plant interactions (Nepenthes). (i) Ant foraging on peristome nectaries. When it rains, the peristome undulates with raindrops, acting as a mechanism to catch ant prey. (j,k) Mutualistic interaction between Camponotus schmitzi and Nepenthes bicalcarata. (j) Camponotus schmitzi ants live inside the hollow petiole of N. bicalcarata (arrowhead) and are able to walk inside the pitcher and swim to steal Nepenthes prey (k). (l,m) Ant/fungus interaction (see also (l) Trachymyrmex ants farm fungus cultivar). (m) Allomerus ants cultivate fungi to make carton scaffold to catch insect prey, here a horsefly. (n) Ant/microorganism interaction. Blochmannia endosymbionts in bacteriocytes (green) in the midgut tisue of a pupa (shortly after pupation) of Camponotus floridanus ants. Red cells are midgut cells that do not (yet) contain any bacteria. Photo credit: (a) Susanne Foitzik. (b) Florian Menzel. (c) School of Ecology and Conservation, UAS Bangalore, India. (d) Christoph von Beeren. (e) Brigitte Marazzi. (f) María García, Xavier Espadaler, Jens Olesen. (g) Guillaume Chomicki. (h) Rumsais Blatrix. (i,k) Ulrike Bauer. (l) Scott Solomon. (m) Claude Delhaye. (n) Sascha Stoll.

Figure 2.

Phylogenetic distribution of ant symbioses with hemipterans, plants, and fungi. The tree from Moreau & Bell [99] was kindly provided by Corrie Moreau.