Resources and/or protective services provided by ant colonies are exploited in manifold ways by an amazing diversity of other organisms acting as guests or parasites. Such associations can be obligatory or facultative, permanent or temporary, harmful or beneficial for the host. Due to the diversity of interactions, an understanding of the nature of these relationships and the mechanisms of integration used by parasites as well as the defense strategies developed by their potential host remains a challenge. Despite their apparent importance, detailed knowledge is lacking, for example, about diversity and abundance of ant parasites or selection pressures imposed through parasitism on host reproductive strategies. Moreover, considering the increasing losses in biodiversity due to habitat destruction and climate change, the diversity of the associations involving ants as hosts and the exact nature of these associations require accurate surveys.

Parasitism in ants has attracted the attention of numerous scientists in the last two centuries but, in spite of the accumulation of much information in the last decades, this important topic has not been brought together in a usable format, except in rare occasions. The first issue of this series, published in May 2012, examined a wide range of species: viruses, bacteria, fungi, nematodes, silverfishes, flies, butterflies, beetles, spiders, wasps, and ants themselves. However, it could not cover all possible ant parasites. More studies examining their complex interactions from every possible angle, attempting to bring a more global vision of the functioning of such an evolutionary important relationship, is a challenging and fascinating goal. In this second volume, we will continue giving specific attention to both the mechanisms used by ant parasites to integrate into their host colony, and to the way parasitism pressure could affect patterns of reproduction and life history in ant hosts. We will also try to focus on the diversity of ant social parasites and the other kinds of myrmecophiles not tackled in the first issue. We invite investigators to contribute original research articles as well as review articles on various aspects concerning ants and their parasites. Potential topics include, but are not limited to:

• Biodiversity of ant parasites (including ant social parasites)
• Dynamics of host-parasite association
• (Co)evolution and phylogeny
• Host specificity
• Hyper-, super-, and multiparasitism
• Mechanisms of integration in host colonies and host defense
• Natural history and behavior
• Community impact of ant parasites
• Potential for biological pest-ant control
• Life-cycles and reproductive strategies
• Reciprocal fitness impacts (symbiosis, mutualism, commensalism, parasitism)

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