Hermaphrodites and parasitism: size-specific female reproduction drives infection by an ephemeral parasitic castrator.

Sex can influence patterns of parasitism because males and females can differ in encounter with, and susceptibility to, parasites. We investigate an isopod parasite (Hemioniscus balani) that consumes ovarian fluid, blocking female function of its barnacle host, a simultaneous hermaphrodite. As a hermaphrodite, sex is fluid, and individuals may allocate energy differentially to male versus female reproduction. We predicted the relationship between barnacle size and female reproductive function influences the distribution of parasites within barnacle populations. We surveyed 12 populations spanning ~400 km of coastline of southern California and found intermediate-sized barnacles where most likely to be actively functioning as females. While it is unclear why larger individuals are less likely to be actively reproducing as females, we suggest this reduced likelihood is driven by increased investment in male reproductive effort at larger sizes. The female function-size relationship was mirrored by the relationship between size and parasitism. We suggest parasitism by Hemioniscus balani imposes a cost to female function, reinforcing the lack of investment in female function by the largest individuals. Within the subset of suitable (=female) hosts, infection probability increased with size. Hence, the distribution of female function, combined with selection for larger hosts, primarily dictated patterns of infection

A structural approach to politicisation in the Euro crisis

Domestic opportunity structures and political actors’ positions are widely regarded as the most important explanatory factors for EU politicisation. The euro crisis, however, has revealed cleavages across rather than within countries, suggesting structural factors as a potential explanation for politicisation. Based on the political economy literature on Europe’s Economic and Monetary Union, this contribution develops a structural approach to politicisation with respect to countries’ power and variety of capitalism. Using a content and claims analysis of business papers in Germany, France, Austria and Ireland before and during the crisis, the findings reveal a differentiated pattern of politicisation. While an expansion of actors indicates that EMU became more politicised during the crisis, polarisation remained low within countries. Countries’ variety of capitalism and their perceived power in the EU largely explain the substance and objects of politicisation. The findings encourage further research considering structural explanations for differentiated politicisation in less elite-centred settings of politicisation