Environmental variation shapes and links parasitism to sexual selection

Parasite-driven population divergence in hosts can be exacerbated by environmental factors affecting host parasitism, as well increasing sexual selection against parasitized hosts. Environmental influence parasitism directly parasite survival, and indirectly condition, which turn shape selection. To disentangle these potential alternative paths, we used a damselfly (host) - water mite (parasite) system to examine how drive heterogeneity across populations the strength of acting males. We found substantial populations, driven mainly lake pH, density. Although this did not translate into variation selection, density predatory fish increased strength, likely through effects on condition. These results imply that alone may cause differences but when linked with underlying conditions, increase More broadly, suggest elucidating requires consideration intwined ecological processes.