Triarylselenonium triflates provide efficient access to no-carrier-added ortho-, meta-, and para-[(18)F]Fluoroarenes.

The ability to resist or combat infection by pathogens, that is mount an effective immune response, is a major factor determining survival. However, developing and maintaining an immune system is costly (Lochmiller & Deerenberg, ). As a consequence, investment in immune function should trade off with investment in life‐history traits (Lee, ; Rauw, ; Rolff, ; Stoehr & Kokko, ; Zuk & Stoehr, ). Moreover, sex differences in reproductive effort or survival can be expected to cause trade‐offs involving immunity to differ between the sexes. For example, female mammals typically live longer than males (Lemaître et al., ; Promislow, ; Staerk et al., ). Several authors have proposed that in such species, males tend to invest less than females in immune defences because increased allocation of resources to sexually selected traits in males, such as ornaments, weapons or aggressive behaviours, can increase mating success and outweigh the costs of reduced lifespan (Lee, ; Zuk & Stoehr, ). While it is commonly asserted that immune responses are lower in males than in females in many species (Klein & Flanagan, ; Nunn et al., ), a recent meta‐analysis that included data from over 100 invertebrate and vertebrate species failed to find evidence of an overall sex difference in immune function after controlling for effects of phylogeny (Kelly et al., ). However, this analysis did not consider the possibility that sex differences in immunity may vary among individuals depending on the mating system. In vertebrates, sex differences in immunity are expected to be greater for species with polygynous than monogamous mating systems (Klein, ; Zuk & Stoehr, ), especially if the hormones that enhance male mating success, for example androgens, suppress immune function (Folstad & Karter, ; Klein, ). While an early meta‐analysis of studies manipulating testosterone and measuring immune function failed to find evidence that testosterone impairs immune function (Roberts et al., ), a larger more recent meta‐analysis found that testosterone does have significant immunosuppressive effects (Foo et al., ). Investment in each component of the vertebrate immune system, either the nonspecific innate or the specific acquired (adaptive), can be expected to be influenced by nutrition, pathogen exposure and extrinsic mortality risk. In particular, poor nutrition, low pathogen exposure and high mortality risk should favour investment in innate immune defences, while the opposite conditions should favour investment in adaptive immune defences (McDade et al., ). Evidence consistent with trade‐offs between immune components comes from artificial selection for reduced innate immunity in stickleback fish (), which resulted in upregulation of adaptive immune genes (Wegner et al., ). In addition, comparative studies in birds found that species with greater investment in adaptive immunity exhibit downregulation of their innate immune system (Minias et al., ).