Experimentelle Untersuchungen zur Salzadaptation verschiedener Rassen des Dreistachligen Stichlings (Gasterosteus aculeatus L.)

Abstract

Experimental Studies on Adaptation to Salinity Shown by the Different Races of the Three‐Spined Stickleback (Gasterosteus aculeatus L.)

Adaptive Divergence in the Thyroid Hormone Signaling Pathway in the Stickleback Radiation

“…Thyroid hormone plays a key role in regulating many of the physiological and behavioral changes associated with migration in fish and birds [16–19]. For example, thyroid hormone regulates metabolic rate [20, 21], swimming behavior [22, 23], salinity preference [24], salinity tolerance [25], silvering [26], olfactory cellular proliferation [27], and sexual maturation [23] in fishes. Therefore, we examined whether thyroid hormone physiology has diverged between marine and stream-resident sticklebacks with contrasting migratory behaviors.…”

“…Because thyroid hormone can regulate metabolic rate in fishes [20, 21], we tested whether the differences in thyroid hormone concentration are related to differences in metabolic rate between the ecotypes. We treated fish with T4 and a T4 synthesis inhibitor (thiourea; TU).…”

“…Because thyroid hormone has diverse functions related to migration, divergence in thyroid hormone physiology might contribute to adaptation not only in metabolic rate and swimming activity, but also in other phenotypic traits that are known to differ between marine and freshwater sticklebacks. For example, marine and stream-resident sticklebacks differ in salinity preference behavior [24], salinity tolerance [21], the timing of sexual maturation [15], and many morphological traits [5]. There is evidence for the regulation of both osmoregulatory ability [25] and reproduction by thyroid hormone in fishes [53].…”

Parallel transcriptome evolution in stream threespine sticklebacks

“…Taurine plays diverse physiological roles, including osmoregulation (Huxtable, ). It is a dominant osmolyte in sticklebacks and shows plastic changes in tissue concentrations depending on the environmental salinity (Divino et al., ; Gutz, ; Schaarschmidt, Meyer, & Jürss, ). However, the inter‐population variations in the taurine concentration and their response to salinity do not show clear patterns of parallelism and are also greatly influenced by environmental temperature (Gutz, ; Schaarschmidt et al., ).…”

“…It is a dominant osmolyte in sticklebacks and shows plastic changes in tissue concentrations depending on the environmental salinity (Divino et al., ; Gutz, ; Schaarschmidt, Meyer, & Jürss, ). However, the inter‐population variations in the taurine concentration and their response to salinity do not show clear patterns of parallelism and are also greatly influenced by environmental temperature (Gutz, ; Schaarschmidt et al., ). Because the analyses of variations in the ability to synthesize taurine among fish species suggest that marine predatory fishes tend to lose the synthetic ability possibly because they can uptake taurine from their diets (Goto, Mochizuki, & Hasumi, ; Salze & Davis, ; Yokoyama, Takeuchi, Park, & Nakazoe, ), divergent adaptation to diets may contribute to variations in taurine synthetic ability between ecotypes.…”