Hypersalinity drives physiological and morphological changes in Limia perugiae (Poeciliidae)

Area of Science:

• Ecology
• Evolutionary Biology
• Physiology

Background:

• Organismal morphology and physiology are shaped by environmental factors.
• Hypersaline environments present unique physiological challenges for aquatic organisms.

Purpose of the Study:

• To evaluate the effects of a hypersaline environment on the morphology and physiology of Limia perugiae.
• To investigate osmoregulatory protein expression and morphological changes in fish adapted to hypersalinity.

Main Methods:

• Sampling of Limia perugiae from freshwater and hypersaline habitats in the Dominican Republic.
• Western blot analysis to quantify osmoregulatory proteins (Na+/K+ ATPase).
• Geometric morphometrics to assess changes in fish size and shape.

Main Results:

• Hypersaline fish exhibited significantly higher expression of Na+/K+ ATPase proteins in gill tissue.
• Mitochondrial changes were observed, with increased expression of Complex I and ATP synthase in gills of hypersaline fish.
• Hypersalinity was associated with reduced body size, altered head morphology, and impeded development of secondary sexual characteristics in males.

Conclusions:

• The energetic demands of hypersaline environments drive significant physiological and morphological adaptations in Limia.
• Changes in osmoregulation and energy metabolism contribute to phenotypic diversity within the genus Limia.
• Environmental salinity acts as a selective pressure influencing growth, body shape, and reproductive development in livebearing fish.