Chromosome inversion polymorphisms influence morphological traits in Trimerotropis pallidipennis (Orthoptera)

Area of Science:

• Evolutionary Biology
• Genetics
• Ecology

Background:

• South American populations of Trimerotropis pallidipennis exhibit polymorphism for six pericentric inversions.
• Previous research indicated correlations between inversion frequencies and climatic variables, suggesting adaptive patterns.
• The study investigates the phenotypic effects of these chromosomal inversions within natural populations.

Purpose of the Study:

• To determine if chromosomal inversions in Trimerotropis pallidipennis affect exophenotypes.
• To analyze the relationship between inversions and body size characteristics.
• To explore the adaptive significance of body size variation in relation to inversions and climate.

Main Methods:

• Analysis of 268 male Trimerotropis pallidipennis from a natural population in Uspallata, Mendoza, Argentina.
• Phenotypic measurements, including tegmina length, were taken.
• Statistical analysis to assess the effects of inversions on phenotypes and correlations with environmental factors.

Main Results:

• Most chromosomal inversions showed significant effects on the exophenotypes of Trimerotropis pallidipennis.
• Body size and tegmina length were correlated with the number of inversions.
• Smaller body size in individuals with standard sequences was observed in higher altitude/latitude populations (lower minimum temperatures).

Conclusions:

• Chromosomal inversions influence phenotypic traits, including body size, in Trimerotropis pallidipennis.
• The observed smaller body size in colder climates may be an adaptive response mediated by inversions.
• Reduced body size could be advantageous for survival during shortened development seasons in cooler environments.