Drosophila mitotypes determine developmental time in a diet and temperature dependent manner

Area of Science:

• Evolutionary biology
• Genetics
• Animal physiology

Background:

• Mitochondrial DNA (mtDNA) mutations can impact organismal fitness and mitochondrial-nuclear interactions.
• Identifying beneficial mtDNA mutations has been challenging.
• Drosophila melanogaster serves as a model organism for studying genetic and environmental influences on development.

Purpose of the Study:

• To determine if specific mitochondrial DNA (mtDNA) mutations can be beneficial.
• To investigate the effects of diet and temperature on Drosophila melanogaster larval development and physiology.
• To explore mitochondrial-nuclear interactions under varying environmental conditions.

Main Methods:

• Utilized two Drosophila melanogaster mitotypes (Alstonville and Dahomey) in two nuclear genetic backgrounds.
• Manipulated isocaloric diets using the nutritional geometric framework with differing protein: carbohydrate (P:C) ratios (1:2 and 1:16).
• Raised larvae at three temperatures (19°C, 23°C, and 27°C) and measured developmental time, weight, feeding rate, and movement.

Main Results:

• Dahomey mtDNA larvae developed slower than Alstonville on a 1:2 P:C diet across all temperatures.
• Dahomey mtDNA larvae developed faster than Alstonville on a 1:16 P:C diet at 23°C and 27°C.
• On the 1:16 P:C diet, Dahomey larvae exhibited increased feeding, reduced movement, and higher weight, with temperature modifying these responses.

Conclusions:

• Specific mtDNA changes, potentially among four identified, are likely responsible for the observed adaptive responses.
• mtDNA variations appear to moderate a physiological trade-off between food consumption and foraging behavior.
• Environmental factors like diet and temperature interact with mitochondrial genotype to influence Drosophila development and fitness.