Mitochondrial polymorphism shapes intrapopulation behavioural variation in wild Drosophila

Intrapopulation variation in personality, including activity, boldness,
and aggressiveness, is becoming more widely recognised and is hypothesised
to substantially affect ecological and evolutionary dynamics. Although
previous studies utilised candidate-gene approaches and genome-wide
association analyses to identify genes correlated with variations in
activity and aggressiveness, personality variation may not be fully
captured in the nuclear genome, as it does not account for mitochondrial
genomes. Mitochondrial genes encode products that are key regulators of
the cellular energy-producing pathways in metabolic processes and are
thought to play a significant role in life history and reproductive
traits. In this study, we considered many isofemale lines of Drosophila
immigrans established from two wild populations to investigate whether
intrapopulation variation in the mitochondrial genome affected activity
level within this species. We identified two major haplogroups in these
populations, and activity levels in both larvae and adults differed
significantly between the two haplogroups. This result indicated that
intrapopulation activity level may be partially controlled by
mitochondrial genes, along with the interaction between nuclear and
mitochondrial genes and the age of individual organisms.