Mitochondrial plasticity and life history in field crickets

Mitochondria serve as critical producers of both cellular energy and
metabolic precursors for biosynthesis required for organismal growth,
activity, somatic maintenance, and reproduction. Consequently, variation
in mitochondrial function is commonly associated with variation in life
histories both within and across species. For instance, flight-capable
long-winged crickets have mitochondria with larger bioenergetic capacities
than flightless short-winged crickets investing in early lifetime
fecundity instead of flight. However, we do not know whether differences
in mitochondrial function associated with life history are fixed or result
from flexible changes in metabolism throughout the life cycle. We measured
mitochondrial function of fat body tissue across early adulthood of
long-winged and short-winged crickets from two species of wing-polymorphic
field crickets (Gryllus firmus and Gryllus lineaticeps). Fat body is a
multifunctional organ that supports both flight and reproduction in
insects. Consistent with flexibility in mitochondrial function specific
for alternative life histories, capacity for oxidative phosphorylation
increases in mitochondria throughout early adulthood in fat body of
long-winged but not short-winged crickets. Furthermore, fat body
mitochondrial oxidative phosphorylation capacities declined rapidly when
long-wing crickets degraded their flight muscles and initiated large-scale
oogenesis. This finding suggests that shifts in tissue function require a
concurrent shift in mitochondrial function and that tissue-specific
functional constraints may underpin the flight-oogenesis trade-off. In
conclusion, changes in mitochondrial bioenergetics form a component of
alternative life histories, indicating that mitochondrial function is
dynamic and set to a level that matches current and future energetic
demands and biosynthetic requirements of life history.