Abstract:
Adult holometabolous insects may derive metabolic resources from
either larval or adult feeding, but little is known of whether adult diets
can compensate for deficiencies in the larval diet in terms of stress
resistance. We investigated how stress resistance is affected and
compensated for by diet across life stages in the marula fruit fly
Ceratitis cosyra (Diptera: Tephritidae). Larvae were fed diets
containing either 8% torula yeast, the standard diet used to rear this
species, or 1% yeast (low protein content similar to known host fruit).
At emergence, adults from each larval diet were tested for initial
mass, water content, body composition, and desiccation and
starvation resistance or they were allocated to one of two adult diet
treatments: sucrose only, or sucrose and yeast hydrolysate. The
same assays were then repeated after 10 days of adult feeding.
Development on a low protein larval diet led to lower body mass and
improved desiccation and starvation resistance in newly emerged
adults, even though adults from the high protein larval diet had the
highest water content. Adult feeding decreased desiccation or
starvation resistance, regardless of the diet provided. Irrespective of
larval diet history, newly emerged, unfed adults had significantly
higher dehydration tolerance than those that were fed. Lipid reserves
played a role in starvation resistance. There was no evidence
for metabolic water from stored nutrients extending desiccation
resistance. Our findings show the possibility of a nutrient-poor larval
environment leading to correlated improvement in adult performance,
at least in the short term.
