Effect of tomato-fruit cultivar and ripening stage on Bactrocera tryoni (Froggatt) egg and larval survival

In studies of frugivorous tephritids, determining when offspring (i.e. egg and three larval instars) mortality occurs within the fruit can greatly improve the mechanistic understanding of the fly/host interaction.  Previous research has demonstrated that the Queensland fruit fly, Bactrocera tryoni, has differential offspring performance in two tomato cultivars Cherry and Roma, but when juvenile mortality was occurring was not determined.  We examined B. tryoni egg and larval survival in three different ripening stages (immature-green (IG), colour-break (CB) and fully-ripe (FR)) of Cherry and Roma tomato cultivars through destructive fruit sampling at 72 and 120 hrs for eggs, and 48 (1st instar), 96 (2nd instar) and 120 hours (3rd instar) after fruit inoculation with neonates for larvae. Cultivar and ripening stage had no significant effect on egg survival, nor larval survival at 48 hrs: egg survival was high across all treatments, while 1st instar larval was low across all treatments.  ...