The timing of resource availability does not affect reproductive allotment or the rate of oocyte development in the flesh fly, Sarcophaga crassipalpis

Abstract

1. The flesh fly, Sarcophaga crassipalpis, is anautogenous and largely relies on adult-acquired income resources for reproduction, but allocates some larvally derived capital into the first clutch. Therefore, the timing of adult resource acquisition may be important for both reproductive timing and magnitude of capital vs. income resources allocated to reproduction. Specifically, we predict that flesh flies that wait longer to acquire adult income resources will allocate greater quantities of larvally derived capital to the first clutch.2. To test how reproductive allocation in flesh flies responds to the timing of adult protein availability, we provided pulses of protein only on day 3, 6, 9, or 12 after eclosion, a series of times equivalent to the onset of oogensis and early, middle and late oogenic development in individuals fed ad libitum. Protein pulses contained isotopically distinct carbon ( 13 C), allowing us to distinguish between larval capital and adult-income resources allocated towards reproduction.3. Neither the timing of oocyte development nor reproductive allotment (egg number by egg size) was altered by the timing of protein availability.4. There was no effect of adult protein acquisition timing on the quantity of larvally derived somatic capital vs. adult-acquired income carbon allocated to reproduction. While flesh flies have remarkable pre-feeding plasticity in reproductive timing, they appear to have little post-feeding plasticity in allocation of stored reserves towards reproduction.