Net reproductive rate and generation time
To quantify ontogenetic and transgenerational effects of thermal
environment on R0 and Tg ,
newly emerged adults from both in P and F1 were collected within 8 h of
hatching and transferred to vials containing 6 g of culture medium.
Since temperature may impact fitness-related traits, and that effect
could be mediated by population density (Estay et al. , 2011;
Royama, 2012; Clavijo-Baquet et al. , 2014), four different
population densities were established following the discrete design of
Utida (1941) and Royama (1992), which included two, four, eight, and
sixteen individuals per vials (sex ratio 1:1). We prepared at least 7
glass vial (cohorts) per density, resulting in a minimum of 28 cohorts
per experimental group. Every other day, vials were checked to determine
the number of dead flies and to replace the culture medium until
complete mortality of the cohort. We then counted the number of eggs
from the removed medium to estimate daily fecundity. A Lotka life table
(Carey, 2001) was constructed to estimate \(R_{0}\) and \(T_{g}\)combining data on fecundity (\(m_{x}\)) and the proportion of the
surviving individuals at age x (lx ) for
each replicate. We estimated \(R_{0}\) and \(T_{g}\) as\(R_{0}=\sum{l_{x}m_{x}}\) and\(t_{g}=\sum{x\ l_{x}}\frac{m_{x}}{R_{0}}\).