Correlated changes in life history traits in response to selection for faster pre-adult development in the fruit fly Drosophila melanogaster

Abstract

Insects including the fruit fly Drosophila melanogaster are under intense pressure to develop rapidly because they inhabit ephemeral habitats. We have previously shown that when selection for faster development was artificially imposed on D. melanogaster in the laboratory, reduction of pre-adult development time and shortening of the clock period occurs, suggesting a role for circadian clocks in the regulation of life history traits. Circadian clocks in D. melanogaster have also been implicated in the control of metabolic pathways, ageing processes, oxidative stress and defense responses to exogenous stressors. In order to rigorously examine correlations between pre-adult development time and other life history traits, we assayed pre-adult survivorship, starvation and desiccation resistance, body size and body weight, fecundity and adult lifespan in faster developing populations of D. melanogaster. The results revealed that selection for faster pre-adult development significantly reduced several adult fitness traits in the faster developing flies without affecting pre-adult survivorship. Although overall fecundity of faster developing flies was reduced, their egg output per unit body weight was significantly higher than that of controls, indicating that reduction in adult lifespan might be due to disproportionate investment in reproduction. Thus our results suggest that selection for faster preadult development in D. melanogaster yields flies with higher reproductive fitness. Because these flies also have shorter clock periods, our results can be taken to suggest that pre-adult development time and circadian clock period are correlated with various adult life history traits in D. melanogaster, implying that circadian clocks may have adaptive significance.

Atrazine exposure affects longevity, development time and body size in Drosophila melanogaster

“…In addition, at the highest atrazine exposure level, the flies developed more quickly but were larger as adults. This is contrary to past work that has asserted that faster development time is correlated with smaller adult body size (Yadav and Sharma, 2014). Development time and body size are correlated traits which are controlled by similar pathways (Colombani et al, 2005; Mirth et al, 2014; Ono, 2014) thus the mechanisms that cause an acceleration in development time may also be related to the mechanism that causes the increase in body size.…”

Experimental Evolution under Fluctuating Thermal Conditions Does Not Reproduce Patterns of Adaptive Clinal Differentiation inDrosophila melanogaster

“…To avoid confounding effects of selection on early-life reproduction, which can result in correlated selection for a number of life-history traits (Rose and Charlesworth 1981;Khazaeli and Curtsinger 2013), flies for each generation were alternatively collected from the first or second egg-laying period. Furthermore, to avoid selection on development time, which could also contribute to correlated selection in other traits (Yadav and Sharma 2014), eclosing flies used to initiate the next generation were collected across a number of days (which varied depending on the temperature of the cabinet) until all flies had eclosed. Flies were collected every day without the use of CO 2 .…”

Spatial selection and local adaptation jointly shape life-history evolution during range expansion

“…a longer development time, hence slower development, results in an increased fecundity) (e.g. Nunney 1996; Tsikliras, Antonopoulou et al 2007; Lewis, Brakefield et al 2010; Yadav and Sharma 2014). This trade-off can be mediated through a positive correlation between development time and adult size ( e.g .…”