Caterpillars selected for large body size and short development time are more susceptible to oxygen‐related stress

Abstract

Recent studies suggest that higher growth rates may be associated with reduced capacities for stress tolerance and increased accumulated damage due to reactive oxygen species. We tested the response of Manduca sexta (Sphingidae) lines selected for large or small body size and short development time to hypoxia (10 kPa) and hyperoxia (25, 33, and 40 kPa); both hypoxia and hyperoxia reduce reproduction and oxygen levels over 33 kPa have been shown to increase oxidative damage in insects. Under normoxic (21 kPa) conditions, individuals from the large-selected (big-fast) line were larger and had faster growth rates, slightly longer developmental times, and reduced survival rates compared to individuals from a line selected for small size (small-fast) or an unselected control line. Individuals from the big-fast line exhibited greater negative responses to hyperoxia with greater reductions in juvenile and adult mass, growth rate, and survival than the other two lines. Hypoxia generally negatively affected survival and growth/size, but the lines responded similarly. These results are mostly consistent with the hypothesis that simultaneous acquisition of large body sizes and short development times leads to reduced capacities for coping with stressful conditions including oxidative damage. This result is of particular importance in that natural selection tends to decrease development time and increase body size.

Elucidating mechanisms for insect body size: partial support for the oxygen-dependent induction of moulting hypothesis

“…As predicted, unnaturally low P O2 (hypoxia) decreases the critical mass (Callier and Nijhout, 2011;. Hypoxia also decreases size at the next moult, final body size and growth rate, and prolongs development (Loudon, 1988;Greenberg and Ar, 1996;Frazier et al, 2001;Henry and Harrison, 2004;VandenBrooks et al, 2012;Harrison et al, 2013;reviewed by Harrison et al, 2006reviewed by Harrison et al, , 2010but Loudon, 1988 showed that hypoxia had no effect on final size). By contrast, the effect of unnaturally high P O2 (hyperoxia) on the critical mass, moulting size and final body size is contradictory (Greenberg and Ar, 1996;Frazier et al, 2001;Henry and Harrison, 2004;Harrison et al, 2010;Callier and Nijhout, 2011;VandenBrooks et al, 2012;.…”

“…By contrast, the effect of unnaturally high P O2 (hyperoxia) on the critical mass, moulting size and final body size is contradictory (Greenberg and Ar, 1996;Frazier et al, 2001;Henry and Harrison, 2004;Harrison et al, 2010;Callier and Nijhout, 2011;VandenBrooks et al, 2012;. Furthermore, there are no consistent hyperoxia effects on growth and development rates (Greenberg and Ar, 1996;Frazier et al, 2001;Harrison et al, 2006Harrison et al, , 2013VandenBrooks et al, 2012;. The contradictory results concerning hyperoxia effects may arise either because the ODIM hypothesis is unrealistic or because the applied hyperoxia manipulations have been unrealistically strong.…”

Evaluating the role and measures of juvenile growth rate: latitudinal variation in insect life histories

“…However, importantly, the so far recognised costs of fast growth are primarily manifested not as costs of integral growth rates but rather as costs of high differential growth rates. The latter included lower starvation resistance (Stoks et al 2006, Scharf et al 2009), oxidative stress (De Block and Stoks 2008, Harrison et al 2013, Smith et al 2016, and higher vulnerability of actively foraging larvae to predators (Gotthard 2000, Stoks et al 2005). An explicit attention to DGR is therefore needed in the optimality analyses of growth rate.…”

Effect of rearing conditions on the correlation between larval development time and pupal weight of the rice stem borer, Chilo suppressalis

“…Because body size affects reproductive capacity (Davidowitz, ; Honek, ; Kingsolver & Pfennig, ) and development time is related to generation time (Roff, ), both can affect the rate of population increase or the rate of spread of favorable genes. Increase in body size and decrease in development time are the usual result of natural selection acting on individual organisms (Eck, Shaw, Geyer, & Kingsolver, ; Harrison, Cease, VandenBrooks, Albert, & Davidowitz, ; Kingsolver & Huey, ; Kingsolver & Pfennig, ).…”

“…size and decrease in development time are the usual result of natural selection acting on individual organisms (Eck, Shaw, Geyer, & Kingsolver, 2015;Harrison, Cease, VandenBrooks, Albert, & Davidowitz, 2013;Kingsolver & Huey, 2008;Kingsolver & Pfennig, 2004).…”