Effect of Prolonged Coldness on Survival and Fertility of Drosophila melanogaster

Abstract

The laboratory fruit fly, Drosophila melanogaster, is used widely in biological research, but the requirement to maintain stocks with a roughly biweekly generation time imposes substantial burdens of labor, potential cross-contamination and mutation accumulation. The purpose of this study was to assess the impact of prolonged cold stress or milder cooling on survivorship and fertility. The hypothesis was that cold storage would result in postponement of reproduction and a longer generation time. Flies of several genotypes were maintained continuously at 4–11°C; recovery rates and subsequent yields of adult progeny were recorded. Adults and pupae of a relatively long-lived y w lineage were more resistant to severe cold stress than embryos and larvae. Adults exhibited minimal mortality up to at least 5 d at 4°C, 20 d at 8°C and 12 weeks at 11°C. Reproduction did not occur at these temperatures, but progeny were obtained after recovery at 25°C. At all temperatures, chilling caused a rapid, severe and progressive decrease in fertility during the first 2 d of recovery. The impact on fertility during the subsequent 2–4 d was much milder and it occurred only after prolonged incubation at low temperatures. The total reproductive output during the first 6 d of recovery was sufficient to replace the parental population after 12 weeks at 11°C. Food spoilage had an unexpectedly low impact on survivorship and fertility, and the reproductive output of F1 progeny was not affected by storing parental flies at 11°C for 8–10 weeks. In the case of w 1118 flies, replacement of the parents within 6 d of recovery was possible for up to 60 d at 11°C. Among less fertile genotypes, replacement of the parents was possible within 18 d after 4–10 weeks at 11°C. These results show that the 2-week maintenance interval of stocks of D. melanogaster can be extended 3–7 fold, at least for 1 generation, by storing adult flies at 11°C.

Enhanced fertility and chill tolerance after cold-induced reproductive arrest in females of temperate species of the Drosophila buzzatii complex

“…Although this species originated in a tropical area, its status as a genetic model organism permitted important insights into the metabolic and genomic mechanisms involved in the interplay between cold tolerance and reproductive arrest (Kubrak et al, 2014). Although this has not been well tested, cold-adapted species are expected to maintain fertility after prolonged exposure to cold in order to succeed at high latitudes (Mockett and Matsumoto, 2014;Marshall and Sinclair, 2010).…”

Prolonged coldness on eggs reduces immature survival and reproductive fitness in Tetranychus urticae (Acari: Tetranychidae)

“…It is well known that diapause-terminated individuals are most likely to experience cold temperature of various durations during early spring (aseasonal short-term events that can not be predicted) which may influence their development, survival and reproduction, but receiving less attention (see Tauber et al 1986). Only a few studies follow the reproductive fitness of resultant females after insects have passed several live stages under the cold conditions (e.g., Jones & Kunz 1998;Chen et al 2008Chen et al , 2011Mockett & Matsumoto 2014). Our study investigated the effect of prolonged chilling duration of T. urticae eggs at 5 °C on egg hatching, immature development and survival as well as reproductive fitness of resultant females.…”

“…However, our results clearly show that chilling for ≥ 48 hours significantly decreased the survival of deutonymphs which may be the cause of significantly lower total immature survival rate detected for chilling durations of ≥ 48 hours (Figure 1). Prolonged exposure to low temperatures associated with poor survival of immature stages is common (Hofsvang & Hågvar, 1977;Jones & Kunz 1998;Leopold 1998;Chen et al 2008;Colinet & Boivin 2011;Mockett & Matsumoto 2014). According to Storey & Storey (1988), Rojas & Leopold (1996) and Leopold (1998), it is suggested that despite the 'normal' development of eggs, oxidative stress caused by build-up of reactive oxygen species in eggs might have occurred during the lengthy exposure to lower temperature, and such oxidative stress was passed into and caused injury to the subsequent immature stages.…”

“…The long-term influence of prolonged chilling of an immature stage on the female reproductive fitness is species specific, having significant negative effect (e.g., Jones & Kunz 1998;Mockett & Matsumoto 2014) or no significant effect (e.g., Chen et al 2008Chen et al , 2011. In the present study, the survival of immature stages (56.9% ~ 65.2%) in next generation was not significantly affected by egg chilling, and significant difference in longevity of male adults was only detected between chilling durations of 24 and 96 hours ( Figure 3A).…”

“…Furthermore, Abukhashim & Luff (1997) detected the reproduction of chilled females but did not follow the reproductive fitness of resultant females whose early immature stage(s) had experienced the low temperatures. The fitness of those resultant females may be impacted by the prolonged chilling duration that they have experienced during parental generation (e.g., Jones & Kunz 1998;Chen et al 2008;Mockett & Matsumoto 2014). Cone et al (1986) have also preliminarily observed the reproduction and sex allocation of overwintered T. urticae females at constant temperature (18~20 ºC), but they did not investigate the possibility of low temperature, for example during spring, affecting the survival and development of egg and immature stages.…”