X-irradiation of pupae of the house fly Musca domestica L. and adult survival

Exploring the hormetic effects of radiation on the life table parameters of Spodoptera frugiperda

BACKGROUND

Spodoptera frugiperda, a global agricultural pest, can be effectively controlled through the sterile insect technique. However, exposure to low-dose radiation below the sterilization threshold may induce hormetic effects. Here, the biphasic aspects of the fertile progeny population of S. frugiperda were analyzed using an age-stage, two-sex life table after dosing male and female pupae with 10-350 Gy gamma radiation.

RESULTS

The parental sterilizing dose for 6-day-old female and male pupae was 200 and 350 Gy, respectively. The total longevity, pre-adult survival rate, net reproduction rate, and intrinsic growth rate of the offspring population increased with decreasing radiation doses from 250 to 10 Gy. Offspring population of parents treated with low doses of 10-100 Gy showed better life table parameters compared to non-irradiated controls. Females and males fecundity irradiated with 10, 50, and 100 Gy and 10 Gy, respectively, exceeded controls, producing 2339.4, 2726.4, 2311, and 2369 eggs, as opposed to 1802.9 eggs produced by the controls. Males irradiated with 10 Gy displayed the highest intrinsic rates of increase and net reproduction rate, at 0.1709 and 682.3, respectively. Projections from the survival rate and fecundity indicated that female and male S. frugiperda populations after 10 Gy irradiation may grow considerably faster than the controls.

CONCLUSION

This study explores the hormetic effects of low-dose radiation on S. frugiperda through life table analysis, while providing enhancements for utilizing substerilizing gamma dose in a modified F1 sterility technique. © 2023 Society of Chemical Industry.

Radiation induces stress and transgenerational impacts in the cricket, Acheta domesticus

PURPOSE

Radiation exposure of crickets during their fourth juvenile molt inflicted ionizing radiation damage and altered growth rate, adult size at sexual maturity. High levels of ionizing radiation also impacted the subsequent generation, likely via heritable epigenetic mechanisms. Using radiation as a proxy for external stress, we aim to understand the transgenerational impacts of stress on non-irradiated offspring.

METHODS AND MATERIALS

We assess the impacts of ionizing radiation on maturation mass and growth rate in F0 male and female house crickets (Acheta domesticus). We also assessed trans-generational impacts of irradiation on growth rate and maturation mass on non-irradiated offspring of irradiated parents compared to non-irradiated controls.

RESULTS

Early-life exposure to high levels of ionizing radiation-induced lower growth rate and maturation mass compared to controls (p < .0001). Non-irradiated male F1 offspring of irradiated parents demonstrated significantly lower mass at maturation (p = .0012) and significantly faster time of maturation (p < .0001) compared to F1 non-irradiated controls.

CONCLUSION

Our results show that a single early-life exposure to ionizing radiation can alter male offspring development through accelerated maturation and reduced maturation mass.

Low doses of radiation can enhance insect lifespans

This paper assesses the capacity of ionizing radiation to extend the lifespans of experimental insect models based on the peer-reviewed literature. Ionizing radiation biphasically affects the lifespans of adult males and females for a broad range of insect models with high doses reducing lifespan whereas lower doses can enhance lifespan, typically in the 20-60 % range. The average adult insect lifespan can be increased when ionizing radiation exposure is administered during early developmental stages or during the adult stage. The effective dose inducing the average adult insect lifespan enhancement may vary considerably depending upon which life stage is exposed. Recent findings have identified specific genes affecting anti-oxidant defenses, DNA repair, apoptosis and heat shock proteins as well as several cell signaling pathways that mediate the longevity enhancing hormetic response.

Radiation hormesis: data and interpretations

Although the biological effects of large doses of ionizing radiation are predominantly harmful, low-to-intermediate doses have been observed to enhance growth and survival, augment the immune response, and increase resistance to the mutagenic and clastogenic effects of further irradiation in plants, bacteria, insects, and mammals. The existence of these stimulatory, or "adaptive", responses implies that the dose-response relationships for genetic and carcinogenic effects of radiation may be similarly biphasic, or hormetic, in nature, a possibility with far-reaching implications for radiation protection. As yet, however, the extent to which such responses may actually reduce the risks attributable to low-level irradiation remains to be determined, pending further elucidation of the relevant dose-response relationships and the apparent lack of responsiveness in some individuals. Therefore, further research is needed to resolve this question.

Life extension by dietary restriction in the bowl and doily spider, Frontinella pyramitela

Longevity of free-living female adult bowl and doily spiders was compared with that of captive spiders fed at dietary regimes of one, three, and five Drosophila melanogaster per week. Adult females lived, on average, only 8 days in the field and the pattern of survivorship showed no evidence that senescence contributed to mortality. In the laboratory, mean adult life span was 81.3, 63.9, and 42.3 days on the one, three, and five Drosophila diets, respectively. Decreased feeding rate also delayed egg laying and reduced total fecundity. Survival and reproductive patterns indicated the manifestation of spider senescence at all laboratory feeding levels, with a younger onset of senescence at the higher feeding rates.