Alternative food sources have become an important focus of research due to increased food demand coupled with reductions in traditional food productivity. In particular, substitutes for protein sources have been of increasing interest due to the unsustainability of traditional protein sources. Insects have been identified as a sustainable alternative to traditional protein sources, as they are easy to produce and contain essential proteins, fats, and minerals. However, mass-rearing insects requires similar considerations as farming traditional protein sources. To increase productively, growth and survival must be maximized at the highest possible densities while minimizing disease and food requirements. Here, we use the house cricket Acheta domesticus, a highly cultivated insect species, to investigate optimal densities for mass rearing at 14 days of age (4th instar). Nymphs were separated into density groups of 0.09, 0.19, 0.47, and 0.93 cricket/cm2 and monitored for growth and survival. Multiple regression revealed sex (p < 0.0001), density (p < 0.0001), and sex*density interaction (p = 0.0345) as predictors of growth rate. Survival to maturation was significantly reduced in both 0.47 (31%) and 0.93 (45%) cricket/cm2 groups compared to the controls. A second experiment was then conducted to investigate the starvation resistance of adult crickets reared from 14 days of age at 0.09, 0.19, 0.93, and 1.86 cricket/cm2. A second multiple regression analysis revealed only density (p < 0.0001) and to a lesser extent sex (p = 0.0005) to be predictors of starvation resistance. These results indicate that mass-rearing house crickets is most optimal at densities < 0.93 cricket/cm2, where impacts on survival and starvation are minimal. Although these results have implications for cricket mass rearing, research on other endpoints, including reproduction and the synergistic effects of other environmental factors, such as temperature and humidity, should be conducted.

Environmental disasters and growth of nuclear power contribute to increasing levels of radiation pollution in the biosphere. Major impacts concern development, fertility, and survivorship in diverse species. Subtle impacts are less appreciated even though they may have profound effects on individuals and populations. Here, we examined radiation impacts on male crickets, Acheta domesticus (L.) (Orthoptera: Gryllidae), specific to wing development. Alterations in global wing morphology are detectable, but this is a flightless species. However, mating success of males is highly dependent on specialized courtship songs generated by structures associated with the opposing forewings. Such signals identify males as both conspecific and ‘attractive/fit’ mates. Highly specialized structures found on male forewings include the chord, harp, mirror, plectrum, and file. These work in concert to generate the species‐specific male courtship song. Even slight alterations in wing morphology can alter these signals, and variation may also vary acoustic signals among populations. Here, we analyze the impacts of early‐life radiation exposure (0–10 Gy) on male forewing shape and size using morphometric analysis. A canonical variate analysis (CVA) illustrated that wing shape was significantly altered in a dose‐dependent basis: 10 Gy (P<0.0001), 7 Gy (P<0.0001), and 2 Gy (P = 0.0001). Principal component (PC) analysis as well as the CVA indicated that most variation in wing structure was associated with the mirror, one of the two main resonating regions on the forewing. Analysis of centroid size found significant reductions with 7 and 10 Gy radiation exposures. Significant radiation‐induced increases in fluctuating asymmetry were also detected, with fluctuating asymmetry values increasing with dose. Due to the known specialized nature of song‐producing structures and its association with both courtship songs and mating, it is likely that the alterations observed in shape and size will have larger impacts on male reproductive success. We are currently quantifying this and analyzing recordings of song structure to detect and characterize specific alterations by radiation.

Animals exposed to significant stress express multi-modal responses to buffer negative impacts. Trans-generational impacts have been mainly studied in maternal lines, with paternal lines having received less attention. Here, we assessed paternal generational effects using irradiated male crickets ( Acheta domesticus), and their F1 offspring (irradiated males mated to unirradiated females). Paternal transmission of radiation impacts emerged in multiple life history traits when compared to controls. Irradiated males and their F1 offspring expressed hormetic responses in survivorship and median longevity at mid-range doses. For F0 males, 7 Gy & 10 Gy doses extended F0 longevity by 39% and 34.2% respectively. F1 offspring of 7 Gy and 10 Gy sires had median lifespans 71.3% and 110.9% longer, respectively. Survivorship for both F0 7 Gy (p < 0.0001) and 10 Gy (p = 0.0055) males and F1 7 Gy and 10 Gy (p < 0.0001) offspring significantly surpassed that of controls. Irradiated F0 males and F1 offspring had significantly reduced growth rates. For F0 males, significant reductions were evident in 4Gy-12 Gy males and F1 offspring in 4 Gy (p < 0.0001), 7 Gy (p < 0.0001), and 10 Gy (p = 0.017). Our results indicate paternal effects; that irradiation directly impacted males but also mediated diverse alterations in the life history features (particularly longevity and survivorship) of F1 offspring.

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