Biology subjects

Kong, J. D.

Publications and source records attributed to Kong, J. D..

4 recordsLinked to original sources

bioRxiv2024

Growth, development, and life history of a mass-reared edible insect, Gryllodes sigillatus (Orthoptera: Gryllidae)

Insects provide a potential source of sustainable, alternative protein that can help meet the protein demands of a growing population. Efficient farming of insects to meet this demand depends on an understanding of insect life history. Yet, detailed information and expertise about a single species are not always available for practitioners to make informed decisions about rearing practices or identify arising issues. The cricket (Gryllodes sigillatus) is commonly farmed for human consumption or animal feed, but few studies have characterized the life history of this species throughout ontogeny. Here, we describe the growth and development of G. sigillatus from hatch to adulthood and quantify reproductive traits relevant to mass-rearing and colony management, including egg development. This information provides foundation to start and manage a cricket colony and to conduct research on growth and performance. We highlight ways that a fundamental understanding of cricket biology can be informative for optimizing cricket growth, reducing variability in yield and informing future precision farming practices.

zoology↗

bioRxiv2024

Larger diet particle sizes cause crickets to grow faster with no effect on final body size

Artificial diets are costly to produce, so diet efficiency is critically important to the success of mass rearing insects. One way to improve feed efficiency is through dietary particle size optimization. We used a commercially reared species, Gryllodes sigillatus, to test whether individual crickets reared from hatch to adulthood on diets of different particle sizes would grow differently. Crickets fed a diet [≥]0.5 mm grew heavier during the first three weeks but weighed the same after six weeks regardless of diet size. We then provided crickets with a choice of particle size throughout development to test for dietary size preference. Given a choice, crickets consumed the most food from the 1.0-1.4 mm diet. Crickets also preferentially select ingredients from mixed diets, so to test whether grinding a conventional diet to a finer particle size could influence performance traits, we ran a large-scale group rearing experiment and found no effect of further grinding on colony mass gain or development time. Pelleting diet is another method for eliminating self-selection of ingredients, and so we tested whether pelleting finely ground conventional cricket feed would result in any substantial changes to the developmental life history of individual crickets. Crickets fed a 2 mm pelleted diet grew larger body size but were not significantly heavier. Overall, our results demonstrate that particle size optimization can be leveraged to enhance cricket life history traits important to mass production, as growth was accelerated on larger particle size diets and crickets preferred to eat larger-sized diets. Researchers focusing on physical properties of insect diets should carefully consider the timing of growth and development through which diet particle size may influence feed efficiency.

ecology↗

bioRxiv2022

Can we improve our ability to interpret ectotherm thermal tolerance?

Thermal tolerances, such as critical temperatures, are important indices for understanding an organisms vulnerability to changing environmental temperature. Differences in thermal tolerance over ontogeny may generate a thermal bottleneck that sets the climate vulnerability for organisms with complex life cycles. However, a species microhabitat preference and life history can hinder our ability to assess climate change vulnerability in large-scale comparative studies as these reflect local adaptation. Here, we used phylogenetically informed, multi-level models with a global dataset of upper critical temperatures from 438 Anuran species that explicitly included microhabitat preferences and ontogenetic stage to examine variation in upper critical temperatures. We found ontogenetic trends in thermal tolerance were similar across microhabitat preferences. We then used microclimate-driven models of the heat and water budget of a thermoregulating frog to show the contribution of behavioural thermoregulation towards mitigating exposure to thermal stress. Our results suggested thermal bottlenecks are not strongly present in Anurans but instead implied strong developmental or genetic conservatism of thermal tolerance within families and ecotypes, and that behavioural thermoregulation has a strong potential for buffering frogs against extreme temperatures.

zoology↗

bioRxiv2022

Heating tolerance of ectotherms is explained by temperature's non-linear influence on biological rates

The capacity of ectotherms to adjust their thermal tolerance limits through evolution or acclimation seems relatively modest and highly variable, and we lack satisfying explanations for both findings given a limited understanding of what ultimately determines an organisms thermal tolerance. Here, we test if the amount of heating an ectotherm tolerates throughout a heating event until organismal failure scales with temperatures non-linear influence on biological rates. To account for the non-linear influence of temperature on biological rates on heating tolerance, we rescaled the duration of heating events of 316 ectothermic taxa acclimated to different temperatures and describe the biological rate-corrected heating duration. This rescaling reveals that the capacity of an organism to resist a heating event is in fact remarkably constant across any acclimation temperature, enabling high-precision estimates of how organismal thermal tolerance limits vary under different thermal regimes. We also find that faster heating consistently reduces biological rate-corrected heating durations, which helps further explain why thermal tolerance limits seem so variable on absolute temperature scales. Existing paradigms are that heating tolerances and thermal tolerance limits reflect incomplete metabolic compensatory responses, are constrained by evolutionary conservatism, or index failure of systems such as membrane function; our data provide a different perspective and show that an organisms thermal tolerance emerges from the interaction between the non-linear thermal dependence of biological rates and heating durations, which is an approximately-fixed property of a species.

ecology↗