Biology subjects

Perl, C. D.

Publications and source records attributed to Perl, C. D..

4 recordsLinked to original sources

bioRxiv2026

Potential acoustic signatures of stress in black soldier fly (Hermetia illucens; Diptera: Stratiomyidae) larvae

Black soldier fly larvae (BSFL) have quickly become one of the most farmed animals in the world. However, little is known about how to monitor stress and welfare in these animals. The difficulty of welfare assessment is compounded by the fact that BSFL live in their feed and prefer darkness. This behaviour makes it challenging to observe potential welfare indicators without inducing stress via disturbing the larvae or moving them into the light. However, acoustic devices may be able to pick up signatures of stress in the population even while they are out of sight, allowing for remote monitoring of animals in natural conditions (in the feed and/or in the dark). Acoustic monitoring of this type has been deployed for the detection of insects in stored grains, suggesting this method holds some promise for assessing insect behavioural signatures. In this study, we aimed to identify general, acoustic signatures of stress in BSFL by recording them during exposure to two stressors (light or shaking) or in a low-stress control condition. Our data suggest there are consistent differences in the acoustic recordings of the non-stressed and stressed conditions that may indicate the animals behaviours shift consistently in response to stress. Ultimately, the data suggest acoustic monitoring may hold promise for larval behaviour and/or welfare assessment and should be further explored in response to a variety of stressors across the larval life stage.

zoology↗

bioRxiv2026

Evolution of neurometabolic frugality in harvester ants

Despite the importance of neurometabolic costs in brain size evolution, quantitative data on brain metabolic rates are lacking. We measured ex vivo brain metabolic rates among species of the ant genus Pogonomyrmex to differentiate the roles of sociality and body size in brain evolution in a phylogenetic context. Worker body size and colony size (a proxy for social complexity) vary significantly among Pogonomyrmex species and were positively correlated. However, sociality was not a determinant of brain energetics. Worker body size strongly affected brain metabolism: 38% of resting metabolic rate was attributable to brain metabolism in species with the smallest workers, compared to 6% in species with the largest workers. More derived species had strikingly lower mass-specific brain metabolic costs, suggesting that increases in worker body size have selected for neurometabolic frugality through reductions in brain mass-specific metabolic rate. Additionally, smaller worker body sizes may require higher brain mass-specific energetic costs to achieve comparable performance by absolutely smaller brains. Our study shows that the social brain hypothesis does not explain patterns of brain size in Pogonomyrmex, but body size and evolutionary history strongly influence brain evolution in regard to both size and metabolic cost.

zoology↗

bioRxiv2025

High protein diets early in life improve survival, reduce cannibalism, and increase growth and yield in farmed yellow mealworms

In the wild, animals may be able to compensate for nutritional inadequacies through foraging for novel resources; however, on farms, animals have more limited nutritional options. Therefore, providing adequate and accessible nutrition is essential to positive farmed animal welfare. Billions of yellow mealworms (Tenebrio molitor; Coleoptera: Tenebrionidae) are farmed as mini-livestock each year for use as food and feed. The major feedstock used, wheat bran, can sustain complete development of the species, but has been shown to have significantly lower protein content than yellow mealworms would typically self-select, particularly at early developmental stages. This can reduce growth, survival, and adult oviposition, and may contribute to high rates of cannibalistic behaviour among larvae (as larvae may have few options but to seek protein from the bodies of conspecifics). In this study, we use 20% nutritional yeast as a dietary protein supplement for larvae in early (0-4 weeks) and later life (4-8 weeks) to assess the effects on survival, growth rate, and rates of cannibalism, as well as any effects on growth, development timing, and adult body size. We also investigated the impact of this higher protein diet, when fed to either larvae or adults, on fecundity. We find that protein supplementation in larval diets increased survival by 23%, growth rate by 200%, and total biomass at eight weeks by up to 272%. Larval cannibalistic behaviour was reduced and development time was shorter. The high protein diet, whether fed to adults or to larvae, increased the number of offspring per female by 34-36%. Survival and growth benefits of protein supplementation were especially pronounced when fed to early juvenile instars, but can benefit mealworms across the entire first eight weeks of development. We highlight the need for further research into dietary protein supplementation for yellow mealworms across development to better align with their dietary choices, thereby improving fitness, yield, and welfare.

zoology↗

bioRxiv2023

Complex allometric relationships and ecological factors shape the development and evolution of eye size in the modular visual system of spiders

Eye size affects many aspects of visual function, most notably including contrast sensitivity and achievable spatial resolution, but eyes are costly to grow and maintain. The allometry of eyes can provide insight to this trade-off in the context of visual ecology, but to date, this has mainly been explored in species that have a single pair of eyes of equal size. By contrast, animals possessing larger visual systems can exhibit variable eye sizes within individuals. Spiders have up to four pairs of eyes whose size often varies, but their ontogenetic, static, and evolutionary allometry has not yet been studied in a comparative context. We report variable evolutionary and developmental dynamics in eye size across 1098 individuals in 39 species and 8 families, indicating selective pressures and constraints driving the evolution of different eye pairs and lineages. We observed variation in the relationship between eye and body size not only between taxa and visual ecologies, but between eye pairs within species, indicating that growth dynamics are variable and can be divergently adapted in particular eye pairs. Supplementing our sampling with a phylogenetically comprehensive dataset recently published by Wolff et al. (2022), we confirmed these findings across more than 400 species, found that ecological factors such as visual hunting, web building, and diurnality can also impact eye diameter, and identified significant allometric shifts across spider phylogeny using an unbiased approach, many of which coincide with ecological changes such as visual pursuit hunting strategies. This study represents the first detailed comparative exploration of visual allometry in spiders, revealing striking differences in eye growth not only between families but also within species. Our findings shed light on the relationship between spider visual systems and their diverse ecologies, and how spiders exploit the modular nature of their visual systems to balance selective pressures and optical and energetic constraints.

evolutionary biology↗