Efficient digestion is essential for survival, as it regulates energy intake in animals. One particularly important digestive parameter is gut passage time (GPT), which must be optimized to ensure effective nutrient absorption. In reptiles, GPT is influenced by various factors, including environmental temperature, physiological and behavioral adaptations, age, and body condition.

A 2022 study published in Acta Herpetologica sheds light on how prey characteristics—specifically prey type and weight—affect GPT. The research focused on 12 adult Atlas day geckoes (Quedenfeldtia moerens), a species endemic to Morocco. Each gecko was housed individually in laboratory terraria and sequentially fed marked prey items: house cricket nymphs and mealworm larvae, each in three different weight classes. GPT was measured by checking the terraria hourly for fecal material containing the markers.

Results showed that mealworm larvae led to significantly longer GPTs compared to cricket nymphs. This is likely due to differences in nutrient composition: mealworms contain roughly twice the caloric content of crickets and are richer in proteins and lipids. The higher nutrient load of mealworms likely demands longer digestion times, extending GPT.

Additionally, heavier prey resulted in longer GPTs—a predictable outcome, as larger prey takes more time to be broken down for efficient energy extraction. Notably, this weight effect was more pronounced for mealworms than for crickets, suggesting that the geckoes’ digestive systems adjust GPT more sensitively when processing nutrient-dense food to maximize energy uptake.

Read the full paper here.

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