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Detection and Quantification of House Crickets (Acheta domesticus) in the Gut of Yellow Mealworm (Tenebrio molitor) Larvae Fed Diets Containing Cricket Flour: A Comparison of qPCR and ddPCR Sensitivity
by
, and
Pavel Vejl
1,*, 
Agáta Čermáková
1,
Martina Melounová
1,
Daniela Čílová
1,
Kamila Zdeňková
2,
Eliška Čermáková
2,3 and
Jakub Vašek
1 1
Department of Genetics and Breeding, Faculty of Agrobiology Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Prague, Czech Republic
2
Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague, Czech Republic
3
Department of Food Science, Czech Agrifood Research Center, Drnovská 507/73, 161 00 Prague, Czech Republic
*
Author to whom correspondence should be addressed.
Insects 2025, 16(8), 776; https://doi.org/10.3390/insects16080776
Submission received: 10 June 2025
/
Revised: 16 July 2025
/
Accepted: 24 July 2025
/
Published: 28 July 2025
(This article belongs to the Section Insect Molecular Biology and Genomics)
Simple Summary
In recent years, insects have been recognised as a promising food source thanks to their high nutritional value and low environmental impact. In Europe, only certain species of insect are approved for use in food and feed, and products containing them must be clearly labelled. To help ensure correct labelling, scientists are developing genetic methods to identify the species of insects used in food and feed products. In our study, we focused on yellow mealworm larvae (Tenebrio molitor), which are commonly farmed and approved for human consumption. These larvae are usually fed a plant-based diet, but some producers are experimenting with feeding them insect-based flours to enhance their growth and nutritional quality. Therefore, we fed Tenebrio molitor larvae diets containing various proportions of house cricket (Acheta domesticus) flour and then tested for traces of this feed in their bodies, even after starving them for 48 h. We used two molecular methods (qPCR and ddPCR) to detect insect DNA in the larvae. Both methods were successful, with ddPCR proving to be more sensitive. Our results demonstrate that the presence of another insect’s DNA in mealworms reflects their diet, rather than contamination or fraud, which is important for food labelling and traceability.
Abstract
Due to their nutritional value and sustainability, edible insect-based foods are gaining popularity in Europe. Their use is regulated by EU legislation, which defines authorised species and sets labelling requirements. Molecular tools are being developed to authenticate such products. In this study, yellow mealworm (Tenebrio molitor) larvae authorised for human consumption were fed wheat flour-based diets containing varying proportions of house cricket (Acheta domesticus) flour for 21 days. This was followed by a 48 h starvation period to assess the persistence of insect DNA in the digestive tract. Two novel, species-specific, single-copy markers were designed: ampd gene for the Acheta domesticus and MyD88 gene for the Tenebrio molitor. These were applied using qPCR and ddPCR. Both methods successfully detected cricket DNA in the guts of starved larvae. Linear regression analysis revealed a strong, statistically significant correlation between the proportion of Acheta domesticus flour in the diet and the normalised relative quantity of DNA. ddPCR proved to be more sensitive than qPCR, particularly in the detection of low DNA levels. These results suggest that the presence of DNA from undeclared insect species in edible insects may be indicative of their diet rather than contamination or adulteration. This highlights the importance of contextual interpretation in food authenticity testing.
