To date, at least 11 insect species, mostly in the larval stage, have been identified as capable of biodegrading plastics. The most thoroughly documented in terms of efficiency are T. molitor, Tenebrio obscurus, Zophobas atratus, and Galleria mellonella —all noted for their ability to consume and transform EPS and other types of plastic. Similar behaviors have also been observed in other insects such as the black soldier fly, cockroaches, and termites, though more research is needed to confirm their actual effectiveness in plastic degradation.
Rodrigo Llauradó Casares
Communicator & Content Strategist
Imagine a larva that eats plastic, digests it, and transforms it into protein for fish — which then feeds people. Not only that: It also produces fertilizer for crops. It sounds promising. But it also raises important questions: Is it safe? Is it viable? In this article, we explore the latest scientific evidence behind this emerging method for reducing plastic waste and generating valuable bio inputs.
THE GLOBAL PLASTIC WASTE PROBLEM
Each year, humanity produces more plastic than it can manage. In 2021, global plastic production surpassed 390 million tonnes (Yang et al., 2024).
Once used, plastic begins a second life —as waste— found in the oceans, in the soil, and even in human bodies:
• It is estimated that around 6.4 million tonnes of plastic enter the ocean every year and that over 60% of marine litter is composed of plastic (Yang et al., 2024).
• As plastics break down into microplastics and nanoplastics, they alter the composition and function of soil microbiomes, release toxins, and disrupt both root development and nutrient flow in crops (Siddiqui et al., 2024).
• Microplastics have been detected in human blood, lungs, and even in the placenta. Although research is still underway, scientists are increasingly concerned about their possible effects — including damage to our cells and organs, problems with reproduction and metabolism, and increased stress in the body (Yang et al., 2024).
THE CHALLENGE OF PLASTIC DEGRADATION
There are still no truly safe and effective processes for breaking plastic down. Chemical treatment, while more advanced, requires months of processing and the use of corrosive substances such as nitric acid, posing serious environmental risks (Bonilla-Amaya et al., 2024).
Degrading plastic is challenging due to its chemical structure, designed to resist attack by most microorganisms and prevent decomposition
But why are plastics so hard to degrade? Because they are designed to last. Their structure is so stable that most microorganisms cannot break them down. They lack weak points for easy cleavage, and their large molecular chains are too big to enter microbial cells where digestion should occur (Yang et al., 2024).
Since the 1960s, scientists have searched for microbes capable of degrading plastic, but very few have proven effective. That’s why plastics can persist in the environment for decades or even centuries.
Still, while the term “biodegradation” is usually linked to microbes, new frontiers are being explored —and some of them involve insects as a promising and sustainable alternative.
A DUAL SOLUTION WITH PLASTIC-EATING LARVAE
Although the plastic problem has been studied for over half a century, the idea that certain insects could degrade it is relatively recent. In 2015, collaborative studies across 28 countries confirmed that larvae of Tenebrio molitor —also known as yellow mealworm— were able to consume expanded polystyrene (EPS) (Yang et al., 2024).
Insect species known for their ability to consume various plastics primarily include beetle and moth larvae
To date, at least 11 insect species, mostly in the larval stage, have been identified as capable of biodegrading plastics. The most thoroughly documented in terms of efficiency are T. molitor, Tenebrio obscurus, Zophobas atratus, and Galleria mellonella —all noted for their ability to consume and transform EPS and other types of plastic (Siddiqui et al., 2024; Yang et al., 2024). Similar behaviors have also been observed in other insects such as the black soldier fly, cockroaches, and termites, though more research is needed to confirm their actual effectiveness in plastic degradation.
This approach becomes even more relevant when we consider that, beyond the environmental crisis, the global food system also faces urgent challenges: A growing population and the rising cost of animal feed inputs.
In this context, insect larvae emerge as a potential dual-purpose solution: They could help degrade certain types of plastic while also serving as an alternative protein source for animal feed. One organism — two functions.
Before delving into protein production using plastic-eating larvae, it’s important to understand how this degradation process occurs.
HOW LARVAE BREAK DOWN PLASTIC AND HOW EFFICIENT THIS PROCESS IS
Certain insect larvae are capable of biodegrading plastic thanks to a combination of digestive enzymes, gut microbiota, and a physiological system adapted to fragment polymer chains (Yang et al., 2024). While the process varies by species and plastic type, recent studies have proposed a generalized biodegradation model, primarily observed in T. molitor, T. obscurus, Z. atratus, and G. mellonella:
1. Initial contact: The larva bites into the plastic and its saliva begins to partially oxidize the material using enzymes.
2. Ingestion and fragmentation: The plastic enters the digestive system, where it is physically shredded by the mouthparts and intestinal movement, reducing its size and increasing surface area.
3. Enzymatic and microbial action: Inside the gut, the plastic is exposed to a mix of digestive enzymes, bioemulsifying compounds, and intestinal microbes that work together to break down the polymer chains (depolymerization).
4. Oxidation and mineralization: Some plastic fragments are oxidized and converted into simpler molecules, such as water (H₂O) and carbon dioxide (CO₂); others are assimilated by the larva or its microbiota.
5. Excretion: The non-degraded material and byproducts of the process are expelled as frass.
A generalized model of insect biodegradation, represented in this image by a T. molitor larva, combines digestive enzymes, gut microbiota, and a physiological system adapted to break down polymer chains
Among the bacteria identified as capable of breaking down complex polymers are Enterobacter, Bacillus, Pseudomonas, and Staphylococcus, while enzymes involved include lipases, esterases, cutinases, and proteases. However, in some cases, certain species appear able to degrade plastics even without microbial assistance, according to studies referenced in Yang et al. (2024). Still, other researchers argue the opposite: One study showed that when gut microbiota was suppressed using antibiotics, T. molitor larvae lost their ability to degrade plastic (Siddiqui et al., 2024).
Studies show that T. molitor can convert up to 48% of EPS carbon into CO₂ in just 16 days, while another 49% is excreted as frass (Zielińska et al., 2021). Additionally, this same species fed with EPS maintained high protein levels (48.6%) without signs of toxicity, suggesting potential use in animal feed, if safety is ensured.
It seems that efficiency improves when plastic is combined with a nutrient-rich diet like wheat bran, and pre-treatment methods such as UV light or plasma may further enhance degradation (Yang et al., 2024; Siddiqui et al., 2024).
Taken together, these advances demonstrate that the process is functional, measurable and has the potential to be scaled up as a dual solution for plastic reduction and alternative protein production, but only if the safe use of these larvae as feed can be guaranteed.
CAN WE FEED FISH WITH PLASTIC-EATING INSECTS?
A recent study explored whether plastic-degrading larvae could be used to feed fish intended for human consumption —contributing to a circular approach in aquaculture (Bonilla-Amaya et al., 2024). The trial tested diets for juvenile red-bellied pacu (Piaractus brachypomus), replacing fishmeal with insect meal made from T. and Z. atratus fed a mixture of 25% PS and 75% wheat bran.
A recent study concluded that up to 100% of the fishmeal could be replaced in the diet of juvenile red-bellied pacu with meal from larvae fed polystyrene, although further studies are needed to assess the possible presence of toxins
The results were promising. This combination not only promoted greater PS degradation —up to 65% in 64 days for T. molitor and 12% in 32 days for Z. atratus— but also yielded insect meals with high protein content: 51% for T. molitor and 42.6% for Z. atratus, comparable to values reported for conventionally reared insects.
Fish fed with these insect-based meals grew normally, with no differences in development observed. The authors concluded that up to 100% of fishmeal could be replaced by insect meal from larvae reared on PS, without compromising performance or apparent health.
However, they also emphasized the need for further safety evaluations, particularly regarding the potential accumulation of microplastics or toxic residues in the insect biomass.
ENSURING THE SAFETY OF LARVAE FOR FEED
During degradation, plastics break down into increasingly smaller particles, including micro- and nanoplastics, raising concerns about the potential accumulation of toxic compounds in the larvae or their transformation into harmful substances.
Studies show that Tenebrio molitor can convert up to 48% of expanded polystyrene carbon into CO₂ within 16 days, with another 49% excreted as frass
In in vitro cellular analyses, extracts from Tenebrio molitor and Zophobas morio larvae fed with EPS did not show cytotoxic effects (Zielińska et al., 2021). No adverse impact on the intestinal health of the larvae was observed either.
Still, more evidence is needed to confirm that these insects pose no health risks when used in feed. Ensuring safety —for the larvae and for the end consumers— remains a critical priority in the development of this technology.
POTENTIAL APPLICATIONS IN FERTILIZERS
Beyond feed, the byproducts of plastic-fed larvae are also being evaluated for use in agriculture. Frass produced by these larvae could be used as a biofertilizer. In a recent study, T. molitor larvae fed exclusively with EPS produced less frass than those fed organic or mixed diets (Bastidas Proaño, 2024).
Moreover, the presence of microplastic fragments in the frass could not be ruled out, since chewing alone can generate small particles that may bypass digestion. This highlights the need to assess whether frass contains plastic residues before it can be safely applied to soil.
That said, other studies have found cases in which EPS was fully degraded, and the resulting frass showed no detectable plastic traces when analyzed using detailed chemical methods (Siddiqui et al., 2024).
Further investigation is needed to ensure that frass derived from plastic-fed insects can be safely used as a fertilizer —without compromising soil health or crop safety.
A NEW STUDY QUESTIONS THE EFFECTIVENESS OF PLASTIC DEGRADATION BY INSECTS
Although many studies have documented the ability of T. molitor to degrade EPS, a recent study (Mohammadizadeh Tahroudi et al., 2025) challenges this view. It found that larvae could not survive or complete their life cycle on EPS alone, with mortality matching or exceeding that of starved controls. The authors argue that T. molitor may lack the enzymes or microbiota needed to degrade EPS under lab conditions.
While not dismissing earlier findings, the study calls for a critical reassessment of insect-based plastic degradation strategies.
WHAT’S NEXT FOR PLASTIC-EATING LARVAE?
Insect larvae capable of degrading plastic represent a disruptive solution, which could simultaneously address two global challenges: Plastic waste and sustainable protein production for feed.
Over the past decade, significant progress has been made, yet several aspects require further evaluation —from feed performance and long-term health effects, to frass quality and microplastic residues. Beyond aquaculture, the potential use of these larvae in feeding other animals such as poultry, pigs, and pets also needs to be carefully assessed to understand nutritional performance, digestibility, and safety risks. The advancement of this insect-based solution must also address external barriers such as regulatory frameworks and consumer acceptance.
References
1. Bastidas Proaño, D. (2024). Entomoremediación: Influencia de una dieta plástica en el desarrollo de Tenebrio molitor para generar biofertilizante. Revista Politécnica, 53(2), 7–16. https://doi.org/10.33333/rp.vol53n2.01
2. Bonilla-Amaya, M. F., Muñoz-Ramírez, A. P., Aguilar-Aguilar, F. A., & Barragán-Fonseca, K. B. (2024). Consumption of expanded polystyrene by Tenebrio molitor and Zophobas atratus, and use of their meal as feed for Piaractus brachypomus. Archivos Latinoamericanos de Producción Animal, 32(3), 121–132. https://doi.org/10.53588/alpa.320301
3. Mohammadizadeh Tahroudi, Z., Flematti, G., Joshi, J., Fritz, G., & Atkin, R. (2025). Expanded polystyrene is not chemically degraded by mealworms. RSC Sustainability, 3, 383–394. https://doi.org/10.1039/d4su00618f
4. Siddiqui, S. A., Abdul Manap, A. S., Kolobe, S. D., Mabelebele, M., Yudhistira, B., & Fernando, I. (2024). Insects for plastic biodegradation – A review. Process Safety and Environmental Protection, 186, 833–849. https://doi.org/10.1016/j.psep.2024.04.021
5. Yang, S.-S., Wu, W.-M., Bertocchini, F., Benbow, M. E., Devipriya, S. P., Cha, H. J., Peng, B.-Y., Ding, M.-Q., He, L., Li, M.-X., Cui, C.-H., Shi, S.-N., Sun, H.-J., Pang, J.-W., He, D., Zhang, Y., Yang, J., Hou, D., Xing, D.-F., Ren, N.-Q., Ding, J., & Criddle, C. S. (2024). Radical innovation breakthroughs of biodegradation of plastics by insects: History, present and future perspectives. Frontiers of Environmental Science & Engineering, 18(6), Article 78. https://doi.org/10.1007/s11783-024-1838-x
6. Zielińska, E., Zieliński, D., Jakubczyk, A., Karaś, M., Pankiewicz, U., Flasz, B., Dziewięcka, M., & Lewicki, S. (2021). The impact of polystyrene consumption by edible insects Tenebrio molitor and Zophobas morio on their nutritional value, cytotoxicity, and oxidative stress parameters. Food Chemistry, 345, 128846. https://doi.org/10.1016/j.foodchem.2020.128846
About Rodrigo Llauradó Casares
Rodrigo Llauradó Casares is a communicator and content creator with over 10 years of experience researching the use of insects for food, feed, and non-feed applications. With a background in Social Sciences and Marketing, he has founded startups, written scientific articles, created courses, and participated as a seminar speaker. He currently supports companies across the insect protein value chain through content and strategies that communicate science-based innovation and industry impact.
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