DOI: 10.5061/dryad.3tx95x6qk
title: Partial consumption of medical face masks by a common beetle species

description: The widespread distribution of microplastics (MPs) in the environment has
 motivated research on the ecological significance and fate of these
 pervasive particles. Recent studies have demonstrated that MPs may not
 always have negative effects and in contrast, several species of
 Tenebrionidae beetles utilized plastic as a food source in controlled
 laboratory experiments. However, most studies of plastic-eating insects
 have not been ecologically realistic, and thus it is unclear whether
 results from these experiments apply more broadly. Here we quantified the
 ability of mealworms (Coleoptera: Tenebrionidae) to consume MPs derived
 from polypropylene (PP) and polylactic acid (PLA) face masks; these are
 two of the most commonly used conventional and plant-based plastics. To
 simulate foraging in nature, we mixed MPs with wheat bran to create an
 environment where beetles were exposed to multiple food types. Mealworms
 consumed ~50% of the MPs, egested a small fraction, and consumption did
 not affect survival. This study adds to our limited knowledge of the
 ability of insects to consume MPs. Understory or ground-dwelling insects
 may hold the key to sustainable plastic disposal strategies, but we
 caution that research in this field needs to proceed concomitantly with
 reductions in plastic manufacturing.
description: This is a laboratory experiment. Data were collected in a
 spreadsheet and analyzed in R.
description: # Partial consumption of medical face masks by a common beetle species
 [https://doi.org/10.5061/dryad.3tx95x6qk](https://doi.org/10.5061/dryad.3tx95x6qk) We created microplastics from two types of medical face masks (polypropylene and polylactic acid). We mixed plastic particles with wheat bran and fed the mixture to Tenebrio molitor. Beetle larvae consumed and partially biodegraded both plastic types. Plastic consumption did not affect beetle development or survival.  ## Description of the data and file structure Data were collected and compiled using Excel. Column headings are described below:  Beaker – number assigned to the beaker Mealworms – whether mealworms were added to the beaker or not Treatment – type of microplastic added to the food mixture Cumulative Pupae – number of pupae produced throughout the experiment. Live worms last day – number of live worms at the end of the experiment.  Est.start.plastic.particles – number of plastic particles in the food at the beginning of the experiment. Avg.total.starting.plastic.particles – average number of plastic particles across all beakers per treatment; calculated using the following formula (also see Methods: Data Collected): (mixture weight (mg) on day 1) x 0.295 x (average microplastics of polypropylene or polylactic acid per mg, Table 1) Percent.mix.weight.remaining.day1.day.23 – fraction of food mixture remaining at the end of the experiment (also accounts for weight loss due to evaporation); calculated using the following formula (also see Methods: Data Analysis): food weight (mg) on day 23 / food weight (mg) on day 1 Est.particles.consumed.per.mealworm – number of plastic particles consumed per mealworm. Percent.particles.consumed – the number of plastic particles consumed divided by the starting number of plastic particles Particle.egestion.rate.per.mg.frass – number of plastic particles egested per mg of frass NA = no data collected