Gravimetric, culture-based and public transcriptomic perspectives on low-density polyethylene feeding in Galleria mellonella

Galleria mellonella can remove substantial amounts of low-density polyethylene (LDPE), but host and microbial contributions remain unresolved. We examined whether antimicrobial exposure altered time-dependent LDPE mass disappearance and integrated gravimetric, culture-based, taxonomic and transcriptomic evidence. Across five independent runs, larvae received approximately 100 mg LDPE with vehicle-control, neomycin- or amphotericin-B-supplemented beeswax. LDPE disappearance increased with time and showed significant treatment and treatment-by-time effects ( P < 0.001). At 120 h, mean disappearance was 83.4, 80.0 and 89.9 mg in the vehicle-control, neomycin and amphotericin B groups, respectively. Larval-associated bacteria exhibited measurable hydrolytic and oxidative activities, while 16 S sequencing and taxonomic classification of public bulk RNA-seq libraries (PRJNA759905) recovered overlapping bacterial signals. Host-centred analysis identified 11,408 of 26,563 differentially expressed features, enriched in oxidative phosphorylation, fatty-acid metabolism and cytochrome P450-linked pathways. Antimicrobial exposure produced class-specific associations but did not establish microbial dependence. Because gravimetry cannot distinguish chemical degradation from fragmentation or incomplete recovery, the findings demonstrate LDPE mass disappearance rather than confirmed biodegradation.