%0 Journal Article %T Microplastics impair the reproductive behavior and life history traits of the amphipod Parhyale hawaiensis. %A Ramírez-Olivares AI %A Vargas-Abúndez JA %A Capparelli MV %J Mar Pollut Bull %V 205 %N 0 %D 2024 Jun 25 %M 38925027 %F 7.001 %R 10.1016/j.marpolbul.2024.116630 %X We investigated the distribution and effects of waterborne microplastic (MP) (polyethylene microspheres, 53-63 um) on the emergent model for ecotoxicology, the amphipod Parhyale hawaiensis, during 30 days of exposure. The following life-history traits were measured: (1) survival, (2) specific growth rate (SGR), (3) reproductive performance (precopulatory pairing behavior, fecundity, and time to release neonates), (4) molting frequency, (5) F1 newborn offspring survival and (6) MP bioaccumulation. No significant mortality or molt was seen in any of the treatments. MP caused a reduction in SGR, being more pronounced in females. The time for precopulatory pairing was 3-fold longer in amphipods exposed to MP. Fecundity decreased by 50 %, and the time to release juveniles was 6.7 days longer for amphipods exposed to MP. Finally, neonate survival decreased by 80 % after ten days of release. MP disrupts the reproductive mechanisms and triggers adverse effects on life history traits in P. hawaiensis.