The challenging role of life cycle monitoring: evidence from bisphenol A on the copepod Tigriopus japonicus

Abstract

We used the marine model copepod taxon T. japonicus Mori, 1938 for a first short sublethal life cycle assay of the endocrine-disrupting chemical bisphenol A (BphA) where we studied life cycle and reproductive success. Individual copepodid-I-stages were reared in 96-well microplates to adulthood in as short as 6 days in only 200 mu l of 0.1 mg bisphenol (BphA/L) or seawater solution as a control (CON). Males and females were then mated in one well and checked daily for the following endpoints: postmating days to female brood sac extrusion, days from brood sac extrusion to naupliar hatching, first clutch brood size, hatching success, and reproductive success. Mean naupliar hatching times ranged from 1.3 days for CON-reared mating pairs to 2.7 days for BphA-reared mating pairs; mean brood size was significantly lower for CON females mated with BphA males than for all other mating combinations; reproductive success of CON females mated with BphA males and BphA females mated with BphA males showed significant differences between females and males. In conclusion, T. japonicus complete life cycle exposures to BphA at an environmentally realistic concentration resulted generally in reproductive depression with effect values depending on the exposure history of the different gender.