Delayed egg hatching accounts for replacement of burrowing mayflies Hexagenia rigida by Hexagenia limbata after recolonization in western Lake Erie

► We conducted a lab experiment to examine species replacement of burrowing mayflies. ► At 20 °C, Hexagenia rigida had higher egg hatching survivorship than H. limbata. ► After 2 and 6 months at 8 °C, H. limbata hatched earlier than H. rigida. ► After 12 months at 8 °C, H. limbata eggs continued to hatch; H. rigida eggs did not. ► Viability of H. limbata eggs may account for the dominance of nymphs in Lake Erie.