We find that post peak, synchrony degrades in all groups (Figure 4a), the timing of peak ring density shifts or becomes more variable within groups (Figure 4b,c), and IDCs 3–4 became 3–4 hours longer in infections that had to reschedule (ie WT mismatched and Per1/2‐null TRF groups) and 6 hours longer in Per1/2‐null all‐day fed hosts (Table 1). The gene discussed is PER1; the disease is infection.