2.5. Determination of Phenoloxidase (PO) Activity

Hemolymph was collected from the silkworms at the indicated times after modeling, and hemolymph samples were centrifuged under 4 °C (12,000 ×g for 5 min). In a 96-well plate, 280 μL PBS was added to each well and preheated at 28 °C for 30 min. Next, 10 μL hemolymph and 10 μL 0.01 mM L-Dopa was added in sequence. An OD value under A490 nm was continuously measured with a microplate reader (20 min period, time interval 2 min, reaction temperature 28 °C). The calculation process was performed as described previously [49]. The PO activity was measured in three female individuals, and each individual was measured three times.