[2] Sphaerularia vespae is characterized by the round, finger-like tip tail of females and the conspicuous male bursa.

[3] Normally, in the fall, healthy queen hornets visit various nooks and crannies, such as decayed logs in the forest, to find a spot to hibernate.

When the queen finds a suitable site, she lines it with plant fibers that serve as nesting material.

However, queen hornets that have been infected by S. vespae have become sterilized due to their undeveloped ovaries and start visiting decaying logs much earlier in the year, during early to mid-summer.

Once deposited in the soil, these juveniles wait for new hosts that settle in for hibernation in the fall and the cycle repeats itself.