[2] P. grandis flies live in various ecosystems, ranging from streams to flatlands to forests to mountains.

[5] The life stage duration varies depending on the type of aquatic environment they live in.

[6] Adult P. grandis flies feed on the nectar inside Japanese chestnut flowers, usually at night.

[8] However, when only small prey are available to eat, the size of the P. larvae decreases as they enter the pupal stage of the lifecycle, resulting in dwarfism.

[9] P. grandis fly larvae utilize an "ambush" method of foraging, hiding and remaining motionless, which helps them avoid being attacked by predators.

[4] The various colors of the substances secreted by the female flies aids in crypsis of the eggs, causing them to blend into the surroundings and making them harder for predators to detect.