Do Insects Expel Liquid Waste Like Humans And Other Animals Do?
For those of you who have ever wondered if insects urinate in the same manner as humans and other mammals, you are in luck, as numerous studies exist that have explored this very topic. Of course insects expel waste, but not many insects expel waste in liquid form. However, some insects do, and a few expel massive amounts of liquid waste. In order to address this particular topic accurately, it may be necessary to define urination. If urination is taken to mean the expulsion of liquid waste from the genitals, then it can be said with certainty that this is not the typical manner in which insects expel waste. Most insects expel only one form of waste despite consuming both liquids as well as solid food items.
Insect waste is usually expelled in the form of mucky droppings. The excretory system of insects can be found in their gut, as they do not possess true kidneys as mammals do. However, many insects possess what are called Malpighian tubules. These are tubes that protrude from their guts in order to filter nitrogenous excreta from the blood. Although the collected nitrogenous excreta is a fluid, it is not expelled as a fluid because it winds up in the hindgut where it is reabsorbed for hydration purposes. Nitrogenous excreta is the closest thing to urine that insects possess, but since it is redirected to the hindgut where solid waste exists before ultimately being reabsorbed, insect waste is expelled through one single orifice. Considering this excretory process, it could be said that most insects do not urinate at all; instead, insects only defecate. For example, caterpillars do not urinate, but they do often defecate. Caterpillar feces is commonly spotted by gardeners in the form of tiny black bags around plant stems. Of course, numerous insects do expel liquid waste, but they are in the minority. Aphids expel a droplet of liquid waste called honeydew which provides other insects with a tasty snack. Cicadas are notorious for expelling voluminous amounts of liquid waste, as some unlucky outdoorsmen have been inadvertently showered with the fluid while standing beneath a tree canopy inhabited by the insects.
Have you ever witnessed an insect expelling waste of any form?