Ladybugs do not produce a liquid pee as mammals do; they instead make a concentrated version known as uric acid. What many people mistake for pee is actually the ladybug warning them to stay away by expelling some of its noxious yellow blood.
What is pee?
Pee, or urine, is a liquid created to eliminate nitrogenous waste and other excess biological dross that the body doesn’t need. It is created in the kidneys and then stored in the bladder before being expelled. The majority of urine in mammals is made up of water, and it is also a way to get rid of excess liquids when they aren’t required. Mammals can use urine for a variety of purposes, including marking their territory and even scent-marking themselves. However, birds, reptiles, and most insects do not produce liquid urine; they instead produce uric acid, which is ejected from the same place as their faeces.
Why don’t insects pee?
Like most animals, an insect’s digestive system is made of an alimentary canal, essentially a string of connected organs which take food from the mouth to the rectum. The digestive system is made up of three parts, the foregut, the midgut and the hindgut. The foregut contains a crop, which, much like a bird’s crop, is used for storing food. In the midgut, enzymes help to break down and digest it. Finally, the hindgut allows the reclaiming of essential nutrients and water. Much of the system is very similar in principle to that of mammals; however, insects treat their waste somewhat differently due to their constant battle with osmoregulation, the control of how much water is within their bodies.
The terrestrial environment is highly desiccating for insect life, with a constant battle not to lose too much water. Most acquire water through the food they eat; however, they don’t want to lose it through their urine or faeces because it is so precious. To help them solve this problem, they have what’s called malpighian tubules. These are located in the midgut, and they take nitrogen out of the hemolymph (the insect’s blood) and transport it down to the digestive system. In a mammalian body, the kidneys would help remove toxins from the blood and create urine to dispose of them. In contrast, the malpighian tubules just add it to the same system that is dealing with any digested food waste. Once in the hindgut, any water, and essential sugars or salts that have been transported with the nitrogen, will be reabsorbed, and the remaining waste will form a paste or powder of uric acid.
Therefore, for most insects, they do not ‘pee’ in the sense that we think of it, instead expelling everything from the same place in a fairly solid form. Insect excrement can be called frass, and can look very different depending on which insect has produced it. Wasps leave a smear on the surface of the vegetation they were stood on, whereas wood-eating insects, such as termites, can leave something that looks remarkably like sawdust. The only insects that feel the need to excrete something more watery are those who are struggling with too much, rather than too little, liquids in their systems. Cicadas are a famous example, squirting out their waste so readily that people walking below can mistake it for rain. This is because the cicadas diet is tree sap, high in water. In order to stop themselves from filling up like balloons, they regularly need to expel what they can’t use.
Also read: Do Ladybugs Eat Plants? (Explained)
How do ladybugs pee and poo?
As the ladybug’s diet isn’t very high in liquids, being most commonly aphids, whitefly or scale bugs, they don’t need to struggle with an excess of liquids. They, too, can concentrate largely on more solid excretions. A lady bird’s poo is relatively small and round, reminiscent of a fly dropping. It’s their size that accounts for why we don’t really notice them. Like all insect faeces, it will eventually rot down into the soil, and on mass, can help to fertilise the plants that the ladybugs spend their time on.
However, the ladybug’s main food are largely sap-suckers, meaning these species do have the issue of too much water. In order to overcome this, they do as the cicadas do and excrete the excess. As this waste product is incredibly sweet, from the sugars that have accumulated in the aphid’s body, it’s known as honeydew. Honeydew is consumed by all kinds of insects, either eaten off the plants it lands on or directly from the source. Many ant species have developed a symbiotic relationship with the aphids, farming them for honeydew whilst protecting them from the predators which might otherwise wipe them out, including our hungry and very thirsty ladybugs!
Is that yellow liquid that ladybug’s give out pee?
One of the things often mistaken for ladybirds urine is a smelly yellow liquid that the insects sometimes release when disturbed. This isn’t actually the ladybug relieving itself, but a desperate attempt to get rid of you. It’s what’s known as ‘reflex bleeding’, and it comes from the joints in their legs rather than their gut. The ‘hemolymph’ is ladybug blood and tastes foul. The aim of releasing it is that a predator will see how horrible its dinner tastes without ever having to crunch down on its exoskeleton and hopefully spit it out. Or even better, it’ll smell the nasty liquid and be put off before it even gives it a try.
To avoid having a ladybug bleed all over you, it’s best just to let them go about their business without disturbing them. As you can imagine, giving up some of your all-important hemolymph can wear an insect down if it becomes a regular occurrence. As for watching a ladybug visit the little girls (or boys) room? Well, perhaps if you watch one for long enough, you might just get lucky.