The April Fool’s Day Files: Natural born liars

April Fool’s Day is a time when fibs, fabrications, and falsehoods come to the fore! While we humans do this in (mostly) good fun, in nature deception is a serious business, often with life-or-death stakes. In this post, Phil Sirvid and Lara Shepherd share some of their favourite liars from the natural world.

How camouflage works isn’t always black and white

The North Island lichen moth (Declana atronivea) is such an expert deceiver, it should be called a lie-chen moth. The moth has a striking black and white wing pattern and if you see one resting on a plain background it sticks out like a sore thumb.

However, against lichen, it’s another story. The wings blend in nicely, but it’s not just about the matching colour schemes. This species is one of very few insects with asymmetric wing patterns, which means the wings on one side are not a mirror image of the other.

Lichen is irregular in appearance, and experiments have shown the lichen moth’s slightly uneven patterning breaks up the moth’s outline against this background more than a symmetrical pattern does. This makes the moth much harder to spot.

It’s not just the moths that are tricky. Depending on how they pose themselves, caterpillars can look like twigs (body straight) or bird poop (body curled up).

Looks can be deceiving…and so can smells!

And speaking of bird poop, we have bird-dropping spiders (genus Celaenia). Some species resemble bird droppings, which is a nice form of camouflage as predators aren’t likely to look too closely at something so unappealing.

However, that’s not where the lies end. Bird-dropping spiders are not just visual mimics, they’re also chemical mimics. While these spiders are part of the orbweaver family Aranaeidae, they don’t build the classic cartwheel shaped webs associated with this group. Instead, they hang on a line of silk and wait for moths to obligingly fly right up to them to be grabbed and bitten.

Male moths rely on pheromones produce by females to find them, but the spider has copied these chemical signals. The only warm embrace the moth will find is from a spider’s legs before it’s bitten.

Intriguingly, bird-dropping spiders copy different pheromones as they grow. The moths are too big for young bird-dropping spiders to tackle, so they instead mimic the pheromones of smaller insects called moth flies (family Psychodidae), switching to moth pheromones when they are large enough.

Better than a flower – pretty little liar

At first glance, the orchid mantis (Hymenopus coronatus) from Southeast Asia (and a star in our Bug Lab exhibition) is a textbook case of camouflage. With it’s pink and white colouring and petal-like body parts, it looks like it would blend in nicely with orchid flowers as it lies in wait for its prey. But that’s not what is happening here.

While the orchid mantis is the first animal known to mimic flowers, it doesn’t have a particularly close resemblance to any one kind of orchid. Yet insects fly right up to it.

Why? To flower-visiting insects, the mantis isn’t hiding, it’s standing out. Insects see more of the ultraviolet (UV) part of the light spectrum than we do, and how flowers look under UV light can help attract insect pollinators.

Experiments have shown the fiendish genius of the orchid mantis is that under UV light, it’s even more attractive than an orchid so a pollinator is more likely to choose it over a flower. Lunch delivers itself in a dramatic case of fatal attraction!

A grand seduction

Not only are there insects that look like flowers but the reverse is also true. Some plants, especially orchids, have evolved flowers that closely resemble the females of particular insects. Not only do the flowers look like female insects (wasps, bees, flies or beetles, depending on the plant species) but they also produce the same pheromones.

Male insects after a good time are attracted to these flowers and attempt to mate with them. The insect leaves unsatisfied with nothing to show for their dalliance but a dollop of pollen, which is then transferred to the next flower the male tries it on with. Watch this in action:

https://www.youtube.com/watch?v=6yLnKfhmUzg?si=d9XdJfj7cQt9Z5xV&start=54

Plants playing dead

Some plants employ more gruesome tactics to get pollinated. A number of unrelated plants have evolved flowers that look and smell like rotting animal carcasses – this is not a bunch of flowers you want to give to your beloved!

These ‘carrion flowers’ often heat up and have hairy surfaces, features which help disperse the rotten smell to attract insects from far and wide. By resembling a dead body, the flowers trick insects whose larvae eat meat (mostly flies but also some beetles) into laying their eggs on them, thus moving pollen between flowers in the process.

We don’t have any native carrion flowers in Aotearoa New Zealand, but our stinkhorn fungus and austral poop moss use a similar smelly approach to trick insects into dispersing their spores.

You can’t see me!

Other plants appear to have evolved mimicry not to attract animals but to keep them away. These masters of disguise closely resemble objects that are unappealing or inedible to browsing animals, such as a clump of dead grass or rocks.

In New Zealand the leaves of our own toropapa (Alseuosmia) have been suggested to mimic a range of unrelated plant species. The most convincing example is Alseuosmia pusilla, whose leaves closely match the colouration, size and shape of those of horopito (Pseudowintera colorata), a species whose leaves produces chemicals imparting a hot peppery taste.

So, there you have it. We’ve covered insects that look like flowers and flowers that look like insects, fake smells, canny camouflage, and plants that copy other plants and even rocks. These are some of our favourite fibbers from the natural world and trust us, they’re all real plants and animals. After all, would we lie to you?