Meet the ladybug mimic spider.

Meet the ladybug mimic spider. Ladybugs
are bright red with black spots. This
intense coloration is a warning to
predators that they don't taste very nice.
This is known as aposematic (“warning”)
coloration. There are plenty of examples of
this is nature - monarch butterflies, bees,
wasps and skunks all have aposematic
coloration. Their colors act as a genuine
warning to predators to steer clear.
Once a species has evolved aposematic
coloring, there is an opportunity for other
species to take advantage by mimicking it.
These species evolve the colors, but don't
bother to produce the expensive poisons
and toxins. This is called Batesian
mimicry.
This particular spider mimics the ladybug
and gets all the benefits of the warning
colors - but doesn't need to bother
producing the horrible tasting alkaloids that the ladybug has.