[Sally Le Page (OP)]

We got this question from listener Ruomei:

"Why do ladybugs [ladybirds] have different numbers of spots on their backs?"

What do you think?

[alancalverd]

They are all different species. Apparently there are over 1000 recognised species, with between 0 and 13 spots and various "shell" colors.

[Bored chemist]

It's an interesting thought. A big part of the reason is so (or because) they recognise eachother for mating.
Which means they can "count"...

[Sally Le Page (OP)]

We asked ladybird expert Helen Roy to answer this on our show, which you can listen to here:

https://www.thenakedscientists.com/podcasts/question-week/why-do-ladybirds-have-varying-spot-numbers [nofollow]

[alancalverd]

It's an interesting thought. A big part of the reason is so (or because) they recognise eachother for mating.
Which means they can "count"...

This is of fundamental importance to those philosophers who want you to wonder whether other animals have consciousness or a sense of self. If you are a 4-spot gentlemanbird you only want to mate with 4-spot ladybirds so however your philosopher defines self or consciousness, you obviously demonstrate it in your mating behavior.
The fact that you only eat aphids and don't generally attack other ladybirds also implies that you have an acute sense of "other" and "same" which is a lot better developed than that of many humans.

[evan_au]

A lot of species also use pheromones to distinguish their own species.