[Pontiac]

The trained bees were then shown a card that was empty versus one that had symbols on it. Without any prior training, the bees flew more often to the empty card — thereby demonstrating that they understood that "zero" was a number less than the others, according to the study

An alternative theory would be that the bees were flying to the card with the most uniform coloring.

The card with the fewest symbols on it would be the card most uniform in color.

[GOP Poet]

Yes. This crossed my mind as well. It was certainly another variable that needs to be tested in the future if they are to solidify the first theory.

[Honest Nigerian]

An alternative theory would be ..........
^^^^^^^^^^^^^^^^^^^^^^^
Thanks for sharing that.
And I agree. There are a number of possible conclusions. I am not going to read the linked article, or look for the actual paper. but this is just one more instructive example of how many “scientists” claim to have PROVEN something (and/or how shoddy journalism has become) when all they have done is collect some data (and then imposed some construct/interpretation on it).