A cute analogy: Similar molecules which differ slightly in chain length cause similar behavioral reactions in ants. Therefore, similar chemicals are like lexical synonyms in human language. This is a rough paraphrase of the brief post Chemical Ant Language Has Synonyms.
But is the analogy valid?
The blog was referring to a study that investigated what appeared to be a pretty straight forward stimulus-response reaction. Ants were exposed to a variety of chemicals which differed minimally and their reactions were recorded. Upon first pass, it appears as though no sort of cognitive processing occurred in the ants (I cannot speak with any authority on the state of cognitive processing in ants, but I'm guessing it's limited at best). The blog post author took the sysnonym analogy straight from the original study Deciphering the Chemical Basis of Nestmate Recognition (full citation below). From the abstract:
This study contributes to our understanding of the chemical basis of nestmate recognition by showing that, similar to spoken language, the chemical language of social insects contains “synonyms,” chemicals that differ in structure, but not meaning (emphasis added).
Linguists have been justly accused of having both physics envy and biology envy for our tendency to borrow concepts from those fields to help understand linguistic processes. This, however, may be a case of linguistics envy. The use of language as a metaphor for anything remotely communicative is all too familiar to many of us and typically wrong. And the public's love of animal language stories fuels the fire.
Clearly the findings are interesting to the extent that they show a certain categorical response. Apparently ants respond to a set of chemicals in a similar way and this set of chemicals might be loosely compared to a set of synonyms like run, jog, trot, scurry, scamper, sprint, etc. But the most interesting thing about lexical synonyms is that they DO differ in meaning and distributional properties. Even if the differences are nuanced, they are real. Their semantics are related, but it's the differences that are the object of linguistic inquiry. So, if the ant response is to be a viable analogy to lexical synonyms, we're going to have to see that each chemical variant produces a similar but interestingly different response in ants.
Now, what might be a closer linguistic analogy is that of phonemes. Here we have a well undersood phenomenon whereby a set of similar but interestingly different sounds are perceived as belonging to a single class. There is also the interesting categorical perception phenomenon where slight differences in sounds can be perceived as whole category differences, not unlike molecules of different chain length causing a similar reaction in ants (I think).
Wilgenburg, E., Sulc, R., Shea, K., & Tsutsui, N. (2010). Deciphering the Chemical Basis of Nestmate Recognition Journal of Chemical Ecology, 36 (7), 751-758 DOI: 10.1007/s10886-010-9812-4