Btukfyl

My question parallels that of https://english.stackexchange.com/q/99886/117318, which asks whether "Gamma et al." should be considered singular or plural for verb conjugation. The top and accepted answer says that it depends whether the verb refers to the researchers (since the translation of the Latin is "Gamma and others", which is plural), or if it refers to the publication/work.

Which usage is conventional in academia?
Is there significant variation across fields that anyone is aware of? Are there best practices to avoid confusion?

I'm going out on a limb here and making a wild guess. "Academia" is too broad. Some fields may use one more often than another, but I really doubt that it goes much beyond a single author and how he/she is thinking at the moment. I think you will find wide variety of usage even in the same field.

However, I'll go out even further on the limb and suggest both a reason for this and what I consider a sensible way to write.

Sometimes you want to refer specifically to a particular paper and your phrasing or context makes that clear. Whether the paper has multiple authors or not isn't relevant. The paper is it and it is singular.

However, sometimes you want to refer more generally to the work of an author or a group of authors, of which a particular paper is only an instance. In such cases it is entirely natural to use singular or plural depending on the number of authors.

But it is a bit more complicated. You could, in fact, even refer to the work of a particular lab (in general) independent of its members, in which case, it is, again, singular (in the US, at least - see below), depending on your overall phrasing and context.

There is, I've noticed, a per-country convention in some of this. In the US, if I refer to the work of, for example, Google, I would use the singular (Google has produced...). But in the UK an organization is considered to be plural (Google have produced...). This same convention would naturally be applied to a lab considered as an organization.

So, my conclusion is, don't look for any consistency for Academia. But try to make clear in your writing whether you are referring to a particular paper (singular) or to the work, more generally, of its authors (varies).

If you say "Gemma et al." to mean the paper, then it is singular. (This is the usual case.) If you say "Gemma et al." to mean all the authors of the paper, then it is plural.

Gemma et. al. describes the ants of Southeast Asia.

But note: Gemma et. al. have never actually been to Southeast Asia.