Why does changing the bibliography style to "agsm" randomly bold the journal volume numbers?

Question

I'm using the natbib package for the bibliography, and initially had the plainnat style but have since been told that I've got to use Harvard referencing only. So I tried changing the bibliography styles to ones I've found on online reference sheets - e.g. agsm.bst, but the only ones I find that work and put the bibliography references in the order they need to be ('Author;Year;Title;Journal;Volume;Pages') will bold the volume number like this:

JR Krebs. 1980. Optimal foraging, predation risk and territory defence. Ardea, 68:83-90

It looks very odd and I would like to remove this but I don't know how - do I need to change the code, or is there a style package that I should be using?

Here's the code I have set up:

\documentclass[12pt]{article}

\usepackage{fontspec}
\setmainfont{Arial}

\usepackage{natbib}
\usepackage{graphicx}

\usepackage{listings}
\lstset{frame=single,breaklines=true}
\setcounter{secnumdepth}{4}
\sloppy

\usepackage{geometry}
\geometry{margin=1in}


\title{PAPER TITLE}
\date{}

\begin{document}
TEXT HERE
\bibliographystyle{plainnat}
\bibliography{bibliography.bib}

and the bibliography entries are being entered like this:

@article{krebs1980optimal,
  title={Optimal foraging, predation risk and territory defence},
  author={Krebs, JR},
  journal={Ardea},
  volume={68},
  pages={83--90},
  year={1980},
  publisher={BioOne}
}

Answer 1

It does change because this is simply what that particular style does in the BibTeX layer. You can see easily what happens if you look into the derived .bbl:

\begin{thebibliography}{xx}
\harvarditem{Krebs}{1980}{krebs1980optimal}
Krebs, J.  \harvardyearleft 1980\harvardyearright , `Optimal foraging,
  predation risk and territory defence', {\em Ardea} {\bf 68},~83--90.
\end{thebibliography}

The '68' is inside a group in which the (obsolte) font command \bf is issued, which formats the groups content bold. You can try

% arara: xelatex
% arara: bibtex
% arara: xelatex
% arara: xelatex
\RequirePackage{filecontents}
\begin{filecontents*}{\jobname.bib}
  @article{krebs1980optimal,
    title={Optimal foraging, predation risk and territory defence},
    author={Krebs, JR},
    journal={Ardea},
    volume={68},
    pages={83--90},
    year={1980},
    publisher={BioOne}
  }
\end{filecontents*}

\documentclass[12pt]{article}
\usepackage{fontspec}
  \setmainfont{Arial}
\usepackage{natbib}

\let\oldthebibliography\thebibliography
\renewcommand\thebibliography{\let\bf\relax\oldthebibliography}

\begin{document}
\nocite{*}
\bibliographystyle{agsm}
\bibliography{\jobname}
\end{document}

It is worth noting that this will disable \bf in the whole bibliography.

Answer 2

You can quite easily modify the bst file.

1. Find the file agsm.bst in your TeX system

2. Copy it in the same folder as your .tex document, with the name agsm-nobf.bst

3. Open the new file with any text editor

4. Find in it the only line containing the string \bf

5. Edit so that it becomes

   FUNCTION {embolden}
   { duplicate$ empty$
       { pop$ "" }
   %    { "{\bf " swap$ * "}" * }
       { "{" swap$ * "}" * }
     if$
   }
   

   (I left the original one, but commented out, for future memory)

Now your file can become

\begin{filecontents*}{\jobname.bib}
@article{krebs1980optimal,
  title={Optimal foraging, predation risk and territory defence},
  author={Krebs, JR},
  journal={Ardea},
  volume={68},
  pages={83--90},
  year={1980},
  publisher={BioOne}
}
\end{filecontents*}

\documentclass[12pt]{article}

\usepackage{fontspec}
\setmainfont{Arial}

\usepackage{natbib}
\usepackage{graphicx}

\usepackage{listings}
\lstset{frame=single,breaklines=true}
\setcounter{secnumdepth}{4}

\usepackage{geometry}
\geometry{margin=1in}


\title{PAPER TITLE}
\date{}

\begin{document}
TEXT HERE \nocite{*}

\bibliographystyle{agsm-nobf}
\bibliography{\jobname}

\end{document}

A few things to note. I removed \sloppy and you should do it as well. The filecontents* environment is just for convenience here, in order to make the example self-contained; you'll use your bibliography.bib file, but the call should be

\bibliography{bibliography}

without .bib.

Compile, run BibTeX and compile again.

Answer 3

You wrote:

I'm using the natbib package for the bibliography, and initially had the plainnat style but have since been told that I've got to use Harvard referencing only. So I tried changing the bibliography styles to ones I've found on online reference sheets - e.g. agsm.bst, ...

It is not necessary to change bibliography styles if all you need to do is change the style of the citation call-outs from numeric style to "harvard" style, which is also known as author-year style. While it is true that agsm is one of the style files provided by the harvard package, you do not have to switch to agsm (or one of the six other bibliography styles provided by the harvard package) in order to generate authoryear-style citation call-outs.

There are lots and lots of bibliography styles out there capable of generating authoryear-style citation call-outs. In fact, if you are otherwise satisfied with the formatting generated by the plainnat bibliography style, all you need to do is state the option authoryear while loading natbib. (By default, square brackets will be used; if you prefer round parentheses, state the option round as well.) Use \citet to generate "textual" citation call-outs and \citep to generate "parenthetic" citation call-outs.

Of course, if you prefer the formatting generated by the agsm style, by all means switch to agsm style. Just be aware that it is not necessary to do so if all you need to do is change the style of the citation call-outs.

---

\RequirePackage{filecontents}
\begin{filecontents}{bibliography.bib}
@article{krebs1980optimal,
  title={Optimal foraging, predation risk and territory defence},
  author ={Krebs, J. R.},
  journal={Ardea},
  volume={68},
  pages={83--90},
  year={1980},
  publisher={BioOne}
}
\end{filecontents}

\documentclass[12pt]{article}
\usepackage{fontspec}
\setmainfont{Arial}
\usepackage[authoryear,round]{natbib}
\bibliographystyle{plainnat}
\usepackage{geometry}
\geometry{margin=1in}

\begin{document}
\citet{krebs1980optimal}; \citep{krebs1980optimal}
\bibliography{bibliography}
\end{document}