Use the cover letter communicate to the editor why your manuscript should be published in their journal. So address how your topic is a good fit for the journal and its readers, how it is within the scope of the journal. You may also want to mention the type of article that best matches your manuscript (common article types are original research article, review, perspective, methods paper).
Below is a basic template for a cover letter.
Your name
Your main institutional or professional affiliation
Your main institutional or professional address
Date
Dear Editor name,
We are writing to accompany our submission, “article title” by authors for consideration by Integrative and Comparative Biology. We confirm that this manuscript has not been published elsewhere and is not under consideration for other publications.
[select appropriate option for how your manuscript was invited]:
Option (1) This manuscript was invited as part of a SICB symposium, where I/we/[name of co-author] presented a talk / poster entitled [presentation title] by [presentation authors] at the symposium / complimentary session to the symposium entitled [symposium name].
Option (2) This manuscript was invited as part of a special issue [title of the invited issue]
Option (3) This manuscript was invited in recognition of being awarded the [insert name of SICB award, e.g. Dorothy Skinner Award, or best student presentation in [division name]]…
Option (4) Our manuscript was invited by the editor [insert name] on [date] for submission to ICB.
Give here a brief statement about the content of your manuscript. Such as “Our study shows… and these findings are important because ….” or “Our review discusses …” or “Our manuscript describes …” or “Our study is relevant to Integrative and Comparative Biology’s readership because… ”
Correspondence may be addressed to [insert name and contact details of corresponding author].
All authors of the paper have fulfilled criteria for authorship and agreed to submit to the journal.
Thank you for your consideration.
Sincerely,
Your name