If you don’t have field data of your own, you can use an example dataset on water beetles in Northern Ireland, collected by the Balfour-Browne Club over more than a century
These data are a subset of the openly-licenced water beetle survey data from the UK’s National Biodiversity Network Atlas, DOI: https://doi.org/10.15468/npcgrp
You can download the survey data below. Clicking on the links below should open a ‘Download’ pop-up in your browser, asking you where to save the file