Size and reproduction: compiling a database

In 2018, we published a number of papers that addressed a core area of research for the Centre. These papers considered the relationship between size and reproductive output and what that meant for our understanding of patterns of growth.

In order to do this, researchers compiled a database that accessed published work from the past 100 years that included data on fish size and reproductive output.  When they examined the data from 342 species of fish they found that there was a hyper-allometric relationship between size and reproductive output in 95% of the species they looked at.

This information has massive repercussions for the way in which we manage our fisheries but also, if it is a more general rule, it may change the way we understand growth.

So, is it a more general rule: do larger individuals produce disproportionately more gametes / offspring than smaller individuals in taxa other than fish?

The Centre for Geometric Biology is collating data to enable them to ask if larger individuals produce disproportionately more gametes / offspring than smaller individuals in taxa other than fish? Photo credits: Alligator – skeeze via Pixabay. Centipede – Marshal Hedin via Wikimedia Commons.

Michaela Parascandalo joined the team towards the end of 2018 to focus on gathering data to address this question. Initially she searched for data on invertebrates but has since expanded her search to include a total of 10 phyla. Michaela uses Google Scholar as the search engine and inputs a range of search terms that relate to body size and reproductive output. For each query entered, she looks at every paper displayed on the first 6 pages of results.  She is looking for graphs of length/mass and reproductive output.

Michaela will then open the graph in Data Thief, a program that allows you to extract datapoints from a picture of a graph. In some cases, she has to do additional searches to get a conversion of length to mass for that species and latitudes and longitudes for the study.

All this information is entered into the database; the master copy has only one example of each species while the ‘duplicates’ file stores data from overlapping species’ that might be from different times or locations.

So far there are 75,000 data points in the master file, 30,000 data points in the duplicates file, 10 phyla, 978 species, a data span of 92 years and Michaela has repeatedly been identified as a ‘bot’.

There is more to do, but once Michaela has finished compiling the data, the team will be in a good position to assess the generality of hyperallometry in species other than fish. They will also be able to use the ‘duplicate’ database look at how relationships between size and reproductive output vary through space and time.