Visualising weevil-plant associations with network graphs

I have been transcribing host plant association data from Colonnelli (2004)’s catalogue of the Ceutorhynchinae (Fig. 1). With more than 1320 species, the Ceutorhynchinae is a relatively small (we are talking about weevils!) subfamily of weevils. Enzo Colonnelli worked on this catalogue for more than 20 years to bring it to fruition.

Figure 1. Cover page of the Ceutorhynchinae catalogue

Almost half (609) of the valid species have host records, which are reported as ‘ecology’ in the catalogue (Fig. 2). A host record here is just a plant name, usually at the species or genus level. Figure 2 also gives us a glimpse of the organisation of a taxonomic catalogue, which typically follows the taxonomic hierarchy,  here as Tribe-genus-species. There could be intermediate ranks such as subtribe and subgenus.

Figure 2. Excerpt from Colonnelli (2004), showing an example of host plant records

The host plant association data was transcribed to a spreadsheet (Fig. 3) from the PDF file manually, a rather laborious process. One could have probably written a script to automatically parse the text.

Figure 3. Screenshot of spreadsheet of transcribed host plant association data from Colonnelli (2004)

I then made some network graphs using a Weevil-plant association fusion table to visualise weevil-plant associations (Fig. 4). The association of two entities are being visualised here: weevil tribe and plant genus. There are several interesting observations we can make from this graph. (1) Each weevil tribe has a non-overlapping cluster of associations. (2) Ceutorhynchini has the largest number of associations and hence the largest cluster. (3) A small number of plants are shared between weevil tribes. The same network graph can also be made for other pairs of entities (weevil genus and plant genus).

Figure 4. Weevil-plant association network graph made with Google Fusion Table. Each blue circle is a weevil tribe and yellow circle a plant genus. The size of a circle represents the number of associations.



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