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.

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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.

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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.

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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).

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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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