Dwarf Blue refreshed after 142 years

What are all these citizen scientists focused on? The temperature in the Robertson Valley is a warm 32°C. It is 1pm on 2 March 2019.

They are taking photographs of South Africa’s tiniest butterfly, the Dwarf Blue Oraidium barbera. It’s inside here, sitting on a little yellow flower! At the bottom of this blog, there is a hint if you can’t find it!

Here it is close up. The flower it is sitting on has a diameter of 10mm. This photo was taken by Fanie Rautenbach. In the LepiMAP section of the Virtual Museum you find this record at  http://vmus.adu.org.za/?vm=LepiMAP-673920.

Here is the distribution map from LepiMAP for the Dwarf Blue before the trip. The grid cells for which there are Virtual Museum records have turquoise circles. These are the records with photographs. The orange squares are specimen records dating back to the year dot, assembled with great love and care from museums and other collections during the Butterfly Atlas Project, SABCA. There is an orange square in grid cell 3319DD Robertson (in the centre of the red circle), the which one we visited. This means that the records here are based by one or more specimen records.

Checking the LepiMAP database shows that two specimens were collected in this grid cell. The details of one of them are shown above! They were collected in January 1876, and are curated by the Natural History Museum in London. The specimens are still there, carefully preserved by generations of museum staff! These are the only records ever made of Dwarf Blue in this grid cell! In the Virtual Museum, the information is stored electronically (and accessibly!) at http://vmus.adu.org.za/?vm=LepiMAP-230827

And here is the new distribution map, updated to show the turquoise circle! Awesomely well done, citizen scientist Basil Boer, on finding the Dwarf Blue. This record is the ultimate “refreshment” of an almost prehistoric record, made 142 years ago.

The team also added two species to the list for the grid cell: Tinktinkie Blue Brephidium metophis and Dwarf Sandman Spialia nanus. The list of Lepidoptera recorded in grid cell 3319DD Robertson since 1980 now totals 36 species. For an up-to-date list, click on http://vmus.adu.org.za/vm_locus_map.php?vm=LepiMAP&locus=3319DD. At present the median date of the “Last recorded dates” lies in 2008. In words, what this statistic means is that half of the species in this grid cell have not been recorded for 10 or more years! They badly need to be “refreshed.” Do they still occur here? To achieve this will take a series of trips, to different habitats within the grid cell, and at different times of the year.

The citizen scientists who were part of the 2 March 2019 trip to the Robertson District (N1 to Worcester, then the R60 towards Robertson) were Fanie Rautenbach, Wilna Steenkamp, Corrie du Toit, Basil Boer and myself. Besides butterflies, we had a good selection of dragonflies and damselflies to submit to OdonataMAP and a carnivore scat full of hair for MammalMAP (http://vmus.adu.org.za/?vm=MammalMAP-27384).

 

The HINT follows!

HINT: Did you battle to  find the Dwarf Blue in this photo? Here is the hint. there are three minute yellow flowers a bit below the centre. They form a triangle. The Dwarf Blue is sitting on the flower at the top right of the triangle.

Did you find the butterfly? Here is a close up of the three yellow flowers. They form a triangle. The Dwarf Blue is sitting on the flower at the top right of the triangle, near the top edge of the picture.

 

Les Underhill
Les Underhill
Prof Les Underhill has been Director of the Animal Demography Unit (ADU) at the University of Cape Town since it started in 1991. Although citizen science in biology is Les’s passion, his academic background is in mathematical statistics. He was awarded his PhD in abstract multivariate analyses in 1973 at UCT and what he likes to say about his PhD is that he solved a problem that no one has ever had. He soon grasped that this was not the field to which he wanted to devote his life, so he retrained himself as an applied statistician, solving real-world problems.

1 Comment

  1. We have found Dwarf Blue in the Muden Valley KZN, eggs were collected and the full life-cycle recorded, the eggs were found on Crassula fragilis, and the caterpillars reared on this plant. It would be interesting to know if C.fragilis was found in the Robertson Valley. Comment would be interesting!
    Well done!

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