The photo above (by Gerhard Diedericks) can be viewed in OdonataMAP here.
Find this species in the FBIS database (Freshwater Biodiversity Information System) here.
Orthetrum julia – JULIA SKIMMER
Length up to 57mm; Wingspan attains 74mm.
The most reliable way to differentiate between Orthetrum julia and Orthetrum stemmale is by examining the characteristic shapes of the males secondary genitalia. In addition the Julia Skimmer has black, rather than yellowish pterostigmas and all blackish wing venation. The Bold Skimmer has white subcostal Ax-veins. Furthermore Orthetrum julia shows a single cell row in the Rspl loop, whereas Orthetrum stemmale generally has two cell rows in the Rspl loop.
Julia and Cape skimmers have very similarly shaped secondary genitalia. They can, however, be told apart by other features. Orthetrum julia has blackish pterostigmas and white claspers, while Orthetrum capicola shows yellow-brown pterostigmas and dark claspers.
Click here for more details on identification.
Inhabits shaded streams, rivers, pools and dams in dense forested or wooded areas. Inhabits both still and flowing waters. Regularly found away from water when not breeding.
Breeding individuals found on waterside vegetation, but often found away from water in the surrounding forest or woodlands. Favours shady sites where it sits on exposed twigs in dappled light.
On the wing from September to May.
Status and Conservation
Common and widespread. Listed as of Least Concern in the IUCN Red List of Threatened Species.
Widespread in the higher rainfall regions across Sub-Saharan Africa.
In South Africa it is found in the eastern half where it is most numerous in KwaZulu-Natal, Mpumalanga, Gauteng and Limpopo.
Below is a map showing the distribution of records for Julia Skimmer in the OdonataMAP database as at February 2020.
The next map below is an imputed map, produced by an interpolation algorithm, which attempts to generate a full distribution map from the partial information in the map above. This map will be improved by the submission of records to the OdonataMAP section of the Virtual Museum.
Ultimately, we will produce a series of maps for all the odonata species in the region. The current algorithm is a new algorithm. The objective is mainly to produce “smoothed” maps that could go into a field guide for odonata. This basic version of the algorithm (as mapped above) does not make use of “explanatory variables” (e.g. altitude, terrain roughness, presence of freshwater — we will be producing maps that take these variables into account soon). Currently, it only makes use of the OdonataMAP records for the species being mapped, as well as all the other records of all other species. The basic maps are “optimistic” and will generally show ranges to be larger than what they probably are.
These maps use the data in the OdonataMAP section of the Virtual Museum, and also the database assembled by the previous JRS funded project, which was led by Professor Michael Samways and Dr KD Dijkstra.