Bold Skimmer (Orthetrum stemmale)

The photo above (by Alan Manson) can be viewed in OdonataMAP here.

Find this species in the FBIS database (Freshwater Biodiversity Information System) here.

Family Libellulidae

Orthetrum stemmale – BOLD SKIMMER

Identification

Medium sized

Length up to 50mm; Wingspan reaches 81mm.

Most similar to Orthetrum julia (Julia Skimmer) and Orthetrum brachiale (Banded Skimmer). The most reliable way to differentiate between the three is by examining the characteristic shapes of the secondary genitalia.

Click here for more details on identification.

Habitat

Inhabits the grass, reed and bush fringes of rivers, streams, pools, dams and marshes. A species of well-wooded savanna regions. Non-breeding individuals are often found in woodlands away from the water.

Behaviour

Breeding individuals are found on waterside vegetation, but often found away from water in the surrounding woodlands. Perches on exposed twigs among bushes where it hawks insects in rapid flight.

Status and Conservation

Common in NE KwaZulu-Natal and in the Lowveld, scarce elsewhere. Listed as of Least Concern in the IUCN Red List of Threatened Species.

Distribution

Widespread over much of the savanna regions of Sub-Saharan Africa.

Occurs in the North and East of South Africa where it is most numerous in NE KwaZulu-Natal.

Below is a map showing the distribution of records for Bold 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.