Black-splashed Elf (Tetrathemis polleni)

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

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

Family Libellulidae

Tetrathemis polleni – BLACK-SPLASHED ELF

Identification

Small size. Length up to 35mm; Wingspan attains 63mm.

Banded males are striking and distinctive. Unbanded males can be mistaken for skimmers (Orthetrum spp.) but can be separated on wing venation and behaviour.

Females are quite similar to those of Notiothemis jonesi (Eastern Forestwatcher). They are best identified by wing venation. Tetrathemis polleni has a four-sided discoidal cell in the forewings, while the fore wing of Notiothemis jonesi has a triangular discoidal cell.

Click here for more details on identification.

Habitat

A shade loving species of calm, forested rivers, streams and pools. They favour areas where trees overhang the water. Frequents both coastal and inland forests, mostly in warmer areas.

Behaviour

Males perch conspicuously on overhanging branches and twigs. Usually 1 to 3m above the water. Females are not seen as often and frequently sit higher up and slightly further away from the water. The flight is fast and the males black wing splashes give a fluttering effect. They don’t fly for long and quickly return to their perch. Tetrathemis polleni characteristically sit with their wings drooped forward and abdomen held up at an angle.

Status and Conservation

Tetrathemis polleni is a common but localised species. It is listed as of Least Concern in the IUCN Red List of Threatened Species. The Black-splashed Elf is most common in undisturbed habitats but can occur at suitable man-made ponds and impoundments. It is moderately sensitive to habitat degradation. This species tolerates some turbid or stagnant water and abandons sites extensively lined with alien trees. Sensitive to deforestation of overhanging indigenous trees that results in a loss of shady habitat.

Distribution

This species is most widespread in the Eastern parts of Africa from South Africa to Uganda, Somalia and Ethiopia. There is also a population in West Africa ranging from Nigeria to Guinea.

Below is a map showing the distribution of records for Black-splashed Elf 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.