Halfshade Dropwing (Trithemis aconita)

Cover photo by Desire Darling.

Find the Halfshade Dropwing in the FBIS database (Freshwater Biodiversity Information System) here.

Family Libellulidae

Identification

Small size

Length up to 41mm; Wingspan attains 67mm.

The overall appearance of the Halfshade Dropwing is of a small, slender, and entirely dark blue species. It is one of a handful of small, dark blue species in the region. Trithemis aconita can be told apart from other similar species by its noticeably slender abdomen and its shady riverine habitat.

Males most resemble the Silhouette Dropwing (Trithemis hecate). The Halfshade Dropwing can be differentiated by its thin black abdomen with yellow streaks. This abdomen pattern seldom becomes obscured with pruinosity, unlike the Silhouette Dropwing. Young male Silhouette Dropwings (Trithemis hecate), also have thin abdomens with yellow streaks. However, this pattern becomes obscured with dark blue pruinosity once mature. The two species also differ markedly in their behaviour and habitat choices.

Females are easily confused with other Trithemis species. They are best identified by their association with the males.

Click here for more details on identification of the Halfshade Dropwing.

Habitat

The Halfshade Dropwing frequents shaded rivers and streams in riverine, swamp, and coastal forests, as well as dense woodland. It favours areas with leafy trees overhanging the river, often where there is running water with rocks or shaded pools.

Behaviour

The Halfshade Dropwing is a shade loving species, often perching on shaded twigs over the water. It also sits in dappled light and sunspots near the water but is seldom found far from shade. The Halfshade Dropwing is shy and weary and flies into the treetops at the slightest sign of disturbance. It usually perches under the overhanging canopy of trees, often fairly high up but sometimes also low down, close to the water on rocks and exposed tree roots.

The Halfshade Dropwing flies from November to April.

Status and Conservation

The Halfshade Dropwing is uncommon and very localised in South Africa. It is listed as of Least Concern in the IUCN Red List of Threatened Species. This species is intolerant of damage to its riverine home and is only found in high-quality habitats.

Distribution

The Halfshade Dropwing is erratically distributed throughout most of sub-Saharan Africa. It is largely absent from the dry arid parts of Namibia, Botswana, and South Africa. Its South African range is confined to low altitudes along the perennial savanna rivers of the Limpopo and Mpumalanga provinces and the forested rivers of coastal Kwa-Zulu-Natal.

Below is a map showing the distribution of records for Halfshade Dropwing in the OdonataMAP database as at February 2020.

Below is a map showing the distribution of records for Halfshade Dropwing in the OdonataMAP database as at December 2024.

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.

Further Resources

The use of photographs by John Wilkinson, and Sharon Stanton is acknowledged.

Halfshade Dropwing Trithemis aconita (Lieftinck, 1969)

Other common names: Monk’s Hood Dropwing (Alt. English); Skaduvalvlerkie (Afrikaans).

Recommended citation format: Loftie-Eaton M; Navarro R; Tippett RM; Underhill L. 2025. Halfshade Dropwing Trithemis aconita.  Biodiversity and Development Institute. Available online at https://thebdi.org/2020/05/12/halfshade-dropwing-trithemis-aconita/

References: Tarboton, M; Tarboton, W. (2019). A Guide to the Dragonflies & Damselflies of South Africa. Struik Nature.

Samways, MJ. (2008). Dragonflies and Damselflies of South Africa. Pensoft

Samways, MJ. (2016). Manual of Freshwater Assessment for South Africa: Dragonfly Biotic Index.Suricata 2. South African National Biodiversity Institute, Pretoria

Martens, A; Suhling, F. (2007). Dragonflies and Damselflies of Namibia. Gamsberg Macmillan.