Opal Slim (Aciagrion dondoense)

Find the Opal Slim in the FBIS database (Freshwater Biodiversity Information System) here.

Family Coenagrionidae

Aciagrion dondoenseOPAL SLIM

Identification

There are currently no photographs of this species in the OdonataMAP database.

Aciagrion dondoense are small, elongate and slender damselflies with small heads.

Males are bright greenish-blue on the upper thorax. The sides of the thorax are bright blue. The long, slender abdomen is black above and brownish below. The terminal segments are bright blue, as are the postocular spots.

Most similar to Aciagrion gracile, which occurs in the same areas. The two species are best told apart in the hand by the shape of the males claspers.

Habitat

Found in coastal grassland/forest mosaic where it inhabits flooded, marshy areas and the grassy fringes of pans.

Habitat – Cape Vidal, iSimangaliso Wetland Park, KwaZulu-Natal
Photo by Ryan Tippett

Behaviour

Found low down, close to the water where it moves about among the grass stems. Also recorded away from the water in the shade of fringing bush and forest.

In South Africa it has thus far only been recorded in February. See Phenology below.

Status and Conservation

Very little is currently known about this species. Seemingly rare and erratic in occurrence. Listed as Vulnerable in the IUCN Red List of Threatened Species.

Distribution

Only known from central and southern Mozambique, southern Zimbabwe and NE KwaZulu-Natal in South Africa.

In South Africa it is only known from Cape Vidal in the iSimangaliso Wetland Park. Records show that it was abundant there subsequent to strong cyclonic weather in the early 2000’s. It has not been recorded there since.

Below is a map showing the distribution of records for Opal Slim 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.

Phenology

Dragonfly Atlas: Megan Loftie-Eaton, Sally Hofmeyr, Ryan Tippett & Les Underhill
Dragonfly Atlas: Megan Loftie-Eaton, Sally Hofmeyr, Ryan Tippett & Les Underhill
Megan Loftie-Eaton is our communications, social media and citizen science coordinator. Prior to her work for the BDI, she coordinated OdonataMAP, the Atlas of African Odonata. Sally Hofmeyr has many years' experience in the academic world, writing her own material and editing the work of others. Her academic background is in the natural sciences: her PhD and first postdoc in ornithology and environmental change (Animal Demography Unit, University of Cape Town). Ryan Tippett is an enthusiastic contributor to Citizen Science and has added many important and interesting records of fauna and flora. He has been a member of the VMU since 2014 and has currently submitted over 11000 records. He is also on the expert identification panel for the Odonata Map project. 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.