Seychelles fineliner (Teinobasis alluaudi)
|Synonyms:||Seychellibasis alluaudi, Teinobasis malawiensis|
Classified as Vulnerable (VU) on the IUCN Red List (1). The subspecies ‘Seychelles fineliner damselfly’ (T. a. alluaudi), originally classified as Critically Endangered (CR) on the IUCN Red List, is no longer regarded as a distinct subspecies, but synonymous with the nominate species (2).
The Seychelles fineliner has a vivid orange to red thorax and tip to the long, slender abdomen, and distinctive black markings on its head. However, individuals observed found on Pemba Island and Zanzibar, Tanzania, Africa, during a survey in October 2001, have only been observed with a greenish thorax. Since these individuals showed no mating or egg-laying behaviour at the time (dry season), it is possible that either the orange-red colour develops only in the breeding season, or that this green colouration simply represents a natural population difference in these regions. Nevertheless, specimens found in the Buda Forest (Kenya) and Ngumburuni Forest (Tanzania) during the breeding season showed the vivid orange thorax as described above. Females appear similar to males, but tend to be slightly paler in colour (2).
The Seychelles fineliner has a fragmented, disjunct distribution across East Africa, Madagascar and the Seychelles. In East Africa it has been recorded from Buda forest, south-east Kenya; Ngumburuni Forest in the Rufiji Delta, Zanzibar and Pemba Island, east Tanzania; and Mkuwadzi Forest at Nkhata Bay, south-east Malawi (1). The population confined to the Seychelles was considered extinct until its remarkable rediscovery in 1997 (3). Nevertheless, the species remains extremely scarce here, and is known only from the islands of Silhouette and Mahé (1).
Recent evidence suggests that the currently classified species Teinobasis malawiensis, found in Mkuwazi Forest, Malawi, in fact belongs to T. alluaudi. The official publication of these findings is due out early 2007 (2) (4).
Found in dense, damp, shady, coastal forests, with seasonal swampy areas of stagnant water or sluggish, slow-flowing streams providing the main breeding ground (1) (2). Although clear, rocky streams have been cited as breeding grounds, it is more likely that areas of damp soil or swampy areas from seasonal flooding, often near streams, are used instead (2).
Dragonflies and damselflies (Odonata) start their life as aquatic larvae or nymphs, passing through a series of developmental stages or ‘stadia’, undergoing several moults as they grow. Before the final moult (emergence), metamorphosis occurs in which the larvae transform into the adult form. After emergence, adults undergo a pre-reproductive phase known as the maturation period, when individuals normally develop their full adult colour (5).
As an adult damselfly, the Seychelles fineliner likes to perch for long periods on the tips of fern or palm leaves one to two metres above the ground, only occasionally leaving to glean small insects from nearby leaves and twigs (2).
In Buda forest, south-east Kenya, mating and egg-laying (oviposition) have been observed to begin in April, at the onset of the long rains. Males approach females from their perching positions and mate without any courtship behaviour. Females then place their eggs into damp, muddy soil or leaf-litter, still in the tandem position, guarded by the male until the end of oviposition. Oviposition in water, common to most damselflies and dragonflies (Odonata), has not been observed in this species (2).
Habitat removal for agriculture is probably the biggest threat to this damselfly in Africa (1), although heavy logging pressure in Kenya is also a significant concern (2). Although coastal swamp forests, which once covered large areas of the coastal forest belt from southern Somalia to southern Mozambique, are considered important areas for the conservation of a number of endemic species, they have been shrinking at an alarming rate over recent years and are still under heavy pressure (1) (2). As a result, this habitat type is now reduced to tiny, fragmented forest pockets (1).
The Nature Protection Trust of the Seychelles plans to investigate the ecology of Odonata species on the island of Silhouette, including that of the Seychelles fineliner, in order to identify key sites for their conservation (3).
The largest populations of the Seychelles fineliner are found in the Ngezi Forest, Pemba Island, and in Jozani Forest, Zanzibar. Although these have both been reduced to mere fragments of their original size, they are fairly well protected today (1). Jozani Forest Conservation Project has concentrated great effort on publicity work recently, which has apparently been successful in cutting illegal activities such as logging. The Ngezi Forest is still fairly large, but the growing human population is beginning to encroach upon the forest, and it has been suggested that the area should be promoted as an eco-tourism site, thereby generating income and involving local people with forest protection. This colourful damselfly is also thought to occur in as yet un-surveyed locations along the forest belt of Tanzania and Mozambique, but it is uncertain as to whether such populations will be found before the habitat is destroyed (2).
For more information on the Seychelles fineliner see:
Clausnitzer, V. (2003) Teinobasis alluaudi Martin, 1896 From Mainland Africa: Notes on Ecology and Biogeography (Zygoptera: Coenagrionidae). Odonatologica, 32(4): 321 – 334.
Authenticated (07/11/2006) by Dr Viola Clausnitzer, Chair, IUCN/SSC Odonata Specialist Group, and also by Justin Gerlach, Scientific Co-ordinator, The Nature Protection Trust of Seychelles.
- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Metamorphosis: an abrupt physical change from the larval to the adult form.
- Thorax: part of the body located near the head in animals. In insects, the three segments between the head and the abdomen, each of which has a pair of legs.
IUCN Red List (February, 2010)