Westfall’s knobtail  (Epigomphus westfalli)

Classified as Endangered (EN) on the IUCN red List 2006 (1).

This colourful dragonfly is a typical member of the Gomphidae family, commonly known as ‘clubtail dragonflies' for the enlarged area at the tip of their abdomen. Like other members of this distinctive family, this species possesses green to yellow colouration with black stripes, and small, widely separated eyes (2).

Endemic to Nicaragua (1).

Found in and around lowland to montane rain-forest streams, at between 700 and 1,250 m above sea level (1).

Virtually nothing has been recorded of Westfall’s knobtail’s social, reproductive or feeding behaviour, but certain details can be inferred from what is known about damselflies and dragonflies (Odonata) generally. Odonata species start their life as aquatic larvae or nymphs, passing through a series of developmental stages or ‘stadia', and undergoing several moults as they grow. This larval period can last anything between three months and ten years, depending upon the species. 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 (3).

There is often fierce competition between male dragonflies and damselflies for access to reproductive females, and mature males normally establish territories at choice breeding sites along a stretch of river. Females typically begin to lay eggs in water immediately after copulation, often guarded by their mate. However, females of some species can store live sperm in their body for a number of days (3).

Odonata usually feed on flying insects and are generalised, opportunistic feeders, often congregating around abundant prey sources such as swarms of termites or near beehives (3).

Westfall’s knobtail is known from only two locations, and much of its known range has been deforested, with ongoing habitat loss posing a serious threat to the species (1).

There are currently no known conservation measures targeting this species, but there is an urgent need to search for other subpopulations and to determine the extent of suitable habitat remaining in the general area (1).