Yellow club-tailed dragonfly  (Gomphus simillimus)

The yellow club-tailed dragonfly has not yet been globally assessed, but is classified as Near Threatened (NT) on the IUCN Mediterranean Red List (1).

Like all members of the Gomphidae Family, the yellow club-tailed dragonfly (Gomphus simillimus) is distinguished by having eyes that are widely separated, rather than touching as in other dragonfly species (2) (3). As its name suggests, the adult yellow club-tailed dragonfly is bright yellow in colour, with bold, black markings on the abdomen and thorax (4) (5). The legs are striped with yellow and the eyes are pale blue (5).

In general, members of the Gomphidae Family do not show much variation in colour between the sexes, although the female of some species may be slightly duller (3). The male yellow club-tailed dragonfly has a distinctly club-shaped tip to the abdomen (2).

The yellow club-tailed dragonfly occurs in southern Europe, inhabiting the Iberian Peninsula and south and central France (2) (4) (5). It also occurs in isolated populations in Belgium, southern Germany and Switzerland (5).

Breeding only in flowing water, the adult yellow club-tailed dragonfly can be found around large, relatively warm and clear rivers, with a low to medium flow velocity and fairly high levels of vegetation (2) (5). The larva inhabits sandy to muddy sediments (5).

Like other dragonfly species, the yellow club-tailed dragonfly has a complex lifecycle which includes a fully aquatic larval stage (2). As larvae or ‘nymphs’, dragonflies are effective sit-and-wait predators with the fascinating feature of being able to fire out the lower portion of the mouth, known as the ‘mask’, in order to grasp passing prey (2) (6). As well as being able to walk, dragonfly larvae are able to move through the water by jet propulsion, expelling water from a specialised rectal chamber to propel themselves along (2).

The total length of time spent in the larval stage varies between dragonfly species, with some species spending a few months and others several years as a larva (2). The larva undergoes several moults before finally emerging from the water as the readily recognisable adult dragonfly (2) (6). The yellow club-tailed dragonfly emerges in June and July, and the flying season of the adult dragonfly lasts until late August (5). Dragonflies are skilled aerial predators, typically feeding on small insects caught on the wing (2) (6).

After maturing, the male yellow club-tailed dragonfly can be found at the edge of rivers, where it tends to rest on exposed gravel banks, large stones or dirt roads in wait for females with which to mate. Reproduction in dragonflies generally involves very little courtship behaviour, and begins with the male grasping the female by the back of the head with claspers at the tip of the abdomen (2). Mating in the yellow club-tailed dragonfly takes up to an hour, and the female then lays the eggs in relatively still areas of water (5).

Approximately 15 percent of dragonfly species in Europe are currently considered to be threatened with extinction (7). The main threat to many species is the drying out of their freshwater habitats as a result of warmer, drier weather and unsustainable extraction of water for drinking and irrigation (7). Pollution and the construction of dams and reservoirs are also impacting some dragonfly populations (7).

Climate change is also expected to impact dragonfly species in the future, increasing the level of desiccation in some freshwater habitats and also causing species’ ranges to shift northward, potentially causing a decrease in the amount of available habitat (7).

Specific threats currently facing the yellow club-tailed dragonfly include river bank stabilisation measures and the use of motor boats, which can cause waves that wash away the newly hatched larvae. Recreational use of rivers for swimming is also reported to result in the trampling of larvae (5).

Recommended conservation actions for the yellow club-tailed dragonfly include the maintenance of its habitat, both through the regulation of bank stabilisation work and through the control of motor boat traffic. It is also believed that distributing educational leaflets will help in the conservation of this species, as will carrying out further monitoring and research in order to better understand its ecology (5).

General plans for conserving dragonfly species across Europe include plans for river systems that will work to conserve ecosystems while addressing the needs of agriculture and development (7).

Find out more about the conservation of the yellow club-tailed dragonfly and other European dragonfly species:

• Kalkman, V.J. et al. (2010) European Red List of Dragonflies. Publications Office of the European Union, Luxembourg. Available at:
  http://ec.europa.eu/environment/nature/conservation/species/redlist/downloads/European_dragonflies.pdf

Find out more about species in the Mediterranean Basin:

• ARKive - Mediterranean Basin:
  http://www.arkive.org/eco-regions/mediterranean-basin/