Species

BackXanthandrus azorensis Frey, 1945

Xanthandrus azorensis Frey, 1945

Hoverfly, Flower fly

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Diptera
  • Family: Syrphidae
NT Near Treatened
IUCN Red List Status:

Countries of Occurrence:
Portugal - Azores

Archipelago(s):
Azores

Reviewer/s:
Russell, N.

Contributor/s:

Facilitators / Compilers/s:


Assessment Rationale:

Xanthandrus azorensis is an endemic species of the Azores (Portugal), being present in historical and recent records from Faial, Pico, S. Jorge, and S. Miguel islands. It is apparently widespread through natural and man-made/disturbed habitats. This species has an extent of occurrence of 5,765 km2, although its potential area of occupancy is small (132 km2). It is possible that this species has declined in the past as a result of human activity, even if apparently adapted to artificial habitats and also associated with introduced vegetation. The present situation of this species needs to be assessed and further research is needed into its population, distribution, threats, ecology and life history. Conservation of native habitats could potentially aid this species conservation. Overall, precautionarily, this species is assessed as Near Threatened.

Geographic Range:

Xanthandrus azorensis is a hoverfly species from the islands of Faial, Pico, S. Jorge and S. Miguel (Azores, Portugal) (Frey 1945), known from several distinct habitats, some degraded. Based on the old historical data and more recent records, the extent of occurrence (EOO) is ca. 5,765 km2 and the estimated area of occupancy (AOO) is ca. 132 km2.

Regions:
Portugal - Azores
Extent of Occurrence (EOO):
5765 (km2)
Area of Occupancy (AOO):
132 (km2)
Elevation Lower Limit:
0 (m)
Elevation Upper Limit:
900 (m)
Biogeographic Realms:
Palearctic
Presence:
Extant
Origin:
Endemic Azores
Seasonality:
Resident

Population:

No current population size estimates exist for this species. Nevertheless, this species is relatively widespread through part of the Azores archipelago, in a wide variety of habitats, which might be assumed as an indicator of a stable population.

Habitat and Ecology

Although the larvae of this species are not described (Speight 2018), Xanthandrus azorensis presumably has aphidophagous larvae, like other congeneric species. It has been found visiting flowers of exotic plants (e.g. Hydrangea macrophylla) and endemic plants (e.g. Euphorbia stygiana) (Frey 1945). This species has been collected in several different habitats, including swampy meadows and deciduous forests, and also disturbed or urbanised areas. According to Rojo et al. (1997), its preferred environment is peaty wetland. The species has been found flying from June to September (Rojo et al. 1997).

Major Threat(s):

The lack of information regarding the present distribution and ecology of this species, precludes a complete assessment of potential threats. Nevertheless, from the ecology of the Syrphidae family and known habitat preferences, this species has probably declined in the past due to changes in habitat size and quality, mostly due to human action. On the other hand it seems adapted to some disturbed habitats and is associated with both endemic and introduced flowering plant species; although pesticides and herbicides will most likely have an impact on this species. Based on Ferreira et al. (2016) the habitat will likely further decline as a consequence of climate change (increasing number of droughts and habitat shifting and alteration).

Conservation Actions

Historically, this species was present in areas that are currently included in the Natural Parks of Faial, Pico and S. Miguel, disturbed or otherwise. The species is not protected by regional law. It has been collected in some native vegetation areas, but also in degraded areas. From what is known of its habitat preferences, conservation of native wet or dry grasslands and other natural habitats could potentially aid this species conservation. Degraded habitats could also be restored. Additionally, a strategy needs to be developed to address the future threat by climate change. Further research is also needed into this species population, distribution, threats, ecology and life history.