Countries of Occurrence:
Portugal - Azores
Facilitators / Compilers/s:
Sphaerophoria nigra is unique within the genus Sphaerophoria with a completely black thorax and abdomen with the exception of the yellow scutellum. Males can also be distinguished from rare other melanic specimens of Sphaerophoria with the male genitalia figured in Vockeroth (1971). Sphaerophora nigra is an endemic species from the Azores (Portugal), with historical and recent records in Flores, Faial, Pico, S. Jorge, Terceira and S. Miguel islands. It is apparently widespread through natural and man-made/disturbed habitats, and occurs in areas that are currently Nature Reserves. This species has an extent of occurrence of 22,957 km2, although the area of occupancy is small (152 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; and conservation of native habitats could potentially aid this species conservation. Overall, precautionarily, this species is assessed as Near Threatened.
Sphaerophora nigra is a hoverfly species, described from the islands of Flores, Faial, Pico, S. Jorge, Terceira and S. Miguel (Azores, Portugal) (Frey 1945, Borges et al. 2010). It is known from several distinct habitats, some degraded, but also from areas that are Nature Reserves (Caldeira do Faial - Faial and Pico da Vara - S. Miguel). Based on the old historical data and more recent records, the extent of occurrence (EOO) is ca. 22,957 km2 and the estimated area of occupancy (AOO) is ca. 152 km2.
No current population size estimates exist for this species. Nevertheless, this species is relatively widespread through the archipelago, in a wide variety of habitats, which might be assumed as an indicator of a stable population. However, some fluctuations can be assumed in aphidophagous species with a wide range of suitable habitats.
The ecology and traits of this species are unknown. Larvae are presumably aphidophagous and, according to the wide habitat spectrum and altitudinal range on the Azores, no specialisation is expected on one or only a few aphid species. Most adults are very active fliers and often visit flowers, feeding on nectar and pollen (McAlpine 1987), and are also important pollinators. Other species of the genus Sphaerophora are usually associated with grasslands, woodlands or marshes. Several specimens of this species were collected in shady forest areas, or in association with flowers of Euphorbia stygiana and Hydrangea macrophylla. It was also reported from higher altitude areas in Pico Mountain (Pico).
A 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, it is likely that 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).
Historically at least, this species was present in areas that are currently included in the Natural Parks of Flores, Faial, Terceira and S. Miguel, disturbed or otherwise.; but the species is not protected by regional law. A habitat management plan is needed and one is anticipated to be developed during the coming years. Further research is also needed into this species population, distribution, threats, ecology and life history, and degraded habitats could also be restored. Additionally, a strategy needs to be developed to address the future threat by climate change.