BackCixius azopicavus Hoch, 1991

Cixius azopicavus Hoch, 1991

Cave lacehopper (English)

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Hemiptera Fulgoromorpha
  • Family: Cixiidae
EN Endangered
IUCN Red List Status:

Countries of Occurrence:
Portugal - Azores


Danielczak, A.

Lamelas-Lopez, L.

Facilitators / Compilers/s:

Assessment Rationale:

Cixius azopicavus is a cave lacehopper endemic to Pico Island (Azores, Portugal) (Borges et al. 2010). It has a very small extent of occurrence (EOO = 140 km²) and reduced area of occupancy (AOO = 24 km²).  The species is very rare and only known from six genetically isolated natural subpopulations. The main threat to this species is above cave deforestation which will reduce the amount of suitable roots as food resources, increased nitrogen levels derived from the use of pesticides in neighbouring pastures and increased dryness due to climate change. We suggest as future measure of conservation the regular monitoring of the species (every ten years) and the creation of a fence in the entrance of the caves. The species is assessed as Endangered (EN), mostly due to fragmentation of the six populations and declining of AOO.

Geographic Range:

Cixius azopicavus is a single island endemic cave lacehopper species from Pico Island (Azores, Portugal) (Borges et al. 2010), where it is restricted to six lava tubes (Furna dos Montanheiros, Gruta das Canárias, Gruta da Agostinha, Gruta do Mistério da Silveira I, Gruta do Soldão  and Gruta das Torres). Its extent of occurrence (EOO) and area of occupancy (AOO) are 140 and 24 km² respectively.

Portugal - Azores
Extent of Occurrence (EOO):
140 (km2)
Area of Occupancy (AOO):
40 (km2)
Elevation Lower Limit:
10 (m)
Elevation Upper Limit:
770 (m)
Biogeographic Realms:
Endemic Azores


The species only occurs in six lava tubes (caves) in Pico Island (Azores) and is particularly rare in terms of abundance in all caves. This species is assessed here as severely fragmented as at least 50% of its population can be found in subpopulations that are 1) smaller than would be required to support a viable population, and 2) separated from other habitat patches by a large distance. Some current impacts of agriculture are high

Habitat and Ecology

This is a troglobitic species (Hoch 1991) with low dispersal ability. It is known to feed on roots of the above cave vegetation. It only occurs in six lava tubes in Pico Island were it is restricted to the deep dark cave zone.

Major Threat(s):

This species is threatened by above cave deforestation which will reduce the amount of suitable roots as food resources. Increasing nitrogen levels derived from the use of pesticides in neighbouring agricultural land are also a threat since change the adequate cover by native trees and shrubs above ground.  However, there are  also several future potential threats: climatic changes (see Ferreira et al. 2016) that can change the conditions inside the caves; change in the road infrastructure around the caves; potential human recreational activities with radical cave visitation and geological events (volcanic activity and earthquakes).

Conservation Actions

This species is not protected by law in the Azores, but part of its distribution is included in protected areas namely in a protected landscape area (Furna dos Montanheiros inside de Pico Natural Park) and a natural monument (Gruta das Torres). Degraded habitats should be restored and a strategy needs to be developed to address the future threat by climate change that may change the vegetation cover of caves. Further research is needed into its ecology and life history in order to find extant specimens in additional caves. A habitat management plan with associated education outreach initiatives is needed and anticipated to be developed during the coming years. It is necessary a monitoring plan for the invertebrate community in the habitat in order to contribute to the conservation of this species.