IUCN SSC Mid-Atlantic Island Invertebrates Specialist Group

Species

BackCalacalles subcarinatus (Israelson, 1984)

Calacalles subcarinatus (Israelson, 1984)

True weevil (English); Gorgulho (Portuguese)

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Coleoptera
  • Family: Curculionidae
LC Least Concern
IUCN Red List Status:

Countries of Occurrence:
Portugal - Azores

Archipelago(s):
Azores

Reviewer/s:
Danielczak, A.

Contributor/s:

Facilitators / Compilers/s:


Assessment Rationale:

Calacalles subcarinatus is an endemic species present in all islands of the Azorean archipelago (Azores, Portugal). It has a relatively large extent of occurrence (EOO = ca 42,600 km²) and area of occupancy (AOO = 420 km²). The species is found in endemic trees but it also seems to be adapted to non-native trees and therefore is expanding its distribution. Living in the canopy of endemic trees it is protected from soil invasive plants. No threats are currently known for this species. Based upon the large area of occupancy and absence of threats it is assessed as Least Concern (LC).

Geographic Range:

Calacalles subcarinatus is an endemic species present in all islands of the Azorean archipelago (Azores, Portugal) (Borges et al. 2010), known from Natural Forest Reserves of Caldeiras Funda e Rasa and Morro Alto e Pico da S? (Flores); Caldeira do Faial (Faial); Mist?rio da Prainha (Pico); Pico Pinheiro and Topo (S. Jorge); Biscoito da Ferraria, Pico Galhardo, Serra Sta. B?rbara and Terra Brava (Terceira); Atalhada e Pico da Vara (S. Miguel) and Pico Alto (Sta. Maria). The extent of occurrence (EOO) is ca 42,600 km² and the maximum estimated area of occupancy (AOO) is 220 km².

Regions:
Portugal - Azores
Extent of Occurrence (EOO):
42600 (km2)
Area of Occupancy (AOO):
220 (km2)
Elevation Lower Limit:
100 (m)
Elevation Upper Limit:
1200 (m)
Biogeographic Realms:
Palearctic
Presence:
Extant
Origin:
Endemic Azores
Seasonality:
Resident

Population:

C. subcarinatus is a widespread  and highly abundant species. The species is expanding to exotic habitats and population is increasing. We assume no impact for the population as it occurs naturally in several native and exotic patches in all islands of the archipelago.

Habitat and Ecology

The species occurs in several habitats and in all islands of the Azorean arquipelago, with an altitudinal range between 100 and 1200 m. C. subcarinatus inhabits the native forests dominated by native and endemic vegetation, prefering Ilex perado subsp. azorica but also occurring in Juniperus brevifolia, Frangula azorica, Vaccinium cylindraceum and Erica azorica; exotic forests (mainly plantations and forests of Pittosporum spp. and Eucalyptus spp.); in agricultural areas occurs associated with Castanea sativa. Adults and larvae are herbivores and feed of plant tissues both during the day and night. Based on seasonal data from SLAM traps obtained in several islands between 2012 and 2016, the adults are active all year, being most abundant in spring and summer (Borges et al. 2017).

Major Threat(s):

In the past, the species has probably strongly declined due to changes in habitat size and quality (Triantis et al. 2010; Terzopoulou et al. 2015). However, the species seems to be adapting to other non-native trees and is expanding its range. No threats are known for this species.

Conservation Actions

The species is not protected by regional law. Its habitat is in regionally protected areas (Natural Parks of Flores, Faial, Pico, S. Jorge, Terceira, Graciosa, S. Miguel and Sta. Maria). No special measures of conservation are needed since the species also occurs in non-native plants and is expanding its range. Some research is needed to understand the population dynamics in exotic trees and orchards.  A monitoring every ten years using the BALA protocol will inform about habitat quality (see e.g. Gaspar et al. 2011).