A 13-year termite (Insecta, Blattodea) monitoring programme in the Azores: Dataset and findings

Biodiversity Data Journal 13: e164834 doi: 10.3897/BDJ.13.e164834 Data Paper A 13-year termite (Insecta, Blattodea) monitoring programme in the Azores: Dataset and findings Paulo A.V. Borges , Sónia Bettencourt , Dejalme Vargas , Raquel Medeiros , João Melo , Ana Rodrigues ‡ University of Azores, CE3C—Centre for Ecology, Evolution and Environmental Changes, Azorean Biodiversity Group, CHANGE —Global Change and Sustainability Institute, School of Agricultural and Environmental Sciences, Rua Capitão João d’Ávila, Pico da Urze, 9700-042, Angra do Heroísmo, Azores, Portugal § IUCN SSC Atlantic Islands Invertebrate Specialist Group, Angra do Heroísmo, Azores, Portugal | IUCN SSC Monitoring Specialist Group, Angra do Heroísmo, Azores, Portugal ¶ Secretaria Regional do Ambiente e Acão Climática, Direção Regional do Ambiente e Ação Climática, Rua Cônsul Dabney, Colónia Alemã, Apartado 140, 9900-014, Horta, Azores, Portugal Corresponding author: Paulo A.V. Borges ([email protected]) Academic editor: Edward Baker Received: 11 Jul 2025 | Accepted: 11 Oct 2025 | Published: 23 Oct 2025 Citation: Borges PAV, Bettencourt S, Vargas D, Medeiros R, Melo J, Rodrigues A (2025) A 13-year termite (Insecta, Blattodea) monitoring programme in the Azores: Dataset and findings. Biodiversity Data Journal 13: e164834. https://doi.org/10.3897/BDJ.13.e164834 Abstract Background From 2011 to 2024, the Azorean Government tested two coordinated monitoring programmes across the archipelago to survey four invasive termite species: the West Indian drywood termite, Cryptotermes brevis (Walker, 1853); the yellow-necked drywood termite, Kalotermes flavicollis (Fabricius, 1793); the Western European subterranean termite, Reticulitermes grassei Clément, 1978; and the eastern subterranean termite, Reticulitermes flavipes (Kollar, 1837). The monitoring programme was mostly directed to the detection of C. brevis in new locations. Drywood species were detected on multiple islands, with C. brevis established on six islands (from west to east: Faial, Pico, São Jorge, Terceira, São Miguel and Santa Maria) and exhibiting the highest infestation densities in the urban centres of the three most important islands in terms of economic activity and human population (São Miguel, Terceira and Faial). Kalotermes flavicollis occurs more sporadically, primarily along the south coasts of Terceira, São Miguel and ‡,§,| ¶ ¶ ¶ ¶ ¶ © Borges P et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. southeast coast of Faial and seldom attains the pest status of C. brevis. In contrast, the two Reticulitermes species remain restricted to localised subterranean infestations: Reticulitermes grassei in Horta (Faial) and R. flavipes near Lajes Air Force Base (Terceira), each detected via house inspection visits. Collectively, these efforts provide the first comprehensive, archipelago-wide dataset on termite presence, laying the groundwork for targeted Integrated Pest Management strategies in the Azores. New information Records of Cryptotermes brevis overwhelmingly dominated the monitoring data, comprising 1,801 of the 1,832 total events (98%), a pattern consistent with previous surveys of its rapid spread in the Azorean urban environment. These detections were heavily concentrated on two islands: Terceira (n = 919) and São Miguel (n = 755). In contrast, Faial, Pico and Santa Maria each yielded roughly 40 records and São Jorge only seven. Annual trap‐capture counts across all islands increased steadily from approximately 40 captures in 2011 to 154 in 2024, peaking at 185 in 2023. Kalotermes flavicollis was the second most frequently recorded species (n = 24), with most records originating on São Miguel, mirroring its more restricted distribution. The two subterranean termites, Reticulitermes grassei and R. flavipes, were documented exclusively on Faial and Terceira, respectively, consistent with their historically limited foothold in the archipelago. Now established on every surveyed island and exhibiting an upward trajectory in annual detection counts, C. brevis remains the foremost urban termite threat in the Azores. To forestall further structural outbreaks, Integrated Pest Management should place sustained emphasis on early detection — through year-round trap checks — and on heightened public awareness, by encouraging residents to report both the characteristic pin-sized faecal pellets and any termite occurrence observed during swarming periods. Keywords Azores Archipelago, termite monitoring, invasive termites, long-term dataset, urban pests. Introduction Termites play a central role in tropical and subtropical ecosystems, driving decomposition of lignocellulosic material, enhancing soil structure and fertility and facilitating nutrient turnover (Fox-Dobbs et al. 2010, Jouquet et al. 2011). Indeed, termites are frequently described as ecosystem engineers due to their impact on soil structure and nutrient distribution (Jouquet et al. 2011, Lavelle et al. 2021). Despite these benefits, several native (autochthonous) and invasive termite species have become major urban pests, causing structural damage that costs billions of euros 2Borges P et al annually and necessitates costly control measures (Buczkowski and Bertelsmeier 2017). Termites are causing extensive damage to buildings, wooden structures and furniture by feeding on cellulose‐based materials, including framing timbers, flooring, door and window frames and even decorative veneers (Ridout 2023). In addition to direct structural harm, termite galleries facilitate moisture ingress and fungal decay, further accelerating wood degradation and increasing repair costs (Martín and López 2023). Islands are especially susceptible to termite introductions, since reduced native termite diversity and limited natural enemies often allow colonisers to proliferate unchecked once established (Austin et al. 2012, Su and Scheffrahn 2000). In the Azores Archipelago, four invasive termites are currently known (Borges et al. 2022): the West Indian drywood termite, Cryptotermes brevis (Walker, 1853); the yellow-necked drywood termite, Kalotermes flavicollis (Fabricius, 1793); the Western European subterranean termite, Reticulitermes grassei Clément, 1978; and the eastern subterranean termite, Reticulitermes flavipes (Kollar, 1837). Recent work revealed rapid spread of C. brevis across several islands and localised subterranean infestations of Reticulitermes spp. (Austin et al. 2012, Ferreira et al. 2013, Borges et al. 2014). The West Indian drywood termite C. brevis is the most destructive drywood species in the Azores, able to tolerate low moisture and to establish hundreds of small colonies within a single piece of timber (Ferreira et al. 2013, Borges et al. 2014, Guerreiro et al. 2014). The Western European subterranean termite R. grassei is, so far, confined to the City of Horta (Faial Island), where it builds extensive soil nests and can form multinucleate colonies comprising millions of individuals (Duarte et al. 2018, Hernández-Teixidor et al. 2024). The eastern subterranean termite R. flavipes (Kollar, 1837) is restricted, so far, to Terceira Island (Austin et al. 2012). While K. flavicollis remains largely restricted to moist heartwood in living trees, C. brevis thrives in low-moisture, seasoned timber, often penetrating deeply and causing severe damage to structural elements, floors and furnishings (Ferreira et al. 2013). In contrast, both R. flavipes and R. grassei forage subterraneously, locating and exploiting isolated wood through soil‐borne galleries and feature a high proportion of neotenic reproductives that enhance their invasive potential (Austin et al. 2012, Duarte et al. 2018). In response to mounting threats against built heritage and private residences, the Azorean regional government and research teams at the University of the Azores have, over the past two decades, implemented systematic monitoring and control programmes (e.g. TermoDisp, TERMIPAR), pilot chemical wood treatments and fumigation trials (Borges and Myles 2007, Ferreira et al. 2013, Guerreiro et al. 2014). General description Purpose:To present the results of the Azorean Government termite monitoring carried out in the Azores between 2011 and 2024. Additional information:From 2011 through 2024, the Regional Government of the Azores has sustained and expanded two island-wide, multi-species termite‐monitoring A 13-year termite (Insecta, Blattodea) monitoring programme in the Azores: ... 3 initiatives (Secretaria Regional do Ambiente e Alterações Climáticas 2023, Secretaria Regional do Ambiente e Ação Climática 2024): Infestation Inspection Certificates (SCIT) Since 2011, every home, commercial building or public facility offered for sale or rent in designated “at‐risk” parishes must present a valid Termite Infestation Inspection Certificate (“SCIT”). Trained technicians — graduates of the University of the Azores’ dedicated pest-inspection course — survey interior woodwork (floors, door‐ and window‐ frames, skirting boards), attics and crawl-spaces for six key signs of infestation (live insects, alate wings, mud tubes, frass, damage galleries and feeding holes). Results are logged centrally, driving annual updates of geographic risk maps used by municipalities to target preventative treatments and to inform prospective buyers. Chromotropic Light Trap Network In spring 2022, the Government launched a dispersal‐flight surveillance system across all nine islands. Over 1,200 yellow sticky traps (45 × 24 cm) were installed on street‐lights, public parks and private‐property exteriors, attracting alates of the four invasive termite species during their evening swarms (May–September). Each trap was serviced by certified field teams, with catch counts uploaded via mobile app; these data were fed into GIS to reveal new infestation foci, colony density hotspots and year‐to‐year spread dynamics. Project description Title:Monitoring Termites in the Azores Archipelago: A Comprehensive Dataset (2011– 2024). Personnel:Species recorded by: Adalberto Borges Couto; Aida de Fátima Brasil Vieira; Ana Casals; Ana Margarida Moniz Soares; Aniceto A. Cordeiro; Annabella Borges; Dejalme Vargas; Emanuel Duarte Costa; Fábio André Azevedo Cerqueira; Fernando Eduardo Costa e Silva; Filipa Vasconcelos da Ponte Valadão Garrett; Filomena Tavarela Ferreira; Francisco Fernandes Lopes; Francisco Mota Vieira Rodrigues da Câmara; Gil da Silva Navalho; Jaime B. Bairos; Joana Correia Soares; Joana Pombo Sousa Tavares; João Luís de Oliveira Pacheco; João M. Sousa; João Manuel Correia Pimentel; João Pedro Martins Gonçalves; João Pedro Pedroso de Lima Ferreira de Matos; Jorge Manuel Lopes Amorim da Cunha; Kenny F. Alves; Lisandra Câmara Miranda; Luís Miguel Gomes Vieira; Luís Miguel Resendes Fernandes Bettencourt da Silva; Luís Miguel Taraio dos Santos Antunes; Luís Paulo Ramalho da Silva Garcia; Manuel António Braga Pinheiro; Manuel José Gonçalves Goulart de Sequeira; Maria L.P.C.B.M. Sequeira; Marina Ponciano Lima; Mauro José Silva Lourenço; Miguel da Cunha Pacheco Ribeiro de Borba; Nélson Simas; Nuno Filipe Ferreira Bicudo da Ponte; Nuno Marco Botelho Soares; Orlando Guerreiro; Paulo Alão Nunes de Sousa; Paulo Alexandre Vilela Martins Raimundo; Pedro Fernando Gonçalves Ribeiro; Pedro Manuel Parreira Brito Do Rio; Pedro Medeiros; Pedro Miguel Machado da Silveira; Rodrigo Cordeniz Ferreira; Rui 4Borges P et al Filipe Mota Dutra; Rui Manuel de Jesus Martins; Sérgio Cardeira; Tatiana Branco; Tiago M. Silva; Vanessa C.B. Mendonça. Species Identification: Adalberto Borges Couto; Aida de Fátima Brasil Vieira; Ana Casals; Dejalme Vargas; Emanuel Duarte Costa; Fábio André Azevedo Cerqueira; Filipa Vasconcelos da Ponte Valadão Garrett; Jaime B. Bairos; Joana Pombo Sousa Tavares; Jorge Manuel Lopes Amorim da Cunha; João Luís de Oliveira Pacheco; Lisandra Câmara Miranda; Luís Miguel Gomes Vieira; Luís Paulo Ramalho da Silva Garcia; Manuel António Braga Pinheiro; Manuel José Gonçalves Goulart de Sequeira; Maria LPCBM. Sequeira; Miguel da Cunha Pacheco Ribeiro de Borba; Nélson Simas; Nuno Filipe Ferreira Bicudo da Ponte; Orlando Guerreiro; Paulo Alão Nunes de Sousa; Pedro Fernando Gonçalves Ribeiro; Pedro Medeiros; Pedro Miguel Machado da Silveira; Rui Filipe Mota Dutra; Rui Manuel de Jesus Martins; Sérgio Cardeira; Tatiana Branco. Data acquisition: Secretaria Regional do Ambiente e Ação Climática (SRAAC). Darwin Core Database: Paulo A.V. Borges. Study area description:The Azores are a Portuguese archipelago of nine volcanic islands stretching over 600 km in the mid-North Atlantic (37–40° N, 25–31° W), roughly 1600 km west of mainland Portugal. Geologically they lie along the Mid-Atlantic Ridge, rising abruptly from the ocean floor to summits over 2,300 m (Mount Pico, 2,351 m) and are grouped into three groups of islands from west to east (Fig. 1): Flores (143 km²) and Corvo (17 km²) (Western Group); Faial (173 km²), Pico (447 km²), São Jorge (237 km²), Graciosa (60 km²), Terceira (401 km²) (Central group); and São Miguel (744 km²) and Santa Maria (97 km²) (Eastern group). The climate is mild maritime–subtropical, with year-round high humidity, average temperatures of 14–25°C and persistent “Azores High” anticyclones in summer. Volcanism remains active (e.g. Capelinhos 1957–58) and frequent seismicity reflects ongoing rift and fault dynamics. The archipelago’s largest city and administrative capital is Ponta Delgada (São Miguel, ~ 68,000 inhabitants), followed by Angra do Heroísmo (Terceira, ~ 35,000 inhabitants) and Horta (Faial, ~ 14,000 inhabitants). Design description:The Azorean termite surveillance combined two complementary sampling schemes: Chromotropic‐Trap Network Trap type and placement: Yellow, chromotropic sticky‐card traps (45 × 24 cm) affixed to public street‐lights and luminaires in 121 parish of the nine islands. Deployment density: Traps were allocated by island in proportion to the previous knowledge of termite extent of occurrence (e.g. São Miguel 401, Terceira 300, São Jorge 151 etc.) and sited to maximise coverage of both urban cores and peri‐urban fringe zones. A 13-year termite (Insecta, Blattodea) monitoring programme in the Azores: ... 5 SCIT (Infestation Inspection Certificate) System Mandatory inspections: In every parish where the sale or rental of a building requires a termite-inspection certificate (Resolution no. 219/2021), trained technicians certified by the University carried out on-site surveys of interior woodwork, crawlspaces and attics. However, any homeowner may also request an inspection at any time and for any purpose. Spatial analysis: Each confirmed infestation point was georeferenced and fed into a GIS‐ based risk‐mapping protocol. Drywood‐termite risk zones were delineated using 100 m a b Figure 1. The Azores Archipelago. A The location of Azores; B The geography of the nine Azorean islands. 6Borges P et al buffers around infested structures, whereas subterranean‐termite feeding zones used 500 m buffers (with further subdivisions at 25 m and 50 m radii) to capture colony foraging areas. Together, these two designs — an archipelago‐wide, systematically serviced trap network and a legally mandated, spatially explicit building‐inspection regimen — ensure robust, year‐round detection of both dispersing alates and established infestations across the Azores. Sampling methods Description:The monitoring and certification surveys were conducted across the entire Autonomous Region of the Azores, encompassing all nine islands and every municipality. Two complementary sampling frames were defined: Chromotropic‐Trap Network Between spring and autumn 2022 and 2023, a total of 1,314 yellow, chromotropic sticky traps were deployed outdoors on public luminaires and street-lights to intercept alate termites. Trap allocation by island was as follows: Terceira (300), São Miguel (401), São Jorge (151), Santa Maria (92), Pico (150), Graciosa (40), Flores (50), Faial (100) and Corvo (30). SCIT (Infestation Inspection Certificate) Area In parallel, the study harnessed data from the Regional Termite Infestation Certification System (SCIT). The defined SCIT area includes all civil parishes (“freguesias”) in which the sale or rental of any building legally requires presentation of a valid termiteinspection certificate, per Resolution no. 219/2021 of 16 September 2021. These parishes span the nine islands, ensuring that every locale subject to mandatory building certification is represented in the infestation‐mapping framework. Together, these two sampling domains — extensive trap coverage across all islands and targeted SCIT‐mandated parishes — provide a robust, island-wide portrait of both subterranean and drywood termite occurrence and risk. Quality control:All termite sampling followed standardised methods (see above) and the taxonomy of the four species follows the last checklist of Azorean arthropods (Borges et al. 2022). The spatial resolution of the SCIT inspection occurrence records was reduced to 353.6 m coordinate uncertainty to safeguard the privacy of homeowners and all precise locality information was removed. Trap data, however, were retained without modification. Methodological bias – the Chromotropic‐Trap sampling methods used are biased towards Cryptotermes brevis captures. Kalotermes flavicollis often occurs in trees (e.g. A 13-year termite (Insecta, Blattodea) monitoring programme in the Azores: ... 7 public parks) and subterranean species may not produce alates; if they do, these can be difficult to distinguish from C. brevis, although swarming seasons differ. Geographic coverage Description:This study covered all Azorean islands, but termites were found only in six islands, from west to east: Faial, Pico, São Jorge, Terceira, São Miguel and Santa Maria. Coordinates:36.938 and 38.779 Latitude; -28.643 and -25.015 Longitude. Taxonomic coverage Description:Four species of termites (Insecta, Blattodea) were surveyed: the West Indian drywood termite, Cryptotermes brevis (Walker, 1853); the yellow-necked drywood termite, Kalotermes flavicollis (Fabricius, 1793); the Western European subterranean termite, Reticulitermes grassei Clément, 1978; and the eastern subterranean termite, Reticulitermes flavipes (Kollar, 1837). Temporal coverage Notes:2011-02-16 / 2024-12-27 Usage licence Usage licence:Creative Commons Public Domain Waiver (CC-Zero) Data resources Data package title:Monitoring Termites in the Azores Archipelago: A Comprehensive Dataset (2011–2024) Resource link: http://ipt.gbif.pt/ipt/resource?r=termites_scit Alternative identifiers: https://www.gbif.org/dataset/781731ba-9e43-434a-9950-38ac 37b3959f Number of data sets:1 Data set name:Occurrence Table Character set:UTF-8 Download URL: http://ipt.gbif.pt/ipt/resource?r=termites_scit Data format:Darwin Core Archive 8Borges P et al Data format version:1.2 Description: The dataset was published in the Global Biodiversity Information Facility platform, GBIF (Borges et al. 2025). The following data-table includes all the records for which a taxonomic identification of the species was possible. The dataset submitted to GBIF is structured as a sample occurrence dataset that has been published as a Darwin Core Archive (DwCA), which is a standardised format for sharing biodiversity data as a set of one or more data tables. The core data file contains 1832 records (eventID; and occurrenceID). This GBIF IPT (Integrated Publishing Toolkit, Version 2.5.6) archives the data and, thus, serves as the data repository. The data and resource metadata are available for download in the Portuguese GBIF Portal IPT (Borges et al. 2025). Column label Column description type The nature of the record, typically used to distinguish Darwin Core Archives (in this case "PhysicalObject"). licence A legal document giving official permission to do something with the data. institutionID An identifier for the institution having custody of the item. datasetID An identifier for the dataset from which the record was derived. institutionCode The code (often alphanumeric) for the institution having custody of the item (in this case UAc). datasetName The name of the dataset from which the record was derived. basisOfRecord The specific nature of the data record (in this case “HumanObservation”), a subtype of dcterms:type; recommended to use the Darwin Core Type Vocabulary. dwc.tdwg.orgdocs.google.com. occurrenceID An identifier for the Occurrence (as opposed to the specimen, observation or other data). recordedBy A list of names (concatenated and separated) of people, teams or organisations who recorded the original Occurrence. establishmentMeans The process by which the organism(s) represented became established at the location (e.g. “native”, “invasive”); controlled vocabulary defined by the TDWG establishmentMeans list dwc.tdwg.org. occurrenceRemarks Comments or notes about the Occurrence. eventID An identifier for the sampling event (as distinct from the occurrence). eventDate The date-time or interval during which the event occurred; in YYYY-MM-DD or ISO 8601 format. year The four-digit year in which the event occurred. month The integer month in which the event occurred (1–12). A 13-year termite (Insecta, Blattodea) monitoring programme in the Azores: ... 9