Research Article |
Corresponding author: Nicolas J. Vereecken ( nicolas.vereecken@ulb.be ) Academic editor: Jack Neff
© 2023 Nicolas J. Vereecken, Carlos Ruiz, Leon Marshall, Mónica Pérez-Gil, Jean-Marc Molenberg, Bernhard Jacobi, Francisco La Roche, Jessica R. Litman.
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.
Citation:
Vereecken NJ, Ruiz C, Marshall L, Pérez-Gil M, Molenberg J-M, Jacobi B, La Roche F, Litman JR (2023) A new small carder bee species from the eastern Canary Islands (Hymenoptera, Megachilidae, Anthidiini). Journal of Hymenoptera Research 96: 983-1015. https://doi.org/10.3897/jhr.96.111550
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Recent field surveys in the eastern Canary Islands (Spain), followed by contributions of new occurrence records through the citizen science platform iNaturalist.com and the social media photo repository Flickr.com have revealed the presence of an overlooked small carder bee species (genus Pseudoanthidium Friese (Megachilidae: Anthidiini)) on the islands of Lanzarote and Fuerteventura. Here, we combined morphology, DNA barcodes (mitochondrial cytochrome c oxidase subunit I, COI) and ecological data (distribution, altitudinal ranges and environmental niche classification) to describe this species as Pseudoanthidium (Pseudoanthidium) jacobii sp. nov. We provide an illustrated description along with diagnostic morphological characters to separate it from P. (P.) canariense (Mavromoustakis, 1954), the only other congeneric species known from the neighbouring islands of La Gomera, Tenerife and Gran Canaria and from which it is separated by a genetic distance of 2.7%. We also evaluated the extent of shared environmental niche space among the two Pseudoanthidium species, and our results show a significant difference in elevation range as well as a very small (less than 1%) overlap between the modelled climatic niche of P. jacobii and that of P. canariense. Given the extremely restricted geographic distribution and the fragile and isolated nature of the habitat and host plants of this new island endemic species, we assign it an IUCN conservation status of “EN” (endangered) and discuss avenues for future research on the ecology and conservation of wild bees in the Canary Islands and neighbouring regions.
Archipelago, biogeography, Canary Islands, COI mtDNA, genetic divergence, IUCN assessment, Red List, taxonomy
Within Macaronesia and its oceanic islands, the Canary Islands (CI) archipelago encompasses seven islands with contrasting climates, topography, and geological history. Among the many fascinating facets of the CI archipelago for the island biogeographer is the diversity of environmental conditions, as well as the ecological and geological gradients observed within and among the islands. The CI are a well-known hotspot of biological endemism ever since Von Humboldt’s first visit in 1799, for both plants and animals (
By contrast, historical surveys across the CI by hymenopterists (except myrmecologists), have lagged behind for decades. Although there are early reports on wild bees tracing back to the early 20th century, it was not until 1993 that the first comprehensive and annotated catalogue of the 127 species and subspecies of wild bees (of which 38% are strict CI endemics) was published (
Despite these advances, it is clear that gaps in our knowledge on CI bees are persistent, as demonstrated by the new island records of native species (
Here, we report on the results of recent field surveys focusing on wild bees in the CI archipelago, followed by observations shared through the citizen science platform iNaturalist.com and the social media photo repository Flickr.com. By combining detailed morphological analysis, DNA barcodes (mitochondrial cytochrome c oxidase subunit I, COI) and ecological data (distribution, altitudinal ranges and environmental niche classification), we concluded that specimens of a solitary bee belonging to the genus Pseudoanthidium (Megachilidae, Anthidiini) collected and photographed in situ in Lanzarote and Fuerteventura on multiple occasions in recent years, represents a hitherto unknown species of small carder bee that we describe below.
As part of an ongoing collaboration between the Université libre de Bruxelles (NJV, LM, JMM) and the Departamento Biología Animal, Edafología y Geología of the University of La Laguna (CR) on apple tree pollinators, as well as the biogeography of the Canary Islands bees and the development of new taxonomic tools on the bees of Europe, field surveys have been conducted on the islands of Tenerife, Fuerteventura and Lanzarote in April 2021.
On 18.iv.2021, a male Pseudoanthidium was photographed by NJV (Fig.
Ecology and distribution of Pseudoanthidium jacobii in the Canary Islands A, B male nectaring on an inflorescence of Asteriscus intermedius (Asteraceae) (Photos NJ Vereecken) C female collecting pollen on an inflorescence of A. intermedius (Photo B Jacobi) D female nesting in a pre-existing cavity located in a volcanic lava rock (Photo B Jacobi) E distribution map showing all occurrence records available to us and relevant to both P. canariense and P. jacobii in the Canary Islands.
On 12.ii.2023, a female Pseudoanthidium was photographed at Bco. Valle del Palomo (Lanzarote) by MPG, and two female specimens were collected by MPG at Haría (Lanzarote), one on 21.ii.2023 (Bco. Valle del Palomo), and another one on 16.iv.2023 (Bco. de Elvira Sánchez). These specimens were sent to CR to be pinned, prepared for identification and deposited at the entomological collection curated by CR at the University of La Laguna (Tenerife). On 19.iv.2023, CR collected one female Pseudoanthidium species at Bco. de Elvira Sánchez (Haría, Lanzarote) now included in the
On 12.iii.2023 and on 16.iii.2023, two female Pseudoanthidium specimens were photographed by BJ at Mácher (Lanzarote) (Fig.
Finally, G. Peña Tejera notified CR of another observation made and published on Flickr.com on 7.iii.2020 at Betancuria (Fuerteventura) by photographer L. Mullins.
DNA extractions were performed on single legs from one male and one female specimen of this new species using Nucleospin tissue DNA extraction kits (Macherey - Nagel). A 658 base pair fragment of the mitochondrial gene cytochrome c oxidase (CO1) was amplified using the primers Lep-F1 and Lep-R1 under the PCR conditions described in
Sequences were edited using Geneious (
ULB Agroecology Lab, Brussels School of Bioengineering, Université libre de Bruxelles, Belgium
FLR Private collection of F. La Roche, San Cristóbal de La Laguna, Tenerife, Spain
The morphological terminology used in the description follows
BL (body length): measured as the shortest absolute distance from the base of the antennal socket to the apex of the metasoma (see Niu et al. 2021);
ITD (inter-tegular distance): measured as the shortest absolute distance between the tegulae (scale-like structure covering the insertion point of the wings on the thorax) in dorsal view;
OOD (ocellar-occiput distance): assessed in dorsal view, under a stereomicroscope with continuous LED light, as a ratio between the distance separating the lateral ocelli and the posterior occiput (dorsal margin of the vertex) on one hand, and the ocellar diameter on the other hand;
MPD (median punctuation density): assessed as the ratio between the distance separating neighbouring points in the median region of the tergites and the puncture diameter;
LPD (lateral punctuation density): measured as the ratio between the distance separating neighbouring points in the lateral region of the tergites, particularly on T2 (second tergite) and T3 (third tergite), and the puncture diameter;
SSPD (scutum and scutellum punctuation density): measured under a stereomicroscope with continuous LED light as the distance between neighbouring points on the scutum (dorsal side of the thorax/mesonotum) and on the scutellum (dorso-apical plate of the thorax/mesonotum) on one hand, and the puncture diameter;
TEG (tegulae): colour of the scale-like structures covering the insertion point of the wings on the thorax/mesonotum;
ProN (pronotum): colour of the dorsal lobe of the first thorax/mesonotum segment;
ProLo (pronotal lobe): colour of the protonal lobe (also known as “humeral tubercles”) located just next to the tegulae, towards the anterior site of the thorax/mesonotum;
TCP (tergite colour patches): colour, size and delineation between the orange colour patches on the tergites and the surrounding black cuticle;
FACE (face): colour of the clypeus, mandibles, lower part of paraoccular region;
LEGS (legs): colour of the coxae, femurs, tibiae on each pair of legs.
Photographs of the type material were taken using a Leica S8APO equipped with a Leica MC190 HD digital camera and a Leica LED3000 DI light dome. Series of shots were taken by manually adjusting the precision dial to cover the sharpness of the target body parts. The specialized hooked and waved hairs on the metasomal sterna (S3-S4-S5) in males were photographed using a Canon 5DS R equipped with a Canon MP-E 65mm lens at 5× and (set at f/3.2 and ISO 100), mounted on a StackShot macro rail (distance/step = 0.01mm) and lit with two custom diffused, IR-operated Godox 860vii cobra flashes. All resulting photos were stacked with Helicon Focus (version 8.2.6.) using the software’s “Depth Map mode (Method B)”. Resulting stacked shots were slightly edited in Adobe Lightroom and cleaned in Adobe Photoshop 2023.
Shapefiles and map data derived from OpenStreetMap (copyrighted OpenStreetMap contributors and available from https://www.openstreetmap.org) were downloaded from GeoFabrik (https://download.geofabrik.de). Species distribution points were plotted using QGIS 3.22 -Białowieża (
Finally, we used the elevatr package (version 0.4.2.) (
To evaluate the extent of shared environmental niche space among the two Pseudoanthidium species, we conducted an analysis of ecological niche characteristics. Significant niche differentiation is anticipated owing to the contrasting habitats between the eastern islands of Lanzarote and Fuerteventura and the western islands. The comparison is intended to illustrate the prevailing climatic conditions for the two species. For each occurrence record of the two species, we extracted environmental data from a 200m buffer. BIOCLIM data was obtained from CHELSA (Climatologies at High resolution for the Earth’s Land Surface Areas) climate dataset at 30 arc seconds resolution (
We used the “red” package (version 1.5.0) (Cardoso 2017) and all occurrence records to compute the extent of occurrence (EOO) and area of occupancy (AOO) of P. canariense and the newly discovered Pseudoanthidium species described below. EOO encompasses the total geographic range of a species, while AOO focuses on the current occupied area of a species within its known habitat; both metrics are vital for assessing a species’ conservation status and can influence its IUCN Red List categorization. We then used the rCAT package (version 0.1.6) (
Assessing the extinction risk of a species, including of hitherto overlooked, or newly described taxa, requires using a series of criteria listed by the International Union for the Conservation of Nature (IUCN) Red List (
Our study reveals the presence of a hitherto overlooked species within the subgenus Pseudoanthidium (Pseudoanthidium) in the Canary Islands. A closer examination of the only earlier and unpublished record of a Pseudoanthidium from Lanzarote, a female specimen collected by F. La Roche in Lanzarote 1997, curated in the private collection of F. La Roche (San Cristóbal de La Laguna, Spain) and identified by the late Czech entomologist B. Tkalçů as P. stigmaticorne, revealed that this specimen also belongs to the species we describe here below.
Holotype. Spain • 1♂; Lanzarote, Haría, 19 Apr. 2021; NJ Vereecken leg.;
Paratypes. Spain • 1♀; Lanzarote, Haría, 18 Apr. 2021; J-M Molenberg leg.; ULB • Spain • 1♂; same collection data as for preceding, 19 Apr. 2021; J-M Molenberg leg.; ULB • 1♂; same collection data as for preceding, 18 Apr. 2021; J-M Molenberg leg.;
Spain • 1♂; Lanzarote, Haría; 21 Feb. 2023; M Pérez-Gil leg.;
Besides differences in their distribution pattern across the Canary Islands archipelago (Fig.
Illustration of some key morphological traits that characterise females of Pseudoanthidium jacobii A head capsule and first half of the mesonotum in dorsal view B abdomen in dorsal view C tergites 1-2 (from top to bottom) in dorsal view D face in frontal view E mandibles and clypeus in frontal view. Photos NJ Vereecken; see description of each sex and the diagnosis in the text for more details.
Illustration of some key morphological traits that characterise males of Pseudoanthidium jacobii A head capsule and first half of the mesonotum in dorsal view B abdomen in dorsal view C tergites 1-2-3 (from top to bottom) in dorsal view D face in frontal view E gonostyli in dorsal view. Photos NJ Vereecken; see description of each sex and the diagnosis in the text for more details.
Both Pseudoanthidium jacobii and P. canariense share the same overall structure of specialized hooked and waved hairs on their metasomal sterna (S3-S4-S5) in males, as well as their dark brown to black apicolateral combs on each lateral arm of S5. The present photo illustrates the structure in a male P. jacobii where S3 also exhibits a short, dense, velvety pubescence anteriorly, posteriorly with pre-marginal brush of hairs, hooked at the tips, as well as an underlying comb of thickened, wavy hairs (Photo NJ Vereecken).
Female. The female of P. jacobii may be distinguished from P. canariense by the following combination of characters: BL minimally only half size (4–7 mm in P. jacobii, 6–9 mm in P. canariense), ITD shorter (on average: 2.13 mm in P. jacobii, 2.91 mm in P. canariense), OOD shorter (~ 1 ocellar diameter in P. jacobii, ~ 1.5–2 ocellar diameters in P. canariense), TPD lower (spaces between points at least ~ 1–1.5 diameter of a single point in P. jacobii, < 0.5 diameter of a single point in P. canariense), SSPD slightly higher (~ 0.5 diameter of a single point in P. jacobii, < 0.5 diameter of a single point in P. canariense), TEG brighter (orange-yellow in P. jacobii, black in P. canariense), ProN brighter (orange-yellow in P. jacobii, black in P. canariense), ProLo mostly brighter (orange-yellow like the tegulae in P. jacobii, black in P. canariense, but more specimens of each species should be examined), TCP wider, brighter (wide and orange-yellow in P. jacobii, narrower and dark orange in P. canariense), and with a better defined maculation margin (gradual infiltration of the black colour into the orange yellow maculations of the integument in P. jacobii, well-defined colour boundary/contrast between darker orange maculations and black cuticule in P. canariense), FACE brighter (orange-yellow clypeus, mandibles, lower part of paraoccular region in P. jacobii, all black in P. canariense) and wider (face broader than long in P. jacobii, face longer than broad in P. canariense), LEGS brighter (all legs black only from the coxa to the very base of the femur black, the rest of the femur and other leg segments are orangish yellow in P. jacobii, all coxae, femurs but only posterior tibiae black in P. canariense).
Male. The male of P. jacobii may be distinguished from P. canariense by the following combination of characters: BL minimally only half size (4–6 mm in P. jacobii, 6–8 mm in P. canariense), ITD shorter (on average: 2.22 mm in P. jacobii, 2.95 mm in P. canariense), OOD shorter (~ 1 ocellar diameter in P. jacobii, ~ 1.5–2 ocellar diameters in P. canariense), TPD lower (spaces between points at least ~ 1–1.5 diameter of a single point in P. jacobii, < 0.5 diameter of a single point in P. canariense), SSPD slightly higher (~ 0.5 diameter of a single point in P. jacobii, < 0.5 diameter of a single point in P. canariense), TEG brighter (orange-yellow in P. jacobii, black in P. canariense), ProN brighter (orange-yellow in P. jacobii, black in P. canariense), ProLo mostly brighter (orange-yellow like the tegulae in P. jacobii, black in P. canariense, but more specimens of each species should be examined), TCP wider, brighter (wide and orange-yellow in P. jacobii, narrower and dark orange in P. canariense), and with a better defined maculation margin (gradual infiltration of the black colour into the orange yellow maculations of the integument in P. jacobii, well-defined colour boundary/contrast between darker orange maculations and black cuticule in P. canariense), FACE brighter (orange-yellow clypeus, mandibles, lower part of paraoccular region in P. jacobii, all black in P. canariense) and wider (face broader than long in P. jacobii, face longer than broad in P. canariense), LEGS brighter (all legs black only from the coxa to the very base of the femur black, the rest of the femur and other leg segments are orangish yellow in P. jacobii, all coxae, femurs but only posterior tibiae black in P. canariense). Brushes of thickened, wavy hairs on S3, as well as the lateral dark brown comb of S5, identical in both species.
Female. Head: Mandible orange-yellow, except for teeth and apex of anterior margin, which are reddish-brown. Pilosity on clypeus and tufts at base of antenna white; on anterior margin of clypeus off-white, and on vertex blond. Clypeus dark yellow with black anterior margin. Punctures of clypeus dense and small anteriorly and laterally, with interspaces not larger than diameter of one-half puncture. Punctures become sparser and larger medially and posteriorly, where the maximum distance between punctures reaches two puncture diameters or more in the posterior-medial zone. Interspaces between punctures on clypeus shiny, most notably so where punctures are least dense. Paraocular area dark yellow and densely punctate, with interspaces not over the diameter of one-half puncture. Antenna with scape and pedicel black; flagellar segments dark brown. Flagellar segments shorter than wide, except for the first and the last, which are longer than wide. Frons with punctuation nearly honeycomb areolate, punctuation becoming slightly less dense toward the vertex, with shiny interspaces. Vertex with dark yellow triangle behind each eye, meeting or nearly meeting at midline of vertex. Vertex densely punctate, with interspaces not over 0.5 puncture diameter wide. Punctation on vertex mostly homogenous, with punctures just posterior to median ocellus slightly larger. Gena densely, evenly punctate, with spaces between points less than 0.25 puncture diameter wide.
Mesosoma : Scutum black. Punctuation dense, with spaces between punctures shiny, not more than one-quarter puncture diameter wide. Tegula dark yellow anteriorly, translucent yellow posteriorly. Pronotal lobe dark yellow apically, black basally. Scutellum black with dark yellow band medially on posterior margin. Punctures on black part of scutellum slightly larger and less dense than on scutum, with spaces between punctures on the median part of the scutellum shiny and up to one half a puncture diameter wide; punctation on yellow part of scutellum even less dense, with spaces between punctures over one puncture diameter wide. Mesepisternum densely punctate, punctures becoming smaller and less dense around episternal groove; spaces between punctures shiny. Propodeum laterally and anteriorly finely, densely punctate; medially shiny and without punctuation. On all legs, coxa, trochanter and base of femur black; the rest of the femur, tibia and tarsal segments orange-yellow. Wings infuscate.
Metasoma : T1 anteriorly brownish-yellow, posteriorly reddish-brown. A dark yellow spot present laterally, slightly masked by the colour of the anterior margin of the tergite. Lateral spots vaguely joined medially on the tergite by a faint yellow band connecting the posterior margin of each spot. Punctuation relatively dense, even laterally, with spaces between punctures not greater than the diameter of half a puncture. T1 with unpunctured, shiny, translucent brown posterior margin measuring about two punctures wide. T2 anteriorly black with diffuse dark yellow lateral spots; posteriorly, T2 brownish-yellow. Lateral spots on T2 placed slightly medially to those on T1. Punctation on T2 dense but less so than on T1, with spaces between punctures laterally up to nearly one puncture diameter. Diameter of punctures of T2 greater than those of T1. T2 with unpunctured, shiny, translucent brown posterior margin measuring about two punctures wide. T3 like T2 in colour, with punctation slightly less dense. Punctation of T4 similar to that of T3; T4 mostly black with yellow spots laterally and with shiny, translucent brown posterior margin; anterior edge of this margin with a single row of punctures medially. T5 black, densely punctate, with spaces between punctures shiny and measuring less than 0.25 puncture diameter. T6 black, densely punctate, spaces between punctures less shiny than those of T5 and measuring less than 0.25 puncture diameter, overall texture T6 somewhat rough.
Male. Head: Mandible orange-yellow, except for teeth and apex of anterior margin, which are reddish-brown. Pilosity on clypeus and tufts at base of antenna white; on anterior margin of clypeus off-white, and on vertex dark blond to brown. Clypeus rugose-punctate, orange-yellow with black anterior margin. Paraocular area orange-yellow and rugose-punctate, with interspaces not over the diameter of half a puncture. Antenna with scape and pedicel black; flagellar segments dark brown. Flagellar segments shorter than wide, except for the first and the last, which are longer than wide. Frons with punctuation nearly honeycomb areolate, punctuation becoming slightly less dense toward the vertex, with shiny interspaces. Vertex with orange-yellow triangle behind each eye, widely interrupted towards the midline of the vertex by a black punctured space. Vertex densely punctate, with interspaces not over 0.5 puncture diameter wide. Punctation on vertex mostly homogenous, with interspaces between punctures increasing towards the eye margin and the latero-posterior part of the vertex. Gena densely, evenly punctate, with spaces between points less than 0.25 puncture diameter wide.
Mesosoma : Scutum black. Punctuation dense, with spaces between punctures shiny, not more than one-quarter puncture diameter wide. Tegula orange-yellow anteriorly, translucent orange brown posteriorly. Pronotal lobe orange-yellow apically, black basally. Scutellum black with orange-yellow band medially on posterior margin. Punctures on black part of scutellum slightly larger and less dense than on scutum, with spaces between punctures on the median part of the scutellum shiny and up to one half a puncture diameter wide; punctation on yellow part of scutellum even less dense, with spaces between punctures over one puncture diameter wide. Mesepisternum densely punctate, punctures becoming smaller and less dense around episternal groove; spaces between punctures shiny. Propodeum laterally and anteriorly finely, densely punctate; medially shiny and without punctuation. On all legs, coxa, trochanter and base of femur black; the rest of the femur, tibia and tarsal segments orange-yellow. Wings infuscate.
Metasoma : T1 brownish-orange on its anterior half, with an orange-yellow spot present laterally, slightly masked by the colour of the anterior margin of T1. Lateral spots joined medially on the tergite by a brownish-orange band connecting each spot. Punctuation relatively dense, even laterally, with spaces between punctures not greater than the diameter of half a puncture. T1 with unpunctured, shiny, translucent brown posterior margin measuring about two punctures wide. T2 anteriorly black with diffuse orange-yellow lateral spots; posteriorly, T2 brownish. Lateral spots on T2 placed slightly medially to those on T1. Punctation on T2 dense but less so than on T1, with spaces between punctures laterally up to nearly one puncture diameter. Diameter of punctures of T2 greater than those of T1. T2 with unpunctured, shiny, translucent brown posterior margin measuring about two punctures wide. Lateral spots on T3 placed slightly medially to those on T2. T3 similar to T2 in colour, with punctation slightly less dense. Punctation of T4 similar to that of T3; T4 mostly black with less diffuse orange-yellow spots laterally and with shiny, translucent brown posterior margin; anterior edge of this margin with a single row of punctures medially. T5 black, densely punctate, with spaces between punctures shiny and measuring less than 0.25 puncture diameter. T6 black, densely punctate, spaces between punctures less shiny than those of T5 and measuring less than 0.25 puncture diameter, overall texture T6 somewhat rough. T7 black, densely punctate, with rounded notch on posterior margin. Genitalia with semi-translucent, apically rounded (i.e., unnotched) and flattened gonostyli; penis valves flattened and rounded. S3 with short, dense, velvety pubescence anteriorly, posteriorly with premarginal brush of hairs, hooked at the tips, as well as an underlying comb of thickened, wavy hairs. S5 laterally with dark brown comb.
Pseudoanthidium (Pseudoanthidium) jacobii is dedicated to Mr. Bernhard Jacobi (Oberhausen, Germany), naturalist extraordinaire and talented macrophotographer who has a genuine and boundless passion for wild bees, particularly for species found in Europe and Australia. Bernhard’s interest for the Canary Islands has grown steadily and uninterrupted ever since the publication of
The results of CO1 analyses demonstrate that P. jacobii is strongly supported as the sister species to P. canariense (ML bootstrap value = 96%) (Fig.
Maximum likelihood-based tree based on analysis of a 658 base pair fragment of COI sequenced from selected Pseudoanthidium species in the P. scapulare complex. Maximum likelihood bootstrap support values, based on 1,000 replicates, are shown over nodes; only nodes with support values >90% are shown. Terminals are labelled with species names, as well as the BOLD sample IDs corresponding to each specimen. Outgroup removed from figure for convenience. Individuals shown in photographs were not those sequenced for analysis A P. scapulare (Photo NJ Vereecken) B P. nanum (Photo NJ Vereecken) C P. tenellum (Photo B Jacobi) D P. stigmaticorne (Photo H Wallays) E P. canariense (Photo G Peña); and F P. jacobii (Photo NJ Vereecken).
In Lanzarote, the vegetation at the localities of Haría and Bco. de Elvira Sánchez where males and females of P. jacobii were recorded was composed of a chamaephytic substitutional flowering plant community established on old agricultural land with deep soils, generally on eroded slopes and on stony slopes, ravines, ledges physiognomically characterised by the presence of Asteriscus intermedius (DC.) Pit. & Proust (Asteraceae) and Lavandula pinnata L. (Lamiaceae) among others (see also Rámon Arévalo et al. 2016). By contrast, the localities of Teguise and Macher are peri-urban or rural anthropic areas with sparse natural vegetation, and the locality of Valle del Palomo is composed of xeric shrubland with a physiognomy of dendroid spurge shrubland, dominated by Euphorbia regis-jubae J. Gay (Euphorbiaceae). This is secondary vegetation typically found on abandoned arable or pastureland, roadsides and watercourse-beds (
A single observation by co-author BJ in Lanzarote on 16.iii.2023 of a female nesting in a pre-existing cavity formed in a lava rock (Fig.
The environmental niche space occupied by P. canariense encompasses a large part of the total environmental niche space available in the Canary Islands, covering wide elevation (from 70 m to 2,046 m with a mean of 952 m), mean annual temperature (8.3 °C to 20.9°C, µ=15.2 °C), and mean annual rainfall (135 kg m-2 to 534 kg m-2, µ=354.7 mm) gradients with greater temperature (1.9 °C to 2.2 °C, µ=2.1 °C) and lower precipitation seasonality (73 kg m-2, 90 kg m-2, µ=81.2 kg m-2) gradients and occupying a variety of land cover types (Fig.
Distribution of elevation records relevant to A Pseudoanthidium jacobii and B P. canariense in the Canary Islands. Different letters right to the boxplots indicate highly significant differences in the elevation range and mean elevation of occurrence (black dot in boxplots) of both species (Kruskal-Wallis test: χ2 = 12.425, df = 1, p-value < 0.0005). Photo of P. jacobii M Pérez-Gil and of P. canariense G Peña.
Ecological niche overlap between Pseudoanthidium jacobii and P. canariense in the Canary Islands represented by a principal component analysis (PCA). Light grey diamonds represent occurrence records of P. jacobii, and the small underlying dark grey area represents its niche space. Black triangles represent occurrence records of P. canariense and the light grey underlying area represents its niche space. The small black area represents shared niche space between the two species. Small grey dots are background environmental samples from the Canary Islands. Schoener’s D statistics and the p-value from the niche equivalence test are also shown. See methods and results sections for more details.
Due to a lack of historical baseline data, we could not evaluate P. jacobii using IUCN Criterion A (population reduction). However, with an EOO of 326 km2 and an AOO of 28 km2, P. jacobii fulfils both Criteria B1 and B2 (restricted geographic range; EOO < 5,000 km2 and AOO < 500 km2, respectively) (IUCN 2023).
Our current knowledge suggests that P. jacobii is known only from Mediterranean type shrubland vegetation localities on the islands of Lanzarote and Fuerteventura (Fig.
According to the IUCN, populations are considered “severely fragmented” if most individuals are found in small and relatively isolated subpopulations, where the probability of recolonization is reduced, should these subpopulations go extinct (IUCN 2023). Under this strict definition, populations of P. jacobii, restricted to extremely isolated pockets on Lanzarote and Fuerteventura, may be considered severely fragmented, thus fulfilling both criteria B1a and B2a. Furthermore, the continuous development of touristic infrastructures on both islands, the increase of pollution brought about by new roads facilitating transport and tourism across the islands (
Our field experience further suggests that P. jacobii is characterised by very small population sizes: this can be argued based on the fact (i) that we failed to collect more than two specimens at each sampled locality when the number of specimens should have been at its peak, (ii) that P. jacobii has been completely overlooked up to the present day, and (iii) that females and males are relatively conspicuous in colour, sharing their pollen host plant species with other Canarian bee species active at the same time of the year, namely in early Spring. Hence, P. jacobii also fulfils Criterion C2a(i) based on a conservative estimation of the total number of mature individuals < 2,500 across its distribution, as well as an estimated, projected, or inferred decline for reasons detailed above and < 250 mature specimens per subpopulation (IUCN 2023).
Because of a lack of population size estimation or comprehensive evaluation of the number of extant populations and their trends, we were unable to classify P. jacobii under Criteria D and E (IUCN 2023).
Last, we obtained convergent results through the parallel calculation of the IUCN rating based on EOO Area (in km2) with the “EOORating” function in the rCAT package, which suggests that P. jacobii should be classified as “EN” (endangered).
Given the above results, P. jacobii thus qualifies for “EN” (endangered) conservation status under IUCN Criteria B1ab(i,ii,iii,iv,v), B2ab(i,ii,iii,iv,v) and Criterion C2a(i); this status is also supported by the results of the “EOORating” analysis mentioned above. We thus propose an IUCN conservation status of “EN” (endangered) for this species.
Twenty-two years after the last description of two new Megachilidae bee species in the CI archipelago, Osmia palmae Tkalçů (
Most females in the subgenus Pseudoanthidium (Pseudoanthidium), and particularly in the P. scapulare species complex, appear to have a strong preference for host plants in the family Asteraceae (
The Pseudoanthidium scapulare complex of species is distributed throughout the Palaearctic region. Certain members of the complex represent closely related species pairs that are sympatric throughout a part of their distributions, including P. nanum - P. scapulare and P. tenellum - P. cribratum. Both of these pairs are morphologically distinct but exhibit relatively low levels of genetic differentiation in analyses of CO1 (0.35% and 0.59%, respectively) (
Our morphological analysis and that of
Given the lack of resolution in our analyses of CO1, namely regarding the phylogenetic relationships among different clades within the complex, we can only propose hypotheses to explain the presence of a rounded gonostylus in P. jacobii and P. canariense. If the clade represented by these two species is the sister group to all other members of the P. scapulare complex, then one possible explanation is that the common ancestor of P. jacobii and P. canariense colonised the Canary Islands prior to the origin of other members of the P. scapulare complex (
Ever since Antiquity, historians, traders and (bio)geographers have acknowledged the peculiar nature of Lanzarote and Fuerteventura, these “Eastern Islands” of the Canary archipelago. Although they form two islands today, they are, geologically speaking, the oldest emerging part of the archipelago that used to be merged during the Pleistocene glacial cycles, forming the paleo-island of Mahan (
By describing P. jacobii as an endemic species from the Purpurarias, we provide further evidence for the peculiar environmental conditions met on the islands of Lanzarote and Fuerteventura within the Canary Islands archipelago, and how original life forms have evolved solely on these two islands. Single-island endemics are reported in the eastern CI, such as Tetralonia lanzarotensis Tkalçů, 1993 (Apidae) and Dioxys (Dioxys) lanzarotensis Tkalçů, 2001 (Megachilidae) from Lanzarote, or Megachile (Eutricharaea) hohmanni Tkalçů, 1993 (Megachilidae) and Dufourea fortunata Ebmer, 1993 (Halictidae), both recorded exclusively from Fuerteventura within the CI archipelago (
Examples of other wild bee species sharing a distribution restricted to these two islands include Anthophora purpuraria Westrich, 1993 (Apidae) (whose specific epithet derives directly from the “Purpurarias”), as well as other Anthophorini species like A. (Heliophila) lanzarotensis (Tkalçů, 1993), A. (Heliophila) lieftincki (Tkalçů, 1993), A. (Pyganthophora) porphyrea Westrich, 1993 (all endemic to Lanzarote and Fuerteventura) and some of their associated cuckoos such as Melecta (Melecta) caroli Lieftinck, 1958, and M. (Melecta) prophanta Lieftinck, 1980 (on Lanzarote only) (
It is important to note that some species originally described from a single island (such as A. (H.) lanzarotensis or M. (C.) fuerteventurae, as their specific epithet suggests) turned out to be discovered on both islands after a few decades of field surveys. These recent records contribute to the emergence of distribution patterns among closely related, endemic species in different groups of wild bees, with some restricted to the eastern islands and others present only in the central (and western) islands. For example, the three Megachile (Chalicodoma) species recorded in the archipelago exhibit such a distribution pattern similar to the Pseudoanthidium species discussed here, with M. (C.) canescens (Brullé, 1840) restricted to the central and western islands, whereas M. (C.) sicula (Rossi, 1794) and M. (C.) fuerteventurae are found only on the eastern islands (Lanzarote and Fuerteventura) (
Interestingly, no species in the families Colletidae or Melittidae is endemic to Lanzarote and Fuerteventura: these families encompass CI endemic species distributed across the eastern, central and western islands, but none are restricted to eastern islands. Those that are found on these islands have a much wider distribution encompassing Morocco and sometimes extending to the Levant and even the Arabian Peninsula (e.g., for Melitta schmiedeknechti Friese, 1898 (Melittidae); see
At their nearest point, Lanzarote and Fuerteventura are located just under 100 km (60 miles) off the coasts of Morocco (
Are newly discovered species at a higher risk of extinction than those first described long ago? According to
Here, we classified the new species P. jacobii as Endangered (EN) according to IUCN Criteria B1ab(i,ii,iii,iv,v), B2ab(i,ii,iii,iv,v) and Criterion C2a(i), as well as based on the parallel calculation of the IUCN rating based on EOO Area (in km2). In other words, and practically speaking, this means that P. jacobii is threatened with extinction and might experience continuous decline unless conservation efforts are made. The results of our extinction risk assessment are also motivated by the fact that P. jacobii, similarly to other threatened wild bee species, typically occurs within a few small patches rather than a spatially continuous area of uniform presence. This patchy distribution implies that P. jacobii is exposed to comparatively higher extinction risks, because there is a greater chance that one or several of the identified threats will act in concert and will affect all or most of the distribution within a certain time frame. How imminent the identified risks are has remained elusive for a long time, but in recent years the Canary Islands and the “Purpurarias” in particular have seen droughts and heatwaves, just like large parts of the drought-stricken mainland. These changing weather patterns are the direct outcome of climate change operating in real time, and in the worst-case scenario they have even combined with environmental hazards like the 2021 Cumbre Vieja volcano eruption on the island of La Palma, followed in 2023 by massive wildfires breaking out and threatening all terrestrial forms of life on several of the Western Canary Islands. Such wildfires are less likely on Fuerteventura and Lanzarote due to their scarce vegetation and lack of forested areas (
The Canary Islands archipelago, like many other insular ecosystems renowned for their breath-taking natural beauty, faces major challenges in achieving a delicate balance between promoting recreational activities and preserving its fragile biodiversity as the effects of climate change become increasingly pronounced. Our study illustrates that our understanding of biodiversity in the archipelago is far from complete, and that international scientific collaborations with local experts and citizen science projects can help gain significant insights into species distribution and ecological interactions. This paper also confirms the vivid interest of the international scientific community towards the Canary Islands bee fauna and its conservation (see also
NJV: Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software; Validation; Visualization; Writing - original draft; Writing - review & editing. CR: Data curation; Project administration; Resources; Supervision; Validation; Writing - review & editing. CJP: Formal analysis; Funding acquisition; Investigation; Resources; Software; Visualization; Writing - review & editing. MPG: Data curation; Investigation; Visualization; Writing - review & editing. BJ: Data curation; Investigation; Writing - review & editing. JMM: Data curation; Investigation; Project administration; Resources. LM: Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Resources; Software; Visualization; Writing - review & editing. FLR: Data curation; Writing - review & editing. JRL: Conceptualization; Data curation; Investigation; Methodology; Resources; Supervision; Validation; Writing - review & editing.
NJV and JMM are grateful to the FNRS/FWO joint program “EOS—Excellence of Science” for the financial support to the project “CliPS: Climate change and its impact on Pollination Services” (project 30947854). LM and NJV are grateful to the F.R.S.-FNRS (Belgium) for their financial support to LM for his “Chargé de Recherches” mandate on the global bee island biogeography. Our warmest thanks are also due to C.J. Praz for sequencing COI barcode using our specimens of P. jacobii, and to L. Mullins for letting us use the metadata of his P. jacobii photographic record from Fuerteventura in this study. Last but not least, we are grateful to S.P.M. Roberts for his constructive comments on our IUCN assessment in an earlier version of the manuscript, as well as to A. Müller and an anonymous referee for their positive and constructive comments that helped improve the quality of the manuscript.
Information on Pseudoanthidium specimens used for the barcoding
Data type: csv
Explanation note: List of specimens and associated metadata used for the Maximum likelihood-based tree based on analysis of a 658 base pair fragment of COI sequenced from selected Pseudoanthidium species in the P. scapulare complex.
Distribution data of each Pseudoanthidium species in the Canary Islands
Data type: csv
Explanation note: Distribution data including all occurrence records available to us and relevant to both P. (P.) canariense and P. (P.) jacobii Vereecken & Litman spec. nov. in the Canary Islands.