Spiders on a Hot Volcanic Roof: Colonisation Pathways and Phylogeography of the Canary Islands Endemic Trap-Door Spider Titanidiops canariensis (Araneae,Idiopidae)

Studies conducted on volcanic islands have greatly contributed to our current understanding of how organisms diversify. The Canary Islands archipelago, located northwest of the coast of northern Africa, harbours a large number of endemic taxa. Because of their low vagility, mygalomorph spiders are usually absent from oceanic islands. The spider Titanidiops canariensis, which inhabits the easternmost islands of the archipelago, constitutes an exception to this rule. Here, we use a multi-locus approach that combines three mitochondrial and four nuclear genes to investigate the origins and phylogeography of this remarkable trap-door spider. We provide a timeframe for the colonisation of the Canary Islands using two alternative approaches: concatenation and species tree inference in a Bayesian relaxed clock framework. Additionally, we investigate the existence of cryptic species on the islands by means of a Bayesian multi-locus species delimitation method. Our results indicate that T. canariensis colonised the Canary Islands once, most likely during the Miocene, although discrepancies between the timeframes from different approaches make the exact timing uncertain. A complex evolutionary history for the species in the archipelago is revealed, which involves two independent colonisations of Fuerteventura from the ancestral range of T. canariensis in northern Lanzarote and a possible back colonisation of southern Lanzarote. The data further corroborate a previously proposed volcanic refugium, highlighting the impact of the dynamic volcanic history of the island on the phylogeographic patterns of the endemic taxa. T. canariensis includes at least two different species, one inhabiting the Jandia peninsula and central Fuerteventura and one spanning from central Fuerteventura to Lanzarote. Our data suggest that the extant northern African Titanidiops lineages may have expanded to the region after the islands were colonised and, hence, are not the source of colonisation. In addition, T. maroccanus may harbour several cryptic species.     

Bellwether of the Canaries: anthropogenic effects on the land snail fauna of the Canary Islands

Natural areas near human-modified landscapes experience factors that may affect local biodiversity at levels commensurate with natural environmental factors. The land snails of the Canary Islands provide excellent opportunities to evaluate the importance of anthropogenic agents in mediating the diversity and distribution of species. Land snails are particularly sensitive to disturbance and are an integral part of terrestrial ecosystems. This study analyzed the distributions and abundances of terrestrial macrosnail shell assemblages at 60 localities throughout the coastal scrub biome of the Canary Islands. This was accomplished using data on natural and anthropogenic variables to assess their relative importance in governing land snail diversity. A total of 34,801 dead shells represented a diverse malacofauna with highly localized endemism. Due to uncertain species identifications, samples from the 18 sites from the two easternmost islands are described, but excluded from statistical analyses. Regression tree analysis indicated that proximity to agricultural sites was the most important predictor of species diversity. Sites with no or very little agricultural area (≤ 0.167 km²) within a 1 km radius had significantly higher richness and diversity. These results have implications for Canary Islands conservation. Protected areas that are patchworks of natural and agricultural landscapes are still subject to native biodiversity loss because of anthropogenic impacts even when the footprint of agriculture is small.     

Reconciling gene trees with organism history: the mtDNA phylogeography of three Nesotes species (Coleoptera: Tenebrionidae) on the western Canary Islands

The processes of island colonization and speciation are investigated through mtDNA studies on Canary Island beetles. The genus Nesotes (Coleoptera: Tenebrionidae) is represented by 19 endemic species on the Canary Islands, the majority of which are single island endemics. Nesotes conformis is the most widespread, occurring on Gran Canaria, Tenerife, La Palma and El Hierro. Nesotes conformis forms a paraphyletic assemblage, with a split between Gran Canaria and the other three islands. Nesotes conformis of the western Canary Islands cluster with Nesotes altivagans and Nesotes elliptipennis from Tenerife. Fifty‐two individuals from this western islands species complex have been sequenced for 675 base pairs of the mtDNA cytochrome oxidase II gene, representing Tenerife, La Palma and El Hierro. A neighbour joining analysis of maximum likelihood distances resulted in three distinct mtDNA lineages for N. conformis, two of which also include mitotypes of N. altivagans and N. elliptipennis. Through application of parametric bootstrap tests, we are able to reject hypotheses of monophyly for both N. conformis and N. altivagans. Nesotes altivagans and N. elliptipennis are poorly separated morphologically and mtDNA sequence data adds support to this being one species with a highly variable morphology. We propose that N. altivagans/N. elliptipennis is recently derived from two ancestral mtDNA lineages within N. conformis from the Teno region of Tenerife. We further propose colonization of the younger islands of La Palma and El Hierro by N. conformis from a mitochondrial lineage within the Teno massif (colonization; diversification; mitochondrial DNA; Canary Islands; Coleoptera).     

Phytogeography of Lusitanian Macaronesia: biogeographic affinities in species richness and assemblage composition

Analysis of biogeographic affinities is a key tool to establish and improve the resolution of hierarchical biogeographic systems. We describe patterns of species richness of the marine macroalgal flora across Lusitanian Macaronesia (Azores, Madeira, the Salvage Islands and the Canary Islands), and test (i) whether such differences are related to differences in proximity to the nearest continental shore and size among islands. We also explore biogeographic affinities in the composition of macroalgal assemblages (= presence/absence of each taxon in multivariate datasets) to determine (ii) whether each archipelago is a biogeographic unit within this ecoregion and (iii) whether patterns in assemblage composition are related to proximity (i.e. distances) among islands. Presence/absence matrices were created to test and visualize multivariate affinities among archipelagos. A total of 872 taxa were compiled. Species richness peaked at the Canary Islands and decreased towards the Azores; the pattern matched a progressive increase in distance from the nearest continental shores, matching the classical island biogeography theory. Intra-archipelago differences in species richness were largely related to variations in island size. Biogeographic similarities among archipelagos were hierarchically structured. Madeira and the Salvage Islands constituted one biogeographic unit. Floras from the Azores, Madeira and the Salvage Islands were barely separable from each other, but were different from those at the Canary Islands. Such biogeographic similarities among islands were negatively correlated with the geographical separation (i.e. distances) among them. Proximity to nearby continental shores, in conjunction with large- and meso-scale oceanographic patterns, seems to interact to create patterns in richness and composition of algal assemblages across Lusitanian Macaronesia.     

Molecular and morphological diagnoses of five species of Trichogramma: biological control agents of Chrysodeixis chalcites (Lepidoptera: Noctuidae) and Tuta absoluta (Lepidoptera: Gelechiidae) in the Canary Islands

Prospecting for potential natural enemies of the invasive lepidopteran tomato pest Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and the banana pest Chrysodeixis chalcites (Esper) (Lepidoptera: Noctuidae) on the Canary Islands archipelago, where no Trichogramma species were previously recorded, has led to the discovery of five distinct species. T. achaeae Nagaraja & Nagarkatti, T. bourarachae Pintureau & Babault, T. euproctidis (Girault) and T. evanescens Westwood are relatively widespread species. The fifth is close to T. brassicae Bezdenko, but differs sufficiently in the sequence of the ITS2 region of ribosomal RNA to warrant further investigation as a species probably new to science. Each species is treated in detail in order to facilitate identification in future using molecular and/or morphological characters, or a combination of both. All species are newly recorded for the Canary Islands, and the distribution of each within the islands and elsewhere is provided. Known host records are given within the Canary Islands and elsewhere. The most common species found, T. achaeae, is already being used in biological control programmes against T. absoluta in mainland Spain and field trials are ongoing to evaluate its effectiveness as a biological control agent of C. chalcites in banana crops.     

A review on the impacts of feral cats (Felis silvestris catus) in the Canary Islands: implications for the conservation of its endangered fauna

Feral cats have been directly responsible for the extinction of numerous species on islands worldwide, including endemic species of mammals, birds and reptiles. The diet of feral cats in the main habitats of the Canary Islands, as generally occurred on oceanic islands, is mainly composed of introduced mammals, and native species of birds, reptiles and insects. The impact of feral cat upon the endangered species was assessed by evaluating their relative abundance in the cats’ diet and by considering their current conservation status. A total of 68 different preys were identified at species level in all studies carried out in the Canary Islands (5 mammals, 16 birds, 15 reptiles and 32 invertebrates). From all the species preyed by feral cats in the Canary Islands, only four of them are considered threatened by the IUCN Red List of Threatened Species: one endemic bird Saxicola dacotiae and three endemic giant lizards, Gallotia simonyi, Gallotia intermedia, and Gallotia gomerana. Although some efforts on management control have been carried out, it is necessary to enforce these conservation activities on those areas of Tenerife, La Gomera and El Hierro where giant lizards are still present. Furthermore some local areas where endangered bird species are highly predated should be protected. Nevertheless, it is important to take into account the presence of other introduced species such as rats, mice or rabbits in order to avoid problems derived from the hyperpredation process and mesopredator release effect.     

Complex population genetic structure in the endemic Canary Island pine revealed using chloroplast microsatellite markers

The Canary archipelago, located on the northwestern Atlantic coast of Africa, is comprised of seven islands aligned from east to west, plus seven minor islets. All the islands were formed by volcanic eruptions and their geological history is well documented providing a historical framework to study colonization events. The Canary Island pine (Pinus canariensis C. Sm.), nowadays restricted to the westernmost Canary Islands (Gran Canaria, Tenerife, La Gomera, La Palma and El Hierro), is considered an old (Lower Cretaceous) relic from an ancient Mediterranean evolutionary centre. Twenty seven chloroplast haplotypes were found in Canary Island pine but only one of them was common to all populations. The distribution of haplotypic variation in P. canariensis suggested the colonization of western Canary Islands from a single continental source located close to the Mediterranean Basin. Present-day populations of Canary Island pine retain levels of genetic diversity equivalent to those found in Mediterranean continental pine species, Pinus pinaster and Pinus halepensis. A hierarchical analysis of variance (AMOVA) showed high differentiation among populations within islands (approximately 19%) but no differentiation among islands. Simple differentiation models such as isolation by distance or stepping-stone colonization from older to younger islands were rejected based on product-moment correlations between pairwise genetic distances and both geographic distances and population-age divergences. However, the distribution of cpSSR diversity within the islands of Tenerife and Gran Canaria pointed towards the importance of the role played by regional Pliocene and Quaternary volcanic activity and long-distance gene flow in shaping the population genetic structure of the Canary Island pine. Therefore, conservation strategies at the population level are strongly recommended for this species.Communicated by D.B. NealeA. Gómez and S.C. González-Martínez as joint authors     

Clitopilus canariensis (Basidiomycota, Entolomataceae), a new species in the C. nitellinus-complex (Clitopilus subg. Rhodophana) from the Canary Islands (Spain)

Clitopilus canariensis is described as a new species belonging to Clitopilus subgenus Rhodophana on the basis of a collection from La Palma, Canary Islands. The new species grows on humus of Cistus monspeliensis and is known from a single site. A photograph of fresh basidiomes of the type-collection and line drawings are provided.     

Revision of the species group Napaeus variatus (Gastropoda,Pulmonata, Buliminidae) from the Canary Islands,with description of five new species*

The Napaeus variatus (Webb & Berthelot, 1833) species group from the Canary Islands is reviewed from literature information, types, other museum specimens, and newly collected material. Anatomy data is newly provided for six species. Five new species are described: N. elegans and N. esbeltus from Tenerife, N. orientalis and N. beguirae from La Gomera, and N. exilis from Gran Canaria. Eight species lack a diverticulum and are referred to the subgenus Napaeus (Napaeus) Albers, 1850, whereas five species are provided with a diverticulum and arc referred to Napaeus (Napaeinus) Hesse, 1933. Four species cannot be assigned to a subgenus due to a lack of information. Keys of species from the different islands are provided.     

Evolution of an invasive rodent on an archipelago as revealed by molar shape analysis: the house mouse in the Canary Islands

Aim The aim of this paper is to identify the patterns in the morphological differentiation in Canary Island mice, based on fossil and modern samples. In order to achieve this, the mouse species present on the archipelago were first compared with a set of continental mice. The differences between the continental and Canary Island samples, and among the Canary Island samples, provide insights into the processes of colonization and the subsequent insular evolution. Location Canary archipelago. Methods An outline analysis based on Fourier transformation was used to quantify shape differences between lower molars. Together with the fossil and modern Canary Island samples, a reference set of genotyped continental populations of the commensal Mus musculus and the wild Mus spretus was used for comparison. Results The morphometric analysis showed that all the mouse specimens from the Canary Islands and Cape Verde belonged to Mus musculus domesticus. Lower molars of extant mice from La Gomera, El Hierro, Gran Canaria, Tenerife, and to a lesser degree from Lanzarote, were similar to those of genotyped M. m. domesticus from the continent, while teeth of extant mice from Fuerteventura were more divergent. Fossil mice from Fuerteventura were very similar to the extant representatives on this island, and similar to the fossil mice on the nearby islands of Lobos and La Graciosa. Main conclusions The mouse present on the Canary archipelago has been identified as the house mouse M. m. domesticus. Based on the shape of the lower molar, the Canary Island mice are divergent from the continental ones, but the degree of divergence varies with the geography of the archipelago. Overall, populations from eastern islands are more divergent from the continental mice than populations from western ones. Fossil populations indicate that this situation was established several centuries ago. Two main factors may have contributed to this pattern: the appearance of different types of environment on the islands since the successful settlement of the mouse, and/or the number of subsequent introductions of continental individuals via shipping.     

Population history,gene flow,and bottlenecks in island populations of a secondary seed disperser,the southern grey shrike (Lanius meridionalis koenigi)

Studying the population history and demography of organisms with important ecological roles can aid understanding of evolutionary processes at the community level and inform conservation. We screened genetic variation (mtDNA and microsatellite) across the populations of the southern grey shrike (Lanius meridionalis koenigi) in the Canary Islands, where it is an endemic subspecies and an important secondary seed disperser. We show that the Canarian subspecies is polyphyletic with L. meridionalis elegans from North Africa and that shrikes have colonized the Canary Islands from North Africa multiple times. Substantial differences in genetic diversity exist across islands, which are most likely the product of a combination of historical colonization events and recent bottlenecks. The Eastern Canary Islands had the highest overall levels of genetic diversity and have probably been most recently and/or frequently colonized from Africa. Recent or ongoing bottlenecks were detected in three of the islands and are consistent with anecdotal evidence of population declines due to human disturbance. These findings are troubling given the shrike's key ecological role in the Canary Islands, and further research is needed to understand the community‐level consequences of declines in shrike populations. Finally, we found moderate genetic differentiation among populations, which largely reflected the shrike's bottleneck history; however, a significant pattern of isolation‐by‐distance indicated that some gene flow occurs between islands. This study is a useful first step toward understanding how secondary seed dispersal operates over broad spatial scales.     

Riccia boumanii Dirkse,Losada & M.Stech sp. nov. (Ricciaceae,Marchantiophyta) in the Canary Islands,the first species of Riccia subgenus Riccia section Pilifer Volk outside South Africa

A morpho-molecular study was undertaken to solve the taxonomic identity of Riccia plants from the Canary Islands. These plants were assumed to belong to the South African endemic Riccia section Pilifer, but could not be assigned to a particular species in that section. In the interim they were named R. lamellosa (section Riccia), since R. lamellosa is the only European species with conspicuous white ventral scales. Molecular phylogenetic reconstructions based on trnL-F and ITS2 sequences confirmed that the respective Riccia plants belong to section Pilifer. The respective clade is clearly separated from the clades of R. lamellosa and R. elongata, the latter being morphologically most similar within section Pilifer. Based on the combined molecular and morphological evidence the Riccia plants from Canary Islands are described as a new species, R. boumanii, which represents the first species of section Pilifer outside South Africa. Based on revised herbarium specimens, R. boumanii occurs on five islands of the Canary Islands archipelago, namely El Hierro, Gran Canaria, La Gomera, La Palma, and Tenerife.     

Parasitoids of whiteflies (Hymenoptera: Aphelinidae,Eulophidae, Platygastridae; Hemiptera: Aleyrodidae) from the Macaronesian archipelagos of the Canary Islands,Madeira and the Azores

Data on the whitefly parasitoid species known from the Macaronesian archipelagos of the Canary Islands, Madeira and the Azores are presented, based largely on recently collected material. A total of 26 species are treated, including six new species, six new records for the Canary Islands, two new records for Madeira, and two new records for the Azores. All species are fully described and illustrated. New species described are: Encarsia atlantica Polaszek & Hernández; Encarsia levadicola Polaszek & Hernández; Encarsia melanostoma Polaszek & Hernández; Encarsia noahi Polaszek & Hernández; Euderomphale gomer LaSalle & Hernández; Euderomphale insularis LaSalle & Hernández. A fully illustrated identification key based on females is provided for recognition of whitefly parasitoids in these archipelagos. Data on the known distribution and hosts are provided, as well as references to biology and use in biological control.     

Effects of climate change on the distribution of plant species and plant functional strategies on the Canary Islands

Aim

Oceanic islands possess unique floras with high proportions of endemic species. Island floras are expected to be severely affected by changing climatic conditions as species on islands have limited distribution ranges and small population sizes and face the constraints of insularity to track their climatic niches. We aimed to assess how ongoing climate change affects the range sizes of oceanic island plants, identifying species of particular conservation concern.

Location

Canary Islands, Spain.

Methods

We combined species occurrence data from single-island endemic, archipelago endemic and nonendemic native plant species of the Canary Islands with data on current and future climatic conditions. Bayesian Additive Regression Trees were used to assess the effect of climate change on species distributions; 71% (n = 502 species) of the native Canary Island species had models deemed good enough. To further assess how climate change affects plant functional strategies, we collected data on woodiness and succulence.

Results

Single-island endemic species were projected to lose a greater proportion of their climatically suitable area (x ̃ = −0.36) than archipelago endemics (x ̃ = −0.28) or nonendemic native species (x ̃ = −0.26), especially on Lanzarote and Fuerteventura, which are expected to experience less annual precipitation in the future. Moreover, herbaceous single-island endemics were projected to gain less and lose more climatically suitable area than insular woody single-island endemics. By contrast, we found that succulent single-island endemics and nonendemic natives gain more and lose less climatically suitable area.

Main Conclusions

While all native species are of conservation importance, we emphasise single-island endemic species not characterised by functional strategies associated with water use efficiency. Our results are particularly critical for other oceanic island floras that are not constituted by such a vast diversity of insular woody species as the Canary Islands.     

Amphipod crustaceans from anchihaline cave waters of the Galapagos Islands

Three species of blind Amphipoda are recorded from anchihaline cave waters in the Galapagos Islands. One of these, Galapsiellus leleuporum (Monod, 1970) was previously know from the islands; the male is described for the first time. The other two belong to families with predominantly (though not exclusively) deep-sea members: Valettietta cavernicola sp. nov. (family Lysianassidae; and Antronicippe serrata gen. et sp. nov. (family Pardaliscidae). The genus Valettietta was not previously recorded from caves; it contained two abyssal species in the Atlantic, while a third species was recorded from the Pacific in a vertical haul between 0 and 5300 m. Antronicippe is closely related to Spelaeonicippe, a genus with two species known from anchihaline caves in the Canary Islands and the West Indies.     

SONGS OF BLUE TITS PARUS CAERULEUS PALMENSIS FROM LA PALMA (CANARY ISLANDS)—A TEST OF HYPOTHESES

ABSTRACT

Parus major and Parus caeruleus palmensis have some song types in common. They consist of whistled element-types in different frequency ranges. Both species show territorial reactions to playback of the song-types belonging to the other species. P.c. palmensis does not share any songtypes with Central European Parus caeruleus. This is confirmed by playback experiments with the different song types, which do not elicit any territorial behaviour. The songs of P.c. palmensis also differ from those of blue tits from any other Canary Island. They may be derived from contact calls of the Lanzarote population. They have been developed by young birds that had not yet learnt their songs when they colonized La Palma from Lanzarote without reaching any of the other Canary Islands. It is suggested that the uniform song repertoire was developed by adapting the already learned contact calls to each other. The similarities to song types of P. major are due to convergence rather than character displacement. All other Canary Island tit populations share the main features of their songs, which are characterized by quick frequency changes. It seems most likely that these islands have been colonized by birds which had already learnt their songs. Differences in song repertoires are mainly caused by drift events which happen to occur because of population bottlenecks during the colonization process.     

Phylogeography of island canary (Serinus canaria) populations

Island canaries (Serinus canaria) are characterised as a species living exclusively on North Atlantic islands, mainly on the Azores, Madeira and Canary Islands. Although they are very common in their habitats, their behaviour and breeding system has only recently been studied systematically. To advance the understanding of their ecology and to see if the rather isolated archipelagos are already promoting a genetic differentiation, we investigated their phylogeographic relationship as revealed by mtDNA sequences of the cytochrome b gene and investigated whether this measure corresponds to morphological characteristics within the islands. Genetic distances were very low throughout the distribution range of the species. Although the variation of genetic distances within the population of Pico (Azores) was larger than that on Madeira and Canary Islands, the genetic distances between island populations were very low throughout which prevented a clear phylogeographic differentiation. Moreover, morphological measurements did not reveal a consistent pattern to reliably separate the populations, although the measures of beak length and body weight revealed a clear island-specific differentiation. These data lead to the assumption that the colonisation of the Atlantic islands by the canaries occurred very recently, while there is no persisting gene flow between the populations.     

Mapping unexplored genomes II: genetic architecture of species differences in the woody <Emphasis Type="Italic">Sonchus</Emphasis> alliance (Asteraceae) in the Macaronesian Islands

Despite numerous, well-documented evolutionary histories of plant groups which underwent rapid radiation in various oceanic archipelagos, very little is known about the genetic basis of species differences and adaptive radiation. This paper represents the first such study in the Macaronesian Islands using non-model endemic plants, the woody Sonchus alliance. Here I inferred the genetic basis of species differences between two Canary Island endemics, the herbaceous perennial, shade tolerant Lactucosonchus webbii and the woody, coastal desert perennial Sonchus radicatus by quantitative trait locus (QTL) mapping using AFLP markers. A total of 23 QTL (7.3–23.8% PVE; phenotypic variance explained) for 11 morphological traits were found, one for flowering time (31% PVE), and five QTL (7–10.7% PVE) for two physiological traits (intrinsic water use efficiency and stomatal conductance). Interpreted cautiously, these results suggest that major morphological and some physiological differences between the two species are controlled by numerous genes with small to moderate effect. This implies that major morphological changes in island plants can be more complex than suggested by other studies, such as in Tetramolopium in the Hawaiian Islands. The genetic basis of arborescence on islands, one of the most spectacular convergent features of plants across different lineages and archipelagos, is also discussed.     

A Bryophyte Flora of Kent. IV. Addenda and Corrigenda

Abstract

Based on a revision of Andreaea from the Canary Islands, the occurence of two species is confirmed. A key is provided. A. crassifolia Luisier occurs on Gran Canaria, La Palma and Tenerife. A. heinemannii Hampe &; Müll.Hal. occurs on La Palma. Former records of A. heinemannii s.l. for Gran Canaria and Tenerife refer to A. crassifolia.