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The presence of arbuscular mycorrhizal fungi (AMF) is essential for the survival and establishment of most plant species in nature. The reproductive success of invasive plant species in a particular habitat could also depend on these AM fungi. Cinchona pubescens, commonly known as quinine, is highly invasive on Santa Cruz Island, Galápagos, but at the same time severely endangered in its native range on mainland Ecuador due to overexploitation in the past. In this study, we aim at determining the AMF communities associated with C. pubescens at both locations to investigate whether the successful invasion of C. pubescens on Santa Cruz is related to its association with a particular community of AMF. For this, roots of C. pubescens trees were sampled at three sites, one site on Santa Cruz and two sites in the province of Loja, on mainland Ecuador. Communities of AM fungi were determined through the molecular cloning and sequencing of the 18S nrDNA gene and through the delimitation of Operational Taxonomic Units (OTUs), associated with the plant roots. We found 36 AMF OTUs associated with C. pubescens, most of them belonging to the genus Glomus. The highest richness of AMF OTUs was detected in samples from sites located on mainland Ecuador. The AMF communities between Santa Cruz and mainland Ecuador were significantly different, and only five OTUs were shared between both locations. Two dominant OTUs in C. pubescens from Santa Cruz were detected but no dominant OTUs from mainland Ecuador. Almost two thirds of the OTUs associated with C. pubescens had a wide global distribution. Our results suggest that the successful invasion of C. pubescens on Santa Cruz could have been facilitated by local generalist AMF and not by particular AMF. The observed generalist AMF from both locations could be important for conservation plans of restoring the endangered C. pubescens in the native forests on mainland Ecuador. [ABSTRACT FROM AUTHOR]

Due to its proximity to coastal South America and settlement during the early phase of insular Caribbean occupation, Curaçao's archaeological record offers potential evidence for early overwater exploration and regional interaction. Here, we report new accelerator mass spectrometry (AMS) dates on charcoal from C-1426 at Saliña Sint Marie, an Archaic rockshelter site that extends Curaçao's occupation back to 5735–5600 cal BP, some 290–850 years earlier than the established settlement chronology. This finding makes the C-1426 rockshelter Curaçao's earliest known archaeological site and among the oldest in the insular Caribbean. We describe the site and the archaeological context of dating and conclude by considering the implications of Curaçao's revised occupation chronology for initial Caribbean settlement. [ABSTRACT FROM AUTHOR]

Animals that colonize islands often undergo significant evolutionary changes in comparison with their continental counterparts as a response to specific island conditions. The pace of such changes can be relatively fast, which poses challenges in the evaluation of the taxonomic status of island taxa. The Japanese and Manchurian Bush Warbler species complex (Horornis diphone–canturians), which breeds in East Asia and the Japanese Archipelago, is such an avian example. This species complex exhibits significant morphological differentiation between different taxa, and the taxonomic status and phylogenetic relationships within the complex are debated. Here, we updated the taxonomy of this species complex and shed insight on its evolutionary history using multi‐locus phylogeographic and acoustic analyses. Our results support the conventional treatment of the two continental taxa borealis and canturians as subspecies of H. canturians, contrary to some recent proposals that they are affiliated to H. diphone. We also document a reduction in body size, that is dwarfism, and vocal divergence in the nominate subspecies H. d. diphone, which is endemic to the remote and isolated Ogasawara Islands. These changes may have happened following colonization of these islands, which was estimated to have taken place approximately 0.2 million years ago. Although H. d. diphone is clearly distinctive and deserves recognition as an evolutionarily significant unit, H. d. diphone and other H. diphone samples were not reciprocally monophyletic. Because of this lack of reciprocal monophyly and a relatively recent divergence time, we advocate maintaining its current subspecies status. We also detected reduced genetic diversity, measured as heterozygosity, in H. d. diphone. We suggest that conservation efforts in the Ogasawara Islands should prioritize the protection of this endemic subspecies. Collectively, our findings suggest that the separation between the populations on the East Asian continent and the Japanese Archipelago, followed by colonization of remote oceanic islands through long‐distance dispersal, underlie rapid phenotypic and genetic diversification of the Horornis diphone–canturians species complex. [ABSTRACT FROM AUTHOR]

Thalassochory, the dispersal of propagules through marine currents, is a key long‐distance dispersal (LDD) mechanism with implications for global biogeography and particularly for island colonization. The propagules of coastal plant species are generally assumed to be better adapted for sea dispersal than those of inland plants, but this hypothesis remains largely untested.We conducted experiments on four genera (Juniperus, Daucus, Ferula, and Pancratium) and compared traits among nine species with different habitats and distributions.Our results showed that Juniperus spp. and P. maritimum have strong thalassochorous potential within the Mediterranean Basin. Interestingly, we did not find a clear association on the thalassochorous potential of coastal versus inland species within all the tested genera, apart from P. maritimum compared with the endemic inland P. illyricum.These findings suggest that thalassochory may be a more common dispersal mechanism than previously assumed. The apparently weak link of dispersal syndrome with species ecology broadens the possibility of dispersal by the sea also for inland plants, although considered to be poorly salt‐tolerant. Moreover, our results reveal significant differences in sea dispersal between endemic and widespread species, but do not rule out an important role of thalassochory in shaping the distribution patterns of archipelago endemic flora. The presented method is largely replicable and could be used for further studies with a larger set of species to better delineate trends of sea dispersal syndrome among species with different ecology or dispersal traits. [ABSTRACT FROM AUTHOR]

The human colonization of the Canary Islands represents the sole known expansion of Berber communities into the Atlantic Ocean and is an example of marine dispersal carried out by an African population. While this island colonization shows similarities to the populating of other islands across the world, several questions still need to be answered before this case can be included in wider debates regarding patterns of initial colonization and human settlement, human-environment interactions, and the emergence of island identities. Specifically, the chronology of the first human settlement of the Canary Islands remains disputed due to differing estimates of the timing of its first colonization. This absence of a consensus has resulted in divergent hypotheses regarding the motivations that led early settlers to migrate to the islands, e.g., ecological or demographic. Distinct motivations would imply differences in the strategies and dynamics of colonization; thus, identifying them is crucial to understanding how these populations developed in such environments. In response, the current study assembles a comprehensive dataset of the most reliable radiocarbon dates, which were used for building Bayesian models of colonization. The findings suggest that i) the Romans most likely discovered the islands around the 1st century BCE; ii) Berber groups from western North Africa first set foot on one of the islands closest to the African mainland sometime between the 1st and 3rd centuries CE; iii) Roman and Berber societies did not live simultaneously in the Canary Islands; and iv) the Berber people rapidly spread throughout the archipelago. [ABSTRACT FROM AUTHOR]

ABSTRACT The presence of arbuscular mycorrhizal fungi (AMF) is essential for the survival and establishment of most plant species in nature. The reproductive success of invasive plant species in a particular habitat could also depend on these AM fungi. Cinchona pubescens, commonly known as quinine, is highly invasive on Santa Cruz Island, Galápagos, but at the same time severely endangered in its native range on mainland Ecuador due to overexploitation in the past. In this study, we aim at determining the AMF communities associated with C. pubescens at both locations to investigate whether the successful invasion of C. pubescens on Santa Cruz is related to its association with a particular community of AMF. For this, roots of C. pubescens trees were sampled at three sites, one site on Santa Cruz and two sites in the province of Loja, on mainland Ecuador. Communities of AM fungi were determined through the molecular cloning and sequencing of the 18S nrDNA gene and through the delimitation of Operational Taxonomic Units (OTUs), associated with the plant roots. We found 36 AMF OTUs associated with C. pubescens, most of them belonging to the genus Glomus. The highest richness of AMF OTUs was detected in samples from sites located on mainland Ecuador. The AMF communities between Santa Cruz and mainland Ecuador were significantly different, and only five OTUs were shared between both locations. Two dominant OTUs in C. pubescens from Santa Cruz were detected but no dominant OTUs from mainland Ecuador. Almost two thirds of the OTUs associated with C. pubescens had a wide global distribution. Our results suggest that the successful invasion of C. pubescens on Santa Cruz could have been facilitated by local generalist AMF and not by particular AMF. The observed generalist AMF from both locations could be important for conservation plans of restoring the endangered C. pubescens in the native forests on mainland Ecuador.

Euphorbia canariensis is an iconic endemic species representative of the lowland xerophytic communities of the Canary Islands. It is widely distributed in the archipelago despite having diasporas unspecialized for long‐distance dispersal. Here, we reconstructed the evolutionary history of E. canariensis at two levels: a time‐calibrated phylogenetic analysis aimed at clarifying interspecific relationships and large‐scale biogeographic patterns; and a phylogeographic study focused on the history of colonization across the Canary Islands.For the phylogenetic study, we sequenced the ITS region for E. canariensis and related species of Euphorbia sect. Euphorbia. For the phylogeographic study, we sequenced two cpDNA regions for 28 populations representing the distribution range of E. canariensis. The number of inter‐island colonization events was explored using PAICE, a recently developed method that includes a sample size correction. Additionally, we used species distribution modelling (SDM) to evaluate environmental suitability for E. canariensis through time.Phylogenetic results supported a close relationship between E. canariensis and certain Southeast Asian species (E. epiphylloides, E. lacei, E. sessiliflora). In the Canaries, E. canariensis displayed a west‐to‐east colonization pattern, not conforming to the "progression rule", i.e. the concordance between phylogeographic patterns and island emergence times. We estimated between 20 and 50 inter‐island colonization events, all of them in the Quaternary, and SDM suggested a late Quaternary increase in environmental suitability for E. canariensis.The extreme biogeographic disjunction between Macaronesia and Southeast Asia (ca. 11,000 km) parallels that found in a few other genera (Pinus, Dracaena). We hypothesize that these disjunctions are better explained by extinction across north Africa and southwest Asia rather than long‐distance dispersal. The relatively low number of inter‐island colonization events across the Canaries is congruent with the low dispersal capabilities of E. canariensis. [ABSTRACT FROM AUTHOR]

The first Austronesian settlers at the site of San Roque in Saipan and the southern Mariana Islands began arriving sometime after 1500 BC in what is called the Early Pre-Latte Period. A comparison of San Roque to contemporaneous island sites reveals differences in cooking and habitation features, ceramic vessels and decorative styles, marine shell tools and ornaments, and settlement patterns that were apparent within and between islands and sites until the middle of the first millennium BC. Changes in sea level and natural resource availability then appear to have accompanied changes in material culture, when some coastal sites were abandoned or moved seaward, while other inhabitants moved inland with a more terrestrial subsistence strategy shared elsewhere in Micronesia. [ABSTRACT FROM AUTHOR]

Aim: Evolutionary studies of oceanic island endemics are usually focused on lineages that have experienced in situ radiation, while those that speciated once on the island or archipelago but have not further diversified (single‐species endemics) remain understudied. The Macaronesian archipelagos, in the Atlantic Ocean, are home to significant numbers of single‐species endemics. The genus Hedera L. (12 species) includes three single‐species endemics from three Macaronesian archipelagos with putatively independent origins. Here, we tested the role of phylogenetic niche conservatism in their evolution. To that end, we (1) reconstructed the spatio‐temporal origin of Macaronesian ivies using phylogenomics, and (2) assessed the role of climatic niche during their colonization and speciation. Location: Azores, Canary Islands, Madeira, western Mediterranean. Taxon: Hedera spp. Methods: We used 166 samples representing all Hedera species to generate genotyping‐by‐sequencing (GBS) libraries and performed time‐calibrated phylogenomic and biogeographic analyses. Climatic preferences and climatic niche evolution were assessed using a geo‐referenced database of the western ivy species (2,297 records). Results: Independent and asynchronous colonization and speciation were estimated for the three Macaronesian ivies, resulting in different degrees of phylogenetic and climatic niche differentiation: H. canariensis displayed an early divergence (7.5–12 Ma) and high phylogenetic and niche isolation; H. azorica had intermediate phylogenetic isolation and niche divergence from its closest relative H. helix (4.4–6.8 Ma) and H. maderensis was embedded within the climatically similar H. iberica (2.8–4.6 Ma). A strong phylogenetic signal was suggested for climatic niche in the western clade of Hedera, where the three Macaronesian ivies are placed. Main Conclusions: The three Macaronesian ivies represent the evolutionary stages leading to the emergence of single‐species island endemics. Climatic niche conservatism appears to be involved in the evolution of single‐species endemics, first by facilitating island colonization, and then by limiting in situ diversification. [ABSTRACT FROM AUTHOR]

The origin and evolution of endemic species characterizing the Oreopithecus-faunal assemblages of the Tusco-Sardinian archipelago remain a matter of debate. An emblematic case is the enigmatic giraffid Umbrotherium azzarolii, represented by a single specimen from the type locality of Casteani (Tuscany) and by several isolated teeth and fragmentary mandibles from the locality of Fiume Santo (Sardinia). An exhaustive diagnosis of Umbrotherium has not been firmly established, and its systematic and phylogenetic position remain unresolved. Unpublished remains of giraffids, including an almost complete mandible, several isolated teeth, and other cranial remains are described for the first time in the present work. The specimens were collected from the locality of Botro della Canonica (Pisa), located at the northernmost portion of the Tusco-Sardinian archipelago. The new material sheds light on the morphological and morphometric variability of Umbrotherium, thereby enabling a comparison between specimens collected from different Tusco-Sardinian Miocene localities spanning from the V1 to the V2 Oreopithecus-Zone Faunas and allowing the establishment of the new species U. engesserii sp. nov. from Fiume Santo (Sardinia). This study also reveals that Umbrotherium was more closely related to Decennatherium than to other Late Miocene continental giraffids, suggesting a dispersal of its ancestor from the Iberian Peninsula. Accordingly, a new paleogeographic and biochronological framework is proposed herein for the Tusco-Sardinian archipelago, hypothesizing a fragmentation of the area into several domains, with sporadic reconnections, and the establishment of different faunal assemblages. [ABSTRACT FROM AUTHOR]

Although the distribution patterns of major amphibian lineages are mainly explained by a Pangean origin with subsequent vicariant diversification, dispersal events have exerted a strong influence on present-day distributions. Long-distance dispersal (LDD) involves movements outside the standard geographic limits and outside the genetic neighbourhood area of individuals. Although considered ‘rare’, LDD is disproportionately important to amphibian populations, species and communities. To understand the role of LDD in shaping current biogeographic patterns in these tetrapods, we reviewed the cases reported in the literature. A systematic bibliographic search was performed to obtain information on how many studies have dealt with LDD in amphibians, which methods they used, which taxa and distances were involved, and when/where events had apparently occurred. In 41 studies, we recovered at least 90 LDD events (3 active, 87 passive) involving at least 56 extant species and 38 genera. Most events (73) involved the colonization of islands, with rafting being suggested as the most conceivable means of overwater passive dispersal for these vertebrates. In this review, we show that LDD events have played an important role in shaping current amphibian biogeographic patterns, especially the occurrence of disjunct distributions and the colonization of islands.

Abstract Anopheles hinesorum is a mosquito species with variable host preference. Throughout New Guinea and northern Australia, An. hinesorum feeds on humans (it is opportunistically anthropophagic) while in the south‐west Pacific's Solomon Archipelago, the species is abundant but has rarely been found biting humans (it is exclusively zoophagic in most populations). There are at least two divergent zoophagic (nonhuman biting) mitochondrial lineages of An. hinesorum in the Solomon Archipelago representing two independent dispersals. Since zoophagy is a derived (nonancestral) trait in this species, this leads to the question: has zoophagy evolved independently in these two populations? Or conversely: has nuclear gene flow or connectivity resulted in the transfer of zoophagy? Although we cannot conclusively answer this, we find close nuclear relationships between Solomon Archipelago populations indicating that recent nuclear gene flow has occurred between zoophagic populations from the divergent mitochondrial lineages. Recent work on isolated islands of the Western Province (Solomon Archipelago) has also revealed an anomalous, anthropophagic island population of An. hinesorum. We find a common shared mitochondrial haplotype between this Solomon Island population and another anthropophagic population from New Guinea. This finding suggests that there has been recent migration from New Guinea into the only known anthropophagic population from the Solomon Islands. Although currently localized to a few islands in the Western Province of the Solomon Archipelago, if anthropophagy presents a selective advantage, we may see An. hinesorum emerge as a new malaria vector in a region that is now working on malaria elimination.

The path followed by species in the colonization of remote oceanic islands ultimately depends on their phylogenetic constraints and ecological responses. In this study, we aim to evaluate the relative role of geographical and ecological forces in the origin and evolution of the Madeiran ivy (Hedera maderensis), a single-species endemic belonging to the western polyploid clade of Hedera. To determine the phylogenetic placement of H. maderensis within the western polyploid clade, we analyzed 40 populations (92 individuals) using genotyping-by-sequencing and including Hedera helix as outgroup. Climatic niche differences among the study species were evaluated using a database with 867 records representing the entire species ranges. To test species responses to climate, 13 vegetative and reproductive functional traits were examined for 70 populations (335 individuals). Phylogenomic results revealed a nested pattern with H. maderensis embedded within the south-western Iberian H. iberica. Gradual niche differentiation from the coldest and most continental populations of H. iberica to the warm and stable coastal population sister to H. maderensis parallels the geographical pattern observed in the phylogeny. Similarity in functional traits is observed for H. maderensis and H. iberica. The two species show leaves with higher specific leaf area (SLA), lower leaf dry matter content (LDMC) and thickness and fruits with lower pulp fraction than the other western polyploid species H. hibernica. Acquisition of a Macaronesian climatic niche and the associated functional syndrome in mainland European ivies (leaves with high SLA, and low LDMC and thickness, and fruits with less pulp content) was a key step in the colonization of Madeira by the H. iberica/H. maderensis lineage, which points to climatic pre-adaptation as key in the success of island colonization (dispersal and establishment). Once in Madeira, budding speciation was driven by geographical isolation, while ecological processes are regarded as secondary forces with a putative impact in the lack of further in situ diversification. [ABSTRACT FROM AUTHOR]

Sicily, the largest island in the Mediterranean Sea, is widely known for its crucial role as a crossroads for human colonization from the Holocene through to at least the Middle Ages. Yet the role played by Sicily in terms of human dispersal along the coastal margins of the western and central Mediterranean during the Pleistocene remains largely unclear. For instance, Sicily is often cited in the literature as being the first Mediterranean island to have been populated by Aurignacian human groups—a scenario that has been heavily debated, if not entirely disproven. In this paper, I present a critical reanalysis of the purported early colonization events of the island known from the literature, together with recently published radiometric dates and sophisticated geological modeling, to show that there is currently no basis to postulate a Sicilian Aurignacian phase (∼45 − 33 ka BP). Additionally, I suggest that there is cause to reconsider the timing and modalities of the colonization of the island by Epigravettian human groups and that the colonization of Sicily could represent the first evidence of an island in the Central and Western Mediterranean colonized by watercraft. Contextualizing the relevance of Sicily in the early seafaring debate, the conclusions presented further suggest a reconsideration of the current pre-Holocene model of human dispersion for the entire Mediterranean. [ABSTRACT FROM AUTHOR]

Trinidad and Tobago are home to three endemic species in the anuran genus Pristimantis, of which two (Pristimantis charlottevillensis and Pristimantis turpinorum) occur in Tobago alone and the third (Pristimantis urichi) is present on both islands. Earlier, the IUCN assessed the conservation status of these species as: P. urichi, Endangered (EN); P. charlottevillensis, Least Concern (LC); P. turpinorum, Vulnerable (VU). However, these assessments were based on very little field‐based evidence. Here, we present survey results which contributed to reassessments as LC, VU and Data Deficient for these three species, respectively. Despite the close proximity of Trinidad to northern Venezuela, the islands do not share any Pristimantis species with the mainland, which holds a rich endemicity of Pristimantis regionally. In this study, we used genetic sequencing from several island populations and compared them to northern Venezuelan endemics to assess genetic divergence for the first time. The time tree analyses found that only the northern Tobago species P. turpinorum is closely related to mainland Pristimantis, with a genetic split dating to the Late Miocene, suggesting a vicariant event of mainland and island species. Pristimantis urichi, although identical between the two islands, remains highly divergent from the mainland species. Similar results were found for P. charlottevillensis. In addition, there was a high level of divergence between P. urichi and P. charlottevillensis. These findings indicate different island colonization events by different lineages. Sequencing other Venezuelan species remains pivotal to unravel the complexity of the colonization episodes in the region, likely influenced by the changing topography and multiple connection and isolation episodes of the islands by eustatic sea‐level changes. [ABSTRACT FROM AUTHOR]

Abstract Genome‐wide genotyping and Bayesian inference method (BORICE) were employed to estimate outcrossing rates and paternity in two small plant populations of Tolpis succulenta (Asteraceae) on Graciosa island in the Azores. These two known extant populations of T. succulenta on Graciosa have recently evolved self‐compatibility. Despite the expectation that selfing would occur at an appreciable rate (self‐incompatible populations of the same species show low but nonzero selfing), high outcrossing was found in progeny arrays from maternal plants in both populations. This is inconsistent with an immediate transition to high selfing following the breakdown of a genetic incompatibility system. This finding is surprising given the small population sizes and the recent colonization of an island from self‐incompatible colonists of T. succulenta from another island in the Azores, and a potential paucity of pollinators, all factors selecting for selfing through reproductive assurance. The self‐compatible lineage(s) likely have high inbreeding depression (ID) that effectively halts the evolution of increased selfing, but this remains to be determined. Like their progeny, all maternal plants in both populations are fully outbred, which is consistent with but not proof of high ID. High multiple paternity was found in both populations, which may be due in part to the abundant pollinators observed during the flowering season.

Island colonists are often assumed to experience higher levels of phenotypic diversification than continental taxa. However, empirical evidence has uncovered exceptions to this 'island effect'. Here, we tested this pattern using the geckos of the genus Pristurus from continental Arabia and Africa and the Socotra Archipelago. Using a recently published phylogeny and an extensive morphological dataset, we explore the differences in phenotypic evolution between Socotran and continental taxa. Moreover, we reconstructed ancestral habitat occupancy to examine if ecological specialization is correlated with morphological change, comparing phenotypic disparity and trait evolution between habitats. We found a heterogeneous outcome of island colonization. Namely, only one of the three colonization events resulted in a body size increase. However, in general, Socotran species do not present higher levels or rates of morphological diversification than continental groups. Instead, habitat specialization explains better the body size and shape evolution in Pristurus. Particularly, the colonization of ground habitats appears as the main driver of morphological change, producing the highest disparity and evolutionary rates. Additionally, arboreal species show very similar body size and head proportions. These results reveal a determinant role of ecological mechanisms in morphological evolution and corroborate the complexity of ecomorphological dynamics in continent–island systems. [ABSTRACT FROM AUTHOR]

Humans have made such dramatic and permanent changes to Earth's landscapes that much of it is now substantially and irreversibly altered from its preanthropogenic state. Remote islands, until recently isolated from humans, offer insights into how these landscapes evolved in response to human-induced perturbations. However, little is known about when and how remote systems were colonized because archaeological data and historical records are scarce and incomplete. Here, we use a multiproxy approach to reconstruct the initial colonization and subsequent environmental impacts on the Azores Archipelago. Our reconstructions provide unambiguous evidence for widespread human disturbance of this archipelago starting between 700-60+50 and 850-60+60 Common Era (CE), ca. 700 y earlier than historical records suggest the onset of Portuguese settlement of the islands. Settlement proceeded in three phases, during which human pressure on the terrestrial and aquatic ecosystems grew steadily (i.e., through livestock introductions, logging, and fire), resulting in irreversible changes. Our climate models suggest that the initial colonization at the end of the early Middle Ages (500 to 900 CE) occurred in conjunction with anomalous northeasterly winds and warmer Northern Hemisphere temperatures. These climate conditions likely inhibited exploration from southern Europe and facilitated human settlers from the northeast Atlantic. These results are consistent with recent archaeological and genetic data suggesting that the Norse were most likely the earliest settlers on the islands. [ABSTRACT FROM AUTHOR]

Anopheles hinesorum is a mosquito species with variable host preference. Throughout New Guinea and northern Australia, An. hinesorum feeds on humans (it is opportunistically anthropophagic) while in the south‐west Pacific's Solomon Archipelago, the species is abundant but has rarely been found biting humans (it is exclusively zoophagic in most populations). There are at least two divergent zoophagic (nonhuman biting) mitochondrial lineages of An. hinesorum in the Solomon Archipelago representing two independent dispersals. Since zoophagy is a derived (nonancestral) trait in this species, this leads to the question: has zoophagy evolved independently in these two populations? Or conversely: has nuclear gene flow or connectivity resulted in the transfer of zoophagy? Although we cannot conclusively answer this, we find close nuclear relationships between Solomon Archipelago populations indicating that recent nuclear gene flow has occurred between zoophagic populations from the divergent mitochondrial lineages. Recent work on isolated islands of the Western Province (Solomon Archipelago) has also revealed an anomalous, anthropophagic island population of An. hinesorum. We find a common shared mitochondrial haplotype between this Solomon Island population and another anthropophagic population from New Guinea. This finding suggests that there has been recent migration from New Guinea into the only known anthropophagic population from the Solomon Islands. Although currently localized to a few islands in the Western Province of the Solomon Archipelago, if anthropophagy presents a selective advantage, we may see An. hinesorum emerge as a new malaria vector in a region that is now working on malaria elimination. [ABSTRACT FROM AUTHOR]

Aim: Seed dispersal by oceanic currents (thalassochory) is considered one of the main long‐distance dispersal (LDD) mechanisms for the colonization of oceanic islands by plants. Diaspores of littoral species are often hypothesized to be physiologically adapted to seawater dispersal, favouring interisland colonization. In this study, we experimentally tested the sea dispersal potential of a large proportion of Galápagos littoral flora and explored its correlation with plant distribution across the archipelago. We propose a simple Sea Dispersal Potential index (SDPi) to quantify the thalassochorous potential of any species. Location: Galápagos archipelago. Taxon: Littoral angiosperms. Methods: We combined information on seed floatability (flotation time) and viability experiments (tetrazolium test) into an SDPi for 19 native littoral plants and tested whether increasing dispersal potential is associated with broader interisland distributions. We then tested if the presence of morphological structures related to thalassochory is associated with the functional SDPi. Results: A relatively low, albeit highly variable, SDPi across Galápagos littoral plant species was found. No correlation was found between SDPi and species distributions. Morphological traits hypothesized to favour sea dispersal are not related to thalassorous potentials to reach closest islands, but they are positively associated with SDPi to reach the farthest islands. Main conclusions: SDPi is shown to be a useful tool to compare the thalassochorous potentials of entire floras in a given geographical context. The low performance of most of the species questions the general assumption that most littoral plants are highly adapted to long‐distance sea dispersal. Our results support the view that island colonization is a multifactorial process and that the use of dispersal syndromes is insufficient to make biogeographical predictions in macroecology studies. Further research should integrate functional indices (e.g., SDPi) with complementary tools (genetics, remote diaspore tracking) to determine the actual drivers of species dispersal and establishment. [ABSTRACT FROM AUTHOR]

Pleistocene water crossings, long thought to be an innovation of Homo sapiens, may extend beyond our species to encompass Middle and Early Pleistocene Homo. However, it remains unclear how water crossings differed among hominin populations, the extent to which Homo sapiens are uniquely flexible in these adaptive behaviors, and how the tempo and scale of water crossings played out in different regions. I apply the adaptive flexibility hypothesis, derived from cognitive ecology, to model the global data and address these questions. Water-crossing behaviors appear to have emerged among different regional hominin populations in similar ecologies, initially representing nonstrategic range expansion. However, an increasing readiness to form connections with novel environments allowed some H. sapiens populations to eventually push water crossings to new extremes, moving out of sight of land, making return crossings to maintain social ties and build viable founder populations, and dramatically shifting subsistence and lithic provisioning strategies to meet the challenges of variable ecological settings. [ABSTRACT FROM AUTHOR]

Palynological assemblages from palaeo-islands are scarce in the fossil record and represent an opportunity to explore plant dispersal patterns and colonization strategies in isolated ecosystems. We present a palynological study of a Middle Jurassic volcanic island located in a shallow epicontinental sea, c. 150 km from the palaeo-mainland. The study is based on a 2-m thick succession of calcareous marlstones in the El Pedregal Formation in the eastern part of the Iberian Basin, and the palaeo-island is termed Camarena Island after the village nearest to the fossil site. Eleven samples yielded equivalent assemblages that are here treated as a single palynological suite containing 47 fossil-species belonging to 36 fossil-genera. The abundance of Araucariacites australis and Klukisporites variegatus , together with accessory Cycadopites spp. and the scarcity of Callialasporites turbatus , Manumia irregularis , Staplinisporites caminus and Kekryphalospora distincta , suggest a Toarcian–Aalenian age. Additional stratigraphical data resolve the likely age for the Camarena Island as lower–middle Aalenian. Many palynomorphs in this assemblage have apparent anemophilous and hydrophilous adaptations facilitating long-distance transport. On this basis, some parent plants probably derive from the adjacent mainland or neighbouring islands. Marine palynomorphs or pollen and spores with few adaptations for dispersal may have derived from plant groups that evolved in situ on the volcanic island. The palynological assemblage has some differences from coeval palynofloras from the central Iberian Peninsula, but there are also some similarities with assemblages from post-volcanic deposits and other oceanic islands. It is likely that the seaway separating the volcanic island from the mainland acted as a biological filter enabling colonization by only a selected range of plant groups. [Display omitted] • The microflora describes the colonization of an extinct volcanic island during the Middle Jurassic. • Pollen, spores, scolecodonts, acritarch, fungi, and algae were identified in the assemblage. • Warm and humid conditions are interpreted during the "Island Event". • An early-middle Aalenian age is suggested for the colonization of the volcanic island. [ABSTRACT FROM AUTHOR]

Flightless, phoretic insects of the tribe Meloini include several widespread species able to inhabit both mainland and oceanic and continental islands. Relationships between phoretic and non‐phoretic species of Meloini are unclear, precluding broad evolutionary and biogeographic analyses within the group. We provide a robust molecular phylogenetic framework for Meloini, with finer sampling in the Western Palaearctic, by analysing two nuclear (Wg, 18S) and two mtDNA (cox1, 16S) gene fragments of 24 species representing eight subgenera of Meloe and Physomeloe. Our phylogenetic analyses revealed that Meloe, as currently recognized, is paraphyletic. Our phylogenetic hypothesis clarifies several controversial relationships within the group. We provide a new taxonomic framework that better reflects the evolutionary relationships of the group by raising to genus all previously considered subgenera: Afromeloe Schmidt, 1913, Alveomeloe Pripisnova, 1987, Chiromeloe Reitter, 1911, Desertimeloe Kaszab, 1964, Eurymeloe Reitter, 1911, Lampromeloe Reitter, 1911, Lasiomeloe Reitter, 1911, Listromeloe Reitter, 1911, Meloegonius Reitter, 1911, Mesomeloe Reitter, 1911, Meloenellus Reitter, 1911, Micromeloe Reitter, 1911, Taphromeloe Reitter, 1911 and Treiodous Dugès, 1869; while Anchomeloe Iablokoff‐Khnzorian, 1983, is recovered as subgenus of Meloe. In addition, we conducted an extensive intraspecific sampling for four phoretic taxa (Meloe proscarabaeus, Meloe autumnalis, Eurymeloe mediterraneus and Eurymeloe tuccia) and used mtDNA phylogeographic analyses to unveil patterns of overseas dispersal. Our phylogeographic analyses revealed a high level of geographically unstructured haplotype diversity within taxa, suggesting that transmarine dispersal events have occurred multiple times along the evolutionary history of phoretic species of blister beetles. Larval phoresy may explain the existence of idiosyncratic biogeographic and phylogeographic patterns in these flightless organisms. [ABSTRACT FROM AUTHOR]

The advent of high‐throughput sequencing technologies (HTS) has generated an unprecedented amount of genomic and transcriptomic information. A vast amount of these data is not even used in targeted projects but is made available in public repositories. Previous studies have demonstrated that HTS data constitute a valuable resource to recover mitogenomic information, which is most relevant for studies of non‐model and undersampled taxa. The spider family Dysderidae exemplifies well this situation: It is a highly diverse group, exceptionally well‐suited for evolutionary and ecological research, but with a sparse mitogenomic record. In this study, we used public and in‐house HTS data to assemble and annotate at no cost 13 complete and 6 partial Dysderidae mitogenomes, as well as 34 partial mitogenomes belonging to other taxa within the Synspermiata clade, to which Dysderidae belongs. The mitogenomic information was further used to interrogate on a diverse array of evolutionary questions posed by the family. Phylogenetic inference clarified the evolutionary scenario of the colonization of the Canary Islands by the genus Dysdera, supporting two independent colonizations from the continent. Synteny analyses indicated that gene organization at the mitogenomic level is overall conserved within Dysderidae, the only exceptions being two cave‐dwelling species, each of them with a unique putative transposition not described before in spiders. Finally, tRNA secondary structure reconstruction confirmed that the extreme compaction of tRNA is conserved across the family, suggesting that its origin could be traced back to approximately 100 million years ago (Mya). Altogether, this study demonstrates the potential of publicly available HTS data to conduct low‐cost evolutionary research at different biological levels. [ABSTRACT FROM AUTHOR]

Genome‐wide genotyping and Bayesian inference method (BORICE) were employed to estimate outcrossing rates and paternity in two small plant populations of Tolpis succulenta (Asteraceae) on Graciosa island in the Azores. These two known extant populations of T. succulenta on Graciosa have recently evolved self‐compatibility. Despite the expectation that selfing would occur at an appreciable rate (self‐incompatible populations of the same species show low but nonzero selfing), high outcrossing was found in progeny arrays from maternal plants in both populations. This is inconsistent with an immediate transition to high selfing following the breakdown of a genetic incompatibility system. This finding is surprising given the small population sizes and the recent colonization of an island from self‐incompatible colonists of T. succulenta from another island in the Azores, and a potential paucity of pollinators, all factors selecting for selfing through reproductive assurance. The self‐compatible lineage(s) likely have high inbreeding depression (ID) that effectively halts the evolution of increased selfing, but this remains to be determined. Like their progeny, all maternal plants in both populations are fully outbred, which is consistent with but not proof of high ID. High multiple paternity was found in both populations, which may be due in part to the abundant pollinators observed during the flowering season. [ABSTRACT FROM AUTHOR]

We examine the genetic history and population status of Hawaiian hoary bats (Lasiurus semotus), the most isolated bats on Earth, and their relationship to northern hoary bats (Lasiurus cinereus), through whole-genome analysis of single-nucleotide polymorphisms mapped to a de novo-assembled reference genome. Profiles of genomic diversity and divergence indicate that Hawaiian hoary bats are distinct from northern hoary bats, and form a monophyletic group, indicating a single ancestral colonization event 1.34 Ma, followed by substantial divergence between islands beginning 0.51 Ma. Phylogenetic analysis indicates Maui is central to the radiation across the archipelago, with the southward expansion to Hawai'i and westward to O'ahu and Kaua'i. Because this endangered species is of conservation concern, a clearer understanding of the population genetic structure of this bat in the Hawaiian Islands is of timely importance. [ABSTRACT FROM AUTHOR]

In spite of their potential significance to early human migrants and maritime foragers, small islands often are overlooked in archaeological research projects in favor of mainland coastal and large island counterparts. One excellent example of this is found off the northwestern coast of Baja California, México. Despite the wealth of data from islands to the north and south, the Coronados Islands, a group of four small islands clearly visible and only a short boat ride from the mainland, have seen little scientific archaeological investigation. As part of a collaborative bi-national research project, the first systematic archaeological reconnaissance of the Coronados Islands was completed in October 2016, resulting in the identification of 30 archaeological sites, the collection of diagnostic surface artifacts, and the radiocarbon dating of two prehistoric sites. We detail our efforts to build an island settlement chronology and occupational history and lay the foundation for future archaeological and historical ecological studies of the island group. [ABSTRACT FROM AUTHOR]

Molecular dating offers a tool for inferring the time of divergence between two lineages. In this study, we discuss how dated molecular reconstructions are informative of two different, albeit often intermingled, time estimates with regard to a fundamental process in island biogeography: the time of island colonization (TIC). We illustrate how stem age estimates provide information on the divergence between the extant island lineage and their closest relatives (i.e. the onset of lineage differentiation). Such estimates, however, are typically poor TIC predictors, as they are strongly affected by spatial and temporal uncertainty, particularly in cases of deep stem ages. Crown ages of endemic island lineages, in contrast, provide information on the temporal onset of island in situ diversification, and may represent a better proxy for TIC when the associated uncertainty is taken into account. Thus, the geographic and temporal distance separating the island and mainland lineages in phylogenetic/phylogeographic reconstructions are key factors for determining the reliability of these two estimates as proxies of TIC. We show how divergence times can be used to investigate the biogeographic patterns of two well-studied oceanic archipelagos: Hawaii and the Canary Islands. A compilation of molecular age estimates for nearly one-third of the endemic plant lineages in each archipelago reveals that Canarian plant lineages exhibit significantly younger mean crown ages (2.1 ± 2.4 Myr) than Hawaiian lineages (3.5 ± 2.9 Myr), despite island substrates being much older in the Canarian archipelago. We postulate that this pattern suggests: (1) a more important role of submerged islands during plant colonization in Hawaii, and (2) higher taxon turnover in the Canaries, mediated by relatively young (Mediterranean) lineages, and probably facilitated by the combination of the high incidence of extinction for the last 5 Myr and the close proximity of mainland source areas as compared to Hawaii. [ABSTRACT FROM AUTHOR]

Isle Royale (western Lake Superior, USA) is a geographically isolated archipelago with the potential to sustain endemic populations. The island has served as an ecological model for predator–prey interactions between wolves and moose, but little is known about the 17 other mammalian inhabitants. Previous studies of locally abundant red squirrels (Tamiasciurus hudsonicus) described phenotypic differences in pelage colour and skull size, resulting in the classification of an endemic Isle Royale subspecies (T. h. regalis). However, the phylogenetics of this putative subspecies have not been explored. We sequenced mitochondrial DNA to compare haplotypes and genetic variation of seven red squirrels from Isle Royale to 42 other individuals sampled across North America. We detected 25 haplotypes in total, and four haplotypes within Isle Royale. Sequences obtained from red squirrels inhabiting Isle Royale were not unique and were shared with individuals from across the Great Lakes Region and north-eastern North America. Our results indicate that extant T. hudsonicus on Isle Royale are polyphyletic and should not be considered a unique subspecies. These findings suggest that Isle Royale is less insular and more connected than previously assumed and highlights the need to investigate the origins of other taxa in putatively isolated systems, including Isle Royale. [ABSTRACT FROM AUTHOR]

The biotas of the Galápagos Islands are one of the best studied island systems and have provided a broad model for insular species’ origins and evolution. Nevertheless, some locally endemic taxa, such as the Galápagos Rail Laterallus spilonota, remain poorly characterized. Owing to its elusive behavior, cryptic plumage, and restricted distribution, the Galápagos Rail is one of the least studied endemic vertebrates of the Galapagos Islands. To date, there is no genetic data for this species, leaving its origins, relationships to other taxa, and levels of genetic diversity uncharacterized. This lack of information is critical given the adverse fate of island rail species around the world in the recent past. Here, we examine the genetics of Galápagos Rails using a combination of mitogenome de novo assembly with multilocus nuclear and mitochondrial sequencing from both modern and historical samples. We show that the Galápagos Rail is part of the “American black rail clade”, sister to the Black Rail L. jamaicensis, with a colonization of Galápagos dated to 1.2 million years ago. A separate analysis of one nuclear and two mitochondrial markers in the larger population samples demonstrates a shallow population structure across the islands, possibly due to elevated island connectivity. Additionally, birds from the island Pinta possessed the lowest levels of genetic diversity, possibly reflecting past population bottlenecks associated with overgrazing of their habitat by invasive goats. The modern and historical data presented here highlight the low genetic diversity in this endemic rail species and provide useful information to guide conservation efforts.

The Galápagos Islands constitute one of the most pristine tropical systems on Earth. However, the complex and fragile equilibrium of native species is threatened by invasive species, among which is one of the most successful ants in the world, the tropical fire ant, Solenopsis geminata. We characterized the genetic structure and diversity of populations of S. geminata in the Galápagos Islands and unravelled the archipelago colonization by combining Bayesian clustering methods and coalescent-based scenario testing. Using 12 microsatellite markers and one mitochondrial DNA fragment (COI), we analysed individuals collected in all main invaded islands of the archipelago and from the native areas in Costa Rica and mainland Ecuador. We also used mitochondrial DNA to infer evolutionary relationships of samples collected in Galápagos Islands, Ecuador, Costa Rica and other Latin American countries. Our results showed that genetic diversity was significantly lower in Galápagos Islands and mainland Ecuador populations when compared to Costa Rican populations, and that samples from Galápagos Islands and mainland Ecuador (Guayaquil) clustered in a single group and all share a single mtDNA haplotype. Approximate Bayesian Computation favoured a scenario assuming that populations from Galápagos Islands diverged from mainland Ecuador. The city of Guyaquil, an obligatory hub for tourism and trade, could act as a bridgehead. [ABSTRACT FROM AUTHOR]

The Blackcap, Sylvia atricapilla, is one of the few passerine species that breeds in all the Macaronesian archipelagos. The sedentary habits of these populations contrast with the migratory populations from the Western Europe. However, little is known for Azorean populations. We assessed the phylogeography of populations from the Azores based on sequences of two mitochondrial genes and one nuclear gene in the Z-chromosome. We also analysed differences in eight morphometric characters from a total of 282 Blackcaps from all the Azores islands. Our results suggest the occurrence of historical and/or current gene flow among birds from all the islands. Blackcaps from the Azores are close relatives of those from Madeira and Portugal, indicating a recent range expansion to the Azores in the last 0.1 million years. The analysis of morphometric data showed a high morphological diversity among and within the islands, probably related to ecological traits. [ABSTRACT FROM AUTHOR]

Lesser Antillean anoles provide classic examples of island radiations. A detailed knowledge of their phylogeny and biogeography, in particular how the age of species relate to the ages of their respective islands and the age of their radiation, is essential to elucidate the tempo and mechanisms of these radiations. We conduct a large-scale phylogenetic and phylogeographic investigation of the Lesser Antillean anoles using multiple genetic markers and comprehensive geographic sampling of most species. The multilocus phylogeny gives the first well-supported reconstruction of the interspecific relationships, and the densely sampled phylogeography reveals a highly dynamic system, driven by overseas dispersal, with several alternative post-dispersal colonisation trajectories. These radiations currently occupy both the outer-older (Eocene to Miocene), and the inner-younger (<8mybp), Lesser Antillean arcs. The origin of these radiations corresponds with the age of the ancient outer arc. However, the ages of extant species (compatible with the age of other small terrestrial amniotes) are much younger, about the age of the emergence of the younger arc, or less. The difference between the age of the radiation and the age of the extant species suggests substantial species turnover on older arc islands, most likely through competitive replacement. Although extant anoles are extremely speciose, this may represent only a fraction of their biodiversity over time. While paraphyly enables us to infer several recent colonization events, the absence of the younger arc islands and extant species at the earlier and middle stages of the radiation, does not allow the earlier inter-island colonization to be reliably inferred. Reproductive isolation in allopatry takes a very considerable time (in excess of 8my) and sympatry appears to occur only late in the radiation. The resolved multilocus phylogeny, and relative species age, raise difficulties for some earlier hypotheses regarding size evolution, and provide no evidence for within-island speciation. [ABSTRACT FROM AUTHOR]

Studies in evolutionary biology have commonly been focused on insular systems because of their natural geographic isolation and relatively simpler biotas. Using mitochondrial DNA sequences of 4 passerine bird species distributed in the Tres Marías Archipelago (TMA) and the nearby mainland of western Mexico--Cardinalis cardinalis, Turdus rufopalliatus, Vireo hypochryseus, and Icterus pustulatus--we determined interspecific and intraspecific phylogenetic relationships between insular and mainland populations, conducted insular age-based time calibration for the estimation of divergence times, and used Bayesian analyses to examine the colonization history of islands. Specifically, we tested whether the study species from the TMA share the same colonization history since the emergence of the islands ~120 kya, taking advantage of the reduced isolation due to sea-level fluctuations during the Pleistocene, or whether there were independent colonization events. We also looked for evidence in the genetic structure of the island populations that would support the idea of colonization by a small number of individuals. Phylogenetic relationships consistently recovered lineage divergence between the TMA and mainland populations, with strong support in 3 of the 4 species. Our estimates for the sea level and coastline of the west coast of Mexico during the Pleistocene showed that the distance between the TMA and the mainland was ~25 km. We tested several island colonization scenarios according to the phylogenetic relationships, haplotype networks, divergence time estimates, historical demography, and different glaciation dates. The most supported scenario of colonization of the TMA suggests that a single event occurred ~120 kya when the islands emerged, which is highly concordant with geological evidence, and simultaneously affected the 4 species. [ABSTRACT FROM AUTHOR]

Aim The loss of dispersal on islands hypothesis ( LDIH) posits that wind-dispersed plants should exhibit reduced dispersal potential, particularly if island populations are old. In this study, we tested this hypothesis using a detailed phylogeographical framework across different geographical scales. Location Mainland and island areas of the Atlantic and Mediterranean regions, including Macaronesia (Canary Islands and Cape Verde) and Mediterranean islands in the strait of Sicily. Methods Forty-five populations of Periploca laevigata, a wind-dispersed shrub, were sampled. Plastid and nuclear microsatellite data were used to reconstruct spatio-temporal patterns of island colonization, and estimates of seed terminal velocity used as a surrogate for dispersal ability under both field and common garden conditions. Results Our findings did not provide evidence of loss of dispersability in any island lineage. In all of the regions considered, dispersal ability was similar on island and mainland populations, or higher on islands. Contrary to LDIH expectations, lineages inferred as the oldest (western Canaries and Cape Verde) converged towards the most dispersive seed phenotype. This pattern was supported by data obtained under common garden conditions. Within the western Canarian lineage, successful dispersal was shown to be very rare among islands and extensive within islands, but dispersability did not vary significantly from older to more recent sublineages. Considering all the study islands, we found a strong, positive correlation between dispersal ability and estimates of within-island habitat availability. Main conclusions This study suggests that dispersal ability can be favoured on islands, possibly because traits enhancing wind dispersal are positively selected when habitat availability is high. Our results challenge broad generalizations of the LDIH, but we discuss how overlooking species′ phylogeographical history may give rise to misleading conclusions. [ABSTRACT FROM AUTHOR]

Coastal plain stratigraphy is often over looked in paleo–sea-level reconstructions because carbonate sediments do not precisely constrain former sea level. Pacific Island sedimentology provides an invaluable record of geomorphic and environmental consequences of coastal evolution in response to changes in sea level and local tectonics. A series of coastal auger cores obtained from eastern ʻUpolu reveal a subsurface carbonate sand envelope predominately composed of coral and coralline algae derived from the reef framework. Coupling the sedimentological record with geophysical models of Holocene sea level, we identify a critical value (0.3–1.0 m) during the falling phase of the sea-level high stand (1899–2103 cal yr BP) that represents the transition from a transgressive to a regressive environment and initiates coastal progradation. Correlating the critical value with time, we observe nearly a millennium of coastal plain development is required before a small human population is established. Our findings support previous studies arguing that Sāmoa was colonized by small and isolated groups, as post–mid-Holocene drawdown in regional sea level produced coastal settings that were morphologically attractive for human settlement. As future sea level approaches mid-Holocene high stand values, lessons learned from Pacific Island sedimentological records may be useful in guiding future decisions related to coastal processes and habitat suitability. [ABSTRACT FROM AUTHOR]

Aim The endangered Galápagos shrub snapdragon ( Galvezia leucantha, Antirrhineae, Plantaginaceae) is restricted to small populations on four islands. In this study, we appraised results from taxonomy, genetics, phylogenetics, phylogeography and pollination ecology to reconstruct the evolutionary history of the genus Galvezia. Location Peru, continental Ecuador and Galápagos. Methods We sequenced the nuclear ribosomal ITS and two plastid regions, ndhF and ndhF-rpL32, to infer the origin of Galvezia and patterns of colonization to and across the Galápagos archipelago, based on Bayesian inference and statistical parsimony analyses. To investigate genetic diversity and differentiation within G. leucantha, we screened the genome of six populations and obtained 194 AFLP fingerprints. Autogamy tests and pollination network analyses were performed to evaluate the colonization potential and to investigate the structure of the pollinators' assemblage of Galvezia. Results Relationships of seven nucleotide-substitution haplotypes and 11 nucleotide-substitution ribotypes of Galvezia revealed monophyly for the Galapagos species. Dating estimates indicated divergence of the insular Galvezia lineage in the Middle-Upper Pleistocene (0.66-0.09 Ma). In addition, distribution of genotypes (seven haplotypes, eight ribotypes) across the three continental species showed geographical differentiation, while low differentiation and distribution of G. leucantha. AFLP genetic diversity is relatively high ( HT = 0.109), but a low proportion of the total allelic variance is attributed to variation among subspecies/islands ( Hb = 0.035, hierarchical AMOVA: 3.77% of total variance). The endemic bee ( Xylocopa darwinii) accounted for 87.30% of the floral visits to G. leucantha. Main conclusions We inferred a single origin for an insular lineage that colonized the Galápagos Islands from northern Peru in the Pleistocene. Recent colonization of the archipelago, Pleistocene land bridges between islands and active gene flow promoted by X. darwinii may account for the low-moderate genetic differentiation of G. leucantha subspecies. An unusual pollination shift from ornithophily (hummingbirds on the continent) to entomophily ( Xylocopa in the Galápagos Islands) is supported. [ABSTRACT FROM AUTHOR]

Phenotypic plasticity (i.e. the ability to express different phenotypes under changing environmental conditions) is thought to play a key role in habitat adaptation, but little is known about how trait plasticity evolves following dispersal into novel island habitats. We hypothesize that shifts from seasonal Mediterranean climates to more stable (subtropical) island conditions would promote a net reduction in trait plasticity over time. To test this hypothesis, we set two common gardens with contrasting environmental (low resource vs. mesic) conditions, where we grew seedlings of wild olive (Olea europaea var. sylvestris) populations that represented two Canary Island lineages with different colonization times (old vs. young) and their Mediterranean ancestral lineage (N = 275 individuals). Plasticity was assessed for 12 morphological, photosynthetic and chemical traits by (i) subjecting half of the seedlings to simulated herbivore browsing (50% of aerial biomass removal) and (ii) comparing phenotypic values between both common garden settings. Simulated herbivore browsing induced few plastic responses, mostly restricted to photosynthetic traits, but these were similarly displayed by all lineages. Comparisons between common gardens revealed a contrasting response between the Mediterranean and both subtropical island lineages in leaf phenotypes. Furthermore, the older island lineage showed an overall lack of plasticity (i.e. environmental canalization) in morphological and chemical traits. These results suggest that, unlike photosynthetic traits that are fundamental for fast acclimation to environmental shifts, some developmental traits may lose plasticity over time as a result of phenotypic adjustment to subtropical insular conditions. • Common garden experiments reveal patterns of phenotypic adaptation to oceanic island conditions. • Mediterranean and Canary island lineages of Olea europaea display different phenotypic syndromes. • Within the Canaries, young colonizers are plastic for most physiological and biochemical traits. • Contrarily, older island colonizers are environmentally canalized for most traits. • We hypothesize that subtropical island conditions promote loss of plasticity over time. [ABSTRACT FROM AUTHOR]

Ballooning, a mode of aerial dispersal in spiders, is an innate behavior that requires appropriate physiological and meteorological conditions. Although only rarely reported in the golden orbweb spiders, family Nephilidae, the large geographic distributions of most nephilids—in particular of Nephila species—would imply that these spiders likely routinely disperse by ballooning in spite of giant female sizes. Here we study ballooning behavior in the golden orbweb spider Nephila pilipes (Fabricius, 1793). Specifically, we test for the propensity of spiderlings to deploy ballooning as a dispersal mechanism. We subjected a total of 59 first-instar spiderlings to a wind experiment at two wind speeds (2.17 ± 0.02 m s-1 and 3.17 ± 0.02 m s-1) under laboratory conditions. Under an average wind speed of 3.17 m s-1, none of the spiderlings exhibited pre-ballooning or ballooning behavior. However, at an average wind speed of 2.17 m s-1, 53 (89.8%) spiderlings showed pre-ballooning behavior, and 17 (32.1%) of the pre-ballooners ultimately ballooned. Our results concur with prior reports on spiderlings of other families that pre-ballooning behavior is a requirement for ballooning to occur. Furthermore, although we cannot rule out other dispersal mechanisms such as synanthropic spread, our findings suggest that the widespread N. pilipes uses ballooning to colonize remote oceanic islands.