Simultaneous evolution of multiple dispersal components and kernel

Global climate is changing rapidly and is accompanied by large‐scale fragmentation and destruction of habitats. Since dispersal is the first line of defense for mobile organisms to cope with such adversities in their environment, it is important to understand the causes and consequences of evolution of dispersal. Although dispersal is a complex phenomenon involving multiple dispersal‐components like propensity (tendency to leave the natal patch) and ability (to travel long distances), the relationship between these traits is not always straight‐forward, it is not clear whether these traits can evolve simultaneously or not, and how their interactions affect the overall dispersal profile. To investigate these issues, we subjected four large (n ～ 2400) outbred populations of Drosophila melanogaster to artificial selection for increased dispersal, in a setup that mimicked increasing habitat fragmentation over 33 generations. The propensity and ability of the selected populations were significantly greater than the non‐selected controls and the difference persisted even in the absence of proximate drivers for dispersal. The dispersal kernel evolved to have significantly greater standard deviation and reduced values of skew and kurtosis, which ultimately translated into the evolution of a greater frequency of long‐distance dispersers (LDDs). We also found that although sex‐biased dispersal exists in D. melanogaster, its expression can vary depending on which dispersal component is being measured and the environmental condition under which dispersal takes place. Interestingly though, there was no difference between the two sexes in terms of dispersal evolution. We discuss possible reasons for why some of our results do not agree with previous laboratory and field studies. The rapid evolution of multiple components of dispersal and the kernel, expressed even in the absence of stress, indicates that dispersal evolution cannot be ignored while investigating eco‐evolutionary phenomena like speed of range expansion, disease spread, evolution of invasive species and destabilization of metapopulation dynamics.     

A molecular phylogeny of the freshwater-fish genus Rasbora (Teleostei: Cyprinidae) in Sri Lanka reveals a remarkable diversification—And a cryptic species

The diversity of the freshwater-fish genus Rasbora (Cyprinidae) on Sri Lanka (five species) is high compared with the four species reported from the peninsula of India, from which the island's cyprinid fauna is derived. The paucity of characters by which species of Rasbora can be phenotypically distinguished renders field identification difficult, adversely affecting the estimation of populations and distributions, with consequences for conservation and management, increasing also the risk of taxonomic inflation. From a sampling of 90 sites across Sri Lanka and based on phylogenetic and haplotype analyses of sequences of cox1 and cytb mitochondrial, and rag1 and irbp nuclear markers, we review the species diversity and phylogeography of Rasbora on the island. Molecular analyses recover, in addition to the five species previously reported, a new (cryptic) species: Rasbora adisi sp. nov. Uncorrected pairwise cox1 genetic distances between species range from 2.0 to 12.3 percent. The Sri Lankan diversification derives from a common ancestor which arrived from India during a sea-level low-stand in the mid-Miocene (15.1 Ma [95% HPD: 11.5–19.8 Ma]), when the present-day island was subaerially connected to the Indian subcontinent by a broad isthmus. This gave rise to a clade comprising five species—R. adisi sp. nov.,Rasbora armitagei, Rasbora microcephalus, Rasbora naggsi and Rasbora wilpita—with a crown age of 9.9 Ma (95% HPD: 7.1–13.3 Ma) and to a clade comprising Indian and Sri Lankan populations of Rasbora dandia, which themselves are reciprocally monophyletic. Morphological analysis of 334 specimens discriminates between most species which, however, are most reliably diagnosed by chromatic characters. The four endemic species exhibit a pattern of inter-basin dispersal via headwater capture, followed by vicariance, explaining the high diversity of the genus on the island.     

CONVERGENT AND CORRELATED EVOLUTION OF MAJOR LIFE‐HISTORY TRAITS IN THE ANGIOSPERM GENUS LEUCADENDRON (PROTEACEAE)

Natural selection is expected to cause convergence of life histories among taxa as well as correlated evolution of different life‐history traits. Here, we quantify the extent of convergence of five key life‐history traits (adult fire survival, seed storage, degree of sexual dimorphism, pollination mode, and seed‐dispersal mode) and test hypotheses about their correlated evolution in the genus Leucadendron (Proteaceae) from the fire‐prone South African fynbos. We reconstructed a new molecular phylogeny of this highly diverse genus that involves more taxa and molecular markers than previously. This reconstruction identifies new clades that were not detected by previous molecular study and morphological classifications. Using this new phylogeny and robust methods that account for phylogenetic uncertainty, we show that the five life‐history traits studied were labile during the evolutionary history of the genus. This diversity allowed us to tackle major questions about the correlated evolution of life‐history strategies. We found that species with longer seed‐dispersal distances tended to evolve lower pollen‐dispersal distance, that insect‐pollinated species evolved decreased sexual dimorphism, and that species with a persistent soil seed‐bank evolved toward reduced fire‐survival ability of adults.     

Molecular systematics,species limits,and diversification of the genus Dendrocolaptes (Aves: Furnariidae): Insights on biotic exchanges between dry and humid forest types in the Neotropics

The true diversity and interspecific limits in the Neotropical endemic avian genus Dendrocolaptes (Furnariidae) remain a highly controversial subject, with previous genus‐wide assessments, based mostly on morphological characters, producing poorly resolved phylogenies. The lack of well‐resolved, robust, and taxonomically densely sampled phylogenies for Dendrocolaptes prevents reliable inferences on the genus’ actual species diversity and evolutionary history. Here, we analyzed 2,741 base pairs of mitochondrial and nuclear genes from 43 specimens belonging to all species and the majority of subspecies described for Dendrocolaptes to evaluate species limits and reconstruct its diversification through time. Our phylogenies recovered a monophyletic Dendrocolaptes, with two main highly supported internal clades corresponding to the D. certhia and D. picumnus species complexes. Also, our analyses supported the monophyly of most Dendrocolaptes species recognized today, except D. picumnus, which was consistently recovered as paraphyletic with respect to D. hoffmannsi. A coalescent‐based test supported a total of 15 different lineages in Dendrocolaptes and indicated that the number of currently accepted species within the genus may be greatly underestimated. Particularly relevant, when combined with previous analyses based on plumage characters, comparative high levels of genetic differentiation and coalescent analyses support the recognition of D. picumnus transfasciatus as a full species that is already under threat. Ancestral area reconstructions suggest that diversification in Dendrocolaptes was centered in lowland Amazonia, with several independent dispersal events leading to differentiation into different adjacent dry and high elevation forest types throughout the Neotropics, mainly during the Middle and Late Pleistocene.     

Mechanisms and reproductive consequences of breeding dispersal in a specialist predator under temporally varying food conditions

Individual variation in breeding dispersal has extensive ecological and evolutionary consequences, but the factors driving individual dispersal behaviour and their fitness consequences remain poorly understood. Our data on dispersal events of a rodent‐specialist predator, the Eurasian kestrel Falco tinnunculus, over 20 years in western Finland offers a unique opportunity to explore the mechanisms underlying breeding dispersal behaviour and its reproductive consequences in a wild bird population. Sex, age, body condition and previous breeding success affected breeding dispersal. Dispersal distances were longer in females than in males as well as longer in yearlings than in older individuals. Body condition was positively correlated to breeding dispersal distances, particularly for females. The lowest dispersal distances were recorded for intermediate brood sizes in the year preceding dispersal. Our results highlight sex‐ and environment‐specific consequences of breeding dispersal on reproductive performance. During increase phases of the three‐year vole cycles, males dispersing further had lower reproductive performance after dispersal, whereas in females, long breeding dispersal distances were associated with increased breeding success under all environmental conditions. These results suggest benefits associated to breeding dispersal in females, potentially related to large spatio‐temporal variation in main food abundance and intensity of intra‐specific competition. Breeding dispersal of males was costly during increasing food abundance, indicating the potential fitness benefits of environmental familiarity in this migratory species. Overall, our results indicate that both individual traits and environmental factors interact to shape breeding dispersal strategies in wide‐ranging predator populations under fluctuating food conditions.     

Genomic and phenomic analysis of island ant community assembly

Island biodiversity has long fascinated biologists as it typically presents tractable systems for unpicking the eco‐evolutionary processes driving community assembly. In general, two recurring themes are of central theoretical interest. First, immigration, diversification, and extinction typically depend on island geographical properties (e.g., area, isolation, and age). Second, predictable ecological and evolutionary trajectories readily occur after colonization, such as the evolution of adaptive trait syndromes, trends toward specialization, adaptive radiation, and eventual ecological decline. Hypotheses such as the taxon cycle draw on several of these themes to posit particular constraints on colonization and subsequent eco‐evolutionary dynamics. However, it has been challenging to examine these integrated dynamics with traditional methods. Here, we combine phylogenomics, population genomics and phenomics, to unravel community assembly dynamics among Pheidole (Hymenoptera, Formicidae) ants in the isolated Fijian archipelago. We uphold basic island biogeographic predictions that isolated islands accumulate diversity primarily through in situ evolution rather than dispersal, and population genomic support for taxon cycle predictions that endemic species have decreased dispersal ability and demography relative to regionally widespread taxa. However, rather than trending toward island syndromes, ecomorphological diversification in Fiji was intense, filling much of the genus‐level global morphospace. Furthermore, while most endemic species exhibit demographic decline and reduced dispersal, we show that the archipelago is not an evolutionary dead‐end. Rather, several endemic species show signatures of population and range expansion, including a successful colonization to the Cook islands. These results shed light on the processes shaping island biotas and refine our understanding of island biogeographic theory.     

Speciation in a keystone plant genus is driven by elevation: a case study in New Guinean Ficus

Much of the world's insect and plant biodiversity is found in tropical and subtropical ‘hotspots’, which often include long elevational gradients. These gradients may function as ‘diversity pumps’ and contribute to both regional and local species richness. Climactic conditions on such gradients often change rapidly along short vertical distances and may result in local adaptation and high levels of population genetic structure in plants and insects. We investigated the population genetic structure of two species of Ficus (Moraceae) along a continuously forested elevational gradient in Papua New Guinea. This speciose plant genus is pollinated by tiny, species‐specific and highly coevolved chalcid wasps (Agaonidae) and represented by at least 73 species at our study gradient. We present results from two species of Ficus sampled from six elevations between 200 m and 2700 m a.s.l. (almost the entire elevational range of the genus) and 10 polymorphic microsatellite loci. These results show that strong barriers to gene flow exist between 1200 m and 1700 m a.s.l. Whereas lowland populations are panmictic across distances over 70 km, montane populations can be disjunct over 4 km, despite continuous forest cover. We suggest that the limited gene flow between populations of these two species of montane Ficus may be driven by environmental limitations on pollinator or seed dispersal in combination with local adaptation of Ficus populations. Such a mechanism may have wider implications for plant and pollinator speciation across long and continuously forested elevational gradients if generalist insect pollinators and vertebrate seed dispersers also form populations based on elevation.     

Adaptive radiations in butterflies: evolutionary history of the genus Erebia (Nymphalidae: Satyrinae)

We studied the speciose butterfly genus Erebia by reconstructing its phylogenetic relationships using parsimony and Bayesian approaches. We estimated times and rates of diversification for its lineages and employed a biogeographical analysis in order to reconstruct its evolutionary history. DNA sequence data from one mitochondrial gene and three nuclear genes were analyzed for a total of 74 species in Erebia. The estimated dates of origin and diversification for clades, in combination with a biogeographical analysis, suggest that the genus originated in Asian Russia and started its diversification process around 23 Myr. An important event was the dispersal of a lineage from Asia to Western Europe between 23 and 17 Myr, which allowed the radiation of most of species in the genus. The diversification pattern is consistent with a model of diversity limited by clade richness, which implies an early rapid diversification followed by deceleration due to a decrease in speciation. We argue that these characteristics of the evolutionary history of Erebia are consistent with a density‐dependent scenario, with species radiation limited by filling of niche space and reduced resources. We found that the Boeberia parmenio appears strongly supported in the genus Erebia and therefore we place Boeberia Prout, 1901 as a junior synonym of Erebia Dalman, 1816 ( syn. nov. ).     

Description of a new diatom genus Dorofeyukea gen. nov. with remarks on phylogeny of the family Stauroneidaceae

Type material of Navicula kotschyi was studied, and this species was transferred to Dorofeyukea gen. nov. as D. kotschyi comb. nov. Dorofeyukea was described on the basis of DNA sequence and morphological data. Additional species assigned to this genus that were previously included in Navicula include: D. ancisa comb. nov., D. grimmei comb. nov., D. ivatoensis comb. nov., D. orangiana comb. nov., D. rostellata comb. nov. & stat. nov., D. savannahiana comb. nov., D. tenuipunctata comb. nov., and D. texana comb. nov. All Dorofeyukea species share the same morphological features, including having a narrow stauroid fascia surrounded by 1–3 irregularly shortened striae, uniseriate, and weakly radiate striae, circular, or rectangular puncta in the striae that are covered internally by dome‐shaped hymenes, presence of a pseudoseptum at each apex and absence of septa. Partial DNA sequences of SSU and rbcL loci show Dorofeuykae belongs to the clade of stauroneioid diatoms together with Stauroneis, Prestauroneis, Craticula, Karayevia, Madinithidium, Fistulifera, Parlibellus, and, possibly, Schizostauron. A new species from the monoraphid genus Madinithidium, M. vietnamica sp. nov., was described based on valve and chloroplast morphology as well as DNA sequence data.     

Highlighting convergent evolution in morphological traits in response to climatic gradient in African tropical tree species: The case of genus Guibourtia Benn.

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A Molecular Phylogenetic Study of the Tribe Corallineae (Corallinales,Rhodophyta) with an Assessment of Genus‐Level Taxonomic Features and Descriptions of Novel Genera

A multigene phylogeny using COI‐5P (mitochondrial cytochrome c oxidase subunit 1), psbA (PSII reaction center protein D1), and EF2 (elongation factor 2) sequence data for members of the tribe Corallineae was constructed to assess generic boundaries. We determined that traditional reliance on conceptacle position as an indicator of generic affinities in the Corallineae is not supported and taxonomic changes are required. We found that species currently assigned to Pseudolithophyllum muricatum resolved within the Corallineae in all analyses. This is the first record of crustose members in the subfamily Corallinoideae. Further‐more, the genus Serraticardia was polyphyletic; we propose to synonomize Serraticardia with Corallina, transfer the type species S. maxima to Corallina (C. maxima (Yendo) comb. nov.), and describe the new genus Johansenia for S. macmillanii (J. macmillanii (Yendo) comb. nov.). Our molecular data also indicate that species in the genus Marginisporum have evolutionary affinities among species of Corallina and these genera should also be synonymized. This necessitates the combinations C. aberrans (Yendo) comb. nov. for M. aberrans (Yendo) Johansen & Chihara, C. crassissima (Yendo) comb. nov. for M. crassissimum (Yendo) Ganesan, and C. declinata (Yendo) comb. nov. for M. declinata (Yendo) Ganesan. Corallina elongata was divergent from all other members of Corallina and is transferred to a new genus, Ellisolandia (E. elongata (J. Ellis & Solander) comb. nov). In addition, COI‐5P and internal transcribed spacer (ITS) data combined with morphological characters were used to establish that rather than the four Corallina species recognized in Canada, there are nine.     

Long‐term consistency in spatial patterns of primate seed dispersal

Seed dispersal is a key ecological process in tropical forests, with effects on various levels ranging from plant reproductive success to the carbon storage potential of tropical rainforests. On a local and landscape scale, spatial patterns of seed dispersal create the template for the recruitment process and thus influence the population dynamics of plant species. The strength of this influence will depend on the long‐term consistency of spatial patterns of seed dispersal. We examined the long‐term consistency of spatial patterns of seed dispersal with spatially explicit data on seed dispersal by two neotropical primate species, Leontocebus nigrifrons and Saguinus mystax (Callitrichidae), collected during four independent studies between 1994 and 2013. Using distributions of dispersal probability over distances independent of plant species, cumulative dispersal distances, and kernel density estimates, we show that spatial patterns of seed dispersal are highly consistent over time. For a specific plant species, the legume Parkia panurensis, the convergence of cumulative distributions at a distance of 300 m, and the high probability of dispersal within 100 m from source trees coincide with the dimension of the spatial–genetic structure on the embryo/juvenile (300 m) and adult stage (100 m), respectively, of this plant species. Our results are the first demonstration of long‐term consistency of spatial patterns of seed dispersal created by tropical frugivores. Such consistency may translate into idiosyncratic patterns of regeneration.     

Ecological and evolutionary drivers of range size in Coenagrion damselflies

Geographic range size is a key ecological and evolutionary characteristic of a species, yet the causal basis of variation in range size among species remains largely unresolved. One major reason for this is that several ecological and evolutionary traits may jointly shape species' differences in range size. We here present an integrated study of the contribution of ecological (dispersal capacity, body size and latitudinal position) and macroevolutionary (species' age) traits in shaping variation in species' range size in Coenagrion damselflies. We reconstructed the phylogenetic tree of this genus to account for evolutionary history when assessing the contribution of the ecological traits and to evaluate the role of the macroevolutionary trait (species' age). The genus invaded the Nearctic twice independently from the Palearctic, yet this was not associated with the evolution of larger range sizes or dispersal capacity. Body size and species' age did not explain variation in range size. There is higher flight ability (as measured by wing aspect ratio) at higher latitudes. Species with a larger wing aspect ratio had a larger range size, also after correcting for phylogeny, suggesting a role for dispersal capacity in shaping the species' ranges. More northern species had a larger species' range, consistent with Rapoport's rule, possibly related to niche width. Our results underscore the importance of integrating macroecology and macroevolution when explaining range size variation among species.     

Inter‐individual variation in colour patterns in noctuid moths characterizes long‐distance dispersers and agricultural pests

A high capacity for long‐distance dispersal is a key to success for species confronted with environmental heterogeneity, habitat modification, fragmentation and loss. However, dispersal capacity is difficult to quantify and therefore poorly known in most taxa. Here, we report on a test for an association of variation in dispersal capacity with variable colouration of noctuid moths. First, using data from 12 experienced lepidopterologists, we showed that despite variation among experts in average assessments, different species are consistently classified as having non‐variable, variable or highly variable colour patterns when assessed by different experts. We then compared the incidence of non‐resident species with high inter‐individual variation in colour patterns recorded on the isolated island Utklippan (n = 47), with that in a species pool of potential long‐distance dispersers from the nearest mainland (n = 295). Species with high inter‐individual colour pattern variation were over‐represented on the island compared with species having non‐variable colouration. This finding constitutes rare evidence from the wild of long‐distance dispersal, measured on a spatial scale relevant for moths when tracking habitats in fragmented and changing landscapes or when keeping pace with environmental challenges associated with climate change. Finally, we showed that Swedish noctuid moths classified as agricultural pests (n = 28) had more variable colour patterns compared with non‐pests (n = 368). The majority of agricultural pests were also recorded on the isolated island, an outcome that is indicative of pest species having high dispersal capacity. Data on colour pattern variation may thus offer a simple and cost‐effective proxy to estimate dispersal capacity and can also help identify potential pest species. Our findings are potentially useful when modelling and predicting population and range dynamics of species in spatiotemporally heterogeneous environments, with direct implications for conservation biology and pest management.     

Is geographic variation within species related to macroevolutionary patterns between species?

The relationship between microevolution and macroevolution is a central topic in evolutionary biology. An aspect of this relationship that remains very poorly studied in modern evolutionary biology is the relationship between within‐species geographic variation and among‐species patterns of trait variation. Here, we tested the relationship between climate and morphology among and within species in the salamander genus Plethodon. We focus on a discrete colour polymorphism (presence and absence of a red dorsal stripe) that appears to be related to climatic distributions in a common, wide‐ranging species (Plethodon cinereus). We find that this trait has been variable among (and possibly within) species for >40 million years. Furthermore, we find a strong relationship among species between climatic variation and within‐species morph frequencies. These between‐species patterns are similar (but not identical) to those in the broadly distributed Plethodon cinereus. Surprisingly, there are no significant climate–morphology relationships within most other polymorphic species, despite the strong between‐species patterns. Overall, our study provides an initial exploration of how within‐species geographic variation and large‐scale macroevolutionary patterns of trait variation may be related.     

The effect of landscape structure on dispersal distances of the Eurasian red squirrel

Landscape structure can affect dispersal and gene flow in a species. In urban areas, buildings, roads, and small habitat patches make the landscape highly fragmented and can inhibit movement and affect dispersal behavior. Similarly, in rural forested areas, large open areas, such as fields, may act as barriers to movement. We studied how landscape structure affects natal dispersal distances of Eurasian red squirrels (Sciurus vulgaris) in an urban area and a rural area in Finland, by monitoring juvenile red squirrels with radio telemetry. We observed extremely long dispersal distances—up to 16 km—in the rural study area, but shorter distances—on average only half a kilometer—in the urban study area. The landscape structure affected the eventual dispersal paths; in the rural landscape, dispersers favored spruce dominated areas and avoided fields along their dispersal route, although they occasionally even crossed wide fields. In the urban landscape, squirrels preferred areas with deciduous or coniferous trees. The movement steps made by dispersers were longer in the more hostile landscape compared to forested areas. Despite these effects on movement path, the landscape structure only had a minor effect on straight line dispersal distances moved from the natal nest. In other words, individuals moved longer distances and were likely to circumvent barriers in their path, but this did not affect how far they settled from their natal home. This result indicates that, although landscape structure has obvious effects on movement, it still may have only a small effect on other aspects of the population, for example, gene flow.