Papers by Rosemary GILLESPIE
Molecular Ecology
Insights into Ecological & Evolutionary Processes via community metabarcoding This Special Issue ... more Insights into Ecological & Evolutionary Processes via community metabarcoding This Special Issue brings together papers that highlight the power of high-throughput sequencing (HTS) data to address classic questions in ecology and evolution, particularly focused on metabarcoding (amplicon) datasets in conjunction with complementary-omics data types and/or models/theory to infer overall ecosystem processes. We highlight key papers that show the power of the new technology to address questions related to: (i) dynamics of community assembly and how these may change across environmental conditions, successional processes and extended evolutionary time; (ii) interaction networks, and how these can show predictable patterns over spatial and temporal gradients, providing insights into questions of biotic resilience. Studies also examined (iii) cross-scale interactions and host-microbiome associations, with critical developments demonstrating the ease of comparison and integration across scales of organismic complexity that allow insights at one scale to inform the other. These approaches are also amenable to (iv) studies of invasive species and biotic homogenization, providing insights on shifts in alpha-and beta-diversity across a wide range of spatial scales.
Nature, 2012
Localized ecological systems are known to shift abruptly and irreversibly from one state to anoth... more Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds. Here we review evidence that the global ecosystem as a whole can react in the same way and is approaching a planetary-scale critical transition as a result of human influence. The plausibility of a planetary-scale 'tipping point' highlights the need to improve biological forecasting by detecting early warning signs of critical transitions on global as well as local scales, and by detecting feedbacks that promote such transitions. It is also necessary to address root causes of how humans are forcing biological changes.
F1000 - Post-publication peer review of the biomedical literature, 2000
Pacific Science, 2010
This study examined the endemic species of kleptoparasitic spiders in the genus Argyrodes from th... more This study examined the endemic species of kleptoparasitic spiders in the genus Argyrodes from the Hawaiian Islands, a lineage previously known in the archipelago from only a single described species, Argyrodes hawaiiensis Simon. Here, two additional endemic species are described, A. ilipoepoe Rivera and Gillespie, n. sp., and A. laha Rivera and Gillespie, n. sp., with their biogeographical patterns, and the allotype female and paratypes of A. hawaiiensis are designated. As with A. hawaiiensis, both new species are commonly found as kleptoparasites on the sheet webs of large nocturnal spiders in the genus Orsonwelles (Linyphiidae). Hawaiian Argyrodes are characterized by small and rounded abdomens, unpronounced clypeal projections, and variably long fangs. Argyrodes hawaiiensis; A. ilipoepoe, n. sp.; and A. laha, n. sp., include all the known endemic representatives of the group in the Hawaiian Islands, which mostly occur in wet and mesic forests.
Biological Invasions, 2010
... All Ant invasions in Hawaii 647 123 Page 6. univariate statistical analyses were conducted in... more ... All Ant invasions in Hawaii 647 123 Page 6. univariate statistical analyses were conducted in Minitab (Ryan et al. 2005), and all multivariate analyses were conducted in PC-ORD (McCune and Mefford 2006). Results Patterns of invasion ...
American Scientist, 2005
... seem to get everywhere, which makes them ideal to study the processes of ecology and evolutio... more ... seem to get everywhere, which makes them ideal to study the processes of ecology and evolution ... for ways to test and reconcile ecological and evolutionary theories of species community assembly naturally ... I found at work processes that would delight both the ecologist and the ...
Aim,Phylogenetic,studies,concerning,island,biogeography,have,been concentrated,in a fraction of t... more Aim,Phylogenetic,studies,concerning,island,biogeography,have,been concentrated,in a fraction of the numerous,hot-spot archipelagos,contained within the Pacific Ocean. In this study we investigate relationships among,island populations of the thomisid spider Misumenops rapaensis Berland, 1934 across the Austral Islands, a remote and rarely examined southern Pacific hot-spot archipelago. We,also assess the,phylogenetic,position,of M. rapaensis,in relation to thomisids,distributed,across,multiple,Polynesian,archipelagos,in order,to evaluate,the,proposed,hypothesis,that thomisid,spiders colonized Polynesia from multiple and opposing,directions. The
Hotspot archipelagoes provide exceptional models for the study of the evolutionary process, due t... more Hotspot archipelagoes provide exceptional models for the study of the evolutionary process, due to the eVects of isolation and topograph- ical diversity in inducing the formation of unique biotic assemblages. In this paper, we examine the evolutionary patterns exhibited by the jumping spider genus Havaika Prószyjski, 2001 in the Polynesian islands of the Hawaiian and Marquesas chains. To date, systematic
The Journal of heredity, 2014
Discontinuous variation within individuals is increasingly recognized as playing a role in divers... more Discontinuous variation within individuals is increasingly recognized as playing a role in diversification and ecological speciation. This study is part of an effort to investigate the molecular genetic underpinnings of adaptive radiation in Hawaiian spiders (genus Tetragnatha). This radiation is found throughout the Hawaiian Islands, showing a common pattern of evolutionary progression from older to younger islands. Moreover, the species are characterized by repeated evolution of similar ecomorphs that can be recognized on the basis of color--Green, Maroon, Large Brown, and Small Brown. However, 2 species (including T. kauaiensis from Kauai) are polyphenic, changing from 1 ecomorph (Green) to another (Maroon) at a specific developmental period. The current study focuses on the age-associated color change in the early stages of the radiation to determine whether this ancestral flexibility in phenotype may have translated into diversification of more derived taxa. We conducted a comp...
Ecology and evolution, 2014
The deserts of southwestern North America have undergone dramatic changes over their recent geolo... more The deserts of southwestern North America have undergone dramatic changes over their recent geological history including large changes in size and connectivity during the Pleistocene glaciopluvial cycles. This study examines the population history of the rare spider Saltonia incerta, once thought to be extinct, to determine the role of past climatological events in shaping the structure of the species. This species is restricted to salt crusts of intermittent or dry lakes, streams or rivers in the desert southwest, a region that was much wetter during glacial periods. We examine the distribution and genetic variability of populations to test whether there is recent dispersal throughout the range of the species. Analyses of mitochondrial and nuclear DNA indicate significant population structure, with one major clade comprising New Mexico localities and one comprising California-northern Baja California localities. Finer-scale structure is evident within the California clade, although...
Tetragnatha elongata is associated exclusively with riparian habitats . The physiological suitabi... more Tetragnatha elongata is associated exclusively with riparian habitats . The physiological suitability o f a given environment is determined by accessibility to open water . When this is denied, spiders suffe r dehydration, the rate of which is determined by the temperature and relative humidity . Where th e abiotic environment is suitable, spiders build webs on any available structural support . The webs of T elongata are short lived . Once a web has been built, a spider may rebuild at the same site or move t o a new site . Prey availability appears to be the primary determinant as to which of these alternatives i s adopted .
Islands have traditionally been considered to be any relatively small body of land completely sur... more Islands have traditionally been considered to be any relatively small body of land completely surrounded by water. However, their primary biological characteristic, an extended period of isolation from a source of colonists, is common also to many situations on continents. Accordingly, theories and predictions developed for true islands have been applied to a huge array of systems, from rock pools, to single tree species in forests, to oceanic islands. Here, we examine the literature on islands in the broadest sense (i.e., whether surrounded by water or any other uninhabitable matrix) as it pertains to terrestrial arthropods. We categorize islands according to the features they share. The primary distinction between different island systems is "darwinian" islands (formed de novo) and "fragment" islands. In the former, the islands have never been in contact with the source of colonists and have abundant "empty" ecological niche space. On these islands, species numbers will initially increase through immigration, the rate depending on the degree of isolation. If isolation persists, over time species formation will result in "neo-endemics." When isolation is extreme, the ecological space will gradually be filled through speciation (rather than immigration) and adaptive radiation of neo-endemics. Fragment islands are fundamentally different. In these islands, the ecological space will initially be filled as a consequence of connection to the source of colonists prior to insularization. Species numbers will decrease following fragmentation through the process of relaxation. If these islands become more isolated, species will eventually arise through relictualization with the formation of "paleo-endemics." Given sufficient time, this process can result in generic level endemism on ancient fragment islands, a phenomenon well illustrated in Madagascar and New Zealand. Recognizing the distinction between the different kinds of islands is fundamental for understanding emerging patterns on each, in particular speciation, biodiversity (e.g., neo-endemics versus paleo-endemics), and conservation (e.g., naiveté in interactions with alien species).
Zoological Journal of the Linnean Society, 2009
Although temperate cave-adapted fauna may evolve as a result of climatic change, tropical cave dw... more Although temperate cave-adapted fauna may evolve as a result of climatic change, tropical cave dwellers probably colonize caves through adaptive shifts to exploit new resources. The founding populations may have traits that make colonization of underground spaces even more likely. To investigate the process of cave adaptation and the number of times that flightlessness has evolved in a group of reportedly flightless Hawaiian cave moths, we tested the flight ability of 54 Schrankia individuals from seven caves on two islands. Several caves on one island were sampled because separate caves could have been colonized by underground connections after flightlessness had already evolved. A phylogeny based on approximately 1500 bp of mtDNA and nDNA showed that Schrankia howarthi sp. nov. invaded caves on two islands, Maui and Hawaii. Cave-adapted adults are not consistently flightless but instead are polymorphic for flight ability. Although the new species appears well suited to underground living, some individuals were found living above ground as well. These individuals, which are capable of flight, suggest that this normally cave-limited species is able to colonize other, geographically separated caves via above-ground dispersal. This is the first example of an apparently cave-adapted species that occurs in caves on two separate Hawaiian islands. A revision of the other Hawaiian Schrankia is presented, revealing that Schrankia simplex, Schrankia oxygramma, Schrankia sarothrura, and Schrankia arrhecta are all junior synonyms of Schrankia altivolans.
Zoologica Scripta, 2007
Molecular insights into the phylogenetic structure of the spider genus Theridion (Araneae, Therid... more Molecular insights into the phylogenetic structure of the spider genus Theridion (Araneae, Theridiidae) and the origin of the Hawaiian Theridion -like fauna. -Zoologica Scripta , 36 , 337-352. The Hawaiian happy face spider ( Theridion grallator Simon, 1900), named for a remarkable abdominal colour pattern resembling a smiling face, has served as a model organism for understanding the generation of genetic diversity. Theridion grallator is one of 11 endemic Hawaiian species of the genus reported to date. Asserting the origin of island endemics informs on the evolutionary context of diversification, and how diversity has arisen on the islands. Studies on the genus Theridion in Hawaii, as elsewhere, have long been hampered by its large size ( > 600 species) and poor definition. Here we report results of phylogenetic analyses based on DNA sequences of five genes conducted on five diverse species of Hawaiian Theridion , along with the most intensive sampling of Theridiinae analysed to date. Results indicate that the Hawaiian Islands were colonised by two independent Theridiinae lineages, one of which originated in the Americas. Both lineages have undergone local diversification in the archipelago and have convergently evolved similar bizarre morphs. Our findings confirm para-or polyphyletic status of the largest Theridiinae genera: Theridion , Achaearanea and Chrysso . Convergent simplification of the palpal organ has occurred in the Hawaiian Islands and in two continental lineages. The results confirm the convergent evolution of social behaviour and web structure, both already documented within the Theridiidae. Greater understanding of phylogenetic relationships within the Theridiinae is key to understanding of behavioural and morphological evolution in this highly diverse group.
Journal of Insect Conservation, 1999
The native fauna of isolated island systems is generally unique with acute conservation issues. F... more The native fauna of isolated island systems is generally unique with acute conservation issues. For spiders in Hawaii, the first impediment to effective conservation is lack of taxonomic knowledge. The primary conservation concerns are related to the highly localized areas of endemicity of many species, with associated small population sizes. Species on insular systems tend to occur naturally in small
Trends in Ecology & Evolution, 2012
Tests of hypotheses about the biogeographical consequences of long-distance dispersal have long e... more Tests of hypotheses about the biogeographical consequences of long-distance dispersal have long eluded biologists, largely because of the rarity and presumed unpredictability of such events. Here, we examine data for terrestrial (including littoral) organisms in the Pacific to show that knowledge of dispersal by wind, birds and oceanic drift or rafting, coupled with information about the natural environment and biology of the organisms, can be used to generate broad biogeographic predictions. We then examine the predictions in the context of the origin, frequency of arrival and location of establishment of dispersed organisms, as well as subsequent patterns of endemism and diversification on remote islands. The predicted patterns are being increasingly supported by phylogenetic data for both terrestrial and littoral organisms.
Trends in Ecology & Evolution, 2008
Systematic Biology, 2003
Spiders of the recently described linyphiid genus Orsonwelles (Araneae, Linyphiidae) are one of t... more Spiders of the recently described linyphiid genus Orsonwelles (Araneae, Linyphiidae) are one of the most conspicuous groups of terrestrial arthropods of Hawaiian native forests. There are 13 known Orsonwelles species, and all are singleisland endemics. This radiation provides an excellent example of insular gigantism. We reconstructed the cladistic relationships of Orsonwelles species using a combination of morphological and molecular characters (both mitochondrial and nuclear sequences) within a parsimony framework. We explored and quantified the contribution of different character partitions and their sensitivity to changes in the traditional parameters (gap, transition, and transversion costs). The character data show a strong phylogenetic signal, robust to parameter changes. The monophyly of the genus Orsonwelles is strongly supported. The parsimony analysis of all character evidence combined recovered a clade with of all the non-Kauai Orsonwelles species; the species from Kauai form a paraphyletic assemblage with respect to the latter former clade. The biogeographic pattern of the Hawaiian Orsonwelles species is consistent with colonization by island progression, but alternative explanations for our data exist. Although the geographic origin of the radiation remains unknown, it appears that the ancestral colonizing species arrived first on Kauai (or an older island). The ambiguity in the area cladogram (i.e., post-Oahu colonization) is not derived from conflicting or unresolved phylogenetic signal among Orsonwelles species but rather from the number of taxa on the youngest islands. Speciation in Orsonwelles occurred more often within islands (8 of the 12 cladogenic events) than between islands. A molecular clock was rejected for the sequence data. Divergence times were estimated by using the nonparametric rate smoothing method of Sanderson (1997, Mol. Biol. Evol. 14:1218-1231) and the available geological data for calibration. The results suggest that the oldest divergences of Orsonwelles spiders (on Kauai) go back about 4 million years.
Science, 2004
Communities arising through adaptive radiation are generally regarded as unique, with speciation ... more Communities arising through adaptive radiation are generally regarded as unique, with speciation and adaptation being quite different from immigration and ecological assortment. Here, I use the chronological arrangement of the Hawaiian Islands to visualize snapshots of evolutionary history and stages of community assembly. Analysis of an adaptive radiation of habitat-associated, polychromatic spiders shows that (i) species assembly is not random; (ii) within any community, similar sets of ecomorphs arise through both dispersal and evolution; and (iii) species assembly is dynamic with maximum species numbers in communities of intermediate age. The similar patterns of species accumulation through evolutionary and ecological processes suggest universal principles underlie community assembly.
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Papers by Rosemary GILLESPIE