17 research outputs found
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First Account of Phylogeographic Variation, Larval Characters, and Laboratory Rearing of the Endangered Cobblestone Tiger Beetle Cicindelidia marginipennis, Dejean, 1831 with Observations of Their Natural History
The cobblestone tiger beetle, Cicindelidia marginipennis (Dejean, 1831) is a North American species specializing in riparian habitats from New Brunswick, Canada, to Alabama in the United States. In the United States, this species is state-listed as threatened or endangered range-wide and periodically receives consideration for federal listing, mostly due to habitat decline. Despite its conservation status, intraspecific genetic diversity for this species has not been explored and little is known about its natural history. To support further inquiry into the biology of C. marginipennis, this study provides the first look at range-wide genetic diversity using mitochondrial DNA (mtDNA), describes all three larval instars, and describes natural history characteristics from captive rearing and field observation. Based on mtDNA analyses, our results suggest that geographically based population structure may exist throughout the range, with individuals from Alabama possessing haplotypes not found elsewhere in our sampling. Further genetic analyses, particularly multi-locus analyses, are needed to determine whether the Alabama population represents a separate cryptic species. Our morphological analysis and descriptions of larval instars reveal a combination of characteristics that can be used to differentiate C. marginipennis from closely related and co-occurring species. Based on our field observations, we find that the larval “throw pile” of soil excavated from burrows is a key search image for locating larvae, and we provide descriptions and detailed photographs to aid surveys. Lastly, we find that this species can be successfully reared in captivity and provide guidelines to aid future recovery efforts
Cryptic diversity in the North American Dromochorus tiger beetles (Coleoptera: Carabidae: Cicindelinae): a congruence-based method for species discovery
A fundamental problem in biodiversity science is determining the number of species in any taxon, and there is a growing awareness that cryptic diversity contributes to this problem – even in well-studied groups. Discovering cryptic species requires several lines of evidence to elucidate congruent patterns across data-types, and distinguish unrecognized species. Tiger beetles are among the most well-studied insect groups; yet few new North American species have been described since the mid-20th century, suggesting that that the number of morphologically distinct species is reaching an asymptote. We explore the possibility that more species exist in the fauna as cryptic species, by analysing a broad geographic sample of all species in the genus Dromochorus. We employ a ‘taxonomic congruence’ approach, where we first generate species hypotheses from patterns of reciprocal monophyly across the mitochondrial and nuclear datasets, and test these hypotheses through congruence with population structure, morphological measures and ecological divergence. We find broad congruence that supports eight species of Dromochorus, more than doubling the known diversity. We also validate a previously ambiguous taxon, and re-describe previously named species. Lastly, we identify new diagnostic morphological characters, include an updated dichotomous key and provide updated natural history/ecological characteristics for the genus and individual species
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Geographic Life History Differences Predict Genomic Divergence Better than Mitochondrial Barcodes or Phenotype
Species diversity can be inferred using multiple data types, however, results based on genetic data can be at odds with patterns of phenotypic variation. Tiger beetles of the Cicindelidia politula (LeConte, 1875) species complex have been taxonomically problematic due to extreme phenotypic variation within and between populations. To better understand the biology and taxonomy of this group, we used mtDNA genealogies and multilocus nuclear analyses of 34,921 SNPs to elucidate its evolutionary history and evaluate the validity of phenotypically circumscribed species and subspecies. Genetic analyses recovered two divergent species that are also ecologically distinct, based on adult life history. These patterns are incongruous with the phenotypic variation that informed prior taxonomy, and most subspecies were not supported as distinct evolutionary lineages. One of the nominal subspecies was found to be a cryptic species; consequently, we elevate C. p. laetipennis (Horn, 1913) to a full species. Although nuclear and mtDNA datasets recovered broadly similar evolutionary units, mito-nuclear discordance was more common than expected, being observed between nearly all geographically overlapping taxonomic pairs. Additionally, a pattern of ‘mitochondrial displacement’ was observed, where mitochondria from one species unidirectionally displace others. Overall, we found that geographically associated life history factors better predict genomic divergence than phenotype and mitochondrial genealogies, and consequently taxon identifications based on mtDNA (e.g., DNA barcodes) may be misleading
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Discovery of cryptic species diversity in North American pine-feeding chionaspis scale insects (Hemiptera: Diaspididae)
The pine-needle scale insects; Chionaspis pinifoliae and C. heterophyllae are armored scale insects (Hemiptera: Diaspididae) with extensive native ranges throughout North America. In particular, C. pinifoliae is found on almost every species in the genus Pinus. Both species are economically important pests on pines, and over a century of scientific literature has considered these as only two morphological species. The life history of scale insects suggests they may form strongly structured metapopulations, resulting in high rates of host race formation and possibly speciation. Such newly originated species are likely to be morphologically similar. The geographic distribution and host use of these two species suggests they may represent a group of species that have gone unsampled due to their broad distribution or unrecognized due to their similar morphology. To explore the potential for species diversity in pine-needle scale insects I collected 366 individual insects from 320 localities across North America, representing 51 host species within the Pinaceae. I estimated species diversity by inferring species boundaries using genealogical concordance across allele genealogies of two nuclear loci and one mitochondrial locus. Using Maximum Likelihood allele genealogies in a majority-rule consensus to assess congruence, I conservatively detect 10 species in this group. However some of these 10 species contain morphological subgroups that conventional taxonomy would recognize as their own species. I explored alternate species delimitations using a range of species delimitation schemes based on genealogical concordance and mitochondrial divergence. I analyzed these delimitation schemes as species in a Bayesian species tree analysis, and infer that a delimitation of 26 species is the optimum scheme. This 26-species scheme also recognizes most of the aforementioned unique morphological subgroups, as species. Additionally, the genetic analyses for the above work occasionally recovered parasitoid sequences, from the 28S D2 and D3 subunits of ribosomal RNA. I included these sequences in a phylogeny of over 500 specimens from 18 of 19 families within the Chalcidoidea. I compared the phylogenetic results against a comprehensive list of parasitoids recorded from C. pinifoliae and C. heterophyllae, and find the 28s sequences indicate the parasitoid diversity utilizing these pine-feeding scale insects is much higher than previously thought
Towards a catalogue of biodiversity databases: An ontological case study
Biodiversity informatics depends on digital access to credible information about species. Many online resources host species’ data, but the lack of categorisation for these resources inhibits the growth of this entire field. To explore possible solutions, we examined the (now retired) Biodiversity Information Projects of the World (BIPW) dataset created by the Biodiversity Information Standards (TDWG); this project, which ran from 2007-2015 (officially removed from the TDWG website in 2018) was an attempt at organising the Web's biodiversity databases into an indexed list. To do this, we applied a simple classification scheme to score databases within BIPW based on nine data categories, to characterise trends and current compositions of this biodiversity e-infrastructure. Primarily, we found that of 600 databases investigated from BIPW, only 315 (~53%) were accessible at the time of this writing, underscoring the precarious nature of the biodiversity information landscape. Many of these databases are still available, but suffer accessibility issues such as link rot, thus putting the information they contain in danger of being lost. We propose that a community-driven database of biodiversity databases with an accompanying ontology could facilitate efficient discovery of relevant biodiversity databases and support smaller databases – which have the greatest risk of being lost
Corroborating molecular species discovery: Four new pine-feeding species of Chionaspis (Hemiptera, Diaspididae)
The genus Chionaspis (Hemiptera, Diaspididae) includes two North American species of armored scale insects feeding on Pinaceae: Chionaspis heterophyllae Cooley, and C. pinifoliae (Fitch). Despite the economic impact of conifer-feeding Chionaspis on horticulture, the species diversity in this group has only recently been systematically investigated using samples from across the group’s geographic and host range. This paper provides morphological recognition characters for four new species that were recently hypothesized to exist on the basis of molecular evidence. The new species, here described, are Chionaspis brachycephalon Vea sp. n., Chionaspis caudata Vea sp. n., Chionaspis sonorae Vea sp. n. and Chionaspis torreyanae Vea sp. n. One of the new species, C. caudata Vea, has a gland spine at the apex of the pygidium, between the median lobes, unlike any other species of Chionaspis. An identification key to the species of Chionaspis feeding on pine in North America is provided
First Account of Phylogeographic Variation, Larval Characters, and Laboratory Rearing of the Endangered Cobblestone Tiger Beetle Cicindelidia marginipennis, Dejean, 1831 with Observations of Their Natural History
The cobblestone tiger beetle, Cicindelidia marginipennis (Dejean, 1831) is a North American species specializing in riparian habitats from New Brunswick, Canada, to Alabama in the United States. In the United States, this species is state-listed as threatened or endangered range-wide and periodically receives consideration for federal listing, mostly due to habitat decline. Despite its conservation status, intraspecific genetic diversity for this species has not been explored and little is known about its natural history. To support further inquiry into the biology of C. marginipennis, this study provides the first look at range-wide genetic diversity using mitochondrial DNA (mtDNA), describes all three larval instars, and describes natural history characteristics from captive rearing and field observation. Based on mtDNA analyses, our results suggest that geographically based population structure may exist throughout the range, with individuals from Alabama possessing haplotypes not found elsewhere in our sampling. Further genetic analyses, particularly multi-locus analyses, are needed to determine whether the Alabama population represents a separate cryptic species. Our morphological analysis and descriptions of larval instars reveal a combination of characteristics that can be used to differentiate C. marginipennis from closely related and co-occurring species. Based on our field observations, we find that the larval “throw pile” of soil excavated from burrows is a key search image for locating larvae, and we provide descriptions and detailed photographs to aid surveys. Lastly, we find that this species can be successfully reared in captivity and provide guidelines to aid future recovery efforts