21 research outputs found

    Parasitism of \u3ci\u3eCidia\u3c/i\u3e Spp. (Lepidoptera: Tortricidae) on \u3ci\u3eSophora Chrysophylla\u3c/i\u3e (Fabaceae) Along an Elevation Gradient of Dry Subalpine Forest on Mauna Kea, Hawaii

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    The biology and ecological importance of Hawaiian endemic Cydia spp. (Lepidoptera: Tortricidae) are poorly known. Cydia larvae arc an important food to palila, an endangered Hawaiian bird that inhabits Sophora woodlands on Mauna Kea, Hawaii. We quantified Cydia larval abundance in seeds of Sophora chrysophylla Salisbury (Fabaceae) and larval mortality caused by parasitism. Four new host plant associations are reported: C. crassicornis [Walsingham], C. fulsifalcella [Walsingham], C. obliqlla [Walsingham], and C. storeella [Walsingham]. Four parasitoid wasp species were consistently reared from larval Cydia: Calliephialtes grapholithae [Cresson], Diadegma blackburni [Cameron], Pristomerus hawaiiensis Perkins (Hymenoptera: Ichneumonidae), and Euderus metallicus [Ashmead] (Hymenoptera: Eulophidae). The three Ichneumonidae appear to be accidental introductions, while E. metallicus is likely to be native to Hawaii. Parasitism rates by all four wasps combined decreased with elevation from 94% at 1800 m to 20% at 2700 m

    Parasitism of \u3ci\u3eCidia\u3c/i\u3e Spp. (Lepidoptera: Tortricidae) on \u3ci\u3eSophora Chrysophylla\u3c/i\u3e (Fabaceae) Along an Elevation Gradient of Dry Subalpine Forest on Mauna Kea, Hawaii

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    The biology and ecological importance of Hawaiian endemic Cydia spp. (Lepidoptera: Tortricidae) are poorly known. Cydia larvae arc an important food to palila, an endangered Hawaiian bird that inhabits Sophora woodlands on Mauna Kea, Hawaii. We quantified Cydia larval abundance in seeds of Sophora chrysophylla Salisbury (Fabaceae) and larval mortality caused by parasitism. Four new host plant associations are reported: C. crassicornis [Walsingham], C. fulsifalcella [Walsingham], C. obliqlla [Walsingham], and C. storeella [Walsingham]. Four parasitoid wasp species were consistently reared from larval Cydia: Calliephialtes grapholithae [Cresson], Diadegma blackburni [Cameron], Pristomerus hawaiiensis Perkins (Hymenoptera: Ichneumonidae), and Euderus metallicus [Ashmead] (Hymenoptera: Eulophidae). The three Ichneumonidae appear to be accidental introductions, while E. metallicus is likely to be native to Hawaii. Parasitism rates by all four wasps combined decreased with elevation from 94% at 1800 m to 20% at 2700 m

    Categorization of species as native or nonnative using DNA sequence signatures without a complete reference library.

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    New genetic diagnostic approaches have greatly aided efforts to document global biodiversity and improve biosecurity. This is especially true for organismal groups in which species diversity has been underestimated historically due to difficulties associated with sampling, the lack of clear morphological characteristics, and/or limited availability of taxonomic expertise. Among these methods, DNA sequence barcoding (also known as "DNA barcoding") and by extension, meta-barcoding for biological communities, has emerged as one of the most frequently utilized methods for DNA-based species identifications. Unfortunately, the use of DNA barcoding is limited by the availability of complete reference libraries (i.e., a collection of DNA sequences from morphologically identified species), and by the fact that the vast majority of species do not have sequences present in reference databases. Such conditions are critical especially in tropical locations that are simultaneously biodiversity rich and suffer from a lack of exploration and DNA characterization by trained taxonomic specialists. To facilitate efforts to document biodiversity in regions lacking complete reference libraries, we developed a novel statistical approach that categorizes unidentified species as being either likely native or likely nonnative based solely on measures of nucleotide diversity. We demonstrate the utility of this approach by categorizing a large sample of specimens of terrestrial insects and spiders (collected as part of the Moorea BioCode project) using a generalized linear mixed model (GLMM). Using a training data set of known endemic (n = 45) and known introduced species (n = 102), we then estimated the likely native/nonnative status for 4,663 specimens representing an estimated 1,288 species (412 identified species), including both those specimens that were either unidentified or whose endemic/introduced status was uncertain. Using this approach, we were able to increase the number of categorized specimens by a factor of 4.4 (from 794 to 3,497), and the number of categorized species by a factor of 4.8 from (147 to 707) at a rate much greater than chance (77.6% accuracy). The study identifies phylogenetic signatures of both native and nonnative species and suggests several practical applications for this approach including monitoring biodiversity and facilitating biosecurity

    Differential parasitism of seed-feeding \u3ci\u3eCydia\u3c/i\u3e (Lepidoptera: Tortricidae) by native and alien wasp species relative to elevation in subalpine \u3ci\u3eSophora\u3c/i\u3e (Fabaceae) forests on Mauna Kea, Hawaii

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    Alien parasitic wasps, including accidental introductions and purposefully released biological control agents, have been implicated in the decline of native Hawaiian Lepidoptera. Understanding the potential impacts of alien wasps requires knowledge of ecological parameters that influence parasitism rates for species in their new environment. Sophora seed-feeding Cydia spp. (Lepidoptera: Tortricidae) were surveyed for larval parasitoids to determine how native and alien wasps are partitioned over an elevation gradient (2200–2800 m) on Hawaii Island, Hawaii. Parasitism rate of native Euderus metallicus (Eulophidae) increased with increased elevation, while parasitism rate by immigrant Calliephialtes grapholithae (Ichneumonidae) decreased. Parasitism by Pristomerus hawaiiensis (Ichneumonidae), origins uncertain, also decreased with increased elevation. Two other species, Diadegma blackburni (Ichneumonidae), origins uncertain, and Brasema cushmani (Eupelmidae), a purposefully introduced biological control agent for pepper weevil, did not vary significantly with elevation. Results are contrasted with a previous study of this system with implications for the conservation of an endangered bird species that feed on Cydia larvae. Interpretation of results is hindered by lack of knowledge of autecology of moths and wasps, origins, phylogeny, systematics, competitive ability, and physiological limitations of each wasp species. These factors should be incorporated into risk analysis for biological control introductions and invasive species programs

    California dragonfly and damselfly (Odonata) database: temporal and spatial distribution of species records collected over the past century

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    The recently completed Odonata database for California consists of specimen records from the major entomology collections of the state, large Odonata collections outside of the state, previous literature, historical and recent field surveys, and from enthusiast group observations. The database includes 32,025 total records and 19,000 unique records for 106 species of dragonflies and damselflies, with records spanning 1879–2013. Records have been geographically referenced using the point-radius method to assign coordinates and an uncertainty radius to specimen locations. In addition to describing techniques used in data acquisition, georeferencing, and quality control, we present assessments of the temporal, spatial, and taxonomic distribution of records. We use this information to identify biases in the data, and to determine changes in species prevalence, latitudinal ranges, and elevation ranges when comparing records before 1976 and after 1979. The average latitude of where records occurred increased by 78 km over these time periods. While average elevation did not change significantly, the average minimum elevation across species declined by 108 m. Odonata distribution may be generally shifting northwards as temperature warms and to lower minimum elevations in response to increased summer water availability in low-elevation agricultural regions. The unexpected decline in elevation may also be partially the result of bias in recent collections towards centers of human population, which tend to occur at lower elevations. This study emphasizes the need to address temporal, spatial, and taxonomic biases in museum and observational records in order to produce reliable conclusions from such data

    Availability of food resources, distribution of invasive species, and conservation of a Hawaiian bird along a gradient of elevation

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    Aim We evaluated how an elevation gradient affects: (1) the availability of food required by a specialist seed-eater, Loxioides bailleui Oustalet (Drepanidinae), or palila, and hence the distribution of this endangered Hawaiian bird, and (2) the distribution of alien threats to Loxioides populations, their primary foods, and their dry-forest habitat, and hence strategies for their conservation. Location We worked throughout the subalpine forest that encircles Mauna Kea Volcano, Hawai‘i Island, but we focused our studies mainly on the western slope between 2000 and 3000 m elevation, where the gradient of elevation was greatest and palila were most abundant. Methods We determined phenology and productivity patterns of the endemic dry-forest tree species, Sophora chrysophylla (Salisb.) Seem. (Fabaceae), or māmane, which provides Loxioides with most of their food, and another common endemic tree, Myoporum sandwicense A. Gray (Myoporaceae), or naio, which provides some resources, along a 786-m elevation gradient at monthly intervals for 10 years (Sophora only). We also determined the availability each month of moth larvae (Lepidoptera) for that were important in the diet of nestling and adult palila. In addition, we documented the incidence of parasitism on moth larvae by several wasp (Hymenoptera) and fly (Diptera) species, and we determined the distribution of predatory wasps and ants (Hymenoptera), which potentially threaten insect prey of birds. Percentage cover of alien grass species that pose fire threats in palila habitat and other weeds were assessed during one survey. Small mammal abundance and distribution were determined by trapping during three (rodent) or five (carnivore) surveys. Results Sophora flower and seed (pod) availability varied predictably along the elevation gradient, with about 4 months separating peaks in reproduction at high and low elevations. This, together with highly variable production of flowers and pods within elevation strata, resulted in Sophora resources being available to Loxioides throughout the year on the western slope of Mauna Kea. Sophora produced flowers and pods more seasonally where gradients of elevation were short; thus, resources were available less consistently. In contrast, Myoporum produced flowers and fruits with little variation with respect to season or elevation. The availability of important insect prey of Loxioides was also related to elevation, in part because threats to Lepidoptera larvae from parasitic wasps were generally less at higher elevations. Threats to insect prey from predatory ants was also less at higher elevations but the abundance of predatory wasps was not related to elevation. Several weeds that pose the most serious threats to Loxioides habitat were more abundant at mid and low elevations, and alien grass cover was somewhat greater at mid elevation, thereby increasing fire risks in the centre of Loxioides habitat. Predatory mammals, in particular Felis catus Linnaeus, were common throughout the subalpine forest of Mauna Kea. However, Rattus rattus Linnaeus was rare, especially at higher elevations, whereas Mus musculus Linnaeus was more abundant at lower elevations. Main conclusions Loxioides are concentrated in habitat that is distributed along a substantial gradient of elevation at least in part because food is available throughout the year and threats to food resources are less concentrated. To recover Loxioides elsewhere in its former range, habitats must be restored and alien threats reduced along extensive elevation gradients. Conservation along environmental gradients will likely benefit other Hawaiian birds that track the availability of food across landscapes or that have been stranded in the higher portions of their original ranges because of the greater impacts of alien diseases, predators, food competitors, and habitat stressors at lower elevations
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