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The until now monospecific genus Yaaxkumukia Morón & Nogueira (Coleoptera: Scarabaeoidea: Rutelidae: Anomalinae: Anomalini) occurs in the south of Mexico, Guatemala, and Honduras. Two new species Yaaxkumukia conabioi sp. nov. and Yaaxkumukia moroni sp. nov. are described, and the type species of the genus, Yaaxkumukia ephemera Morón & Nogueira, is redescribed. A key of the species of Yaaxkumukia is provided. Collection records show that the species of Yaaxkumukia are associated with medium-elevation cloud forest, and their scarce mobility together with the fragmentation of this ecosystem threatens their populations. The biogeography of the genus also is discussed.
The larval and biological characteristics of the large Neotropical genus Leucochrysa are poorly known. This report provides the first taxonomic descriptions of the larvae (three instars) of a species from the subgenus Leucochrysa, Leucochrysa (L.) varia (Schneider). In doing so, it confirms and expands the generic diagnosis that was previously formulated on the basis of larvae in the other Leucochrysa subgenus, Nodita. Our report also provides biological data (developmental times and survival rates) from rearings under a range of temperatures (18–30°C). Finally, it describes the remarkable color variation of L. varia adults; this variation is neither maternally determined nor based on a simple (single-gene) mode of inheritance.
Three new species of the xanthopygine staphylinid genus Elmas are described: Elmas strigiformis Ashe & Chatzimanolis (Brazil), Elmas elassoides Ashe & Chatzimanolis (Bolivia), and Elmas similis Ashe & Chatzimanolis (Brazil). The habitus and structural illustrations are provided for their recognition. Previously published keys for identification are modified to incorporate the new species. The phylogenetic relationships are reanalyzed based on addition of the three new species, revision and recoding of 32 previously used characters, deletion of E. modesta (known only from females) from the analysis, and addition of eight new characters. Phylogenetic analysis based on four xanthopygine outgroups and 19 species of Elmas yielded four equally parsimonious trees of length = 135, C.I. = 45, and R.I. = 74. Major results of the phylogenetic analysis are Elmas is robustly monophyletic; E. strigella and E. strigiformis are sister species, and together they are sister to all other known Elmas species; Elmas elassos is sister to Elmas elassoidesElmas similis; E. spinosus is sister to the sister-group pair of E. faliniE. gigas; and E. windorsi and E. costaricensis are sister groups. New records of Elmas lescheni document the presence of Elmas in Colombia for the first time.
Two exotic crane fly species, Tipula (Tipula) paludosa Meigen (Diptera: Tipulidae) and Tipula (Tipula) oleracea L. have spread considerably in North America beyond original areas of detection in eastern and western Canada. These species are endemic in Europe, and pests in pastures and cereals. The two species differ in life cycles and periods when they feed, warranting species-specific control. Identification presents a challenge because the larvae are not easily distinguishable from each other, and resemble native nonpestiferous species present in sympatry. We collected crane flies from urban landscapes and agricultural fields in Oregon in the western United States. Using polymerase chain reaction (PCR), we sequenced a portion of the mitochondrial cytB gene in 55 individuals (eight adults and 47 larvae) from 29 sites. We observed 7% divergence between exotic and native species. Phylogenetic analysis, using Nephrotoma ferruginea F. as an outgroup, resolved four well-supported monophyletic groups: the exotics, T. (Tipula) oleracea and T. (Tipula) paludosa, and two natives, Tipula (Serratipula) tristis Doane and Tipula (Triplicitipula) sp. Nucleotide divergence between T. oleracea and T. paludosa was P = 0.071, whereas within species divergence was very low (P = 0.0018 and P = 0.0022, respectively). The study indicated that mitochondrial cytB sequences provided an accurate, rapid, and economic technique for separation of T. oleracea and T. paludosa from each other and from native species, and insights on their habitats. The technique will facilitate early pest management decisions, and studies on host plants and geographic distribution, as the two exotic species extend their ranges across North America.
Entomophaga Lioy and Proceromyia Mesnil are reviewed. Their phylogenetic relationships are analyzed using adult morphology. Based on the resultant cladograms, Entomophaga is represented as a paraphyletic group and two monophyletic species groups are established: the exoleta group and the nigrohalterata group. The former group includes two species, E. exoleta and E. vernalis sp. nov., and the latter includes three species, E. nigrohalterata, E. sufferta, and E. ussuriensis sp. nov. Monophyly of Proceromyia is confirmed. The new species are described, the male and female postabdomina are illustrated, and a key to the known species of Entomophaga and Proceromyia is provided.
The spring emergence biology of Ceutorhynchus obstrictus (Marsham) was investigated in 2003 and 2004 in relation to habitat type, vegetative cover, and soil temperature in the Mixed Grassland Ecoregion of western Canada. Although total emergence extended over 10–12 wk, emergence patterns were very similar in both years with limited emergence occurring for several weeks before and after a large emergence peak of comparatively short duration. In 2003, peak emergence occurred during a 3-wk period from 28 May to 13 June when 97.6% of C. obstrictus were collected; and in 2004, emergence of 55.6% of weevils occurred during the 1-wk period before 4 June. Peak emergence occurred as mean ground temperature (5 cm in depth) reached 15°C. The greatest number of weevils recorded from a single 1-m2 emergence trap was 956. Significantly more weevils emerged from sheltered and intermediately sheltered locations than from open grassy habitats; sheltered areas were predominantly shelterbelts and yard sites of caragana and poplar trees. No weevils emerged from 14 of 106 cages, and all cages were in open grassy habitat. Spring emergence of weevils in open grassy areas occurred slightly before those in sheltered and intermediately sheltered areas. Cages in open grassy habitat had the highest mean temperature as well as the highest maximum and lowest minimum temperatures in each sampling period. Significantly more males than females emerged early in the season, although during peak emergence there was no difference in sex ratio; and after peak emergence, significantly more females than males emerged.
Two fruit fly species (Diptera: Tephritidae) of economic importance occur in Argentina, the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and Anastrepha fraterculus (Wiedemann). Here, we compared the relative abundance of these fruit pests in 26 fruit species sampled from 62 localities of Argentina in regions where C. capitata and A. fraterculus coexist. In general, C. capitata was predominant over A. fraterculus (97.46% of the emerged adults were C. capitata), but not always. Using the number of emerged adults of each species, we calculated a relative abundance index (RAI) for each host in each locality. RAI is the abundance of C. capitata relative to the combined abundance of A. fraterculus and C. capitata. Some families of fruit species were more prone to show high (Rutaceae and Rosaceae) or low (Myrtaceae) RAI values, and also native plants showed lower RAI values than introduced plants. RAI showed high variation among host species in different localities, suggesting a differential use of these hosts by the two flies. There were localities where A. fraterculus was not found in spite of suitable temperature and the presence of hosts. Most host species showed little variation in RAI among localities, usually favoring C. capitata, but peach, grapefruit, and guava showed high variation. This suggests that these fruit species are suitable for both fruit flies but more favorable to one or the other, depending on local environmental conditions (e.g., relative humidity and degree of disturbance) of each locality.
Demography of Habrobracon hebetor (Say) (Hymenoptera: Braconidae) on two pyralid host species [Galleria mellonella (L.) and Ephestia kuehniella Zeller] (Lepidoptera: Pyralidae) was studied at 28°C in the laboratory. Data were analyzed based on an age-stage, two-sex life table, to take both sexes and variable development into consideration. The intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), gross reproductive rate (GRR), and mean generation time (T) of H. hebetor on G. mellonella were 0.1520 d−1, 1.1640 d−1, 12.5 offspring, 50.1 offspring, and 16.8 d, respectively. These values were not significantly different from the values obtained for E. kuehniella, i.e., 0.1375 d−1, 1.1473 d−1, 11.9 offspring, 54.9 offspring, and 18.2 d. The life expectancy of an H. hebetor egg was 10.6 d on E. kuehniella and 10.4 d on G. mellonella. On both host species, the maximum reproductive value of female H. hebetor occurred on the 12th day.
Laboratory studies with the southern green stink bug, Nezara viridula (L.), indicated the presence of bacteria Klebsiella pneumoniae (Schroeter) and Enterococcus faecalis (Andrewes & Horder) in the crop/stomach (ventriculus 1–3; V1–V3), and possibly Pantoea sp. in the gastric caeca (ventriculus 4; V4). Culturable bacteria were most abundant in V1–V3, and their abundance was drastically reduced in V4. The variable pH in the gut did not affect the presence of bacteria. Elimination of bacteria from the gut, by using the antibiotic kanamicin, did not affect nymphal developmental time or cause mortality, but it did cause reduced weight at adult emergence.
We tabulated plant species that served as floral hosts of adult Syrphidae and Tachinidae (Diptera) as reported by C. Robertson in his 33-yr data set of flower-visiting insects of central Illinois. Of the 186 fly species he recorded, most were visiting species of the Asteraceae and Apiaceae. The most preferred plant species were the asteraceous Aster pilosus Willdenow and Heracleum maximum Bartram and the umbellifer Pastinaca sativa L. The most frequently recorded fly species were three syrphids: the aphidophagous Toxomerus marginatus (Say) and Sphaerophoria contiqua Macquart and the detritivorous Syritta pipiens (L.). Most fly species evidently visited only a few plant species. These findings may have important implications for research in pollination ecology and insect behavior and for use of fly species as agents of conservation biological control.
The blueberry gall midge, Dasineura oxycoccana (Johnson), and blueberry tip midge, Prodiplosis vaccinii (Felt) (Diptera: Cecidomyiidae), are recurring cecidomyiid pests of cultivated blueberries in the southern United States and Mediterranean Europe. Insecticides can give short-term control, but overlap in parasitoid phenologies indicates the potential for natural control of midge populations. Using a combination of laboratory rearing and mitochondrial DNA analysis of field samples, we identified five species of solitary endoparasitoids that killed 30–40% of midges. These species include at least three undescribed platygastrids in the genera Synopeas, Platygaster, and Inostemma. An undescribed prepupal idiobiont, Aprostocetus sp. (Eulophidae: Tetrastichinae) was the only midge parasitoid that was consistently active when rabbiteye blueberries, Vaccinium ashei Reade, were in flower. Six percent of midge prepupae, half of which already contained platygastrid larvae, were parasitized by Aprostocetus.
Alien species are the principal threat to the conservation of the Galápagos Islands, but little is known about the status of nonindigenous Galápagos insects and their effects on the biota. Currently, 463 alien insect species have probably been introduced to the Galápagos, an increase of 186 unintentional species introductions since an inventory in 1998. Alien insects now constitute 23% of the total insect fauna. Six species are known to be invasive and a threat to the biota: two species of fire ant and two wasps, a scale insect, and an ectoparasitic dipteran. The ecological impacts of the remaining species are unknown, making the prioritization of action for conservation management difficult. Thus, a newly developed and simple scoring system is presented to predict their potential invasiveness based on trophic functional role, distribution in Galápagos, and history of invasiveness elsewhere. An additional 52 species are predicted to be highly invasive. The endemic flora is most at risk because the largest proportion (42%) of the introduced species is herbivores. Plant populations are threatened principally by vectors of plant disease and by phloem and leaf feeders. Introduced predators and parasitoids (17%) may either be affecting, or have the potential to affect, the status of terrestrial invertebrate populations. At least 10% of the species are considered to be negligible threats to Galápagos ecosystems.
The diversity of male genitalia observed among many disparate arthropod taxa has stimulated a number of studies investigating which evolutionary factors contribute to this phenomenon. Much of this research, however, is focused on testing patterns of selection on male genitalia only. Because copulatory processes are a joint act between males and females, detailed study of the selection pressures on female morphology seems equally appropriate. In the current analysis, I used geometric morphometrics to quantify intraspecific shape variation of male and female genitalia in the scarab beetle species Phyllophaga hirticula (Knoch). Characters under sexual selection are predicted to be more phenotypically variable than nonsexual characters because of the persistent tendency of sexual selection to eliminate bouts of stabilizing selection. Thus, this analysis tested whether phenotypic variation of male and female genitalia is equivalently higher than shape variation of a nonsexual character, the right elytron. Shape variation was analyzed in SHAPE, a program that transforms two-dimensional outline data into elliptic Fourier descriptors to be analyzed in a principal components analysis. Data from this study supported the hypothesis that male and female genitalia were significantly more variable than the right elytron. In addition, P. hirticula female genitalia were significantly more variable than male genitalia. Comparable phenotypic variation of male and female genitalia suggests that like male genitalia, female genitalia also may be subject to sexual selection and should be considered when testing hypotheses of genitalic evolution.
Previous studies have suggested that the developmental pattern of insect body parts is influenced by food conditions during the nymphal stages. In this study, we compared the developmental patterns of five body parts (body length, fore-femur length, mid-femur length, hind-femur length, and angle of claw) in the predatory insect Lethocerus deyrolli Vuillefroy fed three diets (tadpoles, Odonata nymphs, and tadpole–Odonata nymph mixture) during the nymphal stages. Significant age by sex interactions were detected in body length, fore-femur length, mid-femur length, and hind-femur length, indicating developmental patterns of these traits varied between sexes. Significant age by food interactions were detected in body length and hind-femur length and were marginally significant in mid-femur length, showing developmental patterns of these traits varied among food types. None of the interactions were significant in angle of the claw. A predation experiment was performed using double-claw nymphs as a control and one-claw nymphs (adult type) as a treatment. Double-claw nymphs successfully caught both large and small tadpoles, whereas one-claw nymphs caught small tadpoles more frequently than large tadpoles. Our results suggest that the claw development, which is very likely related to predatory function, may be less affected by nutritional conditions, and that double claws during nymphal stages may be indispensable to increased predation success.
Aedes vexans (Meigen), the vexans mosquito, is a species that prefers mammalian hosts and is a vector of West Nile virus (family Flaviviridae, genus Flavivirus). It is one of the most widespread pest mosquitoes in the world and North America, and it is commonly found in southern Canada and continental United States. Population structure of this species in Kansas was examined using DNA sequences of a 423-bp region of the mitochondrial NADH dehydrogenase subunit 5 (ND5) gene, relative to three other states. From the 54 Kansas samples, a total of 39 nucleotide positions were polymorphic, with 34 haplotypes. Of the 34 haplotypes, 22 (79%) were not shared among populations. The average haplotype diversity (0.953) from 11 Kansas populations indicated a high level of genetic diversity in Ae. vexans. Among the Kansas, South Dakota, Texas, and Louisiana samples, a total of 40 haplotypes were observed. Analysis of molecular variance was conducted on the resulting haplotypes for all populations and no geographical structure was observed among populations by using isolation-by-distance tests. This first genetic study of Ae. vexans provides evidence that there is a large amount of haplotype variation within and among populations, and gene flow occurs across broad geographical areas in this species.
A potential citrus pest, the Old World swallowtail butterfly Papilio demoleus L. was recently discovered in the Dominican Republic; however, there are many subspecies of this butterfly and not all are considered pests of citrus. We used genetic markers to determine the source population (subspecies), by comparing sequences from butterflies collected in the Dominican Republic with individuals whose provenance was known, and to indicate whether single or multiple introductions had taken place. Sequences of up to 1,400 nucleotides from the mitochondrial cytochrome oxidase subunit I gene were characterized from 28 specimens collected in the Dominican Republic and compared with known P. demoleus sequences available from GenBank. We confirmed earlier estimates, based on morphology, that the butterflies had originated in Southeast Asia, where the species is known to be a citrus pest. Lack of sequence variation among specimens from the Dominican Republic suggests that a single introduction in early 2004 was most likely. It is not known how the butterflies reached the Dominican Republic.
The diel periodicity of pheromone-mediated aggregations and mating and feeding cycles of Euschistus conspersus Uhler (Heteroptera: Pentatomidae) was investigated in a series of laboratory and field experiments. The aggregation response of adult E. conspersus to lures loaded with the male-produced aggregation pheromone component methyl E2,Z4-decadienoate placed on common mullein, Verbascum thapsus L., peaked in the early hours of the scotophase, at ≈2100 hours. Peak mating occurred at 2300 hours, with 78.5% of the insects in aggregations mating at this time. Aggregations dispersed and declined to 30% of their maximum level by dawn on pheromone-baited plants. Equal numbers of males and females were found within aggregations. Aggregations continued to form nightly and disperse by morning throughout a 72-h observation period on pheromone-baited and unbaited mullein plants. A laboratory analysis of feeding periodicity indicated that although feeding occurred throughout the 24-h observation period, the percentage of feeding insects was significantly higher during the scotophase. There were no differences between feeding rates of males and females. The implications of these findings for monitoring and management of E. conspersus are discussed.
While studying the potential occurrence of two stored grain bostrichid pests, Rhyzopertha dominica (F.) and Prostephanus truncatus (Horn), in wild habitats near Stillwater, OK, by using their aggregation pheromones, we observed two nontarget species responding to these semiochemicals. Field experiments were conducted from 2002 to 2005 by using Lindgren four-unit traps baited with either synthetic pheromone or natural semiochemicals produced by male bostrichids feeding on grain in small cages attached to traps to investigate responses of the nontarget species. Ethanol was tested as a possible synergist for R. dominica as part of related research. R. dominica were commonly trapped in forested areas with its synthetic and natural pheromone, but P. truncatus were not captured using its natural or synthetic pheromones. Trapping results from these experiments, in conjunction with records of the known subtropical distribution of P. truncatus, led us to conclude that it probably does not occur in Stillwater, OK. However, we captured large numbers of Zelus tetracanthus Stål (Hemiptera: Reduviidae) males by using synthetic pheromones of R. dominica, and this response was reduced by addition of ethanol. No Z. tetracanthus was caught in traps baited with natural pheromones of R. dominica. The results further suggest that Dominicalure-1, one of the pheromones of R. dominica, is attractive to Z. tetracanthus. Additionally, Prostephanus punctatus (Say), a wood-boring congener of P. truncatus, was trapped in large numbers with natural and synthetic pheromones of P. truncatus. It is likely that P. punctatus uses the P. truncatus compounds Trunc-call-1 and Tunc-call-2, or similar compounds, as pheromones. Our study further revealed that Trunc-call-1 alone is attractive to P. punctatus, and the responses were not significantly enhanced or inhibited by the addition of either ethanol or synthetic Trunc-call-2. Responses of Z. tetracanthus males to Dominicalure-1 suggest that this compound, or a structurally similar compound, plays a role in the chemical ecology of this predaceous species. Catches of Z. tetracanthus peaked in mid-April through May followed by a second peak in July through August. Numbers of P. punctatus captured in traps peaked April through May in two consecutive years.
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