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A new species of mites of the genus Eutarsopolipus Berlese, 1911 (Acari: Prostigmata: Podapolipidae) belonging to the biunguis species group, has been described from southern Iran. Eutarsopolipus dryptus Mortazavi and Hajiqanbar n. sp. is a subelytral ectoparasite of the carabid beetle, Drypta lineola MacLeay (Coleoptera: Carabidae). This is the first record of the biunguis species group from Asia. Furthermore, this finding revealed the first record of the association between tribe Dryptini (Coleoptera: Carabidae: Dryptinae) and mites of the family Podapolipidae. A key to the adult females of this species group is provided, and the distribution and host range of all representatives of the group are discussed.
A revision of Xyalaspis (Hymenoptera: Anacharitinae) in the American continent is presented. This genus is mentioned for the first time from the Neotropical region. Xyalaspis flavipes Ashmead, 1896 is synonymized with Xyalaspis microstyla Kieffer, 1907 and is found in the Neotropical region. Five new species are described: Xyalaspis aberrans n. sp. (from the Neotropic), Xyalaspis alveolata n. sp. (from the Neotropic), Xyalaspis arapahoe n. sp. (from the Nearctic), Xyalaspis hirsuta n. sp. (from both regions), and Xyalaspis pilosa n. sp. (from the Neotropic). Diagnostic characters of each species are illustrated and data on the biology, distribution, and mesoscutum sculpturing of the genus Xyalaspis are discussed. A key for differentiating the America species of Xyalaspis is presented.
The species Acerentulus rapoportiCondé, 1963 is redescribed, transferred to genus AndinentulusTuxen, 1984, and synonymized with Andinentulus ebbeiTuxen, 1984 on the basis of type series. Andinentulus rapoporti (Condé, 1963) comb. nov. is characterized by very long and sword-shaped foretarsal sensillum a' sensillum b that is half the length of sensillum c, presence of additional seta d6 on the head, absence of seta P1a on abdominal tergites I–VI, and short oblong accessory setae on tergites I–VI. The differences between the genus Andinentulus and morphologically similar genera, which have three setae on the abdominal legs, are discussed. A key to South and Central American Acerentomidae species and their distribution in America is provided. The mitochondrial cytochrome oxidase subunit I sequence (barcode) is provided for several specimens of the species and compared with other proturan barcodes with a phylogenetic analysis.
Spodoptera frugiperda is an important pest throughout the Western Hemisphere, particularly in corn, cotton, rice, and sorghum, among other crops. This insect has evolved two strains named the corn and the rice strains, as they have been their most frequently used hosts. However, the corn strain can also be found in cotton and the rice strain in pasture grasses and corn. Both strains have been identified by using different molecular markers, including allozymes, polymerase chain reaction—restriction fragment-length polymorphism, amplified fragment-length polymorphism, and FR tandem repeat unit, among others. So far, all reports have claimed no morphological differences between the strains. However, none of these studies have used geometric morphometrics, as we performed in this work. We applied wing morphometrics to analyze wing size and shape in 159 individuals of the corn and the rice strains reared under laboratory conditions since 2009 and already genotyped. Our results demonstrated that wing morphometrics is a promising tool to differentiate both strains, as they were statistically significant in wing shape. We also found that this species presents sexual dimorphism in the rice strain in wing shape and that wing size differs between males of both strains. Further studies will require the use of this new tool in field populations, as their identification is relevant, given that they exhibit reproductive isolation and differences in susceptibility to chemical and biological controls, suggesting they are in the process of speciation via host plant association.
Differences in habitat use and dispersal responses among competing species are mechanisms that may influence patterns of coexistence. Predaceous diving beetles (Coleoptera: Dytiscidae) are a model group for testing these potential coexistence mechanisms because they are abundant, interact in finite habitats, and are mobile among habitats. We focused on two morphologically similar species, Laccophilus fasciatus rufus (Aubé) and Laccophilus proximus (Say), to determine if mechanisms exist that help to explain patterns of their coexistence. Behavioral observations and feeding trials in the laboratory, a field experiment, and a mesocosm experiment were used to determine if habitat use, prey consumption, or dispersal rates of these two species were inherently different or changed when in the presence of intra- or interspecific competitors. We found no difference between habitat use or prey consumption between species in constant depth aquaria, and no effect of intra- or interspecifics on their behaviors. In variable depth aquaria, L. proximus occupied significantly shallower habitat when compared with L. ƒ. rufus; in the former this difference only occurred between conspecific treatments. Field collections confirmed that L. proximus occupied shallower habitats than L. f. rufus. In field mesocosms, L. proximus displayed higher dispersal rates than L. ƒ. rufus. These species also do not appear food limited in the field, suggesting that adult competition for food is unlikely. L.f. rufus and L. proximus exhibit different habitat use and dispersal responses, but this does not seem to be in response to intra- or interspecific competitive interactions.
Gut bacteria play important roles in the biology of insects. In this study, gut bacterial communities were investigated in the rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), which is a serious pest in rice growing-areas of the United States and some Asian countries. Overwintered female adults were collected from rice plants in five geographic locations: Beaumont, TX; Colt, AR; and Biggs, CA; in the United States, and Tanghai of Hebei and Yueqing of Zhejiang in China. Using polymerase chain reaction, bacterial 16S rRNA clone libraries were constructed. From the libraries, we identified 19 bacterial phylotypes (operational taxonomic units, OTUs). Of them, only 3–5 OTUs were identified in each population, except in the Beaumont weevils, which had 10 OTUs. The OTUs were affiliated with the bacteria in six classes of four phyla: α-, β-, γ-proteobacteria, Bacilli, Sphingobacteria, and Actinobacteria, with the γ-proteobacteria being the richest. Bacteria of the genera Pantoea and Wolbachia were detected in all weevil populations examined. There were also some bacteria that were specifically detected in certain locations but had a high relative abundance, such as the ones matched to Enterobacter oryzae, Lactococcus lactis, and Rickettsia felis. Geographic variations were found among bacterial communities in their richness, diversity, and evenness. This was the first study depicting a detailed profile of bacterial communities in L. oryzophilus, and the results provide important information for future studies on the bacterial functions, mutual interactions, and use for developing a biocontrol technique against this weevil.
The association of insect-resistant plants with biological control is important in integrated management to reduce the density of pests below the economic injury level. The behavior, development, and predation of Podisus nigrispinus (Dallas, 1851) (Heteroptera: Pentatomidae) were studied with the prey Spodoptera frugiperda (J. E. Smith, 1797) fed on the leaves of the cotton cultivars ‘NuOpal’ (transgenic), ‘DeltaOpal,’ ‘FMX910,’ ‘FMX993,’ or ‘FMX996′ (conventional). The attraction of P. nigrispinus to S. frugiperda larvae fed on different cotton cultivars was similar. The predation of nymphs and adults, and the life cycle of the P. nigrispinus predator were higher for S. frugiperda larvae fed on the NuOpal; however, the total viability of P. nigrispinus was lower when predating on S. frugiperda fed the NuOpal. S. frugiperda acquires toxins from transgenic cotton, which can affect its natural predator P. nigrispinus.
In December 2006, 495 drosophilids belonging to 19 species were aspirated from inflorescences of Calathea monophylla (Vellozo) Körn at a forest reserve in the city of São Paulo, state of São Paulo, and 42 specimens belonging to three species of Drosophila were aspirated from those of Calathea cylindrica (Roscoe) Karl Schumann in an urban forest in the city of Rio de Janeiro, state of Rio de Janeiro, Brazil. In addition, 20 inflorescences of C. monophylla and 14 inflorescences of C.cylindrica were collected and observed for the emergence of flies in the laboratories. In total, 137 drosophilids belonging to Zygothrica dispar (Wiedemann, 1830) plus five species of Drosophila (Drosophila griseolineata Duda and four undescribed species) emerged from C. monophylla inflorescences, and a total of 22 specimens, all belonging to two undescribed species of Drosophila, emerged from those of C. cylindrica. Drosophila calatheae sp. nov., ungrouped but related to both the xanthopallescens Pipkin and the bromeliae Patterson & Stone species groups, is described based on both aspirated and emerged flies from C. monophylla inflorescences from São Paulo city. This new species was also reared in the laboratory with a new medium recipe, thus providing larvae for chromosomal studies.
Alternative hosts may increase rearing and possibilities of using Trichospilus diatraeae (Cherian & Margabandhu) (Hymenoptera: Eulophidae) for biological control. The aim of this study was to evaluate T. diatraeae reproduction with the alternative host Tenebrio molitor L. (Coleoptera: Tenebrionidae) with life and fertility tables. Twenty-five 24-h-old T. diatraeae females were individualized per Te. molitor pupae of the same age, who were replaced daily until their death of this parasitoid. Survival of T. diatraeae immature in Te. molitor pupae was 92.65%. Longevity of female parasitoids was 8.28 d with an innate density increase of 0.15, net reproductive rate of 37.50, finite rate of increase of 1.16, mean generation time of 23.67, and population doubling time of 4.52 wk. Te. molitor pupae are suitable for development and rearing of T. diatraeae.
The cocoon of Lithurgus chrysurus Fonscolobe, a univoltine species belonging to the megachilid subfamily Lithurginae, was studied using polarization microscopy and topochemical methods. The aim of the study was to establish the composition and structure of the cocoon wall of this bee in comparison with reported data for other species of this subfamily. The cocoon was found to be composed by macromolecularly oriented, positively birefringent silk protein layers that acquire a complex and thicker multilayered distribution at its rear zone. Although the composition and distribution of the silk threads in this species' cocoon was considered similar to the previously described patterns for other lithurgine bees, the absence of a mucous layer, typically produced by Malpighian tubules, differed from reported data for other species of the same subfamily.
The leafcutting bee Megachile (Eutricharaea) minutissima Radoszkowski is a widely distributed species in the Middle East and a promising pollinator of alfalfa. We provide information on the nest architecture, foraging behavior, phenology, and host plants of a wild population of M. minutissima studied between March 2010 and September 2012 in Amariah, a typical desert in central Saudi Arabia. Bees nested in preexisting cavities in the sandy, dry, and loose soil, and built between 2 and 14 leaf-lined brood cells per nest. Females built and provisioned 1–2 cells per day, each consisting of a large oval piece from which the cell cup was made and a small semiround piece that was used as cell cap; however, occasionally small oval pieces were also used in the latter. Cells were built from leaves of Ricinus communis L. (Euphorbiaceae), a locally abundant plant. Both sexes were captured from March to October at flowers of 11 species (10 families), indicating some degree of polylecty as well as either bivoltinism or multivoltinism. We also provide comparative taxonomie comments that will assist bee researchers to easily recognize this species.
The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is an important citrus pest because it vectors bacteria responsible for a serious citrus disease known as huanglongbing (also called citrus greening disease). We conducted research on Asian citrus psyllid heat tolerance, with special emphasis on identifying heat treatments lethal to adult Asian citrus psyllid. Working with an Asian citrus psyllid colony maintained at 27°C, we assessed survival of adult Asian citrus psyllid exposed to temperatures of 43–60°C for various durations in a laboratory oven. We found under our experimental conditions that adult Asian citrus psyllid cannot survive at 50°C for more than ≈10 min and that death occurred faster at higher temperatures; males tended to be more heat-tolerant than females; young adults were less tolerant of high temperatures than older adults; adult Asian citrus psyllids predisposed to warmer temperatures were more heat-tolerant than those predisposed to cooler temperatures; and heat treatments lethal to adult Asian citrus psyllids were lethal to eggs and usually lethal to nymphs. Adult Asian citrus psyllids were less tolerant of heat treatments in the oven when the humidity level was high than when it was low. A number of heat treatments lethal to adult Asian citrus psyllid in an oven situation can be identified from the results of this research and would be useful to regulatory agencies interested in eliminating adult Asian citrus psyllids from shipments of citrus leaves destined for culinary or medicinal markets. Among a number of candidate treatments, 60°C for at least 10 min would be effective against all Asian citrus psyllid life stages and faster killing than lower temperatures.
The tomato-potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), was recently shown to be a vector of “Candidatus Liberibacter solanacearum” (Lso), a phloem-limited bacterium that is the putative causal agent of “zebra chip” in potato and unnamed diseases in other solanaceous species. Despite its importance, very little is known about B. cockerelli stylet probing behaviors that control transmission of Lso to its host plants. Herein, we report the first study characterizing the electrical penetration graph waveforms representing stylet penetration behaviors of the B. cockerelli feeding on potato. Waveforms produced by adult B. cockerelli on potato were also correlated using light microscopy of salivary sheath termini in plant tissue after probes were artificially terminated during the identified waveforms. In addition, behavioral activities were inferred based on electrical origins of waveforms as well as similarities in waveform appearances with those of other psyllids, aphids, and whiteflies. Adult B. cockerelli produced six waveform families and four types, which represent the following proposed biological meanings: family A, initial penetration and sheath salivation; family B, penetration of epidermal cells; family C, secretion of most of the salivary sheath and stylet pathway in mesophyll and parenchyma, with two types, C1 and C2, of unknown meaning; family D, initial contact with phloem cells; family E, activities in phloem cells, with two types, El, putative phloem salivation, and E2, phloem sap ingestion; and family G, xylem ingestion. In addition, a previously unreported variant of waveform G was characterized and correlated with applied signal type. Variation in D and G waveform appearances was correlated with polarity, type, and magnitude of applied signal. Results suggest that active phloem sap ingestion during E2 may play a critical role in acquisition of Lso bacterial cells. E1 may be important in inoculation of the bacterium into phloem sieve elements because it may represent salivation into phloem sieve elements. Analysis of B. cockerelli waveforms could lead to faster development of resistant host plant varieties, strengthen integrated pest management strategies by incorporating alternative plant hosts, and maximize the efficiency of pesticides.
The striped stem borer, Chilo suppressalis, is one of the most serious pests of rice, causing extensive damage and yield loss. This report is a study on the expression patterns of three heat shock protein genes of C. suppressalis. Results indicated that hsp90, hsp70, and hsp60 all expressed within eight tissues (organs) sampled from fifth-instar larvae, with the highest levels being found in the hindgut and the lowest levels in the foregut. Interestingly, an abundance of all three hsps were observed in the head. We also examined heat shock protein expression in different life stages and sexes of rice stem borer. The hsp90 and hsp70 also appeared correlated with the developmental processes of C. suppressalis. The results showed that the transcripts of hsp70 varied remarkably in different developmental stages. The hsp60 demonstrated significantly higher expression in female than male adults. All three hsps of C. suppressalis could be induced by temperature stress, especially heat stress. For example, the highest increase for hsp90, hsp70, and hsp60 was at 42, 36, and 36°C, respectively. All three hsps were more sensitive to heat than cold.
Endophytic fungi are a group of microbial plant symbionts that occur in living tissues of plants without causing visible disease symptoms. The mechanism underlying the anti-insect properties of endophytes is mainly attributed to the production of various alkaloid-based defensive compounds. The current study reveals the cytotoxic effects of endophytic Nigrospora oryzae- and Cladosporium uredinicola-infected cauliflower plants on larval hemocytes of Spodoptera litura (F.). Larvae fed on leaves of endophyte-infected plants exhibited abnormalities such as change in shape, extensive vacuolization, and necrosis in significantly higher percentage of hemocytes. The percentage of abnormal hemocytes increased with increase in feeding duration. The cytotoxic effect of endophytic fungi on the hemocytes ultimately leads to adverse effects on survival and fitness of the insect.
The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is a pest of eastern and Carolina hemlocks (Tsuga canadensis (L.) Carrière and Tsuga caroliniana Engelmann, respectively) in the eastern United States and has already caused catastrophic changes to eastern forests. As one of the significant exotic forest pests, it is imperative that the basic biology of hemlock woolly adelgid be understood for use in novel and improved management techniques. Scanning and transmission electron microscopy and enzyme assays were used to elucidate the feeding biology of hemlock woolly adelgid and are discussed in the context of the pest—plant interactions and the implications for host plant resistance. Morphological characters indicate that hemlock woolly adelgids may use labial sensilla and neural canals within the mandibular stylets to guide their stylets through close-range host acceptance processes. Stylet bundle insertion is likely assisted by external sheath material that secures the stylet bundle to the plant surface and mandibular dentitions that may assist entry into or within plant tissues. In addition, results support the theory that extra-oral digestion is likely used by hemlock woolly adelgid, suggested by both a narrow food canal and the presence of four trophically related enzymes (a trypsin-like enzyme, an amylase-like enzyme, peroxidase, and polyphenol oxidase). The presence of these enzymes also has implications for causing a systemic response in host trees.
To effectively reduce agroforestry pest populations, two or more species of their natural predators, rather than only one, could be released. Podisus nigrispinus (Dallas) and Brontocoris tabidus (Signoret) (Heteroptera: Pentatomidae) are significant pest predators; however, these natural enemies can interact negatively, thereby decreasing the efficacy of biological control. The aim of this research was to study the effect of increasing the density of B. tabidus on the reproduction of P.nigrispinus and vice versa. The number of eggs per egg masses, nymphs, and longevity of P. nigrispinus decreased when the number of B. tabidus females increased. Furthermore, the egg viability was >75% with one, two, three, and four B. tabidus females; however, with five females, the viability of the P.nigrispinus eggs dropped below 70%. The number of egg masses of P. nigrispinus was similar with increasing density of B. tabidus and, even at low density, P. nigrispinus reduced reproduction of B.tabidus. P. nigrispinus and B. tabiclus often occur simultaneously in the field; these predators can coexist without any reproductive damage to any species when both are at low density.
The effect of temperature on tunneling and food transportation activity of four subterranean termite species, Coptotermes formosanus Shiraki, Coptotermes gestroi (Wasmann), Reticulitermes virginicus (Banks), and Reticulitermes flavipes (Kollar), was examined. The experiment was conducted at 15, 20, 25, 30, and 35°C and ≈ 99% relative humidity (RH) using 10- by 10-cm planar arenas. Tunneling areas excavated by termites at 12 and 48 h were analyzed using two-way analyses of variance. The number of food particles and their total linear distance 6 h after termites reached the food source were recorded. The result showed that termites reached the food faster at higher temperatures with the exception of R. virginicus. As the temperature increased, tunneling speed generally increased, though tunnel areas at some temperatures within species at 12 and 48 h were not significantly different from each other. Once they reached the food, the tunneling speed substantially slowed down. In the food transportation study, the number of food particles and their total linear distance from the food source for C. formosanus, R. virginicus, and C. gestroi generally increased with the rise of temperature, while those for R. flavipes were temperature independent. These results may help to explain seasonal activities of the four termite species and to provide information to the application of monitoring and baiting system.
A higher proportion of polygynous ant species in northern areas suggests that cold climates select for increased queen number per colony. However, the types of social conditions within nests that allow polygynous species to inhabit cold climates are unclear. The Japanese twig-dwelling ant, Camponotus yamaokaiTerayama & Satoh, 1990, which has on average two queens per colony, also inhabit colder areas than monogynous related species. C. yamaokai alates remain in natal colonies and always overwinter with workers. A previous study demonstrated that cohabitation by workers facilitates overwintering success of C. yamaokai queens. However, how queen number influences the survival of queens cohabitating with workers and the survival of other castes was not investigated. Here, we compared overwintering survival of queens and workers among experimental groups with different social structures. Wintering experiments revealed that queen survival did not differ between monogynous (one queen) and polygynous (two queens) groups but was correlated positively with worker number. Meanwhile both queen and worker number influenced worker survival, and these factors interacted with worker type (minor or major). Worker survival increased with increasing worker number, but the effect was more pronounced for major workers than for minor workers. With respect to queen number, minor workers survived longer in polygynous groups than in monogynous groups, whereas the opposite pattern was found in major workers. In other words, major worker mortality increased with increasing queen number. These results suggest that cohabitation with workers but not other queens facilitates queen survival, and that queen number increases survival in minor workers but increases mortality in major workers. Possible explanations for this latter pattern are discussed.
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