Xyleborus Affinis Research Articles

Evidence for Succession and Putative Metabolic Roles of Fungi and Bacteria in the Farming Mutualism of the Ambrosia Beetle Xyleborus affinis.

The bacterial and fungal community involved in ambrosia beetle fungiculture remains poorly studied compared to the famous fungus-farming ants and termites. Here we studied microbial community dynamics of laboratory nests, adults, and brood during the life cycle of the sugarcane shot hole borer, Xyleborus affinis We identified a total of 40 fungal and 428 bacterial operational taxonomic units (OTUs), from which only five fungi (a Raffaelea fungus and four ascomycete yeasts) and four bacterial genera (Stenotrophomonas, Enterobacter, Burkholderia, and Ochrobactrum) can be considered the core community playing the most relevant symbiotic role. Both the fungal and bacterial populations varied significantly during the beetle's life cycle. While the ascomycete yeasts were the main colonizers of the gallery early on, the Raffaelea and other filamentous fungi appeared after day 10, at the time when larval hatching happened. Regarding bacteria, Stenotrophomonas and Enterobacter dominated overall but decreased in foundresses and brood with age. Finally, inferred analyses of the putative metabolic capabilities of the bacterial microbiome revealed that they are involved in (i) degradation of fungal and plant polymers, (ii) fixation of atmospheric nitrogen, and (iii) essential amino acid, cofactor, and vitamin provisioning. Overall, our results suggest that yeasts and bacteria are more strongly involved in supporting the beetle-fungus farming symbiosis than previously thought.IMPORTANCE Ambrosia beetles farm their own food fungi within tunnel systems in wood and are among the three insect lineages performing agriculture (the others are fungus-farming ants and termites). In ambrosia beetles, primary ambrosia fungus cultivars have been regarded essential, whereas other microbes have been more or less ignored. Our KEGG analyses suggest so far unknown roles of yeasts and bacterial symbionts, by preparing the tunnel walls for the primary ambrosia fungi. This preparation includes enzymatic degradation of wood, essential amino acid production, and nitrogen fixation. The latter is especially exciting because if it turns out to be present in vivo in ambrosia beetles, all farming animals (including humans) are dependent on atmospheric nitrogen fertilization of their crops. As previous internal transcribed spacer (ITS) metabarcoding approaches failed on covering the primary ambrosia fungi, our 18S metabarcoding approach can also serve as a template for future studies on the ambrosia beetle-fungus symbiosis.

First report of Fusarium oxysporum Causing Fusarium Dieback on Archidendron clypearia in China.

Archidendron clypearia (Jack) Benth. (common name: Monkey-pod) is a perennial arbor tree belonging to the family Fabaceae. It is used to produce a traditional medicine to treat a variety of heat toxicity symptoms in China. The distribution of A. clypearia mainly include Guangdong, Fujian, and Zhejiang provinces in China as well as other countries in Southeast Asia. In 2018, about 30 Monkey-pod trees were observed showing typical dieback symptoms in a commercial plantation (114°36'09.401″E, 22°58'38.553″N) of Huizhou, Guangdong Province, China. In addition, white cylindrical sawdust exudates from exit holes of ambrosia beetles were observed on the trunks and main branches of the diseased trees. Discoloration was seen around the exit holes of the beetles by splitting the wood. Samples of symptomatic and asymptomatic wood tissues of branches, trunks, and roots were collected from 11 trees. To identify the pathogen, the samples were disinfected with a sodium hypochlorite solution containing 50 g/l chlorine for 60 s, rinsed three times with sterile distilled water, and placed on potato dextrose agar (PDA) for culture at 25℃ for 14 days. Beetles from exit holes of the pathogen-infected wood tissues were also collected and identified as Xyleborus affinis by their cytochrome c oxidase I (COI) sequences (GenBank accession numbers: MT921005 and MT921006) as well as morphological features. After two weeks incubation, 37 single-spore isolates were obtained (31 from galleries of branches and trunks, and 6 from mycangia and the body surface of beetles). Colonies on PDA were fusarium-like, pale orange, floccose with abundant aerial mycelia, and growing at the rate of 3.0 to 4.5 mm/d at 25℃. Conidiophores from the aerial mycelia often had single phialides. Microconidia were hyaline, 0-1 septate, (4-)6-12(-16) × 2-4 μm (n=100), Macroconidia were hyaline, ellipsoidal to falcate, 2-4 septate, (10-)25-45(-50) × 3-6 μm (n=100), with basal foot cells shaped to pointed and apical cells tapered and curved. Two representative isolates (CYML 367, 368) were used for molecular identification and pathogenicity tests. The internal transcriptional spacer region (ITS), β-tubulin (TUB), and translation elongation factor-1α (TEF 1-α) regions were amplified with primers ITS1F/ITS4 (White et al. 1990), Bt2a/Bt2b (Glass and Donaldson 1995), and EF1-728F (Carbone and Kohn 1999) /EF-2 (O'Donnell et al.1998), respectively. DNA extraction and PCR conditions were followed the methods described by Yin et al. (2019). The amplified fragments were sequenced. The results of BLAST demonstrated that the fragment sequences of ITS (468 bp), TEF 1-α (616 bp), and TUB (295 bp) of isolates CYML367 and CYML368 had 100% similarity to correspondence sequences from the Fusarium oxysporum Schlecht. emend. Snyder & Hansen species complex (GenBank accession numbers MT032694, JF740777, and MN451171, respectively). Sequences generated from this study were deposited into GenBank under accession numbers MN826824 and MN826825 (ITS), MN839680 and MN839681 (TUB), and MN839682 and MN839683 (TEF 1-α). Pathogenicity tests were conducted on 2-year-old seedlings (60-70 cm height, 1.0-1.2 cm in diameter) of A. clypearia with the representative isolates. Ten seedlings were inoculated with each isolate. The stem surface was disinfected with 75% ethanol for 30 s, and rinsed with sterilized water, wounded by removing part of the phloem and xylem, and placed with a mycelial plug (5 mm diameter) from the margin of a 7-day-old PDA plate with mycelia facing the cambium. The inoculated wounds were wrapped with a medical sterile gauze to prevent desiccation and contamination. Control plants were inoculated with non-colonized PDA plugs. These inoculated and control plants were incubated in a chamber at 25℃, 50% humidity, 12 h light/12 h dark cycle. After 3 weeks, all inoculated plants displayed Fusarium dieback symptoms similar to those observed on the original diseased trees in the plantation. The average lesion lengths (1.2/1.7 cm) caused by two isolates were all significantly longer than the wounds in the negative controls (P<0.05). The same fungus was re-isolated from the symptomatic plants, thus fulfilling the Koch's postulates. Further studies should be conducted on the potential vector association, transmission route, and management strategies of this pathogen on A. clypearia in growing regions of China. To our best knowledge, this is the first report of F. oxysporum causing dieback on A. clypearia in China.

Host selection behavior mediated by differential landing rates of the walnut twig beetle, Pityophthorus juglandis, and associated subcortical insect species, on two western North American walnut species, Juglans californica and J. major

AbstractThe walnut twig beetle, Pityophthorus juglandis Blackman (Coleoptera: Scolytidae), vectors a phytopathogenic fungus, Geosmithia morbida Kolařík et al. (Hypocreales), which causes thousand cankers disease (TCD) in walnut (Juglans sp.) and wingnut (Pterocarya sp., both Juglandaceae) trees. We investigated an early point in disease inception in two walnut species – Juglans californica S. Wats. and Juglans major (Torr. ex Sitsgr.) Heller – native to riparian forests of the western USA by comparing P. juglandis flight and landing responses to small‐diameter branch sections. Twenty unbaited branch sections (10 each of J. californica and J. major) were presented in a completely randomized design to populations of P. juglandis at the USDA Agricultural Research Service, National Clonal Germplasm Repository (NCGR) Juglans collection located at Wolfskill Experimental Orchards (Winters, CA, USA) and at the California State University, Chico, Agricultural Teaching and Research Center (ATRC, Chico, CA). These assays were carried out within a 4‐ to 6‐year period when weekly flight surveys with aggregation pheromone‐baited multiple funnel traps revealed that P. juglandis flight activity–abundance was higher at the NCGR than at the ATRC. For the landing rate assays, adhesive‐coated acetate sheets were wrapped around the branch sections and exchanged weekly. Three assays were completed at the NCGR (assays 1–3), whereas one assay was completed at the ATRC (assay 4). Landing rates on these traps were compared between J. californica and J. major. Two additional assays (5 and 6) were completed at the NCGR to compare responses to branch sections of J. californica and to similarly sized cardboard tubes (negative control). All six assays were completed over a 4‐year span during the 4‐ to 6‐year weekly flight survey period. Pooled landing rates of male and female P. juglandis (assays 1–4) demonstrated a preference by both sexes for J. californica over J. major. In assay 5 there was no preference by males or females for J. californica over the negative control, perhaps due to the low flight activity–abundance of P. juglandis during the assay. When repeated at a time of higher flight activity–abundance (assay 6), male and female landing rates on J. californica exceeded those on the negative control. Females of the invasive fruit‐tree pinhole borer (an ambrosia beetle), Xyleborinus saxeseni (Ratzeburg), and an invasive bark beetle, Hypothenemus eruditus Westwood (both Coleoptera: Scolytidae), showed relatively higher flight responses than either sex of P. juglandis during most assays, suggesting higher population densities of these two other invasive species at the two orchards or a greater sensitivity to host volatiles. Xyleborinus saxeseni and H. eruditus preferred to land on J. major over J. californica and on J. californica over the negative control. Similarly, an invasive longhorned beetle, Nathrius brevipennis (Mulsant) (Coleoptera: Cerambycidae), showed a significant preference for J. major over J. californica, but not for J. californica over the negative control. More male N. brevipennis were trapped than females at both study sites [sex ratio ranged from 5:1 (assay 6) to 39:1 (assay 4)], and flight occurred only in the spring and early summer months. Another ambrosia beetle trapped at the NCGR and ATRC, Xyleborus affinis Eichhoff, represented the first records of this species from western North America. In summary, flight responses recorded in some of our assays for P. juglandis and several other subcortical insects on Juglans indicate that host preference by these insects may be determined by long‐range olfactory cues that do not involve pheromones.

Occurrence of Scolytinae in mangrove with impact trap and in wood of five forest species

Scolytinae is a beetle group belonging to Order Coleoptera; these insects play an essential role in wood degradation in forest ecosystems, since they build galleries that enable substrate colonization by other saprophytic organisms, as well as nutrient cycling. Thus, the aim of the current study was to evaluate the occurrence of Scolytinae in the wood of 5 tree species exposed to mangrove environment, as well as to simultaneously survey Scolytinae specimens captured in ethanol-baited impact traps placed in the same environment. The study was carried out in a mangrove area located in Santa Cruz neighborhood - RJ. Five freshly-harvested Clitoria fairchildiana, Rhyzophora mangle, Corymbia citriodora, Melia azedarach and Eucalyptus pellita wood logs (1 m long and 5-10 cm diameter) were arranged perpendicular to the ground (1 m above it) and spaced 30 cm away from each other. Five impact traps were set up 50 m away from each other, 1.3 m above the ground. Insects were collected for 5 months. One hundred and thirty (130) Scolytinae individuals (14 species in 2 genera) were recorded in the wood logs; the relative frequency (Fr) of the species comprised Xyleborus affinis (33.9%) and Hypothenemus sp.4 (17.7%), which represented 51.6% of the total number of captured individuals. Hypothenemus sp.6 specimens were not collected in ethanol-baited traps, but the wood of C. fairchildiana. E. pellita did not show insect infestation. The traps captured 798 individuals (24 species belonging to 8 genera); the frequency of X. affinis (25.3%) and Hypothenemus eruditus (14.5%) represented 39.8% of the total number of captured insects.

Rediscovery of the Hawaiian endemic bark beetle Xyleborus pleiades Samuleson, 1981 on Moloka‘i, with records of three new exotic bark beetles for the island (Coleoptera: Curculionidae: Scolytinae: Xyleborini)

ABSTRACTDuring the course of a targeted bark beetle survey of the Hawaiian Islands, insect sampling undertaken in native forest biotopes on Moloka‘i island revealed the presence of one native and three exotic species of xyleborine bark beetles (Coleoptera: Curculionidae: Scolytinae: Xyleborini) hitherto not recorded from the island. We present detailed new island records for these species, which include the second record of Xyleborus pleiades Samuelson, 1981, an endemic Hawaiian species not recorded in over 50 years, and previously known only from two specimens from the island of Maui. The three newly recorded introduced species are widespread pantropical beetles of actual or potential pest status: Xyleborus affinis Eichhoff, 1867, Xyleborinus saxesenii (Ratzeburg, 1837), and Xylosandrus crassiusculus (Motschulsky, 1866). The importance of the records is briefly discussed, and all newly recorded species are illustrated in colour photographs.

Bark and Ambrosia Beetle (Coleoptera: Curculionidae: Scolytinae) Diversity in Natural and Plantation Forests in Ecuador.

The Scolytinae is highly diversified in tropical forests, but richness and abundance patterns within most Ecuadorian forest habitat types are not yet characterized. In this study, we assessed patterns of variation in Scolytinae richness, abundance, and species composition in a primary and a secondary natural forest, and a commercial balsa plantation in Ecuador. We conducted a 1-yr survey of Scolytinae communities with baited traps and measured associated environmental variables. In total, 18,169 Scolytinae individuals were captured and comprised 85 species, 16 genera, and six tribes. In the natural forests, main indicator species were Xylosandrus morigerus, Xyleborus affinis, Xyleborus sp.02, and Corthylus sp.01, whereas all species of Hypothenemus were indicator species in the balsa plantation. The exotic Premnobius cavipennis (Ipini), Xylosandrus compactus, and Xylosandrus morigerus were indicator species for the natural forests. We provide evidence that commercial balsa plantations provide abundant favorable resources for native and exotic scolytines in Ecuador, and that scolytine communities in natural forest and in plantations are more likely to differ in their species composition than in their cumulated species richness. In all habitats, species composition, abundance, and species richness showed temporal patterns of variation that coincided with seasonal variations in climatic conditions, with highest records during the coldest and driest months in the primary forest and the balsa plantation. We provide new knowledge on the native Ecuadorian scolytine fauna and a foundation for the monitoring for potential scolytine pest species of natural and planted tropical forest ecosystems.

Impact of Rearing Conditions on the Ambrosia Beetle's Microbiome.

Ambrosia beetles, along with termites and leafcutter ants, are the only fungus-farming lineages within the tree of life. Bacteria harbored by ambrosia beetles may play an essential role in the nutritional symbiotic interactions with their associated fungi; however, little is known about the impact of rearing conditions on the microbiota of ambrosia beetles. We have used culture-independent methods to explore the effect of rearing conditions on the microbiome associated with Xyleborus affinis, Xyleborus bispinatus, and Xyleborus volvulus, evaluating different media in laboratory-controlled conditions and comparing wild and laboratory conditions. Our results revealed that rearing conditions affected the fungal and bacterial microbiome structure and had a strong influence on bacterial metabolic capacities. We propose that the rearing conditions influence the ambrosia-associated fungal and bacterial communities. Furthermore, bacterial microbiome flexibility may help beetles adapt to different substrates.

Spatial distribution of beetle attack and its association with mango sudden decline: an investigation using geostatistical tools.

Ceratocystis fimbriata recognized among the species that induce mango sudden decline (MSD), causes plant death within a short period. The beetles Hypocryphalus mangiferae and Xyleborus affinis (Curculionidae: Scolytinae) are the vectors of MSD. Thorough understanding of the spatial distribution of the pest is crucial to designing control techniques and drawing up sampling plans. This study aimed to identify the beetles and their dispersal pattern in mango trees in MSD-infected commercial orchards, and the association with the severity of the C. fimbriata infestation. Beetle attacks were observed to be maximal on mango tree trunks revealing severe infestation. From the geostatistical analysis, an aggregated pattern was evident as galleries in the trunks and branches of mango trees. This is the first study to employ geostatic tools on a plant scale in MSD-infested mango orchards and to study the incidence of beetle attack. The results may prove a highly effective tool for mango growers, with respect to the management of beetles and MSD, as this will facilitate the monitoring of specific sites where the frequency of beetles and MSD is high. © 2018 Society of Chemical Industry.

Registro de escarabajos descortezadores (Curculionidae: Scolytinae) en el Bosque La Primavera, Jalisco

Se obtuvieron los primeros registros de Scolytinae para el Bosque La Primavera, Jalisco (área natural protegida), con 11 especies y seis géneros, así como su distribución altitudinal. Los insectos fueron capturados mediante trampas, dos de ellas tipo Lindgren de 10 embudos (cebadas con feromonas de Dendroctonus ponderosa e Ips typographus), las cuales se instalaron en vegetación de pino-encino; las otras tres fueron tipo embudo metálica (cebadas con alcohol etílico al 70 %, anticongelante y en el interior de la trampa se colocó thinner), se ubicaron en vegetación de pino, de encino y una más en una asociación de acacias. Las cinco trampas se distribuyeron a diferente gradiente altitudinal: de 1 380 a 1 580 msnm. El grupo más abundante, con respecto a especies fueron Xyleborus affinis, X. ferruginueus, X. volvulus y Gnathotrichus perniciosus. De esta colecta se presentan tres nuevos registros para el estado de Jalisco: Hylurgops subcostulatus alternans, Premnobius cavipennis y Xyleborus horridus; y locales: Ips calligraphus e I. cribicollis. La trampa cinco presentó la mayor captura, con ocho especies (cebada con alcohol etílico al 70 %), seguida por la trampa uno con siete (cebada con feromonas); los dos tipos de trampas demostraron ser eficientes para la captura de insectos descortezadores.

Partnerships Between Ambrosia Beetles and Fungi: Lineage-Specific Promiscuity Among Vectors of the Laurel Wilt Pathogen, Raffaelea lauricola.

Nutritional mutualisms that ambrosia beetles have with fungi are poorly understood. Although these interactions were initially thought to be specific associations with a primary symbiont, there is increasing evidence that some of these fungi are associated with, and move among, multiple beetle partners. We examined culturable fungi recovered from mycangia of ambrosia beetles associated with trees of Persea humilis (silk bay, one site) and P. americana (avocado, six commercial orchards) that were affected by laurel wilt, an invasive disease caused by a symbiont, Raffaelea lauricola, of an Asian ambrosia beetle, Xyleborus glabratus. Fungi were isolated from 20 adult females of X. glabratus from silk bay and 70 each of Xyleborus affinis, Xyleborus bispinatus, Xyleborus volvulus, Xyleborinus saxesenii, and Xylosandrus crassiusculus from avocado. With partial sequences of ribosomal (LSU and SSU) and nuclear (β-tubulin) genes, one to several operational taxonomic units (OTUs) of fungi were identified in assayed individuals. Distinct populations of fungi were recovered from each of the examined beetle species. Raffaelea lauricola was present in all beetles except X. saxesenii and X. crassiusculus, and Raffaelea spp. predominated in Xyleborus spp. Raffaelea arxii, R. subalba, and R. subfusca were present in more than a single species of Xyleborus, and R. arxii was the most abundant symbiont in both X. affinis and X. volvulus. Raffaelea aguacate was detected for the first time in an ambrosia beetle (X. bispinatus). Yeasts (Ascomycota, Saccharomycotina) were found consistently in the mycangia of the examined beetles, and distinct, putatively co-adapted populations of these fungi were associated with each beetle species. Greater understandings are needed for how mycangia in ambrosia beetles interact with fungi, including yeasts which play currently underresearched roles in these insects.

Diversidade de Scolytinae (Coleoptera: Curculionidae) em diferentes paisagens no norte do Brasil

A survey of beetle assemblages of the subfamily Scolytinae was conducted in habitat gradients ranging from primary to secondary forests, cocoa plantations, and pastures in the Amazonian biome. Sampling was carried out in 2015, during February/March (rainy season), June (intermediary season), and September/October (dry season). A total of 4,534 Scolytinae were captured, comprising four genera and nine species. The most abundant species were Xyleborus affinis and Xyleborus volvulus , representing approximately 34% and 31% of the total abundance, respectively. Species of Scolytinae in general showed seasonality and greater abundance and richness in regions with greater coverage of plant litter. Keywords: Amazon, biodiversity studies, habitat preference, insects.

Vertical Distribution and Daily Flight Periodicity of Ambrosia Beetles (Coleoptera: Curculionidae) in Florida Avocado Orchards Affected by Laurel Wilt.

Ambrosia beetles have emerged as significant pests of avocado ((Persea americana Mill. [Laurales: Lauraceae])) due to their association with pathogenic fungal symbionts, most notably Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva (Ophiostomatales: Ophiostomataceae), the causal agent of the laurel wilt (LW) disease. We evaluated the interaction of ambrosia beetles with host avocado trees by documenting their flight height and daily flight periodicity in Florida orchards with LW. Flight height was assessed passively in three avocado orchards by using ladder-like arrays of unbaited sticky traps arranged at three levels (low: 0-2 m; middle: 2-4 m; high: 4-6 m). In total, 1,306 individuals of 12 Scolytinae species were intercepted, but six accounted for ~95% of the captures: Xyleborus volvulus (Fabricius) (Coleoptera: Curculionidae), Xyleborinus saxesenii Ratzeburg (Coleoptera: Curculionidae), Euplatypus parallelus (Fabricius) (Coleoptera: Curculionidae), Xyleborus bispinatus Eichhoff (Coleoptera: Curculionidae), Xyleborus affinis Eichhoff (Coleoptera: Curculionidae), and Hypothenemus sp. (Coleoptera: Curculionidae). The primary vector of R. lauricola, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae), was not detected. Females of X. volvulus showed a preference for flight at low levels and X. bispinatus for the low and middle levels; however, captures of all other species were comparable at all heights. At a fourth orchard, a baiting method was used to document flight periodicity. Females of X. saxesenii and Hypothenemus sp. were observed in flight 2-2.5 h prior to sunset; X. bispinatus, X. volvulus, and X. affinis initiated flight at ~1 h before sunset and Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae) at 30 min prior to sunset. Results suggest that ambrosia beetles in South Florida fly near sunset (when light intensity and wind speed decrease) at much greater heights than previously assumed and have species-specific patterns in host-seeking flight.

Evaluation of the diversity of Scolitids (Coleoptera: Curculionidae) in the forest plantations of the central zone of the Ecuadorian littoral

The species of Scolytinae subfamily have a worldwide distribution, and are found mainly in the Neo-tropic regions. They usually dominate the communities of wood borer insects. The aim of the present study was to determine the diversity among Scolytinae species associated with balsa, teak, rubber and gamhar plantations located in the humid tropical zone of the Ecuadorian littoral. In each plantation seven flight interception traps containing an ethanol / gel mixture were installed, with a collection frequency of 15 days for three months in the dry period. A total of 1437 specimens were collected, represented by Xyleborini, Cryphalini, Corthylini and Ipini tribes. In the four plantations, 18 species of Scolitids were collected, of which 16 were recorded in the balsa plantation, while in the other plantations 10 to 12 species were found. The most abundant Scolitids were Hypothenemus spp., Corthylus spp., Xyleborus affinis, Xyleborinus bicornatulus and Premnobium cavipennis. The Shannon-Wiener diversity index was higher in the balsa culture (H’= 2.37) and lower in Teak (H’= 1.57). The Jaccard similarity index was higher among the teak and rubber plantations (Cj = 0.9090) while the balsa plantation obtained less similarity with respect to the other three plantations. The greatest diversity of Scolitids was recorded in the balsa plantation, which is a native species, unlike the other forest species, which are exotic, indicating that the diversity would be influenced by the host tree and the location where they are found.

Evaluation of the diversity of Scolitids (Coleoptera: Curculionidae) in the forest plantations of the central zone of the Ecuadorian littoral

The species of Scolytinae subfamily have a worldwide distribution, and are found mainly in the Neo-tropic regions. They usually dominate the communities of wood borer insects. The aim of the present study was to determine the diversity among Scolytinae species associated with balsa, teak, rubber and gamhar plantations located in the humid tropical zone of the Ecuadorian littoral. In each plantation seven flight interception traps containing an ethanol / gel mixture were installed, with a collection frequency of 15 days for three months in the dry period. A total of 1437 specimens were collected, represented by Xyleborini, Cryphalini, Corthylini and Ipini tribes. In the four plantations, 18 species of Scolitids were collected, of which 16 were recorded in the balsa plantation, while in the other plantations 10 to 12 species were found. The most abundant Scolitids were Hypothenemus spp., Corthylus spp., Xyleborus affinis, Xyleborinus bicornatulus and Premnobium cavipennis. The Shannon-Wiener diversity index was higher in the balsa culture (H’= 2.37) and lower in Teak (H’= 1.57). The Jaccard similarity index was higher among the teak and rubber plantations (Cj = 0.9090) while the balsa plantation obtained less similarity with respect to the other three plantations. The greatest diversity of Scolitids was recorded in the balsa plantation, which is a native species, unlike the other forest species, which are exotic, indicating that the diversity would be influenced by the host tree and the location where they are found.

ALTURA DE VOO DE ESCOLITÍNEOS (COLEOPTERA, SCOLYTINAE) EM POVOAMENTO DE &lt;i&gt;Pinus taeda&lt;/i&gt; L. NO SUL DO BRASIL

Os escolitíneos (Curculionidae, Scolytinae) são besouros broqueadores, pertencentes à ordem Coleoptera que se desenvolvem no interior de árvores. Em países do hemisfério norte, estes insetos causam prejuízos significativos, principalmente quando ocorrem em surtos epidêmicos. No Brasil, em geral, os danos causados são menores quando comparados aos do hemisfério norte. Tendo em vista a importância da subfamília Scolytinae, este trabalho tem por objetivo proporcionar um melhor entendimento do comportamento destes, principalmente no que tange à altura de voo em povoamento de Pinus taeda L.. Para tanto, foram instaladas 72 armadilhas de interceptação de voo, em área pertencente à Fundação Estadual de Pesquisa Agropecuária (FEPAGRO), localizada em Santa Maria, Rio Grande do Sul. As armadilhas foram distribuídas em diferentes alturas (tratamentos) com três repetições distantes 30 metros entre si. Os tratamentos corresponderam às alturas de 0,5; 1,0; 1,5; 2,0; 2,5; 3,0; 3,5; 4,0; 4,5; 5,0; 5,5 e 6,0 metros. Foram capturados: Hypothenemus eruditus em maior abundância na faixa de 1,0 a 1,5 metros; Xyleborus ferrugineus, Xyleborinus gracilis e Xyleborus affinis a 0,5 metros; Xyleborinus saxeseni e Xylosandrus retusus não apresentaram preferência de altura de voo. Conclui-se que o intervalo situado entre 0,5 e 1,5 metros é ideal para analisar quantitativamente os escolitíneos associados ao Pinus taeda.

Scolytinae y Platypodinae (Coleoptera: Curculionidae) de dos áreas de conservación en Tabasco, México

The Scolytinae and Platypodinae are group of widely distributed tropical insects that are capable of using a wide range of hosts. The study of diversity associated with conservation sites allows estimating the richness and abundance of species, their population dynamics as well as understanding the population behavior over time. The species richness and abundance of Scolytinae and Platypodinae was studied in the Chontalpa Ecological Reserve (REC) and the José Narciso Rovirosa Botanical Garden (JBU) in Tabasco, Mexico. Insects were captured with ethyl alcohol traps. A total of 7 057 specimens belonging to 46 species and 26 genera were collected and identified; 42 species from 23 genera belong to Scolytinae and four species from three genera to Platypodinae. The species Bothrosternus foveatus (Blackman, 1943); Dendroterus luteolus (Schedl, 1951); Dendrocranulus guatemalensis (Hopkins, 1915); Micracis swainei (Blackman, 1920); Pseudothysanoes tenellus (Wood, 1971) y Ambrosiodmus obliquus (Leconte, 1878) are new records for the state of Tabasco. The species Corthylus papulans Eichhoff, 1869 with 2 509 specimens (35.55); Xyleborus volvulus (Fabricius, 1775) with 1 435 (20.33); and Xyleborus affinis Eichhoff, 1868 with 1 061 (15.03) were the most common species, representing 70.9 % of total. The population dynamics of these insects showed its highest peak during February and March with 2 728 specimens in JBU and December with 322 in REC of year 2010.

Globally distributed Xyleborus species reveal recurrent intercontinental dispersal in a landscape of ancient worldwide distributions.

BackgroundInvasive species can have devastating effects on native ecosystems and therefore impose a significant threat to human welfare. The introduction rate of invasive species has accelerated dramatically in recent times due to human activity (anthropogenic effects), with a steadily growing pool of widespread tramp species. We present an in-depth analysis of four pantropical species of Xyleborus ambrosia beetles (Xyleborus volvulus, Xyleborus perforans, Xyleborus ferrugineus, and Xyleborus affinis) with similar ecology (fungus cultivation in dead wood), reproductive biology (permanent inbreeding) and genetic system (haplodiploidy). The unique combination of reproductive traits and broad host plant usage pre-adapts these beetles for colonizing of new areas.ResultsWe found that all four species were broadly distributed long before human-assisted dispersal became common, and that the impact of anthropogenic effects varied among the species. For X. volvulus, X. perforans, and X. affinis there was evidence of ancient establishment in numerous regions, but also of abundant recent introductions into previously colonized areas. For X. ferrugineus, we found clear biogeographical structuring of old clades, but little evidence for recent successful introductions.ConclusionsOur results indicate that current human-aided transoceanic dispersal has strongly affected the genetic makeup of three of the species in this study. However, current biogeographical patterns of all four species are equally, if not more strongly, influenced by ancient establishment on different continents.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-016-0610-7) contains supplementary material, which is available to authorized users.

COLEÓPTEROS EM MADEIRA ESTOCADA E PATIO DE SERRARIA

COLEÓPTEROS EM MADEIRA ESTOCADA E PATIO DE SERRARIA

Ambrosia Beetle Xyleborus affinis Eichhoff, 1868 (Insecta: Coleoptera: Curculionidae: Scolytinae)

Xyleborus affinis is one of the most widespread and common ambrosia beetles in the world. It is also very common in Florida. Like other ambrosia beetles, it bores tunnels into the xylem of weakened, cut or injured trees and farms gardens of symbiotic fungus for food. Females lay eggs in the fungus-lined galleries and larvae feed exclusively on the fungi. Recent studies have shown that Xyleborus affinis can vector the fungus responsible for laurel wilt disease, which is lethal to numerous species of trees in the Lauraceae family. This 5-page fact sheet was written by Lanette Sobel, Andrea Lucky, and Jiri Hulcr, and published by the UF Department of Entomology and Nematology, June 2015. (Photo credit: Juri Hulcr, UF/IFAS)&#x0D; EENY 627/IN1094: An Ambrosia Beetle Xyleborus affinis Eichhoff (1868) (Insecta: Coleoptera: Curculionidae: Scolytinae) (ufl.edu)

Colonization of Artificially Stressed Black Walnut Trees by Ambrosia Beetle, Bark Beetle, and Other Weevil Species (Coleoptera: Curculionidae) in Indiana and Missouri.

Thousand cankers disease (TCD) is a new disease of black walnut (Juglans nigra L.) in the eastern United States. The disease is caused by the interaction of the aggressive bark beetle Pityophthorus juglandis Blackman and the canker-forming fungus, Geosmithia morbida M. Kolarik, E. Freeland, C. Utley & Tisserat, carried by the beetle. Other insects also colonize TCD-symptomatic trees and may also carry pathogens. A trap tree survey was conducted in Indiana and Missouri to characterize the assemblage of ambrosia beetles, bark beetles, and other weevils attracted to the main stems and crowns of stressed black walnut. More than 100 trees were girdled and treated with glyphosate (Riverdale Razor Pro, Burr Ridge, Illinois) at 27 locations. Nearly 17,000 insects were collected from logs harvested from girdled walnut trees. These insects represented 15 ambrosia beetle, four bark beetle, and seven other weevil species. The most abundant species included Xyleborinus saxeseni Ratzburg, Xylosandrus crassiusculus Motschulsky, Xylosandrus germanus Blandford, Xyleborus affinis Eichhoff, and Stenomimus pallidus Boheman. These species differed in their association with the stems or crowns of stressed trees. Multiple species of insects were collected from individual trees and likely colonized tissues near each other. At least three of the abundant species found (S. pallidus, X. crassiusculus, and X. germanus) are known to carry propagules of canker-causing fungi of black walnut. In summary, a large number of ambrosia beetles, bark beetles, and other weevils are attracted to stressed walnut trees in Indiana and Missouri. Several of these species have the potential to introduce walnut canker pathogens during colonization.