Coptoborus ochromactonus, n. sp. (Coleoptera: Curculionidae: Scolytinae), an emerging pest of cultivated balsa (Malvales: Malvaceae) in Ecuador

Catalog of the invertebrate type specimens hosted at the Pontificia Universidad Católica del Ecuador and Escuela Politécnica Nacional natural history collections

This work updates the invertebrate type specimen catalog published by Donoso et al. (2009). The catalog is increased by 2281 type specimens (from 454 species or subspecies) to a total of 4180 type specimens (from 770 species or subspecies) hosted at the Pontificia Universidad Católica del Ecuador and Escuela Politécnica Nacional natural history collections. The new material adds 307 holotypes, 1910 paratypes, and 64 allotypes. It provides original information from four phyla (Arthropoda, Mollusca, Nemata, and Platyhelminthes), eight classes, 21 orders, 73 families, and 156 genera. This updated catalog includes a map showing the type localities in the country, a list of the 71 new type specimens (from 23 species or subspecies) from other countries hosted at both museums, corrections to the previous catalog published by Donoso et al. (2009), and label information from each new specimen.

Ecuadorian Coptoborus beetles harbor Fusarium and Graphium fungi previously associated with Euwallacea ambrosia beetles

Ambrosia beetles from the scolytine tribe Xyleborini (Curculionidae) are important to the decomposition of woody plant material on every continent except Antarctica. These insects farm fungi on the walls of tunnels they build inside recently dead trees and rely on the fungi for nutrition during all stages of their lives. Such ambrosia fungi rely on the beetles to provide appropriate substrates and environmental conditions for growth. A small minority of xyleborine ambrosia beetle-fungal partnerships cause significant damage to healthy trees. The xyleborine beetle Coptoborus ochromactonus vectors a Fusarium (Hypocreales) fungus that is lethal to balsa (Ochroma pyramidale (Malvaceae)) trees in Ecuador. Although this pathogenic fungus and its associated beetle are not known to be established in the United States, several other non-native ambrosia beetle species are vectors of destructive plant diseases in this country. This fact and the acceleration of trade between South America and the United States demonstrate the importance of understanding fungal plant pathogens before they escape their native ranges. Here we identify the fungi accompanying Coptoborus ambrosia beetles collected in Ecuador. Classification based ribosomal internal transcribed spacer 1 (ITS) sequences revealed the most prevalent fungi associated with Coptoborus are Fusarium sp. and Graphium sp. (Microascales: Microascaceae), which have been confirmed as ambrosia fungi for xyleborine ambrosia beetles, and Clonostsachys sp. (Hypocreales), which is a diverse genus found abundantly in soils and associated with plants. Phylogenetic analyses of the Fusarium strains based on ITS, translation elongation factor (EF1-α), and two subunits of the DNA-directed RNA polymerase II (RPB1 and RPB2) identified them as Fusarium sp. AF-9 in the Ambrosia Fusarium Clade (AFC). This Fusarium species was previously associated with a few xyleborine ambrosia beetles, most notably the species complex Euwallacea fornicatus (Eichhoff 1868) (Curculionidae: Scolytinae: Xyleborini). Examination of ITS and EF1-α sequences showed a close affinity between the Graphium isolated from Coptoborus spp. and other xyleborine-associated Graphium as well as the soil fungus Graphium basitruncatum. This characterization of ambrosia fungi through DNA sequencing confirms the identity of a putative plant pathogen spread by Coptoborus beetles and expands the documented range of Fusarium and Graphium ambrosia fungi.

A revision of the Neotropical genus Coptoborus Hopkins (Coleoptera, Curculionidae, Scolytinae, Xyleborini)

The Neotropical xyleborine ambrosia beetle genus Coptoborus Hopkins is reviewed. The following 40 Coptoborus species are described: C. amplissimus sp. nov. (Peru), C. asperatus sp. nov. (Ecuador), C. barbicauda sp. nov. (French Guiana), C. bettysmithae sp. nov. (Ecuador), C. brevicauda sp. nov. (Ecuador), C. brigman sp. nov. (Ecuador), C. busoror sp. nov. (Ecuador), C. capillisoror sp. nov. (Brazil), C. chica sp. nov. (Suriname), C. crassisororcula sp. nov. (Peru), C. doliolum sp. nov. (Ecuador), C. erwini sp. nov. (Ecuador), C. furiosa sp. nov. (Ecuador), C. galacatosae sp. nov. (Ecuador), C. hansen sp. nov. (Brazil), C. incomptus sp. nov. (Peru), C. janeway sp. nov. (Peru), C. katniss sp. nov. (Ecuador), C. leeloo sp. nov. (Ecuador), C. leia sp. nov. (Ecuador, Suriname), C. leporinus sp. nov. (Peru), C. martinezae sp. nov. (Ecuador), C. murinus sp. nov. (Ecuador), C. newt sp. nov. (Peru), C. osbornae sp. nov. (Ecuador), C. panosus sp. nov. (French Guiana), C. papillicauda sp. nov. (Suriname), C. pilisoror sp. nov. (Ecuador), C. ripley sp. nov. (Ecuador), C. sagitticauda sp. nov. (Guyana), C. sarahconnor sp. nov. (Brazil), C. scully sp. nov. (Ecuador), C. sicula sp. nov. (Ecuador), C. sororcula sp. nov. (Peru), C. starbuck sp. nov. (Ecuador), C. trinity sp. nov. (Brazil), C. uhura sp. nov. (Peru), C. vasquez sp. nov. (Panama), C. vrataski sp. nov. (Brazil), and C. yar sp. nov. (Ecuador). Seventeen new combinations are given: Coptoborus amazonicus (Petrov, 2020) comb. nov., C. atlanticus (Bright & Torres, 2006) comb. nov., C. bellus Bright & Torres, 2006 comb. nov., C. coartatus (Sampson, 1921) comb. nov., C. crinitulus (Wood, 1974) comb. nov., C. exilis (Schedl, 1934) comb. nov., C. incultus (Wood, 1975) comb. nov., C. magnus (Petrov, 2020) comb. nov., C. micarius (Wood, 1974) comb. nov., C. obtusicornis (Schedl, 1976) comb. nov., C. paurus (Wood, 2007) comb. nov., C. pristis (Wood, 1974) comb. nov., C. pseudotenuis (Schedl, 1936) comb. nov., C. puertoricensis (Bright & Torres, 2006) comb. nov., C. ricini (Eggers, 1932) comb. nov., C. semicostatus (Schedl, 1948) comb. nov., C. tristiculus (Wood, 1975) comb. nov., and C. villosulus (Blandford, 1898) comb. nov. Two new synonyms are proposed: Coptoborus Hopkins, 1915 (= Theoborus Hopkins, 1915 syn. nov.) and Coptoborus villosulus (Blandford, 1898) (= Theoborus theobromae Hopkins, 1915 syn. nov.). Xyleborus neosphenos Schedl, 1976 comb. res. is removed from Coptoborus. The revised genus now contains 77 species and a key to their identification is provided.

Coleoborers (Curculionidae: Scolytinae) in native and homogeneous systems of Brazil nut (Bertholletia excelsa bonpl.) in the Southern Amazon, Brazil

Brazil nut is one of the most important species of the Amazon due to its socioeconomic importance. Especially in homogeneous production systems, it may be susceptible to damage by wood-boring insects, as by the subfamily Scolytinae (Coleoptera: Curculionidae); thus, inadequate management conditions can cause economic damage. Therefore, the objective of the present work is to evaluate the occurrence of wood-boring insects (Curculionidae: Scolytinae) in native and homogeneous systems of Brazil nut in the Meridional Amazonian, Brazil. The study was conducted in three environments: Brazil Nut Native Anthropized, Homogeneous Brazil Nut and Brazil Nut Native Preserved. Twelve ethanol (96° GL) traps were installed in each environment during four sampling periods. The data were submitted to entomofaunistic analysis, Pearson´s correlation analysis and cluster analysis. A total of 2,243 individuals from 31 species were sampled, of which 23 were from the Brazil Nut Native Anthropized nut, 24 from the Homogeneous Brazil Nut and 26 from the Brazil Nut Native Preserved. Some species are restricted to a specific environment, such as Corthylocurus vernaculus Wood & Bright, 1992 and Xyleborus biconicus Eggers, 1928, in relation to Brazil Nut Native Anthropized, Xyleborus tolimanus Eggers, 1928 that occurred only in Homogeneous Brazil Nut and Corthylus antennarius Schedl and Hypothenus bolivianus Wood & Bright, 1992 verified only in Brazil Nut Native Preserved. In the faunistic analysis, we highlight the species Xyleborus affinis (Eichhoff, 1868), which was the most representative one in the three environments and a super-dominant species in all four sampling periods. Among the species considered indicator due to their high representativeness in the sampling, only Premnobius cavipennis Eichhoff, 1878 showed a significant negative correlation between its abundance and the minimum temperature for environments Homogeneous Brazil Nut and Brazil Nut Native Preserved. There was a greater similarity between the Brazil Nut Native Anthropized and the Brazil Nut Native Preserved; these two environments showed dissimilarity with the Homogeneous Brazil Nut. Monitoring wood-boring insects in Brazil nut agroecosystems is fundamental for the establishment of integrated pest management strategies.

Effects of Climate and Host Age on Flight Activity, Infestation Percentage, and Intensity by Coptoborus ochromactonus (Coleoptera: Curculionidae: Scolytinae) in Commercial Balsa Plantations of Ecuador

Coptoborus ochromactonus (Smith and Cognato) is one of the most common and important pests of balsa, Ochroma pyramidale (Cav. Ex Lam. Urb.), an economic pillar of the wood industry in Ecuador. Commercial balsa plantations have been expanded from humid to dry climate areas to limit insect damage, but basic knowledge is still lacking on the interaction of C. ochromactonus activity with variation in climate and plantation age. We investigated the effects of climate and host age on the seasonal flight activity of C. ochromactonus and its infestation rate and intensity, as well as the effect of age and individual infestation intensity on balsa dieback. Experiments were conducted in 1-, 2-, and 3-yr-old commercial balsa plantations located in areas of humid or dry climates. Seasonal flight activity (monitored with baited traps) differed between study sites and seasons. Increased flight activity was significantly correlated with higher relative humidity, higher mean temperature, and reduced precipitation during the dry season in the humid site and with increased mean and minimum temperature and increased precipitation during the rainy season in the dry site. Infestation rates by C. ochromactonus significantly increased with plantation age, especially in the humid site. Intensity of individual infestations (measured as number of successful insect entry holes per tree) was significantly influenced by both climate and plantation age, and it was particularly severe on 3-yr-old trees in the dry site. Percentage of foliage loss significantly increased with infestation intensity. Overall, our results can be relevant for devising preventive measures and suitable management strategies for this emerging pest in Ecuadorian wood plantations.

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.

Life Cycle and Development of Coptoborus ochromactonus (Coleoptera: Curculionidae: Scolytinae), a pest of balsa

Coptoborus ochromactonus Smith and Cognato is a recently described xyleborine ambrosia beetle pest associated with balsa, Ochroma pyramidale (Cav. Ex Lam.) Urb., in Ecuador. This pest has caused significant loss of cultivated balsa in Ecuador, but little is known of its biology and ecology. Based on examination of multiple gallery systems, this study describes the gallery pattern and life cycle of C. ochromactonus and confirms the generic identity of the symbiotic fungus. Females initiated attack, excavating a gallery perpendicular to the bole. The primary tunnel branched into a secondary tunnel at a mean 3.13 mm. This first secondary tunnel was excavated in a horizontal plane between the phloem and xylem for a mean 18.0 mm. Along its length, two tertiary tunnels were constructed on each side, measuring a mean 26.0 and 20.0 mm, respectively. Conidiophores and conidia of an unidentified Fusarium sp. grew on the tunnel walls and were fed upon by the beetle and her progeny. Coptoborus ochromactonus exhibits sexual dimorphism. The female is 2.6 mm long and possesses a round pronotum, whereas the male is 2.2 mm long and has a quadrate pronotum. The developmental stages last a mean 6, 14, 6, 4 and 30 d for egg, larva, pupa, teneral adult, and adult, respectively, when reared at 25°C. Three larval instars were present, with mean head capsule widths of 0.23, 0.31, and 0.42 mm, respectively. In general, the life cycle of C. ochromactonus is similar to those described for other xyleborine ambrosia beetle species.