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Xyleborus sp beetles are types of ambrosia beetles invasive to the United States and recently also to Mexico. The beetle can carry a fungus responsible for the Laurel Wilt, a vascular lethal disease that can host over 300 tree species, including redbay and avocado. This problem has a great economic and environmental impact. Indeed, synthetic chemists have recently attempted to develop new neonicotinoids. This is also due to severe drug resistance to "classic" insecticides. In this research, a series of neonicotinoids analogs were synthesized, characterized, and evaluated against Xyleborus sp. Most of the target compounds showed good to excellent insecticidal activity. Generally, the cyclic compounds also showed better activity in comparison with open-chain compounds. Compounds R-13, 23, S-29, and 43 showed a mortality percent of up to 73% after 12 h of exposure. These results highlight the enantioenriched compounds with absolute R configuration. The docking results correlated with experimental data which showed both cation-π interactions in relation to the aromatic ring and hydrogen bonds between the search cavity 3C79 and the novel molecules. The results suggest that these sorts of interactions are responsible for high insecticidal activity.

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Despite its high ecological importance, the commensal interactions at community level are poorly studied. In tropical dry forests (TDF) there is a great diversity of species adapted to the high seasonality that characterizes them; however, little is known regarding how the spatial and temporal availability of resources generates changes in the pattern of commensal interactions. We experimentally studied changes in the diversity, composition, and pattern of interactions in spatio-temporal associations between the saproxylophagous beetles and their host trees in a TDF in Morelos, Mexico. A total of 65 host tree species were selected, from which 16 wood sections were obtained per species. These sections were exposed in the field to allow oviposition by the cerambycids under four different (spatio-temporal) treatments. We analyzed the network structure and generated indices at species level (i.e., specialization, species strength, and effective partners) and those related to physical characteristics of the wood (hardness and degradation rate) and the cerambycids (body size). In total, 1,323 individuals of 57 species of cerambycids emerged. Our results showed that, independently of the space and time, the network presented a nested and modular structure, with a high specialization degree and a high turnover of cerambycid species and their interactions. In general, we found that the cerambycids are mostly associated with softwood species with a lower decomposition rate of wood, as well as with the most abundant host species. The commensalistic interactions between the cerambycids and their host trees are highly specialized but are not spatio-temporally static. The high turnover in the interactions is caused by the emergence patterns of cerambycids, which seem to restrict their use to certain species. The knowledge of the spatio-temporal variation in Cerambycidae-host tree interactions allows us to predict how environmental and structural changes in the habitat can modify the species ensemble, and therefore its interactions.

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Beetles (Coleoptera) comprise about one quarter of all described animal species. One of the main contributors to their evolutionary success is the elytra, or hardened forewings, which have protective functions while maintaining their ability to fly. Unlike other beetles, some ship-timber beetles (Lymexylidae) have extremely small elytra and largely exposed functional hindwings. There is little fossil evidence illuminating the evolutionary history of short elytra in lymexylids. Here, I report five well-preserved lymexylid fossils in mid-Cretaceous and Cenozoic ambers from Myanmar (ca. 99 million years ago [Mya]), Russia (ca. 44 Mya), and the Dominican Republic (ca. 16 Mya). Three Cretaceous fossils have strongly reduced, shortened elytra, with unexpected variation in elytral size and shape, whereas very small, modified elytra are found only in much younger Dominican amber. These morphologically diverse extinct lymexylids shed new light on the early origin and evolutionary history of elytra reduction and its diverse variation in the ship-timber beetles. Based on the striking morphological similarities with extant lymexylids, these extinct taxa might have had the same, or similar, ecological, behavioural, and flight modes as the extant ship-timber beetles.

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The death of trees is an ecological process that promotes regeneration, organic matter recycling, and the structure of communities. However, diverse biotic and abiotic factors can disturb this process. Dendroctonus bark beetles (Curculionidae: Scolytinae) are natural inhabitants of pine forests, some of which produce periodic outbreaks, killing thousands of trees in the process. These insects spend almost their entire life cycle under tree bark, where they reproduce and feed on phloem. Tunneling and feeding of the beetles result in the death of the tree and an alteration of the resident microbiota as well as the introduction of microbes that the beetles vector. To understand how microbial communities in subcortical tissues of pines change after they are colonized by the bark beetle Dendroctonus rhizophagus, we compare both the bacterial and fungal community structures in two colonization stages of Pinus arizonica (Arizona pine) employing Illumina MiSeq. Our findings showed significant differences in diversity and the dominance of bacterial community in the two colonization stages with Shannon (P = 0.004) and Simpson (P = 0.0006) indices, respectively, but not in species richness with Chao1 (P = 0.19). In contrast, fungal communities in both stages showed significant differences in species richness with Chao1 (P = 0.0003) and a diversity with Shannon index (P = 0.038), but not in the dominance with the Simpson index (P = 0.12). The ß-diversity also showed significant changes in the structure of bacterial and fungal communities along the colonization stages, maintaining the dominant members in both cases. Our results suggest that microbial communities present in the Arizona pine at the tree early colonization stage by bark beetle change predictably over time.

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We analyze the invasive potential of two Asian ambrosia beetles, Xyleborus glabratus and Euwallacea sp., into Mexico and the southern United States. The fungal symbionts of these beetles have been responsible for damage to trees of the family Lauraceae, including Persea americana and other non-cultivated tree species on both coasts of the United States. We estimate their potential threat using ecological niche modeling and spatial multi-criteria evaluation protocols to incorporate plant and beetle suitabilities as well as forest stress factors across Mexico. Mexico contains higher climatic and habitat suitability for X. glabratus than for Euwallacea sp. Within this country, the neotropical region is most vulnerable to invasion by both of these species. We also identify a corridor of potential invasion for X. glabratus along the Gulf of Mexico coast where most Lauraceae and native Xyleborus species are present; dispersal of either X. glabratus or Euwallacea sp. into this region would likely lead to major disease spread. However, the overall potential damage that these beetles can cause may be a function of how many reproductive hosts and how many other ambrosia beetles are present, as well as of their capacity to disperse. This work can also alert relevant managers and authorities regarding this threat.

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ABSTRACT One of the problems affecting the quality of urban trees is their infestation by mistletoes (aerial hemiparasite plants of the order Santalales). Identification of the main types of trees infested, and of the causes of infestation patterns, can help infestation control and the planning of efficient planting regimes. In this sense, the aim of this study was to evaluate the patterns of hemiparasite infestation in trees in an Amazonian urban environment. We aimed to answer (1) which species of mistletoes occur on urban trees in the city of Santarém, in the Brazilian Amazon; (2) what is the proportion and intensity of infestation on infected trees; and (3) if differences in infestation rates among tree species can be explained by mistletoe-tree compatibility. We assessed mistletoe incidence and intensity of infestation on trees in the main avenues of the city. To evaluate the role of mistletoe-tree compatibility in the observed parasitism patterns, we carried out a seed inoculation experiment with seeds of the most abundant mistletoe, Passovia theloneura. Seeds were planted on three tree species (Andira inermis, Handroanthus serratifolius, and Mangifera indica). The overall infestation rate was 19.3%, with exotic tree species more infested than natives. The experiment showed that incompatibility between P. theloneura and the native H. serratifolius is primarily responsible for the observed non-infestation. Mistletoes germinated on A. inermis grew better than those on M. indica, contrary to the infestation prevalence found in the field, suggesting that patterns of infestation are also influenced by seed deposition processes.(AU)

RESUMO Um dos problemas que afetam a qualidade das árvores urbanas é sua infestação por ervas-de-passarinho (hemiparasitas aéreas da ordem Santalales). Identificação das principais espécies de árvores infestadas e das causas da infestação pode ajudar a controlar as ervas-de-passarinho e orientar o plantio de novas espécies de árvores. Nesse sentido, o objetivo deste estudo foi avaliar o padrão de infestação de hemiparasitas em árvores em um ambiente urbano da Amazônia. Nós buscamos responder: (1) quais espécies de ervas-de-passarinho ocorrem nas árvores urbanas da cidade de Santarém, na Amazônia Brasileira, (2) qual é a proporção e intensidade de infestação nas árvores afetadas e (3) se diferenças nas taxas de infestação entre as espécies de árvores podem ser explicadas pela compatibilidade entre ervas-de-passarinho e hospedeiro. Nós amostramos árvores nas principais avenidas da cidade. Para avaliar o papel da compatibilidade entre a erva-de-passarinho e o hospedeiro nos padrões de parasitismo observados, conduzimos um experimento de inoculação de sementes com a erva-de-passarinho mais abundante, Passovia theloneura. Sementes foram plantadas em três espécies de hospedeiros (Andira inermis, Handroanthus serratifolius e Mangifera indica). A taxa de infestação foi de 19,3%, com espécies exóticas mais infestadas do que as nativas. O experimento mostrou que a incompatibilidade entre P. theloneura e a nativa H. serratifolius é o principal fator responsável por sua não infestação. As ervas-de-passarinho que germinaram em A. inermis cresceram melhor do que aquelas em M. indica, contrário à prevalência de infestação encontrada no campo, o que sugere que os padrões de infestação são também influenciados por processos de deposição de sementes.(AU)

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Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is an insect native to Chile. The larval stages feed on the wood of economically important fruit tree species such as apple, pear, olive, cherry, and avocado, and also on eucalyptus. This causes weakening and, in case of severe infestation, death of the tree. We report identification of the sex pheromone produced by females of this species. Hexane extracts of the abdominal glands of virgin females were analyzed by gas chromatography (GC) with electroantennographic detection, GC coupled with mass spectrometry, and GC coupled to infrared spectroscopy. The major pheromone component was identified as (7Z,10Z)-7,10-hexadecadienal (Z7,Z10-16:Ald), and minor components present in the extracts were (Z)-7-hexadecenal and (Z)-9-hexadecenal, hexadecanal, and (9Z,12Z)-9,12-octadecadienal. Structural assignments were carried out by comparison of analytical data of the natural products and their dimethyl disulfide adducts with those of authentic reference samples. In field tests, traps baited with Z7,Z10-16:Ald captured significantly more males than control traps.

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Tree species distributions associated with rainfall are among the most prominent patterns in tropical forests. Understanding the mechanisms shaping these patterns is important to project impacts of global climate change on tree distributions and diversity in the tropics. Beside direct effects of water availability, additional factors co-varying with rainfall have been hypothesized to play an important role, including pest pressure and light availability. While low water availability is expected to exclude drought-intolerant wet forest species from drier forests (physiological tolerance hypothesis), high pest pressure or low light availability are hypothesized to exclude dry forest species from wetter forests (pest pressure gradient and light availability hypothesis, respectively). To test these hypotheses at the seed-to-seedling transition, the potentially most critical stage for species discrimination, we conducted a reciprocal transplant experiment combined with a pest exclosure treatment at a wet and a dry forest site in Panama with seeds of 26 species with contrasting origin. Establishment success after one year did not reflect species distribution patterns. However, in the wet forest, wet origin species had a home advantage over dry forest species through higher growth rates. At the same time, drought limited survival of wet origin species in the dry forest, supporting the physiological tolerance hypothesis. Together these processes sort species over longer time frames, and exclude species outside their respective home range. Although we found pronounced effects of pests and some effects of light availability on the seedlings, they did not corroborate the pest pressure nor light availability hypotheses at the seed-to-seedling transition. Our results underline that changes in water availability due to climate change will have direct consequences on tree regeneration and distributions along tropical rainfall gradients, while indirect effects of light and pests are less important.

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Mangrove swamps and forests cover over 137,000 km2 distributed latitudinally among subtropical zones, 7% of which are in Brazil, with a greater density in the country's northernmost region. Considering that the community of Myxomycetes recorded for this environment is hardly known, three areas located in the state of Maranhão were investigated. Two field trips were conducted, one at the beginning of the rainy season and another during the dry season. In each area, two plots (125 m2) equidistant 100 m apart from each other were surveyed. In these areas, standing dead tree trunks and dead branches still attached to the mother plant that were above the tideline, were examined. On these same occasions, samples of the aerial litter and from the cortex of living trees (Rhizophora) were collected for the preparation of moist chambers cultures. Twenty-one specimens were obtained from field and moist chambers, belonging to 11 species, distributed in nine genera and five families. Seven species are new records from Maranhão. There was a predominance of r-strategist (73%) over K-strategist (27%) species. Cribraria violacea, Comatricha tenerrima, Echinostelium minutum, and Fuligo septica are new worldwide records from mangrove environments, and Oligonema flavidum is reported for the first time from Brazil.

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Abstract Mangrove swamps and forests cover over 137,000 km2 distributed latitudinally among subtropical zones, 7% of which are in Brazil, with a greater density in the country’s northernmost region. Considering that the community of Myxomycetes recorded for this environment is hardly known, three areas located in the state of Maranhão were investigated. Two field trips were conducted, one at the beginning of the rainy season and another during the dry season. In each area, two plots (125 m2) equidistant 100 m apart from each other were surveyed. In these areas, standing dead tree trunks and dead branches still attached to the mother plant that were above the tideline, were examined. On these same occasions, samples of the aerial litter and from the cortex of living trees (Rhizophora) were collected for the preparation of moist chambers cultures. Twenty-one specimens were obtained from field and moist chambers, belonging to 11 species, distributed in nine genera and five families. Seven species are new records from Maranhão. There was a predominance of r-strategist (73%) over K-strategist (27%) species. Cribraria violacea, Comatricha tenerrima, Echinostelium minutum, and Fuligo septica are new worldwide records from mangrove environments, and Oligonema flavidum is reported for the first time from Brazil.

Resumo Os manguezais ocupam mais de 137.000 km2, distribuídos latitudinalmente entre as zonas subtropicais e 7% encontra-se no Brasil, com maior densidade entre os estados do Pará e Maranhão, na região norte do país. Considerando que a comunidade de mixomicetos registrada para este ambiente é pouco conhecida, três áreas localizadas no estado do Maranhão foram investigadas. Duas excursões foram realizadas, uma no início da estação chuvosa e outra na estiagem. Em cada área, foram georeferenciadas e exploradas duas parcelas (125 m2) equidistantes 100 m uma da outra foram avaliadas. Nestas, foram explorados troncos mortos em pé e galhos mortos ainda presos à planta-mãe, acima da linha da maré. Nas mesmas ocasiões foram coletadas amostras de folhedo aéreo e córtex de árvores vivas (Rhizophora) para montagem de câmaras-úmidas. Foram obtidos 21 espécimes de campo e câmara-úmida, pertencentes a 11 espécies, distribuídas em nove gêneros e cinco famílias. Sete espécies são novos registros para o Maranhão. Predominaram espécies r-estrategistas (73%), e 27% K-estrategistas. Cribraria violacea, Comatricha tenerrima, Echinostelium minutum e Fuligo septica são novos registros para o ambiente de manguezal, e Oligonema flavidum é registrada pela primeira vez no Brasil.

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