Ecological convergence in phytochemistry and flower-insect visitor interactions along an Andean elevation gradient.

The diversity of specialized molecules produced by plants radiating along ecological gradients is thought to arise from plants' adaptations to local conditions. Therefore, closely related species growing in similar habitats should phylogenetically converge, or diverge, in response to similar climates, or similar interacting animal communities. We here asked whether closely related species in the genus Haplopappus (Asteraceae) growing within the same elevation bands in the Andes, converged to produce similar floral odors. To do so, we combine untargeted analysis of floral volatile organic compounds with insect olfactory bioassay in congeneric Haplopappus (Asteraceae) species growing within the same elevation bands along the Andean elevational gradient. We then asked whether the outcome of biotic interactions (i.e., pollination vs. seed predation) would also converge across species within the same elevation. We found that flower odors grouped according to their elevational band and that the main floral visitor preferred floral heads from low-elevation band species. Furthermore, the cost-benefit ratio of predated versus fertilized seeds was consistent within elevation bands, but increased with elevation, from 6:1 at low to 8:1 at high elevations. In the light of our findings, we propose that climate and insect community changes along elevation molded a common floral odor blend, best adapted for the local conditions. Moreover, we suggest that at low elevation where floral resources are abundant, the per capita cost of attracting seed predators is diluted, while at high elevation, sparse plants incur a higher herbivory cost per capita. Together, our results suggest that phytochemical convergence may be an important factor driving plant-insect interactions and their ecological outcomes along ecological gradients.

La gran diversidad de moléculas especializadas producidas por plantas a lo largo de gradientes ecológicos se atribuye a la adaptación de plantas a sus condiciones locales. Por tanto, especies de plantas estrechamente relacionadas que crecen en hábitats similares deberían de converger en la producción de fitoquímicos similares, en respuesta a climas similares o comunidades de animales con las que interactúan. En este estudio exploramos esta hipótesis caracterizando la metabolómica no dirigida de compuestos orgánicos volátiles florales y conduciendo bioensayos olfativos de insectos en especies cogenéticas del género Haplopappus (Asteraceae) que crecen dentro de las mismas bandas altitudinales a lo largo de un gradiente altitudinal andino. Conjuntamente investigamos si el resultado de las interacciones bióticas (ej. polinización versus depredación) también convergen entre especies que crecen dentro de la misma banda altitudinal. Encontramos que los olores de las flores se agrupan de acuerdo con su banda altitudinal, y que el visitante floral más común prefiere los capítulos florales de las especies de bandas de baja elevación. Además, la relación entre el costo (depredación) y beneficio (polinización) es consistente dentro de las bandas de elevación pero incrementa con elevación, de 6:1 en elevaciones bajas a 8:1 en elevaciones altas. Por lo tanto, proponemos que los cambios climáticos y la comunidad de insectos a lo largo de la elevación resultaron en una mezcla común de olores de flores, mejor adaptada a las condiciones locales. Asimismo, sugerimos que a baja altura donde los recursos florales son abundantes, el costo per cápita de atraer a los depredadores de semillas se diluye, mientras que en sitios altos, las plantas escasas incurren en un costo per cápita de herbivoría más alto. Nuestros resultados sugieren que la convergencia fitoquímica puede ser un factor importante que impulsa las interacciones planta­insecto y sus resultados ecológicos a lo largo de gradientes ecológicos.

Arthropod-Microbiota Integration: Its Importance for Ecosystem Conservation.

Recent reports indicate that the health of our planet is getting worse and that genuine transformative changes are pressing. So far, efforts to ameliorate Earth's ecosystem crises have been insufficient, as these often depart from current knowledge of the underlying ecological processes. Nowadays, biodiversity loss and the alterations in biogeochemical cycles are reaching thresholds that put the survival of our species at risk. Biological interactions are fundamental for achieving biological conservation and restoration of ecological processes, especially those that contribute to nutrient cycles. Microorganism are recognized as key players in ecological interactions and nutrient cycling, both free-living and in symbiotic associations with multicellular organisms. This latter assemblage work as a functional ecological unit called "holobiont." Here, we review the emergent ecosystem properties derived from holobionts, with special emphasis on detritivorous terrestrial arthropods and their symbiotic microorganisms. We revisit their relevance in the cycling of recalcitrant organic compounds (e.g., lignin and cellulose). Finally, based on the interconnection between biodiversity and nutrient cycling, we propose that a multicellular organism and its associates constitute an Ecosystem Holobiont (EH). This EH is the functional unit characterized by carrying out key ecosystem processes. We emphasize that in order to meet the challenge to restore the health of our planet it is critical to reduce anthropic pressures that may threaten not only individual entities (known as "bionts") but also the stability of the associations that give rise to EH and their ecological functions.

Austroectobius invunche: new genus and species of Ectobiidae for Chile (Insecta, Blattaria).

We describe a new genus and species of Chilean Blattodea (Ectobiidae), collected on Isla Grande de Chiloé and associated with Fascicularia bicolor (Bromeliaceae). We study the morphology of both sexes with SEM. The new taxon is brachypterous, with tiny ellipsoid tegmina and hind wings absent. The female presents strongly sclerotized genital sclerites and spermathecal plate developed. The male without tergal specializationsand asymmetrical styles. Medium phallomere with modified sclerites, compose a sclerotized complex that includes a long ejaculatory duct.

Pest Cockroaches May Overcome Environmental Restriction Due to Anthropization.

Our species have altered their surroundings since its early dispersion on Earth. Unfortunately, thanks to human-modified habitats, several pest organisms such as domiciliary insects have expanded their distributions. Moreover, pest-related microorganisms may also be aided by anthropization. Pest cockroaches are globally distributed and capable of carrying several diseases. We explored if urbanization may buffer environmental conditions allowing pest insects to expand their distribution. Specifically, we suggest that human settlements may generate suitable microhabitats for synanthropic cockroaches, helping them to survive and establish with disregard to overall climatic restrictions. To test this idea we studied the distribution of pest cockroaches spanning the length of Chilean territory. Chile, along its 4270 km length north to south extent, is a country offering a formidable sampling of Earth's climatic diversity accompanied by dense urbanizations. We studied entomological collections and spatially analyzed pest cockroach distribution found in Chile and discovered that synanthropic cockroach populations are consistently concentrated near most urban developed zones of the country and not limited by overall temperature. Furthermore, health-concern pest cockroach species were widely distributed in Chilean territory, found even in its most southern urban centers as well as Easter Island. Therefore, these disease vectors could exist even in isolated and extreme climatic zones as long as urbanization provides the adequate microhabitat. We discuss the need for further research in order to assess if these distributions can be extrapolated to the pathogenic strains these pest insects may be carrying as reported in other regions of the planet.

Distribution, habitat use and plant associations of Moluchia brevipennis (Saussure, 1864) (Blattodea: Ectobiidae): an endemic cockroach from Chilean Mediterranean Matorral biome

ABSTRACT Wild cockroaches are often described as abundant and diverse insects from wet tropical zones; however, they can also be found in arid and semiarid areas. It is proposed that in these drier environments cockroach survival may dependent on its tight association with native plant species. In this work, using bait trapping and active collection methods, we surveyed cockroach species along central Chile coastal scrubland; the southern limit of the semiarid Mediterranean Matorral biome in the Neotropical Region (32° S). Based on morphological and DNA barcoding methods we found that our collected cockroaches belonged to native species Moluchia brevipennis (Saussure, 1864) (Blattodea: Ectobiidae). Furthermore, thanks to field sampling, we noticed for the first time that M. brevipennis predominantly can be found in patches of native vegetation from Matorral biome, for instance, associated to endemic plant species from Puya (Bromeliaceae) genus, where we recorded these wild cockroaches feeding on flowers at dusk. Under the light of these findings, we discuss the relevance of the association between M. brevipennis and native plants for its survival in this semiarid habitat, its potential ecological function and the ongoing hazards for native insect species resulting from nearby urban sprawl in coastal central Chile.