TREES AS ECOLOGICAL TEMPLATES FOR TROPICAL LITTER ARTHROPOD COMMUNITIES

My dissertation spans five chapters on diverse topics on the ecology and taxonomy of ants in tropical regions. In Chapter 1, I explored if tree species identity explained litter arthropod biodiversity. In Chapter 2, I explored if tree species identity shape the structure of brown food webs. In Chapter 3, I reviewed the systematic status of the Neotropical ant genus Tatuidris. In Chapter 4, I conducted an experiment to explore the consecuences of high ant abundance in brown food webs. In Chapter 5, I explored mechanisms of ant species co-existence using trait- and phylogenetic-based test of community composition

Mapping continental Ecuadorian ant species

Ecuador is considered a megadiverse country but information on the distribution and conservation of its ant species is scarce and scattered through the literature. Here we review 150 years of published literature to assemble the first comprehensive species list of continental Ecuadorian ants (excluding the Galapagos Islands). Our main goals are to provide support to online tools (www.theantsofecuador.com), and to serve as a reference to the various research initiatives currently being done in the country. We found 2,124 ant records, from 679 ant species, in 180 localities, reported in 149 articles. We used a subset of this database (i.e. 1,111 records left after removal of duplicates and records with no locality info) to review the Ecuadorian regions, provinces, and national parks covered by the list. For a tropical country, both the number of records per ant species (mean=1.8, SD=1.9) and the number of ant species per locality (mean=6.2, SD=29.7) are extremely low. Moreover, the ant records in our list are biased towards three provinces (Orellana, 410 ant records and 378 ant spp.; Sucumbios, 212 and 177; Pichincha, 129 and 92), one region (Oriente, 779 records and 487 ant species) and non-protected areas (777 ant records and 510 ant spp.). Endemic ants are poorly covered by the Ecuadorian system of protected areas. This study highlights the gaps and opportunities in ant research for the country

Green bottle flies (Calliphoridae, Luciliinae) of Ecuador: geographic distribution, checklist and DNA barcodes

Green bottle flies (Diptera, Calliphoridae, Luciliinae) comprise a diverse and cosmopolitan taxon, known from at least 1,500 species. They have become crucial elements in forensic investigations, as they spend part of their life cycle in decaying remains. Here, we review the distribution of eleven Luciliinae species in Ecuador: the monotypic Blepharicnema and ten Lucilia species. We identified specimens using morphological characters. Additionally, we DNA barcoded 43 specimens from three species using 658bp segments of the standard Cytochrome Oxidase I (COI) mitochondrial gen. Molecular and morphological identifications presented high correspondence, suggesting COI barcodes are an efficient tool for the identification of these three green bottle flies species. Geographical records are biased towards the northern Andean region, particularly near to large urban settlements. We remark the value to applied forensic research of continuous sampling of necrophagous flies under a variety of habitats and crime conditions.Fil: Moreno Coellar, Emilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentina. Pontificia Universidad Católica del Ecuador; EcuadorFil: Amat, Eduardo. Tecnológico de Antioquia; ColombiaFil: Meneses, Pablo E.. Universidad Regional Amazónica Ikiam; EcuadorFil: Donoso, David A.. Escuela Politécnica Nacional; EcuadorFil: Barragán, Álvaro R.. Pontificia Universidad Católica del Ecuador; Ecuado

ED009. El uso de la ciencia ciudadana para determinar la distribución y prevalencia de la hormiga argentina Linepithema humile (Hymenoptera: Formicidae) en Quito, Ecuador

Invasive species are a serious threat to native biodiversity and ecosystem function, and invertebrates tend to make exceptionally good invasives through their ability to reproduce and disperse readily. A prevalent cosmopolitan invasive species that thrives in urban environments, is the Argentine ant (Linepithema humile). L. humile was first documented in 2014 but it has been present in the country for many years before that. This study sought to understand the distribution and prevalence of L. humile found within the Metropolitan District of Quito (MDQ). Considering the long period since its likely introduction we hypothesized that the population would be well-established and did not expect an increase in the prevalence of L. humile across its distribution. Over three years (2017-2019), we used citizen science by recruiting students from two different universities, to collect 535 samples from 471 sites across the MDQ. In total, L. humile made up 63.18 % of species collected, suggesting the species dominates the local ant community. Contrary to our predictions, the proportion of L. humile increased over time, from 48.96 % in 2017 to 67.37 % in 2019. Additionally, the proportion of “empty” vials, where no ants were found in the sampling site, decreased over time (from 21.88 % to 14.03 %), suggesting that L. humile increased its prevalence in the community and its abundance and distribution. Future analysis will include spatial analysis and the inclusion of new data to better understand how the distribution of L. humile may have changed over time.Las especies invasoras son una seria amenaza para la biodiversidad nativa y el funcionamiento de los ecosistemas, y los invertebrados tienden a ser excepcionalmente buenos invasores a través de su capacidad para reproducirse y dispersarse fácilmente. Una especie invasora cosmopolita prevalente que prospera en entornos urbanos es la hormiga argentina (Linepithema humile; Mayr, 1868). L. humile fue documentado por primera vez en 2014 pero ha estado presente en el país desde muchos años antes. El objetivo de este estudio fue entender la distribución y prevalencia de L. humile encontrada dentro del Distrito Metropolitano de Quito (DMQ). Teniendo en cuenta que el período transcurrido desde su probable introducción es muy largo, planteamos la hipótesis de que la población estaría bien establecida y no esperábamos un aumento en la prevalencia de L. humile en toda su distribución. Durante tres años (2017-2019), utilizamos la ciencia ciudadana al reclutar estudiantes de dos universidades diferentes para tomar 535 muestras de 471 sitios en todo el DMQ. En total, L. humile constituía el 63,18 % de las especies colectadas, lo que sugiere que la especie domina la comunidad local de hormigas. Contrariamente a nuestras predicciones, la proporción de L. humile aumentó con el tiempo, del 48,96 % en 2017 al 67,37 % en 2019. Además, la proporción de viales “vacíos”, donde no se encontró hormigas en el sitio de muestreo, disminuyó con el tiempo (del 21,88 % al 14,03 %), lo que sugiere que L. humile incrementó su prevalencia en la comunidad y su abundancia y distribución. Futuros análisis incluirán un análisis espacial y la inclusión de nuevos datos para comprender mejor cómo la distribución de L. humile puede haber cambiado con el tiempo

Evolution of the Most Massive Galaxies to z ~ 0.6: II. The link between radio AGN activity and star formation

We analyze the optical spectra of massive (log M*/Msun > 11.4) radio-loud galaxies at z~0.2 and z~0.6. By comparing stellar population parameters of these radio-loud samples with radio-quiet control samples, we investigate how the presence of a radio-emitting jet relates to the recent star formation history of the host galaxy. We also investigate how the emission-line properties of the radio galaxies evolve with redshift by stacking their spectra. Our main results are the following. (1) Both at low and at high redshift, half as many radio-loud as radio-quiet galaxies have experienced significant star formation in the past Gyr. (2) The Balmer absorption line properties of massive galaxies that have experienced recent star formation show that star formation occurred as a burst in many of these systems. (3) Both the radio and the emission-line luminosity of radio AGN evolve significantly with redshift. However, radio galaxies with similar stellar population parameters, have similar emission-line properties both at high- and at low-redshift. These results suggest that massive galaxies experience cyclical episodes of gas accretion, star formation and black hole growth, followed by the production of a radio jet that shuts down further activity. The behaviour of galaxies with log M*/Msun > 11.4 is the same at z = 0.6 as it is at z = 0.2, except that higher redshift galaxies experience more star formation and black hole growth and produce more luminous radio jets during each accretion cycle.Comment: 14 pages, 12 figures, submitted to MNRA

Rapid ant community reassembly in a Neotropical forest: Recovery dynamics and land‐use legacy

Regrowing secondary forests dominate tropical regions today, and a mechanistic understanding of their recovery dynamics provides important insights for conservation. In particular, land‐use legacy effects on the fauna have rarely been investigated. One of the most ecologically dominant and functionally important animal groups in tropical forests are the ants. Here, we investigated the recovery of ant communities in a forest–agricultural habitat mosaic in the Ecuadorian Chocó region. We used a replicated chronosequence of previously used cacao plantations and pastures with 1–34 years of regeneration time to study the recovery dynamics of species communities and functional diversity across the two land‐use legacies. We compared two independent components of responses on these community properties: resistance, which is measured as the proportion of an initial property that remains following the disturbance; and resilience, which is the rate of recovery relative to its loss. We found that compositional and trait structure similarity to old‐growth forest communities increased with regeneration age, whereas ant species richness remained always at a high level along the chronosequence. Land‐use legacies influenced species composition, with former cacao plantations showing higher resemblance to old‐growth forests than former pastures along the chronosequence. While resistance was low for species composition and high for species richness and traits, all community properties had similarly high resilience. In essence, our results show that ant communities of the Chocó recovery rapidly, with former cacao reaching predicted old‐growth forest community levels after 21 years and pastures after 29 years. Recovery in this community was faster than reported from other ecosystems and was likely facilitated by the low‐intensity farming in agricultural sites and their proximity to old‐growth forest remnants. Our study indicates the great recovery potential for this otherwise highly threatened biodiversity hotspot

A search of CO emission lines in blazars: the low molecular gas content of BL Lac objects compared to quasars

BL Lacertae (Lac) objects that are detected at very-high energies (VHE) are of fundamental importance to study multiple astrophysical processes, including the physics of jets, the properties of the extragalactic background light and the strength of the intergalactic magnetic field. Unfortunately, since most blazars have featureless optical spectra that preclude a redshift determination, a substantial fraction of these VHE extragalactic sources cannot be used for cosmological studies. To assess whether molecular lines are a viable way to establish distances, we have undertaken a pilot program at the IRAM 30m telescope to search for CO lines in three BL Lac objects with known redshifts. We report a positive detection of M_H2 ~ 3x10^8 Msun toward 1ES 1959+650, but due to the poor quality of the baseline, this value is affected by a large systematic uncertainty. For the remaining two sources, W Comae and RGB J0710+591, we derive 3sigma upper limits at, respectively, M_H2 < 8.0x10^8 Msun and M_H2 < 1.6x10^9 Msun, assuming a line width of 150 km/s and a standard conversion factor alpha=4 M_sun/(K km/s pc^2). If these low molecular gas masses are typical for blazars, blind redshift searches in molecular lines are currently unfeasible. However, deep observations are still a promising way to obtain precise redshifts for sources whose approximate distances are known via indirect methods. Our observations further reveal a deficiency of molecular gas in BL Lac objects compared to quasars, suggesting that the host galaxies of these two types of active galactic nuclei (AGN) are not drawn from the same parent population. Future observations are needed to assess whether this discrepancy is statistically significant, but our pilot program shows how studies of the interstellar medium in AGN can provide key information to explore the connection between the active nuclei and the host galaxies.Comment: 8 pages, 3 figures. MNRAS accepte

Framing the future for taxonomic monography: Improving recognition, support, and access

No abstract available

Species-level predation network uncovers high prey specificity in a Neotropical army ant community

Army ants are among the top arthropod predators and considered keystone species in tropical ecosystems. During daily mass raids with many thousand workers, army ants hunt live prey, likely exerting strong top‐down control on prey species. Many tropical sites exhibit a high army ant species diversity (>20 species), suggesting that sympatric species partition the available prey niches. However, whether and to what extent this is achieved has not been intensively studied yet. We therefore conducted a large‐scale diet survey of a community of surface‐raiding army ants at La Selva Biological Station in Costa Rica. We systematically collected 3,262 prey items from eleven army ant species (genera Eciton, Nomamyrmex and Neivamyrmex). Prey items were classified as ant prey or non‐ant prey. The prey nearly exclusively consisted of other ants (98%), and most booty was ant brood (87%). Using morphological characters and DNA barcoding, we identified a total of 1,103 ant prey specimens to the species level. One hundred twenty‐nine ant species were detected among the army ant prey, representing about 30% of the known local ant diversity. Using weighted bipartite network analyses, we show that prey specialization in army ants is unexpectedly high and prey niche overlap very small. Besides food niche differentiation, we uncovered a spatiotemporal niche differentiation in army ant raid activity. We discuss competition‐driven multidimensional niche differentiation and predator–prey arms races as possible mechanisms underlying prey specialization in army ants. By combining systematic prey sampling with species‐level prey identification and network analyses, our integrative approach can guide future research by portraying how predator–prey interactions in complex communities can be reliably studied, even in cases where morphological prey identification is infeasible