Forests Of Costa Rica Research Articles

The role of sampling methodology and site selection on myxomycete data from the Neotropics

<bold> </bold> Myxomycete sporocarps are practical units that can be used to study the effect of environmental issues such as climate change, urbanization, and natural disasters on microorganisms. Recent scientific literature lacks empirical approaches to understand the impacts of sampling design and site selection on the data obtained in myxomycete field surveys. The present investigation was designed to generate useful data for the evaluation of methodological approaches. Myxomycetes were studied for two years in a tropical premontane wet forest in Costa Rica using two different sampling strategies and several collecting sites to evaluate potential differences in the results. Field collections were used to generate the dataset due to their usefulness for monitoring purposes. Sampling strategies had a smaller impact on the reported structure and composition of obtained species assemblages than site selection, but a combination of both clearly maximized the effort and provided the best results during the field surveys. Functional variables of the forest with direct influence on the myxomycete life cycle such as tree diameter and leaf litter depth impacted the results synergically. Simulations of surveys at two different levels of effort were compared with total yearly efforts and results showed that revisiting sampling sites maximized the field effort. Results demonstrated that the variability of sporocarp production in tropical forests should be considered in the design of long-term field experiments on myxomycetes.

Lissomus cacique, a Remarkable New Species of Click Beetle (Coleoptera: Elateridae) from Cloud Forests in Costa Rica and Panama, with Notes on Lissomus flavipennis Guérin-Méneville

Lissomus cacique Johnson, new species from Costa Rica and Panama is described and discriminated from its morphologically most similar and geographically disjunct congener, Lissomus flavipennis Guérin-Méneville from Guatemala and southern Mexico. These two species form a unique pair in Lissomus Dalman distinguished by their relatively large and robust body form, yellow-brown to orange-red elytra not concolorous with the body, and the presence of a complete arcuate postcoxal carina partially delimiting the meso-metaventral crural impression. This new species is the largest of the genus and is only known from premontane cloud forests in Costa Rica and adjacent Panama. Lissomus flavipennis is known only from comparable premontane cloud forests in Guatemala and Mexico. The habitats of both species are now remnants of formerly more extensive forests and are threatened by anthropogenic activities.

Above- and below-ground functional trait coordination in the Neotropical understory genus Costus.

The study of plant functional traits and variation among and within species can help illuminate functional coordination and trade-offs in key processes that allow plants to grow, reproduce and survive. We studied 20 leaf, above-ground stem, below-ground stem and fine-root traits of 17 Costus species from forests in Costa Rica and Panama to answer the following questions: (i) Do congeneric species show above-ground and below-ground trait coordination and trade-offs consistent with theory of resource acquisition and conservation? (ii) Is there correlated evolution among traits? (iii) Given the diversity of habitats over which Costus occurs, what is the relative contribution of site and species to trait variation? We performed a principal components analysis (PCA) to assess for the existence of a spectrum of trait variation and found that the first two PCs accounted for 21.4 % and 17.8 % of the total trait variation, respectively, with the first axis of variation being consistent with a continuum of resource-acquisitive and resource-conservative traits in water acquisition and use, and the second axis of variation being related to the leaf economics spectrum. Stomatal conductance was negatively related to both above-ground stem and rhizome specific density, and these relationships became stronger after accounting for evolutionary relatedness, indicating correlated evolution. Despite elevation and climatic differences among sites, high trait variation was ascribed to individuals rather than to sites. We conclude that Costus species present trait coordination and trade-offs that allow species to be categorized as having a resource-acquisitive or resource-conservative functional strategy, consistent with a whole-plant functional strategy with evident coordination and trade-offs between above-ground and below-ground function. Our results also show that herbaceous species and species with rhizomes tend to agree with trade-offs found in more species-rich comparisons.

Furfurylation of tropical wood species with and without silver nanoparticles: Part II: Evaluation of wood properties

ABSTRACT The purpose of the work was to assess the combined effect of furfurylation, along with the addition of silver nanoparticles (NPsAg), on the thermal stability, density, water absorption, hardness and biological durability of juvenile tropical woods originating from Costa Rican forest plantations. It was demonstrated that the weight percentage gain (WPG) of wood treated with furfuryl alcohol (FA) varied from 14.44% to 44.26%, and from 12.92% to 44.52% after the addition of NPsAg. Additionally, for species with WPG over 25%, thermal stability as well as durability was greater, while water absorption was lower, compared to species with lower WPGs. Improvement of hardness was only achieved with WPG values over 35%; therefore, only species of high permeability (V. ferruginea, V. guatemalensis, C. odorata, S. saman and E. cyclocarpum) showed improvement regarding this property. The addition of NPsAg induced the same behaviour as when using plain FA treatment, however, regarding wood durability, the addition of NPsAg was effective only for species with WPG under 20%.

Agricultural Fast Food: Bats Feeding in Banana Monocultures Are Heavier but Have Less Diverse Gut Microbiota

Habitat alteration for agriculture can negatively affect wildlife physiology and health by decreasing diet diversity and increasing exposure to agrochemicals for animals foraging in altered landscapes. Such negative effects may be mediated by the disruption of the gut microbiota (termed dysbiosis), yet evidence for associations between habitat alteration, wildlife health, and the gut microbiota remains scarce. We examine the association between management intensity of banana plantations and both the body condition and gut microbiota composition of nectar-feeding bats Glossophaga soricina, which commonly forage within banana plantations across Latin America. We captured and measured 196 bats across conventional monocultures, organic plantations, and natural forests in Costa Rica, and quantified gut microbiome bacterial phylogenetic diversity using 16S rRNA amplicon sequencing. We found that gut microbiota from bats foraging in conventional monocultures were overall less phylogenetically diverse than those from bats foraging in organic plantations or natural forests, both of which were characterized by diverse bacterial assemblages and individualized microbiota. Despite lower diversity, co-occurrence network complexity was higher in conventional monocultures, potentially indicating altered microbial interactions in agricultural landscapes. Bats from both organic and conventional plantations tended to be larger and heavier than their forest counterparts, reflecting the higher food supply. Overall, our study reveals that whilst both conventional monocultures and organic plantations provide a reliable food source for bats, conventional monocultures are associated with less diverse and potentially dysbiotic microbiota, whilst organic plantations promote diverse and individualized gut microbiota akin to their natural forest-foraging counterparts. Whilst the long-term negative effects of anthropogenically-altered microbiota are unclear, our study provides further evidence from a novel perspective that organic agricultural practices are beneficial for wildlife health.

Matelea tarrazuana (Apocynaceae, Asclepiadoideae), a new critically endangered ocellate species from Central Pacific of Costa Rica

Matelea tarrazuana, a new species endemic to Costa Rica, is described and illustrated. It is similar to M. pusilliflora, a vine from Yucatan Peninsula because of its green flowers with a reflective white spot in the apex at the apex of each lobe, but differs from that species by its longer pedicels, larger corolla lobes, staminal corona purple (vs. orange), gynostegium with the style apex purple (vs. green) and inhabiting premontane forests of Costa Rica. Data on its distribution and habitat, phenology, conservation status and taxonomy are included, as well as photographs of the living plant, and a key to identify the five related species in Mesoamerica.

Physical structure and biological composition of canopies in tropical secondary and old-growth forests.

The area of tropical secondary forests is increasing rapidly, but data on the physical and biological structure of the canopies of these forests are limited. To obtain such data and to measure the ontogeny of canopy structure during tropical rainforest succession, we studied patch-scale (5 m2) canopy structure in three areas of 18–36 year-old secondary forest in Costa Rica, and compared the results to data from old-growth forest at the same site. All stands were sampled with a stratified random design with complete harvest from ground level to the top of the canopy from a modular portable tower. All canopies were organized into distinct high- and low-leaf-density layers (strata), and multiple strata developed quickly with increasing patch height. The relation of total Leaf Area Index (LAI, leaf area per area of ground) to patch canopy height, the existence of distinct high and low leaf- density layers (strata and free air spaces), the depth and LAI of the canopy strata and free air spaces, and the relation of the number of strata to patch canopy height were remarkably constant across the entire successional gradient. Trees were the most important contributor to LAI at all stages, while contribution of palm LAI increased through succession. We hypothesize that canopy physical structure at the patch scale is driven by light competition and discuss how this hypothesis could be tested. That canopy physical structure was relatively independent of the identity of the species present suggests that canopy physical structure may be conserved even as canopy floristics shift due to changing climate.

Above-ground biomass storage potential in primary rain forests managed for timber production in Costa Rica

Tropical forests play a fundamental role in mitigating climate change through storage of carbon in above- and below- ground biomass. Their mitigation potential is, however, affected by significant greenhouse gas emissions through tropical deforestation or forest degradation. Mitigating degradation caused by conventional logging is therefore an important challenge for silvicultural management, and various reduced impact logging techniques seek to reduce biomass loss and other logging impacts during forest logging activities.Little knowledge exists about the potential of sustainable management for maintaining and restoring the climate change mitigation capacity of tropical forests. Our research contributes to knowledge about this potential, as our aim is to evaluate the above-ground biomass (AGB) stock of tropical forests managed for sustainable timber production and compare it with that of intact primary forests. We also determine the environmental and spatial factors that influence AGB.We estimated the AGB of 141 permanent sampling plots in Costa Rican tropical forests (71 plots set up in areas managed for timber production forests and 70 plots set up in areas with intact primary forests) using data for the 2000–2015 period. We compared the AGB of timber production forests with that of primary forest using linear mixed models and examined the relationship between forest AGB and climate, soil fertility and spatial variables (PCNM eigenvalues) using variation partitioning (VARPART) and multiple linear regression in the mixed model framework.Mean AGB was higher in forest plots set up in areas managed for timber production than in plots set up in areas with intact primary forests. In VARPART, spatial variables had the strongest effect on AGB with a small but significant effect of soil fertility. Regression showed potassium levels in the soil to be positively related to AGB. There was no significant effect of climate, probably because of the short temperature and precipitation gradients.Sustainable forest management in these Costa Rican forests managed for timber production has enabled them to store as much carbon in biomass as primary forests, due to the low intensity logging and sustainability criteria stipulated by the country’s forestry legislation. As a result, sustainable forest management, in addition to providing a sustainable timber ecosystem service, is also a natural climate solution, maintaining the mitigation potential of Costa Rica’s tropical forests in the current climate context.

Lichen community structure and richness in three mid-elevation secondary forests in Costa Rica

Introduction: Lichen diversity, community structure, composition and species abundance have been used as indicators of the integrity and ecological continuity of tropical forest ecosystems. Objectives: To assess corticolous lichen species composition, diversity, and ecological importance of three forested stands differing in time of abandonment as indicators of how passive restoration influences the lichen community assemblage. Methods: We surveyed individual lichens on tree stems of a reference old secondary forest and a young secondary forest (50 and 14-year-old natural regeneration after pasture abandonment, respectively), and in a 35-year-old exotic cypress tree plantation, in the oriental Central Valley, in Orosí, Costa Rica. Standard diversity, similarity indexes, and the importance value index were calculated. An NMDS analysis was performed on the community structure parameters and in a presence-absence matrix. Results: We found 64 lichen species in 25 families with 42, 21, and 23 species, and 20, 10, and 15 families, in the young and old secondary forests, and the cypress plantation, respectively. Cryptothecia sp. possessed the highest importance across sites. More than 87 % of the species are rare. The combined IVI of the top three families were: 36, 48.5, and 74.8 % in the young and old forests and the Cypress plantation sites, respectively. Overall, Arthoniaceae is in the top three families. The young forest had the highest species richness, but the old forest presented the best evenness. Similarity and diversity indexes suggest a particularly low resemblance in the lichen communities but a smooth gradient differentiation between the three forests, which was confirmed by the NMDS test. The homogeneity test identified great differences in ecological importance and composition. Conclusions: This region contains a distinctive assemblage of species resulting in a strong community differentiation by site, reflecting the influence of ecophysiological and microclimatic factors that define lichen establishment and survival and suggesting a great regional beta diversity, within a fragmented landscape. Greater connectivity and passive restoration strategies resulted in greater diversity and a more heterogeneous community structure on both forests than the corticolous community of the abandoned plantation. Protection of forest fragments will maximize the integrity of future forests.

Impact of a tropical forest blowdown on aboveground carbon balance

Field measurements demonstrate a carbon sink in the Amazon and Congo basins, but the cause of this sink is uncertain. One possibility is that forest landscapes are experiencing transient recovery from previous disturbance. Attributing the carbon sink to transient recovery or other processes is challenging because we do not understand the sensitivity of conventional remote sensing methods to changes in aboveground carbon density (ACD) caused by disturbance events. Here we use ultra-high-density drone lidar to quantify the impact of a blowdown disturbance on ACD in a lowland rain forest in Costa Rica. We show that the blowdown decreased ACD by at least 17.6%, increased the number of canopy gaps, and altered the gap size-frequency distribution. Analyses of a canopy-height transition matrix indicate departure from steady-state conditions. This event will initiate a transient sink requiring an estimated 24–49 years to recover pre-disturbance ACD. Our results suggest that blowdowns of this magnitude and extent can remain undetected by conventional satellite optical imagery but are likely to alter ACD decades after they occur.

Distribution and photosynthetic assimilation of rosulate aroid epiphytes in a Costa Rican lowland rainforest

Relatively few studies are available to characterize the distribution, abundance and ecophysiology of aroid epiphytes, distinct from aroid hemiepiphytes which are more common and abundant. The rosulate growth form is restricted to a relatively small number of aroid species. Field and experimental growth studies and ecophysiological measurements on rosulate aroids were carried out at La Selva Biological Station in the premontane rainforest of the Atlantic lowlands of Costa Rica. Rosulate aroids occur in habitats from forest understory to high canopy, and from old growth wet forest to secondary forest in Costa Rica. The distribution of rosulate and acaulescent aroid epiphytes were determined in multiple stands of old growth and secondary tropical forests at La Selva. Anthurium upalense and Philodendron wendlandii exhibited a preference for upper canopies on trees over 50 cm dbh where irradiance levels are high for much of the day. Anthurium consobrinum and A. bakeri occurred lower in the canopy in more shaded positions. To evaluate how these habitat preferences are related to plant traits, controlled shadehouse growth experiments were conducted to characterize species response to different ambient light environments. We applied conditions of high light (50% full sun), medium light (10% full sun), and low light (2% full sun) to simulate a gradient of canopy and understory light environments. Anthurium consobrinum and A. bakeri exhibited photosynthetic traits characteristic of shade-adapted understory epiphytes. In contrast, A. upalense and Ph. wendlandii, typically high canopy species, had maximum photosynthetic rates of 10.5 and 8.7 µmol m−2 s−1, respectively, higher than those previously reported for other vascular epiphytes. The variability in distribution of epiphytic aroids in Costa Rican premontane rainforest is consistent with their diversity of ecological and ecophysiological traits demonstrating adaptation to diverse canopy habitats in this aroid growth form.

Antlion allometry suggests a greater importance of prey capture among first larval instars

First larval stages require adequate feeding to reach subsequent instars. However, the accumulation of reserves is also important in the last larval instar because it is vital to pupate and successfully perform metamorphosis into adulthood. We indirectly determined the presence of changes in the relative importance of prey capture through larval ontogeny in the antlion larvae (Neuroptera Myrmeleontidae), a sit-and-wait predator with three instar stages that capture preys that fall into their pit-traps. We used scaling relationships between the size of body parts directly related to prey capture (prothorax) versus those that are not (thorax + abdomen). The prothorax (neck, head, and mandibles) is used in the pit building, prey capture, and re-capture, and pit cleaning. We measured the body parts of 70 larvae of Myrmeleon crudelis in a tropical rain forest of Costa Rica. The prothorax showed negative allometry: it was proportionally larger in the first than in the last instars. These results support the growth hypothesis, which states that food acquisition is key in the earlier stages of larval development. First instars can be more food-limited than later instars because they build small pit-traps where only very small arthropods can fall; have smaller mandibles and relatively lower grab force, increasing the probability of the prey escaping; and have smaller fat reserves and thus, are unable to resist long periods of starvation. This illustrates the relevance of using scaling relationships to better understand how ecological pressures change along ontogeny, emphasizing the role of food acquisition at earlier ontogenetic stages

Mantled Howler Monkeys (Alouatta palliata) in a Costa Rican Forest Fragment Do Not Modify Activity Budgets or Spatial Cohesion in Response to Anthropogenic Edges

Forest fragmentation increases forest edge relative to forest interior, with lower vegetation quality common for primates in edge zones. Because most primates live in human-modified tropical forests within 1 km of their edges, it is critical to understand how primates cope with edge effects. Few studies have investigated how primates inhabiting a fragment alter their behaviour across forest edge and interior zones. Here we investigate how anthropogenic edges affect the activity and spatial cohesion of mantled howler monkeys (Alouatta palliata) at the La Suerte Biological Research Station (LSBRS), a Costa Rican forest fragment. We predicted the monkeys would spend greater proportions of their activity budget feeding and resting and a lower proportion travelling in edge compared to forest interior to compensate for lower resource availability in the edge. We also predicted that spatial cohesion would be lower in the edge to mitigate feeding competition. We collected data on activity and spatial cohesion (nearest neighbour distance; number of individuals within 5 m) in forest edge and interior zones via instantaneous sampling of focal animals. Contrary to predictions, the monkeys spent equal proportions of time feeding, resting and travelling in forest edge and interior. Similarly, there were no biologically meaningful differences in the number of individuals or the distance between nearest neighbours in the edge (1.0 individuals; 1.56 m) versus the interior (0.8 individuals; 1.73 m). Our results indicate that A. palliata at LSBRS do not adjust their activity or spatial cohesion patterns in response to anthropogenic edge effects, suggesting that the monkeys here exhibit less behavioural flexibility than A. palliata at some other sites. To develop effective primate conservation plans, it is therefore crucial to study primate species’ responses to fragmentation across their geographic range.

Amphibians and Reptiles of the Tirimbina Biological Reserve:&amp;nbsp;a baseline for conservation, research and environmental education&amp;nbsp;in a lowland tropical wet forest in Costa Rica

The Tirimbina Biological Reserve is located in the lowlands on the Atlantic versant of Costa Rica. We provide an updated comprehensive herpetofauna species list and summarize the results of all the herpetofauna research conducted at Tirimbina over the last 10 years (2009&amp;ndash;2019) across a variety of microhabitats. We also added historical records from occasional sightings and reports from researchers, staff, visitors, interns, fellows, and volunteers since the 1990s. We found 52 amphibian and 78 reptile species on the reserve, including a few species considered at-risk according to the IUCN Red List. We conclude that Tirimbina is a herpetofauna biodiversity hot spot in Costa Rica because it provides unique habitat characteristics for a variety of species, including habitat for both forest and forest-edge specialists.

Set of reference indicators for the evaluation of sustainable management of natural forests in Costa Rica: The relevance of the institutional dimension

Based on a set of reference indicators, a tool was designed for the evaluation “ex post” of sustainability of units of managed natural forests in Costa Rica. This set was developed using a hierarchical structure of principles, criteria and indicators of sustainability. The resulting reference list consists of 5 principles, 12 criteria and 30 indicators, classified as essential by a group of experts in forest management in Costa Rica. The set of indicators allows studying the dimensions and attributes that delimit the sustainability of the ecosystems. The selection procedure and the likely contribution of this set to forest management addresses, firstly, the economic, social, ecosystemic and institutional conditions of Costa Rica. However, the set of indicators is useful for other regions of the world, previous adaptation of the threshold values to the local conditions of the ecosystem. Additionally, the ecosystemic dimension (productivity, stability, adaptability) is ratified as a condition of first order for the sustainability, but the experts reinforce the idea that the institutional dimension (equity and governance) is a challenge for the evaluation of sustainability.

Effect of forest succession and microenvironmental variables on the abundance of two wandering spider species (Araneae: Ctenidae) in a montane tropical forest

This study assessed the effects of forest succession and microenvironmental variables on the abundance of ctenid spiders in a montane tropical forest in Costa Rica. We surveyed 20 plots (5 × 5 m) in both primary and secondary forest for a total of 40 samples measuring the following variables: leaf litter depth, canopy density, slope, number of trees above 3 m and average stem diameter of trees exceeding 3 m in height. A total of 150 adult and subadult specimens belonging to five species were observed. The most abundant species were Spinoctenus escalereteHazzi et al., 2018 which has not previously been recorded in Central America and Kiekie griswoldiPolotow & Brescovit, 2018. The larger species, K. griswoldi was significantly more abundant in primary than in secondary forest. Conversely, S. escalerete was more abundant in the secondary forest. A generalized linear model indicated that the most important variable influencing ctenids abundance was leaf litter depth. Whereas the abundance of K. griswoldi was positively related with leaf litter depth, the abundance of S. escalerete was negatively related to litter depth. Thus, forest succession and leaf litter are important factors that influence the abundance of floor ctenid community and may allow the coexistence of co-occurring species.

Abstract 6544: Macrocybin, a mushroom natural triglyceride, reduces tumor growth in vitro and in vivo through interference with the actin cytoskeleton

Abstract Mushrooms have been used for millennia in Eastern traditional medicine as cancer remedies and recent scientific studies have corroborated the presence of anticancer molecules in mushroom extracts. Our goal in this study was to screen a number of scarcely known mushroom species collected in the rain forest of Costa Rica looking for new antitumor molecules. Mushroom pieces were subjected to diverse extraction procedures involving water or ethanol at different temperatures. Extracts were screened using two human cell lines: A549 (lung adenocarcinoma) and NL20 (immortalized normal lung epithelium). Extracts able to kill tumor cells while preserving the integrity of non-tumor cells were considered “anticancer”. Positive extracts were fractionated with different techniques and the purification of the active compound was guided by its biological activity on the cell lines. When the compound was pure enough, its chemical structure was elucidated through nuclear magnetic resonance, mass spectrometry, and other ancillary techniques. The new molecule was synthesized and tested for biological activity both in vitro and in vivo with a xenograft assay. The mechanism of action was investigated through confocal microscopy, qRT-PCR, and Western blotting. The mushroom species with a better therapeutic window was Macrocybe titans, a local edible mushroom of very large proportions. The active ingredient was found in the precipitated phase of a 95% ethanol extraction with ultrasounds for 30 min, kept at -20°C for 24 h. To purify the active compound this extract was subjected to alkaloidal separation followed by column chromatography with polymeric resin (HP20-SS). The fraction obtained at pH 12 contained the active substance. Chemical analysis of the active molecule showed that it was a triglyceride containing oleic acid, palmitic acid, and a more complex fatty acid with 2 double bonds. Synthesis of all possible triglycerides with those characteristics and biological testing identified the natural compound as the R enantiomer of the triglyceride, which was named Macrocybin. A xenograft study showed that Macrocybin significantly reduces A549 tumor growth. In addition, Macrocybin treatment resulted in the dismantlement of the actin cytoskeleton in tumor cells (but not in normal cells). In conclusion, we have shown that the mushroom Macrocybe titans has anticancer properties and that the active principle is the new triglyceride, Macrocybin. This molecule constitutes a first-in-class new drug that works through the dismantlement of the actin cytoskeleton. Future experiments will establish the usefulness of Macrocybin for different types of cancer, either alone or in combination with other therapies. Citation Format: Marcos Vilariño, Josune García-Sanmartín, Laura Ochoa-Callejero, Rafael Peláez, Alfredo Martinez. Macrocybin, a mushroom natural triglyceride, reduces tumor growth in vitro and in vivo through interference with the actin cytoskeleton [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6544.

Increase in abundance and decrease in richness of soil microbes following Hurricane Otto in three primary forest types in the Northern Zone of Costa Rica.

Little is known of how hurricane-induced deposition of canopy material onto tropical forest floors influences the soil microbial communities involved in decomposition of these materials. In this study, to identify how soil bacterial and fungal communities might change after a hurricane, and their possible roles in the C and N cycles, soils were collected from five 2000 m2 permanent plots in Lowland, Upland and Riparian primary forests in Costa Rica 3 months before and 7 months after Hurricane Otto damaged the forests. The soil Water, inorganic N and Biomass C increased and total organic C decreased Post-Hurricane, all of which best predicted the changes in the Post-Hurricane soil microbial communities. Post-Hurricane soils from all forest types showed significant changes in community composition of total bacteria, total fungi, and five functional groups of microbes (i.e., degrading/lignin degrading, NH4+-producing, and ammonium oxidizing bacteria, and the complex C degrading/wood rot/lignin degrading and ectomycorrhizal fungi), along with a decrease in richness in genera of all groups. As well, the mean proportion of DNA sequences (MPS) of all five functional groups increased. There were also significant changes in the MPS values of 7 different fungal and 7 different bacterial genera that were part of these functional groups. This is the first evidence that hurricane-induced deposition of canopy material is stimulating changes in the soil microbial communities after the hurricane, involving changes in specific taxonomic and functional group genera, and reduction in the community richness while selecting for dominant genera possibly better suited to process the canopy material. These changes may represent examples of taxonomic switching of functionally redundant microbial genera in response to dramatic changes in resource input. It is possible that differences in these microbial communities and genera may serve as indicators of disturbed and recovering regional soil ecosystems, and should be evaluated in the future.

Visits at artificial RFID flowers demonstrate that juvenile flower-visiting bats perform foraging flights apart from their mothers

During the transition from parental care to independent life, the development of adequate foraging skills is a major challenge for many juvenile mammals. However, participating in their parents’ knowledge by applying social learning strategies might facilitate this task. For several mammals, communal foraging of adults and offspring is suggested to be an important mechanism in mediating foraging-related information. For the large mammalian taxon of bats, only little is known about foraging-related social learning processes during ontogeny. It is often suggested that following their mothers during foraging flights would represent a valuable option for juveniles to socially learn about foraging, e.g., where to find resource-rich foraging patches, but explicit tests are scarce. In the present study, we investigated the foraging behavior of juvenile flower-visiting bats (Glossophaga soricina) in a dry forest in Costa Rica. We tested whether recently volant, but still nursed pups perform foraging flights alone, or whether pups follow their mothers, which would enable pups to socially learn where to feed. For that, we trained mothers and pups to feed from artificial flowers with a RFID reading system and, subsequently, conducted a field experiment to test whether RFID-tagged mothers and pups visit these flowers communally or independently. Unexpectedly, pups often encountered and visited artificial flowers near the day roost, while mothers rarely did, suggesting that they foraged somewhere further away. Our results demonstrate that still nursed juveniles perform foraging flights apart from their mothers and might learn about the spatial distribution of food without participating in their mother’s knowledge, for instance, by following other conspecifics or applying individual learning strategies. An initial potential lack of foraging success in this period is likely compensated by the ongoing maternal provisioning with breast milk and regurgitated nectar during daytime. Our results contribute to the growing body of research on the ontogeny of mammalian foraging behavior in general.

Disadvantages of living in a populous neighborhood for sit‐and‐wait predators: Competition for space reduces pit‐trap size in antlion larvae

AbstractThe study of how trap design responds to biotic and abiotic conditions can help to understand the selective forces affecting the foraging of trap‐building organisms. We experimentally tested whether pit design can be modified by intraspecific competition for space in larvae of Myrmeleon crudelis, a common sit‐and‐wait predator that digs conical pit traps in the soil to capture walking arthropods. In a tropical forest in Costa Rica, we measured pit dimensions, larval body size, and the level of competition (i.e., density of neighboring traps) in 40 antlion larvae. These larvae were then taken to the laboratory and allowed to build new traps in individual containers. We measured within‐individual changes in the size of traps in the field and in the laboratory, and related these to the level of competition experienced in the field. Larvae with relatively high levels of competition in the field showed a greater increase in the size of their pits in the laboratory. This change was independent of larval size. Larvae with none or few neighbors in the field showed little change in their pit sizes, whereas those with higher competition levels increased their diameter and depth up to 1,400% and 1,000%, respectively. Our results demonstrate that, at least in high‐density aggregations, pit design is restricted by competition in addition to the constraints imposed by body size. This work suggests that biotic interactions can play a role in the design of extended phenotypes in sit‐and‐wait predators that live in dense aggregations.