DNA Barcoding Reveals Generalization and Host Overlap in Hummingbird Flower Mites: Implications for the Mating Rendezvous Hypothesis.

AbstractHummingbird flower mites are assumed to monopolize single host plant species owing to sexual selection for unique mating rendezvous sites. We tested the main assumption of the mating rendezvous hypothesis-extreme host specialization-by reconstructing interactions among tropical hummingbird flower mites and their host plants using DNA barcoding and taxonomic identifications. We collected 10,654 mites from 489 flowers. We extracted DNA from 1,928 mite specimens and amplified the cytochrome c oxidase I (CO1) DNA barcode. We analyzed the network structure to assess the degree of generalization or specialization of mites to their host plants. We recorded 18 species of hummingbird flower mites from three genera (Proctolaelaps, Rhinoseius, and Tropicoseius) interacting with 14 species of plants. We found that generalist mites are common, and congeneric mite species often share host plants. Our results challenge the assumption of strict specialization that supports this system as an example of mating rendezvous evolution.

Positive genetic covariance and limited thermal tolerance constrain tropical insect responses to global warming.

Tropical ectotherms are particularly vulnerable to global warming because their physiologies are assumed to be adapted to narrow temperature ranges. This study explores three mechanisms potentially constraining thermal adaptation to global warming in tropical insects: (a) Trade-offs in genotypic performance at different temperatures (the jack-of-all-trades hypothesis), (b) positive genetic covariance in performance, with some genotypes performing better than others at viable temperatures (the 'winner' and 'loser' genotypes hypothesis), or (c) limited genetic variation as the potential result of relaxed selection and the loss of genes associated with responses to extreme temperatures (the gene decay hypothesis). We estimated changes in growth and survival rates at multiple temperatures for three tropical rain forest insect herbivores (Cephaloleia rolled-leaf beetles, Chrysomelidae). We reared 2,746 individuals in a full sibling experimental design, at temperatures known to be experienced by this genus of beetles in nature (i.e. 10-35°C). Significant genetic covariance was positive for 16 traits, supporting the 'winner' and 'loser' genotypes hypothesis. Only two traits displayed negative cross-temperature performance correlations. We detected a substantial contribution of genetic variance in traits associated with size and mass (0%-44%), but low heritability in plastic traits such as development time (0%-6%) or survival (0%-4%). Lowland insect populations will most likely decline if current temperatures increase between 2 and 5°C. It is concerning that local adaption is already lagging behind current temperatures. The consequences of maintaining the current global warming trajectory would be devastating for tropical insects. However, if humans can limit or slow warming, many tropical ectotherms might persist in their current locations and potentially adapt to warmer temperatures.

Model Systems in Ecology, Evolution, and Behavior: A Call for Diversity in Our Model Systems and Discipline.

AbstractEcologists and evolutionary biologists are fascinated by life's variation but also seek to understand phenomena and mechanisms that apply broadly across taxa. Model systems can help us extract generalities from amid all the wondrous diversity, but only if we choose and develop them carefully, use them wisely, and have a range of model systems from which to choose. In this introduction to the Special Feature on Model Systems in Ecology, Evolution, and Behavior (EEB), we begin by grappling with the question, What is a model system? We then explore where our model systems come from, in terms of the skills and other attributes required to develop them and the historical biases that influence traditional model systems in EEB. We emphasize the importance of communities of scientists in the success of model systems-narrow scientific communities can restrict the model organisms themselves. We also consider how our discipline was built around one type of "model scientist"-a history still reflected in the field. This lack of diversity in EEB is unjust and also narrows the field's perspective, including by restricting the questions asked and talents used to answer them. Increasing diversity, equity, and inclusion will require acting at many levels, including structural changes. Diversity in EEB, in both model systems and the scientists who use them, strengthens our discipline.

Demographic Attritions, Elevational Refugia, and the Resilience of Insect Populations to Projected Global Warming.

AbstractTropical mountains might protect species from global warming by facilitating biotic migrations upslope. Current predictions of tropical biotic responses to global warming are based on correlations between species elevational distributions and temperatures. Because biotic attritions, range shifts, and mountaintop extinctions result from complex demographic processes, predictive models must be based on mechanistic associations between temperature and fitness. Our study combines long-term temperature records with experimental demography to determine the contribution of local adaptation to organismal resilience in a warming world. On the Barva volcano in Costa Rica, Cephaloleia belti (Coleoptera: Chrysomelidae) displays high-elevation (960-2,100 m asl) and low-elevation (50-960 m asl) mitochondrial haplotypes. We reared haplotype cohorts at temperatures prevalent along the elevational gradient (i.e., 10°-30°C). Based on ambient temperatures recorded every half hour for 4 years, we projected average instantaneous population growth rates ([Formula: see text]) at current and future temperatures (i.e., +1° to 6°C) for each beetle haplotype. Haplotypes are adapted to local temperatures, but with a temperature increase beyond 2°C, both haplotypes will face lower-elevation demographic attritions and extinctions. Upper distribution limits serve as potential elevational refugia from global warming. This study shows how species resilience to global warming emerges from complex fitness responses of locally adapted phenotypes facing novel environments.

Effect of Chemical Pollution and Parasitism on Heat Tolerance in Dung Beetles (Coleoptera: Scarabaeinae).

Ecosystem services provided by insects are threatened by recent increasing global temperatures, particularly in the tropics, where insects live close to their thermal limits. Given that tolerance to high temperatures depends on individual metabolism and physiological stress response, it may also be sensitive to other stressors that are common in natural and human-modified environments, such as pollution and parasite pressure. The effects of multiple stressors could be synergistic and can be particularly relevant in insects that provide highly valuable ecosystem services, such as dung beetles in cattle pastures. Here we measured heat tolerance (critical thermal maximum, CTmax) in dung beetles exposed to ivermectin, a toxic parasiticide excreted in cattle dung, with known negative effects on coprophagous fauna, and in beetles exposed to an immune challenge. We also exposed a group of beetles to a combination of both ivermectin and immune challenge to test for potential synergistic effects of both stressors. Contrary to our predictions, CTmax did not change with ivermectin exposure, but increased in immune-challenged beetles. As found in other insects, CTmax was higher in larger beetles, highlighting the importance of body size on thermal tolerance in ectotherms. We discuss potential mechanisms responsible of increased heat tolerance in immune-challenged beetles and highlight the importance of natural and human-induced environmental pressures that now interact with global warming and threaten ecosystem services provided by wild animals.

Standardized ethograms and a device for assessing amphibian thermal responses in a warming world.

Most predictions of how populations and species of ectotherms will respond to global warming are based on estimates of the temperature at which organisms lose motor control (i.e., CTmax - the Critical Thermal Maximum). Here, we describe a non-lethal protocol and ethograms to estimate the relative tolerance of amphibians to increasing temperatures. These methods-suitable for field or laboratory conditions-are replicable, inexpensive and applicable to both post-metamorphic stages and organisms with direct development. We illustrate the use of this standardized protocol for four amphibians from a tropical cloud forest in Veracruz, Mexico with contrasting life histories: a lungless salamander (Aquiloeurycea cafetalera: Plethodontidae), a leaf-litter frog (Craugastor rhodopis: Craugastoridae), a semiaquatic frog (Lithobates berlandieri: Ranidae), and a tree frog (Rheohyla miotympanum: Hylidae). We identified four behavioral responses preceding CTmax for all amphibians included in this study: 1) Optimal Activity Range, 2) Supra-optimal Activity Range, 3) Heat Stress Range, and 4) Involuntary Movements Range. Additionally, we identified a fifth parameter associated with resilience to heat shock: 5) Recovery Stage after reaching CTmax. We conclude that the behavioral responses preceding the Critical Thermal Maximum are as informative as CTmax. Using behavioral responses to estimate thermal tolerance has the additional advantage of reducing the risk of injury or death of amphibians during physiological experiments.

Energy storage, body size and immune response of herbivore beetles at two different elevations in Costa Rica

The physiological condition and immune responses of organisms living at different elevations are expected to display local adaptations to the different climatic and biotic conditions. Small ectotherms with specialized diets are highly susceptible to environmental change, as their life cycle is largely affected by temperature and by the presence of specific resources. This study focuses on two species of rolled-leaf beetles (Chrysomelidae), both present at two different elevations in Costa Rica: Cephaloleia belti Baly, a diet-generalist, and Chelobasis bicolor Gray, a diet-specialist. Body size, energetic condition (lipid storage), muscle mass and immune condition (melanization response) were compared in beetle populations from a tropical rainforest (50 m elevation) and a tropical montane forest (2 000 m elevation). These measurements reflect current and past nutritional condition and hence are good estimators of individual fitness. We analyzed a total of 172 individuals from both species, sexes and elevations. We predicted that beetles at higher elevation would display larger body size, higher energetic condition and lower immune response associated with metabolic requirements and parasitic pressure in colder temperatures. In general, beetles at high altitude were larger, had more lipids and muscle and showed stronger melanization (i.e., immune response) than beetles at low altitudes. Such differences among populations at different elevations may reflect local adaptation to altitude or phenotypic plasticity. However, the effect of elevation was not equivalent amongst species or sex. Measuring physiological traits in organisms with broad elevational distributions could be useful in understanding possible species responses to climate change.

La condición fisiológica y la respuesta inmune de poblaciones que habitan a distintas altitudes pueden mostrar adaptación local a las condiciones abióticas y bióticas locales. Entre los organismos más susceptibles al cambio ambiental están los ectotermos pequeños con dietas especializadas, debido a que su ciclo de vida es, en gran medida, afectado tanto por la temperatura como por la presencia de recursos específicos. Este estudio se enfoca en dos especies de escarabajos (Chrysomelidae) presentes a lo largo de un gradiente altitudinal en Costa Rica: Cephaloleia belti Baly, una especie de dieta generalista, y Chelobasis bicolor Gray, de dieta especialista. Se comparó el tamaño corporal, la condición energética (almacenamiento de lípidos), la masa muscular y la condición inmunológica (respuesta de melanización) entre poblaciones de escarabajos de un bosque tropical (a 50 m de altitud) y un bosque tropical montano (a 2 000 m de altitud). Las variables seleccionadas reflejan las condiciones nutricionales actuales y pasadas y son buenos estimadores de la adecuación individual. Se analizaron un total de 172 escarabajos de ambas especies, sexos y elevaciones. Predecimos que los escarabajos a mayor elevación tendrán mayor tamaño corporal, mayor condición energética y menor respuesta inmune asociadas con los requerimientos metabólicos y la presión de los parásitos asociados con ambientes fríos. En general, los escarabajos a mayor altitud fueron más grandes, tuvieron más lípidos y masa muscular, y presentaron una mayor respuesta inmune de melanización que los escarabajos a menor altitud. Es posible que las diferencias entre las poblaciones a diferentes altitudes reflejen adaptaciones locales a las condiciones ambientales a distintas altitudes o plasticidad fenotípica. Sin embargo, el efecto de la altitud no fue de la misma magnitud entre las dos especies ni entre los dos sexos. La medición de caracteres fisiológicos en organismos ectotérmicos de amplia distribución altitudinal puede ser útil para entender las respuestas de ciertas especies al cambio climático.

Low quality diet and challenging temperatures affect vital rates, but not thermal tolerance in a tropical insect expanding its diet to an exotic plant.

Determining responses of organisms to changing temperatures is a research priority, as global warming threatens populations and ecosystems worldwide. Upper thermal limits are frequently measured as the critical thermal maximum (CTmax), a quick bioassay where organisms are exposed to increasing temperatures until individuals are not able to perform basic motor activities such as walking or flying. A more informative approach to understand organism responses to global warming is to evaluate how vital rates, such as growth or survival, change with temperatures. The main objectives of this study are: (1) to determine if factors affecting insect vital rates such as diet quality, developmental temperatures or acclimation also affect CTmax and (2) to determine if vital rates of different life stages (i.e., insect larvae or adults) display different responses to temperature changes. If different life stages have particular thermal requirements, this may indicate different susceptibility to global warming. This study focuses on Cephaloleia belti (Coleoptera: Chrysomelidae), a tropical insect currently expanding its diet to an exotic host plant. We determined how high and low-quality diets (i.e., native vs novel host), as well as exposure temperatures affect CTmax of adult beetles. We also estimated larval and adult survival when feeding on high and low quality host plants, when exposed to temperatures typical of the elevational distribution of this species, or when exposed to projected temperatures in 100 years. We did not detect an effect of diet quality or acclimation on CTmax. However, larvae and adults had different thermal requirements. CTmax is not affected by previous diet or acclimation as an adult. We propose that to understand processes involved in the adaptation and persistence of ectotherm populations in a warming world, studies must explore responses beyond CTmax, and focus on the response of vital rates to changing temperatures.

Experimental assemblage of novel plant-herbivore interactions: ecological host shifts after 40 million years of isolation.

Geographic isolation is the first step in insect herbivore diet specialization. Such specialization is postulated to increase insect fitness, but may simultaneously reduce insect ability to colonize novel hosts. During the Paleocene-Eocene, plants from the order Zingiberales became isolated either in the Paleotropics or in the Neotropics. During the Cretaceous, rolled-leaf beetles diversified in the Neotropics concurrently with Neotropical Zingiberales. Using a community of Costa Rican rolled-leaf beetles and their Zingiberales host plants as study system, we explored if previous geographic isolation precludes insects to expand their diets to exotic hosts. We recorded interactions between rolled-leaf beetles and native Zingiberales by combining DNA barcodes and field records for 7450 beetles feeding on 3202 host plants. To determine phylogenetic patterns of diet expansions, we set 20 field plots including five exotic Zingiberales, recording beetles feeding on these exotic hosts. In the laboratory, using both native and exotic host plants, we reared a subset of insect species that had expanded their diets to the exotic plants. The original plant-herbivore community comprised 24 beetle species feeding on 35 native hosts, representing 103 plant-herbivore interactions. After exotic host plant introduction, 20% of the beetle species expanded their diets to exotic Zingiberales. Insects only established on exotic hosts that belong to the same plant family as their native hosts. Laboratory experiments show that beetles are able to complete development on these novel hosts. In conclusion, rolled-leaf beetles are pre-adapted to expand their diets to novel host plants even after millions of years of geographic isolation.

Limited tolerance by insects to high temperatures across tropical elevational gradients and the implications of global warming for extinction.

The critical thermal maximum (CTmax), the temperature at which motor control is lost in animals, has the potential to determine if species will tolerate global warming. For insects, tolerance to high temperatures decreases with latitude, suggesting that similar patterns may exist along elevational gradients as well. This study explored how CTmax varies among species and populations of a group of diverse tropical insect herbivores, the rolled-leaf beetles, across both broad and narrow elevational gradients. Data from 6,948 field observations and 8,700 museum specimens were used to map the elevational distributions of rolled-leaf beetles on two mountains in Costa Rica. CTmax was determined for 1,252 individual beetles representing all populations across the gradients. Initial morphological identifications suggested a total of 26 species with populations at different elevations displaying contrasting upper thermal limits. However, compared with morphological identifications, DNA barcodes (cytochrome oxidase I) revealed significant cryptic species diversity. DNA barcodes identified 42 species and haplotypes across 11 species complexes. These 42 species displayed much narrower elevational distributions and values of CTmax than the 26 morphologically defined species. In general, species found at middle elevations and on mountaintops are less tolerant to high temperatures than species restricted to lowland habitats. Species with broad elevational distributions display high CTmax throughout their ranges. We found no significant phylogenetic signal in CTmax, geography, or elevational range. The narrow variance in CTmax values for most rolled-leaf beetles, especially high-elevation species, suggests that the risk of extinction of insects may be substantial under some projected rates of global warming.

A new species of bromeliad-feeding Cephaloleia Chevrolat (Coleoptera, Chrysomelidae, Cassidinae) from Costa Rica: evidence from DNA barcodes, larval and adult morphology and insect diets.

The Neotropical genus Cephaloleia Chevrolat (Coleoptera: Chrysomelidae: Cassidinae) includes 214 species distributed from the south of Mexico to Argentina. Cephaloleia beetles feed mostly on plants from the order Zingiberales. The interactions between Cephaloleia beetles and their Zingiberales host plants is proposed as one of the oldest and most conservative associations. Here we describe a new species of Cephaloleia (Cephaloleiakuprewiczae sp. n.) that feeds on two species of bromeliads (Pitcairniaarcuata and Pitcairniabrittoniana, Bromeliaceae: Pitcairnioideae). Cephaloleiakuprewiczae was previously described as Cephaloleiahistrionica. This study includes evidence from DNA barcodes (COI), larval and adult morphology and insect diets that separates Cephaloleiakuprewiczae from Cephaloleiahistrionica as a new species.

DNA barcodes for ecology, evolution, and conservation.

The use of DNA barcodes, which are short gene sequences taken from a standardized portion of the genome and used to identify species, is entering a new phase of application as more and more investigations employ these genetic markers to address questions relating to the ecology and evolution of natural systems. The suite of DNA barcode markers now applied to specific taxonomic groups of organisms are proving invaluable for understanding species boundaries, community ecology, functional trait evolution, trophic interactions, and the conservation of biodiversity. The application of next-generation sequencing (NGS) technology will greatly expand the versatility of DNA barcodes across the Tree of Life, habitats, and geographies as new methodologies are explored and developed.

The genus Cephaloleia Chevrolat, 1836 (Coleoptera, Chrysomelidae, Cassidinae).

The species of the Neotropical genus Cephaloleia Chevrolat, 1836 are revised. We present a key to the known larvae of Cephaloleia (8 species), a key to the 95 species known to occur in Mexico, Central America and the West Indies, and a key to the 138 species known to occur in South America. All identification keys were translated to Spanish. Descriptions for the 214 known species of Cephaloleia as well as illustrations for 212 species are presented. The following species are removed from Cephaloleia: C. bipartita Pic, 1926c is transferred to Hybosispa Weise, 1910; C. minasensis Pic, 1931 and C. viridis Pic, 1931 are transferred to Stenispa Baly, 1858. The following species are described as new: C. abdita sp. n. from Brazil; C. amba sp. n. from Colombia, Ecuador, and Peru; C. angustacollis sp. n. from Ecuador; C. brevis sp. n. from French Guiana; C. calathae sp. n. from Costa Rica; C. chica sp. n. from Peru; C. conforma sp. n. from Costa Rica; C. crenulata sp. n. from Ecuador; C. gemma sp. n. from Bolivia and Brazil; C. horvitzae sp. n. from French Guiana; C. interrupta sp. n. from Costa Rica; C. kressi sp. n. from Costa Rica; C. lenticula sp. n. from Ecuador, French Guiana, Peru, and Suriname; C. nana sp. n. from Ecuador; C. ochra sp. n. from Ecuador; C. stainesi sp. n. from Costa Rica; and C. susanae sp. n. from Brazil and Ecuador. Cephaloleia simoni Pic, 1934 is treated as Incertae sedis. The larvae of C. erichsonii Baly, 1858 and C. puncticollis Baly, 1885 are described and illustrated.

Tropical plant-herbivore networks: reconstructing species interactions using DNA barcodes.

Plants and their associated insect herbivores, represent more than 50% of all known species on earth. The first step in understanding the mechanisms generating and maintaining this important component of biodiversity is to identify plant-herbivore associations. In this study we determined insect-host plant associations for an entire guild of insect herbivores using plant DNA extracted from insect gut contents. Over two years, in a tropical rain forest in Costa Rica (La Selva Biological Station), we recorded the full diet breadth of rolled-leaf beetles, a group of herbivores that feed on plants in the order Zingiberales. Field observations were used to determine the accuracy of diet identifications using a three-locus DNA barcode (rbcL, trnH-psbA and ITS2). Using extraction techniques for ancient DNA, we obtained high-quality sequences for two of these loci from gut contents (rbcL and ITS2). Sequences were then compared to a comprehensive DNA barcode library of the Zingiberales. The rbcL locus identified host plants to family (success/sequence = 58.8%) and genus (success/sequence = 47%). For all Zingiberales except Heliconiaceae, ITS2 successfully identified host plants to genus (success/sequence = 67.1%) and species (success/sequence = 61.6%). Kindt's sampling estimates suggest that by collecting ca. four individuals representing each plant-herbivore interaction, 99% of all host associations included in this study can be identified to genus. For plants that amplified ITS2, 99% of the hosts can be identified to species after collecting at least four individuals representing each interaction. Our study demonstrates that host plant identifications at the species-level using DNA barcodes are feasible, cost-effective, and reliable, and that reconstructing plant-herbivore networks with these methods will become the standard for a detailed understanding of these interactions.

Parent-offspring conflicts, "optimal bad motherhood" and the "mother knows best" principles in insect herbivores colonizing novel host plants.

SPECIALIZATION OF INSECT HERBIVORES TO ONE OR A FEW HOST PLANTS STIMULATED THE DEVELOPMENT OF TWO HYPOTHESES ON HOW NATURAL SELECTION SHOULD SHAPE OVIPOSITION PREFERENCES: The "mother knows best" principle suggests that females prefer to oviposit on hosts that increase offspring survival. The "optimal bad motherhood" principle predicts that females prefer to oviposit on hosts that increase their own longevity. In insects colonizing novel host plants, current theory predicts that initial preferences of insect herbivores should be maladaptive, leading to ecological traps. Ecological trap theory does not take into account the fact that insect lineages frequently switch hosts at both ecological and evolutionary time scales. Therefore, the behavior of insect herbivores facing novel hosts is also shaped by natural selection. Using a study system in which four Cephaloleia beetles are currently expanding their diets from native to exotic plants in the order Zingiberales, we determined if initial oviposition preferences are conservative, maladaptive, or follow the patterns predicted by the "mother knows best" or the "optimal bad motherhood" principles. Interactions with novel hosts generated parent-offspring conflicts. Larval survival was higher on native hosts. However, adult generally lived longer on novel hosts. In Cephaloleia beetles, oviposition preferences are usually associated with hosts that increase larval survival, female fecundity, and population growth. In most cases, Cephaloleia oviposition preferences follow the expectations of the "mothers knows best" principle.

Jack of all trades masters novel host plants: positive genetic correlations in specialist and generalist insect herbivores expanding their diets to novel hosts.

One explanation for the widespread host specialization of insect herbivores is the 'Jack of all trades-master of none' principle, which states that genotypes with high performance on one host will perform poorly on other hosts. This principle predicts that cross-host correlation in performance of genotypes will be negative. In this study, we experimentally explored cross-host correlations and performance among families in four species (two generalist and two specialist) of leaf beetles (Cephaloleia spp.) that are currently expanding their diets from native to exotic plants. All four species displayed similar responses in body size, developmental rates and mortality rates to experimentally controlled diets. When raised on novel hosts, body size of larvae, pupae and adults were reduced. Development times were longer, and larval mortality was higher on novel hosts. Genotype × host-plant interactions were not detected for most traits. All significant cross-host correlations were positive. These results indicate very different ecological and evolutionary dynamics than those predicted by the 'Jack of all trades-master of none' principle.

Experimental demography and the vital rates of generalist and specialist insect herbivores on native and novel host plants.

1. Colonization success of species when confronted with novel environments is of interest in ecological, evolutionary and conservation contexts. Such events may represent the first step for ecological diversification. They also play an important role in adaptive divergence and speciation. 2. A species that is able to do well across a range of environments has a higher plasticity than one whose success is restricted to a single or few environments. The breadth of environments in which a species can succeed is ultimately determined by the full pattern of its vital rates in each environment. 3. Examples of organisms colonizing novel environments are insect herbivores expanding their diets to novel host plants. One expectation for insect herbivores is that species with specialized diets may display less plasticity when faced with novel hosts than generalist species. 4. We examine this hypothesis for two generalist and two specialist neotropical beetles (genus Cephaloleia: Chrysomelidae) currently expanding their diets from native to novel plants of the order Zingiberales. Using an experimental approach, we estimated changes in vital rates, life-history traits and lifetime fitness for each beetle species when feeding on native or novel host plants. 5. We did not find evidence supporting more plasticity for generalists than for specialists. Instead, we found similar patterns of survival and fecundity for all herbivores. Larvae survived worse on novel hosts; adults survived at least as well or better, but reproduced less on the novel host than on natives. 6. Some of the novel host plants represent challenging environments where population growth was negative. However, in four novel plant-herbivore interactions, instantaneous population growth rates were positive. 7. Positive instantaneous population growth rates during initial colonization of novel host plants suggest that both generalist and specialist Cephaloleia beetles may be pre-adapted to feed on some novel hosts. This plasticity in host use is a key factor for successful colonization of novel hosts. Future success or failure in the colonization of these novel hosts will depend on the demographic rates described in this research, natural selection and the evolutionary responses of life-history traits in novel environments.

Comparación de dos métodos para medir herbivoría: ¿Es la herbivoría en el Neotrópico mayor de lo que creemos? / Comparison between two methods to measure herbivory: is herbivory in the Neotropics more severe than we thought?

The quantity of plant tissue consumed by herbivores can be recorded 1) by measuring herbivory in previously marked leaves or 2) by performing punctual measures, i.e. selecting leaves at random to measure the tissue absent in each leaf. Punctual measurements are frequently used because they are a faster method to estimate herbivory. However, punctual measures do not include totally consumed leaves, therefore they underestimate the actual herbivory rates. In three species of understory shrubs (Palicourea sp. P.angustifolia and P.ovalis: Rubiaceae) herbivory was measured using punctual measures and marking young leaves in order to determine the degree of herbivory underestimation by punctual measurements. Punctual measurements underestimated herbivory up to three times in the species with a high number of totally consumed leaves. In the species with a lower number of totally consumed leaves, herbivory rates recorded using both methods were similar. These results suggest that herbivory in neotropical forests could be more severe than what is currently suggested.

La cantidad de tejido vegetal consumido por los herbívoros puede ser registrada: 1) midiendo en hojas previamente marcadas el área consumida a lo largo del periodo de expansión de las hojas ó 2) realizando mediciones puntuales, i.e. registrando el área ausente en hojas seleccionadas al azar. El método de mediciones puntuales se usa frecuentemente para medir herbivoría, pues permite realizar las mediciones en un tiempo más corto. Sin embargo, las mediciones puntuales pueden subestimar la herbivoría al no incluir las hojas que fueron totalmente consumidas. Para determinar en que grado las mediciones puntuales subestiman la herbivoría, en tres especies de arbustos de sotobosque (Palicourea sp. P. angustifolia y P. ovalis: Rubiaceae) fueron realizadas mediciones puntuales y estimados de herbivoría marcando hojas jóvenes. El método de mediciones puntuales subestimó tres veces las tasas de herbivoría en las especies donde hubo un mayor número de hojas totalmente consumidas. En la especie con menor número de hojas totalmente consumidas, los resultados obtenidos mediante los dos métodos fueron similares. Estos resultados sugieren que posible que la herbivoría en los bosques neotropicales sea mas intensa de lo que sugieren los estimados actuales

[Comparison between two methods to measure herbivory. Is herbivory in the neotropics more severe than we thought?]. / Comparación de dos métodos para medir herbivoría. Es la herbivoría en el neotrópico mayor de lo que creemos?

The quantity of plant tissue consumed by herbivores can be recorded 1) by measuring herbivory in previously marked leaves or 2) by performing punctual measures. i.e. selecting leaves at random to measure the tissue absent in each leaf Punctual measurements are frequently used because they are a faster method to estimate herbivory. However, punctual measures do not include totally consumed leaves. therefore they underestimate the actual herbivory rates. In three species of understory shrubs (Palicourea sp. P. angustifolia and P. oralis: Rubiaccae) herbivory was measured using punctual measures and marking young leaves in order to determine the degree of herbivory underestimation by punctual measurements. Punctual measurements underestimated herbivory up to three times in the species with a high number of totally consumed leaves. In the species with a lower number of totally consumed leaves, herbivory rates recorded using both methods were similar. These results suggest that herbivory in neotropical forests could be more severe than what is currently suggested.