Assassin bugs enhance prey capture with a sticky resin.

Tool-use in animals is a complex and rare phenomenon, particularly in insects. Tool-use in assassin bugs has been suggested as several species apply adhesive plant resins to their body, which has been hypothesized to function in enhancing prey capture. Here, we staged predatory interactions of resin-deprived and resin-equipped assassin bugs (Gorareduvius sp.) and discovered that applying resin as a tool conveys a clear predatory advantage to the assassin bugs. Gorareduvius sp. can thus be considered a tool-user, and since this behaviour was present in all individuals, including newly hatched nymphs, tool-use can be considered to be stereotyped. Our study, along with others, suggests that, when compared with other insects, tool-use is disproportionately common within the assassin bugs.

A way forward for biodiversity conservation: high-quality landscapes.

We are losing biodiversity quickly, not simply because of development but due to poor spatial planning. Recent findings propose thoughtful configurations and management of human-modified landscapes to protect biodiversity while allowing food production. This opens up a range of feasible actions in the conservation agenda, which overlap with food sovereignty initiatives.

Investigación para la toma de decisiones de manejo en áreas marinas protegidas como la Isla del Coco, Costa Rica

Introducción: En la práctica de la conservación biológica, a menudo se necesita de información científica para guiar las decisiones de manejo, pero esta información es especialmente escasa en áreas marinas protegidas. Las áreas marinas protegidas enfrentan el desafío de proteger especies pelágicas que se desplazan entre zonas protegidas de distintos países y zonas de pesca. En general, un obstáculo para generar la información que requieren las áreas protegidas es que comúnmente existe una disociación entre el sector académico y el sector de gestión, los cuales difieren en sus objetivos, forma de trabajo, y sistemas de recompensa. Esta situación se ve agravada en áreas marinas protegidas que se encuentran lejos de la costa, ya que los costos económicos y logísticos para realizar investigación son muy elevados. Objetivos: Utilizar el contexto del Parque Nacional Isla del Coco para ilustrar dificultades al momento de definir y recopilar la información necesaria para la gestión, y proponer posibles soluciones a este problema. Resultados: Para producir la información relevante, creemos que es necesario tomar en cuenta los siguientes aspectos: i) distinguir entre información biológica e información requerida para la gestión, ii) generar información sobre las amenazas a las especies, aún en ausencia de datos sobre las especies, iii) direccionar los planes de monitoreo, y iv) establecer una coordinación entre dos grupos de personas: las que frecuentan el área y las que están lejos del área en centros académicos. Además, debido a la naturaleza de la información que se requiere, y a la remotidad del sitio, se necesita de una articulación entre sectores (incluido el sector pesquero) para generar los datos. Conclusión: Parece indispensablelograr esta articulación entre sectores, lo cual conlleva grandes retos. Aún así, esta opción parece ser más viable desde el punto de vista logístico y económico que el intentar generar esta información desde una plataforma exclusivamente académica. Además, dicha articulación parece ser la única forma de generar información que es requerida para regular el manejo pesquero; por ejemplo la caracterización adecuada del esfuerzo de captura y de la biomasa extraída.

Introduction: Scientific information is often needed to guide management decisions, but marine protected areas usually lack such information. Further, these protected areas face the challenge of protecting highly-mobile pelagic species that move between protected areas in different countries and across fishing zones. In general, the dissociation that commonly exists between academic and conservation groups, which work under different objectives and reward systems, serves as an obstacle for producing the information that is needed by wildlife managers. This limitation is further enhanced in oceanic islands, such as Isla del Coco because of their mere remoteness, a condition that dramatically increases the economic and operational costs for doing research. Objective: To illustrate the challenge of generating useful scientific information for conservation decision making in protected areas, using Isla del Coco National Park in Costa Rica as a case study, and to propose possible solutions. Results: In order to produce the scientific information that these areas require, it is necessary to: i) distinguish between biologically relevant information, and information required for decision-making, ii) generate information about the threats to biodiversity, even in the absence of information about the species themselves, iii) establish clear goals and objectives for monitoring plans, and iv) build strong links between two types of groups: those that work from mainland and those that operate offshore; this includes working alongside fishing vessels. Conclusions: It will be a great challenge to articulate such relationships between groups, but this option seems more viable (in terms of associated logistic and economical costs) than attempting to collect the required data from an isolated academic platform. Also, this articulation appears to be the only way of generating information that is crucial for stock management, such as the accurate characterization of the fishing activity.

A possible role of decorations in spiderwebs as protection devices that distract predators

Several functions have been proposed for silk decorations (i.e., stabilimenta) in spiderwebs. One hypothesis is that web decorations protect spiders from predators, either by concealing the spiders, physically shielding them, or by deflecting predatory attacks. This study uses data gathered in opportunistic manner when studying the behavior of Stenolemus giraffa, an assassin bug that preys almost exclusively on web-building spiders. Stenolemus giraffa approach orb spiders on foot, and usually capture the spiders at the hub region of the web. When pursuing spiders, S. giraffa routinely tap the web with their antennae, and also tap the spiders prior to attacking them. The observations available from this study suggest that S. giraffa got "distracted" momentarily by the decorations in the webs of Purumitra sp. (Uloboridae) and Argiope katherina (Araneidae). In some instances, the assassin bugs tapped these structures for several seconds or minutes instead of tapping the adjacent spiders. In interactions with A. katherina, S. giraffa was more successful at capturing the spiders when the webs lacked decorations; however, sample sizes are small (this could not be tested for Purumitra sp. because only one web lacked decorations). Finally, some of the spiders detected S. giraffa tapping the decorations or that had begun tapping the spiders and that had interrupted this behavior to tap the decorations. The data available suggest that, for S. giraffa, the decorations in these webs interfered with the process of locating the spiders. If further experiments corroborate this idea, this information would be in accord with Hingston's (1927) hypothesis that web decorations can confuse spider predators.

Muchas arañas agregan a sus telas estructuras de seda, detritos, u otros, que son conocidas como "estabilimentos" o "decoraciones". Varias funciones han sido propuestas para estas estructuras. Una de las hipótesis plantea que las decoraciones protegen a las arañas de los depredadores, ya sea porque ocultan a las arañas, o porque funcionan como una barrera física que separa al depredador de la araña, o porque desvían los ataques de los depredadores. En este estudio, se utilizan datos que fueron tomados de manera oportunista mientras se estudiaba el comportamiento del chinche asesino Stenolemus giraffa, un insecto que se alimenta casi exclusivamente de arañas que hacen tela. Stenolemus giraffa ataca a las arañas en el meollo de la tela, y se acerca hasta estas caminando. Stenolemus giraffa usualmente "toquetea" a las arañas con sus antenas (comúnmente sin hacer contacto con la araña) antes de atacarlas. Las observaciones de este estudio sugieren que S. giraffa se distrajo de forma momentánea con las decoraciones en las telas de Purumitra sp. (Uloboridae) y Argiope katherina (Araneidae). En algunas ocasiones, los chinches toquetearon con sus antenas estas estructuras por algunos segundos o incluso minutos, en vez de toquetear a las arañas que estaban adyacentes a estas. En interacciones con A. katherina, S. giraffa capturó en mayor proporción a las arañas que se encontraban en telas sin decoraciones; sin embargo, el tamaño de la muestra es pequeño. No se pudo realizar una comparación similar para Purumitra sp., ya que todas las telas, excepto una, tenían decoraciones. Algunas de las arañas detectaron a los chinches cuando estos estaban toqueteando las decoraciones, o después de que hubieran toqueteado a las arañas e interrumpieran este comportamiento para toquetear las decoraciones. Dichas observaciones sugieren que las decoraciones en estas telas interfirieron con el proceso de S. giraffa de localizar a las arañas. Si esto se corrobora mediante futuros experimentos, esta información apoyaría la idea de Hingston (1927) de que las decoraciones en las telas funcionan para confundir a los depredadores de arañas.

Extraction of hermit crabs from their shells by white-faced capuchin monkeys (Cebus capucinus).

We observed two capuchin monkeys (Cebus capucinus) feeding on hermit crabs (Coenobita compressus) on the coast, and the tactics they used to extract this well-protected prey. The observations took place during the dry season at Playa Escondida beach, Puntarenas, Costa Rica. The capuchins descended from trees at the back edge of the beach to capture passing hermit crabs. Both capuchins extracted the hermit crabs from their protective shells by holding the shell with one hand and pulling the crab out with the other. Even though this was accomplished within seconds, the extraction of hermit crabs from their shells did not appear to be a straightforward task. Once the capuchins succeeded in pulling the crabs out of their shells, they consumed the soft abdomen and discarded the rest of the crab's body. To our knowledge, the consumption of hermit crabs has not been previously reported for any capuchin monkey (Cebus or Sapajus). Our observations provide a new example of extractive foraging by capuchins, and thus an additional natural context for which fine motor skills (which are highly developed in capuchins) are necessary.

Fine-scale analysis of an assassin bug's behaviour: predatory strategies to bypass the sensory systems of prey.

Some predators sidestep environments that render them conspicuous to the sensory systems of prey. However, these challenging environments are unavoidable for certain predators. Stenolemus giraffa is an assassin bug that feeds on web-building spiders; the web is the environment in which this predator finds its prey, but it also forms part of its preys' sophisticated sensory apparatus, blurring the distinction between environment and sensory systems. Stenolemus giraffa needs to break threads in the web that obstruct its path to the spiders, and such vibrations can alert the spiders. Using laser vibrometry, this study demonstrates how S. giraffa avoids alerting the spiders during its approach. When breaking threads, S. giraffa attenuates the vibrations produced by holding on to the loose ends of the broken thread and causing them to sag prior to release. In addition, S. giraffa releases the loose ends of a broken thread one at a time (after several seconds or minutes) and in this way spaces out the production of vibrations in time. Furthermore, S. giraffa was found to maximally reduce the amplitude of vibrations when breaking threads that are prone to produce louder vibrations. Finally, S. giraffa preferred to break threads in the presence of wind, suggesting that this araneophagic insect exploits environmental noise that temporarily impairs the spiders' ability to detect vibrations. The predatory behaviour of S. giraffa seems to be adaptated in intricate manner for bypassing the sophisticated sensory systems of web-building spiders. These findings illustrate how the physical characteristics of the environment, along with the sensory systems of prey can shape the predatory strategies of animals.

Prospective thinking in a mustelid? Eira barbara (Carnivora) cache unripe fruits to consume them once ripened.

The ability of nonhuman animals to project individual actions into the future is a hotly debated topic. We describe the caching behaviour of tayras (Eira barbara) based on direct observations in the field, pictures from camera traps and radio telemetry, providing evidence that these mustelids pick and cache unripe fruit for future consumption. This is the first reported case of harvesting of unripe fruits by a nonhuman animal. Ripe fruits are readily taken by a variety of animals, and tayras might benefit by securing a food source before strong competition takes place. Unripe climacteric fruits need to be harvested when mature to ensure that they continue their ripening process, and tayras accurately choose mature stages of these fruits for caching. Tayras cache both native (sapote) and non-native (plantain) fruits that differ in morphology and developmental timeframes, showing sophisticated cognitive ability that might involve highly developed learning abilities and/or prospective thinking.