When cheating turns into a stabilizing mechanism of plant-pollinator communities.

Mutualistic interactions, such as plant-mycorrhizal or plant-pollinator interactions, are widespread in ecological communities and frequently exploited by cheaters, species that profit from interactions without providing benefits in return. Cheating usually negatively affects the fitness of the individuals that are cheated on, but the effects of cheating at the community level remains poorly understood. Here, we describe 2 different kinds of cheating in mutualistic networks and use a generalized Lotka-Volterra model to show that they have very different consequences for the persistence of the community. Conservative cheating, where a species cheats on its mutualistic partners to escape the cost of mutualistic interactions, negatively affects community persistence. In contrast, innovative cheating occurs with species with whom legitimate interactions are not possible, because of a physiological or morphological barrier. Innovative cheating can enhance community persistence under some conditions: when cheaters have few mutualistic partners, cheat at low or intermediate frequency and the cost associated with mutualism is not too high. Under these conditions, the negative effects of cheating on partner persistence are overcompensated at the community level by the positive feedback loops that arise in diverse mutualistic communities. Using an empirical dataset of plant-bird interactions (hummingbirds and flowerpiercers), we found that observed cheating patterns are highly consistent with theoretical cheating patterns found to increase community persistence. This result suggests that the cheating patterns observed in nature could contribute to promote species coexistence in mutualistic communities, instead of necessarily destabilizing them.

High levels of phenological asynchrony between specialized pollinators and plants with short flowering phases.

Species phenology plays a key role in determining mutualistic interactions, such as those between plants and pollinators. Notably, temporal synchrony shapes the patterns of interactions by influencing the probability of encounters between interacting partners; thus, species phenology greatly contributes to structuring ecological communities. In these communities, specialized species are expected to show a high level of synchrony with their partners; however, the relationship between species phenology and specialization remains largely unexplored. In three localities in the tropical mountains of Costa Rica, we quantified the level of phenological synchrony in plant-pollinator networks and tested whether phenological synchrony is associated with the degree of pollinator specialization on plant partners. We also tested the relationship between pollinator specialization and the length of the flowering phase of the visited plants. Across all three studied networks, our results show a strong asynchrony between interacting plant and pollinator species. We also found that more specialized pollinators were more asynchronous with their plant partners and, moreover, that specialized pollinators preferably visited plant species with shorter flowering phases compared to generalized pollinators. These patterns suggest that specialized pollinators may be more vulnerable to mutualistic disruptions because they depend primarily on short-lived resources and have a high risk of phenological mismatch. This discovery has important consequences for specialized species' potential to survive and adapt to changes in the phenology of their interacting partners, which is highly relevant in a time characterized by changing climates and associated shifts in species phenology.

Scorpion maintenance in captivity for venom extraction in Costa Rica / Experiencias del mantenimiento en cautiverio de escorpiones en Costa Rica para la extracción de veneno

Abstract:Approximately 2 000 scorpion species can be found around the world; although few species are considered "harmful" to human beings, a high number of scorpionism cases are reported all over the world. The elaboration of anti-scorpion sera requires the establishment of an animal collection maintained in captivity for venom extraction purposes. The Clodomiro Picado Institute (ICP, for its acronym in Spanish), poses a vast trajectory in manufacturing snakebite antivenoms, and starts a scorpion collection in 2005 for this purpose. In total, 2 043 scorpions were classified in 11 species and collected during a seven-year period using a black-light flashlight and an intensive seeking methodology. The scorpions were collected from several localities of the Pacific and the Caribbean versants of Costa Rica. The venom extraction was performed by applying electrostimulation; the collected venom was characterized by total protein content in addition to median lethal doses. Centruroidesbicolor showed higher amounts of venom yield, total protein content and more lethal dose, all of which were correlated with its body mass. The techniques used to keep scorpions in captivity allowed the animals to live several years. Longevity analysis showed significant differences among scorpion genera (H= 353.80; df= 3; P < 0.0001); moreover, the genus Didymocentrus lived longer with an average of 4.46 years. One key factor of its longevity was that it did not go through venom extraction processes. Additionally, a high survival rate of Tityuspachyurus born in captivity, compared to other species within the same genus, was observed (H= 94.32; df= 3; P < 0.0001). This characteristic should be taken into consideration, when programs of reproduction in captivity are designed. In conclusion, the maintenance of a scorpion collection was efficient for venom extraction purposes and a longer life expectancy of the animals. Moreover, there is a scarcity on publications regarding scorpion maintenance in captivity for venom extraction purposes; therefore, a deeper research in aspects such as reproduction, death causes and feeding behaviors is required. Rev. Biol. Trop. 64 (3): 1019-1027. Epub 2016 September 01.

ResumenExisten alrededor de 2 000 especies de escorpiones en el mundo y a pesar de que muy pocas de ellas son consideradas peligrosas para el ser humano se presentan muchos casos de escorpionismo alrededor del mundo. La elaboración de suero antiescorpiónico requiere en primera instancia del establecimiento de una colección en cautiverio para la extracción del veneno, razón por la cual el Instituto Clodomiro Picado (ICP), con una amplia trayectoria en la elaboración de suero antiofídico, inicia en el 2005 una colección para dicho fin. En total 2 043 escorpiones clasificados en 11 especies fueron recolectados en un periodo de siete años mediante búsqueda intensiva con luz ultravioleta en varias localidades de la vertiente Pacífica, así como la vertiente Atlántica de Costa Rica. Las extracciones de veneno se realizaron con electro-estimulación, y el veneno recolectado fue caracterizado por el contenido total de proteínas, además se realizaron pruebas de letalidad, siendo Centruroides bicolor el más letal y el que presento los valores más altos en cantidad de veneno y proteínas totales lo cual es consecuente con su masa corporal. Las técnicas empleadas en el mantenimiento en cautiverio de los escorpiones permitieron que los escorpiones vivieran varios años, en un análisis de la longevidad se obtuvieron diferencias significativas entre los géneros (H = 353.80; g.l = 3; P < 0.0001), siendo el género Didymocentrus el más longevo con un promedio de 4.46 años, un factor importante de su longevidad es el hecho de no haber formado parte del proceso de extracción. También se pudo evidenciar una alta supervivencia de crías nacidas en cautiverio de la especie Tityus pachyurus con respecto a las otras especies del mismo género (H = 94.32; g.l = 3; P < 0.0001), resultado que puede ser tomado en cuenta para reproducir esta especie en cautiverio. El mantenimiento de la colección de escorpiones fue eficiente para el proceso de extracción de veneno y para una supervivencia prolongada de los animales. Existen muy pocas publicaciones en lo que se refiere al mantenimiento de escorpiones en cautiverio para la extracción de veneno por lo que se requiere de una investigación más profunda en aspectos como la reproducción, las causas de muerte y la alimentación.

Scorpions maintenance in captivity for venom extraction purposes in Costa Rica.

Approximately 2 000 scorpion species can be found around the world; although few species are considered "harmful" to human beings, a high number of scorpionism cases are reported all over the world. The elaboration of anti-scorpion sera requires the establishment of an animal collection maintained in captivity for venom extraction purposes. The Clodomiro Picado Institute (ICP, for its acronym in Spanish), poses a vast trajectory in manufacturing snakebite antivenoms, and starts a scorpion collection in 2005 for this purpose. In total, 2 043 scorpions were classified in 11 species and collected during a seven-year period using a black-light flashlight and an intensive seeking methodology. The scorpions were collected from several localities of the Pacific and the Caribbean versants of Costa Rica. The venom extraction was performed by applying electrostimulation; the collected venom was characterized by total protein content in addition to median lethal doses. Centruroides bicolor showed higher amounts of venom yield, total protein content and more lethal dose, all of which were correlated with its body mass. The techniques used to keep scorpions in captivity allowed the animals to live several years. Longevity analysis showed significant differences among scorpion genera (H= 353.80; df= 3; P < 0.0001); moreover, the genus Didymocentrus lived longer with an average of 4.46 years. One key factor of its longevity was that it did not go through venom extraction processes. Additionally, a high survival rate of Tityus pachyurus born in captivity, compared to other species within the same genus, was observed (H= 94.32; df= 3; P < 0.0001). This characteristic should be taken into consideration, when programs of reproduction in captivity are designed. In conclusion, the maintenance of a scorpion collection was efficient for venom extraction purposes and a longer life expectancy of the animals. Moreover, there is a scarcity on publications regarding scorpion maintenance in captivity for venom extraction purposes; therefore, a deeper research in aspects such as reproduction, death causes and feeding behaviors is required.