Disentangling genetic, plastic and social learning drivers of sex-specific foraging behaviour in Trinidadian guppies (Poecilia reticulata).

Evolutionary biologists have long been interested in parsing out the roles of genetics, plasticity and their interaction on adaptive trait divergence. Since males and females often have different ecological and reproductive roles, separating how their traits are shaped by interactions between their genes and environment is necessary and important. Here, we disentangle the sex-specific effects of genetic divergence, developmental plasticity, social learning and contextual plasticity on foraging behaviour in Trinidadian guppies (Poecilia reticulata) adapted to high- or low-predation habitats. We reared second-generation siblings from both predation regimes with or without predator chemical cues, and with adult conspecifics from either high- or low-predation habitats. We then quantified their foraging behaviour in water with and without predator chemical cues. We found that high-predation guppies forage more efficiently than low-predation guppies, but this behavioural difference is context-dependent and shaped by different mechanisms in males and females. Higher foraging efficiency in high-predation females is largely genetically determined, and to a smaller extent socially learned from conspecifics. However, in high-predation males, higher foraging efficiency is plastically induced by predator cues during development. Our study demonstrates sex-specific differences in genetic versus plastic responses in foraging behaviour, a trait of significance in organismal fitness and ecosystem dynamics.

Evolutionary divergence of developmental plasticity and learning of mating tactics in Trinidadian guppies.

Behavioural plasticity is a major driver in the early stages of adaptation, but its effects in mediating evolution remain elusive because behavioural plasticity itself can evolve. In this study, we investigated how male Trinidadian guppies (Poecilia reticulata) adapted to different predation regimes diverged in behavioural plasticity of their mating tactic. We reared F2 juveniles of high- or low-predation population origins with different combinations of social and predator cues and assayed their mating behaviour upon sexual maturity. High-predation males learned their mating tactic from conspecific adults as juveniles, while low-predation males did not. High-predation males increased courtship when exposed to chemical predator cues during development; low-predation males decreased courtship in response to immediate chemical predator cues, but only when they were not exposed to such cues during development. Behavioural changes induced by predator cues were associated with developmental plasticity in brain morphology, but changes acquired through social learning were not. We thus show that guppy populations diverged in their response to social and ecological cues during development, and correlational evidence suggests that different cues can shape the same behaviour via different neural mechanisms. Our study demonstrates that behavioural plasticity, both environmentally induced and socially learnt, evolves rapidly and shapes adaptation when organisms colonize ecologically divergent habitats.

La plasticidad conductual es un factor importante en las primeras fases de adaptación, pero se conocen poco sus efectos sobre la evolución porque la plasticidad conductual en sí puede evolucionar. En este estudio, investigamos cómo los machos del guppy de Trinidad (Poecilia reticulata) adaptados a regímenes de depredación diferentes, han divergido en la plasticidad de su táctica de apareamiento. Criamos juveniles provenientes de poblaciones de alta y baja depredación hasta segunda generación (F2) bajo diferentes combinaciones de señales sociales y de depredación, y evaluamos su comportamiento de apareamiento al llegar a la madurez sexual. Los machos de alta depredación aprendieron su táctica de apareamiento de sus conespecíficos adultos, mientras que los machos de baja depredación no. Los machos de alta depredación aumentaron su cortejo al ser expuestos a señales de depredadores durante su desarrollo; mientras que los machos de baja depredación redujeron su cortejo en respuesta a señales inmediatas de depredadores, pero tan solo cuando no fueron expuestos a tales señales durante el desarrollo. Los cambios conductuales observados inducidos por las señales de depredación están asociados con una plasticidad en el desarrollo de la morfología cerebral, pero los cambios adquiridos por aprendizaje social no. En conclusión, demostramos que las poblaciones de guppy han divergido en su respuesta a señales sociales y ecológicas durante su desarrollo, y mostramos evidencia correlativa que sugiere que diferentes tipos de señales pueden influenciar el mismo comportamiento via mecanismos neuronales diferentes. Nuestro estudio muestra que la plasticidad conductual, tanto inducida por el medio ambiente combo aprendida socialmente, evoluciona rápidamente e influencia la adaptación durante la colonización de hábitats ecológicamente divergentes.

Hanging under the ledge: synergistic consequences of UVA and UVB radiation on scyphozoan polyp reproduction and health.

Overexposure to ultraviolet radiation (UVR) emitted by the sun can damage and kill living cells in animals, plants, and microorganisms. In aquatic environments, UVR can penetrate nearly 47 m into the water column, severely impacting many marine organisms. Jellyfish are often considered resilient to environmental stressors, potentially explaining their success in environmentally disturbed areas, but the extent of their resilience to UVR is not well known. Here, we tested resiliency to UVR by exposing benthic polyps of the moon jellyfish, Aurelia sp., to UVA and UVB-the two types of UVR that reach Earth's surface-both separately and in combination. We quantified asexual reproduction rates and polyp attachment to hard substrate, in addition to qualitative observations of polyp health. There were no differences in asexual reproduction rates between polyps exposed to isolated UVA and polyps that received no UVR. Polyps reproduced when exposed to short term (∼7-9 days) isolated UVB, but long-term exposure limited reproduction and polyp attachment to the substrate. When exposed to both UVA and UVB, polyps were unable to feed and unable to remain attached to the substrate, did not reproduce, and ultimately, experienced 100% mortality within 20 days. Although many studies only examine the effects of UVB, the combination of UVA and UVB here resulted in greater negative impacts than either form of UVR in isolation. Therefore, studies that only examine effects of UVB potentially underestimate environmentally relevant effects of UVR. These results suggest that polyps are unsuccessful under UVR stress, so the planula larval stage must settle in low-UVR environments to establish the success of the polyp stage.

Isolation and Whole-Genome Sequencing of Four Antibiotic-Producing Pseudomonas Strains.

Here, we report the isolation, whole-genome sequencing, and annotation of four novel Pseudomonas isolates. We also evaluate the biosynthetic potential of each genome.