Arthropod outbreaks, stressors, and sublethal stress

Outbreaks are characterized by a sudden increase in population density of a given species, and are recognized as an important phenomenon in both natural and artificial systems. Climate and anthropogenic stressors are the main abiotic drivers of outbreaks directly affecting arthropod populations, or influencing them indirectly through their heterospecifics and resources (e.g., host plants). Both are dose- or intensity-dependent and mainly sublethal when outbreaks are considered. Thus, sublethal stimulation or hormesis is an important phenomenon to consider. However, its study is restricted to a few (agricultural) settings and neglects key complexities of biological systems, including arthropods as an ecocosm of symbionts, the role of arthropod interactions, and the co-occurrence of multiple stressors. Therefore, more research is required to tackle the complexities of biological systems.