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Echinoderms, positioned taxonomically at the base of deuterostomes, provide an important system for the study of the evolution of the immune system. However, there is little known about the cellular components and genes associated with echinoderm immunity. The 2013–2014 sea star wasting disease outbreak is an emergent, rapidly spreading disease, which has led to large population declines of asteroids in the North American Pacific. While evidence suggests that the signs of this disease, twisting arms and lesions, may be attributed to a viral infection, the host response to infection is still poorly understood. In order to examine transcriptional responses of the sea star Pycnopodia helianthoides to sea star wasting disease, we injected a viral sized fraction (0.2 μm) homogenate prepared from symptomatic P. helianthoides into apparently healthy stars. Nine days following injection, when all stars were displaying signs of the disease, specimens were sacrificed and coelomocytes were extracted for RNA-seq analyses. A number of immune genes, including those involved in Toll signaling pathways, complement cascade, melanization response, and arachidonic acid metabolism, were differentially expressed. Furthermore, genes involved in nervous system processes and tissue remodeling were also differentially expressed, pointing to transcriptional changes underlying the signs of sea star wasting disease. The genomic resources presented here not only increase understanding of host response to sea star wasting disease, but also provide greater insight into the mechanisms underlying immune function in echinoderms.

Harvest of wild animals and plants is pervasive, exerts ecological and evolutionary pressure on populations, and is known to drive rapid changes in organismal traits. Although the factors that lead to rapid trait changes have received increased attention, the ecological consequences of harvest‐driven trait changes are less appreciated. We review recent evidence that harvest‐driven trait changes can affect community and ecosystem processes. Growing experimental evidence, modeling studies, and field observations have revealed that common responses to harvest include changes in life‐history and behavioral traits, which have the potential to reshape the ecology of harvested systems. On the basis of existing evidence, we propose a set of general mechanisms that link harvest‐driven trait changes to ecological processes, including trophic cascades, nutrient dynamics, keystone interactions, ecosystem stability, and habitat use. Managing harvested ecosystems sustainably may require strategies that account for harvest‐driven trait changes. We recommend that trait changes be monitored closely as part of ecosystem‐based management plans, especially in cases where targeted traits are known to affect important aspects of ecosystem function.

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