Tissue-specific energetics of the invasive Asian shore crab Hemigrapsus sanguineus throughout its range and through time.

Organisms with broad geographic distributions that inhabit seasonal environments often demonstrate characteristics that differ spatially and temporally. It has been hypothesized that these variable characteristics may play important roles in the success of invasive species. Further, physiological characteristics should be closely linked to individual energetic strategies, which can also vary spatially and temporally. We use tissue-specific energy density and total energy content to examine energy allocation strategies in the invasive Asian shore crab Hemigrapsus sanguineus across seasons and throughout its North American invasive range. We show that tissue energy density and total tissue energy vary considerably with location and season. Energetic strategies are consistent with an expanding northern range edge and a static southern range edge. Our results also provide insight into patterns that occur broadly across phylogeny, including reduced growth rates with body size and seasonal reproductive patterns. This study demonstrates the utility of tissue-specific energetics as an ecophysiological tool for understanding the energetic strategies of invasive (and other) species throughout their ranges and across seasons.