Population sizes of invasive species are commonly characterized by boom-bust dynamics, and self-limitation via resource depletion is posited as one factor leading to these boom-bust changes in population size. Yet, while this phenomenon is well-documented in plants, few studies have demonstrated that self-limitation is possible for invasive animal species, especially those that are mobile. Here we examined the invasive Asian shore crab Hemigrapsus sanguineus, a species that reached very high abundances throughout invaded regions of North America, but has recently declined in many of these same regions. We examined the relationship between diet, energy storage, reproduction, and growth in crabs collected from the New Hampshire coast. We show that energy storage and reproduction both increase with diet quality, while growth declines with diet quality. These results suggest that self-limitation may be a contributing factor to the recent declines of H. sanguineus at sites where this invader was once much more abundant. Further, these results suggest a diet-associated tradeoff in energy allocation to different vital rates, with a focus on reproduction when high quality resources are consumed, and a focus instead on growth when poor quality resources are consumed.

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Although Cossus certterettsis has only recently been discovered, it must have existed for many years in the vicinity of center, N. Y., its present home. More tban trvelr,e years ago, rvhile dding in a central R. R. coach, I noticed certain species oi Poplar, the central shoot of r'vl.rich had perished from canses then ulknoln ; later, 1'hile on an Entomological tour near the same place, I tbund a group of the Polt.tllts tremu/otrles rvhich were similarly affected, as \yere also many other trees of the same species in the vicinitl'. on closer inspectiou many perforations rvere found in the trunks of these trees, some of $'hich were of recent origin, but nothing then rvas discoYered to explain the cause and consequent unhealthy condition of this species of timber I several tirnes each year afterwards this group of P.rplars rvas examined, but nothing definite rvas learned until during the rnonth of Jul_v, r876, rvhen a brittle pupa-case n'as found protruding from one of these openings. 'l'his gave a clue rvhich revealed the trLre nature of the destroyer of this woody grou'th. On the roth of J:ute, t877, a lresh pupa-case \vas discovercd, removed and examined, but the Ca'rszs .ould no1 be found, altho'gh probab.ly resting r.rpon thc trce at that time.