Working less to gain more: when breeding quality relates to foraging efficiency

Abstract

In animal populations, a minority of individuals consistently achieves the highest breeding success and therefore contributes the most recruits to future generations. On average, foraging performance is important in determining breeding success at the population level, but evidence is scarce to show that more successful breeders (better breeders) forage differently than less successful ones (poorer breeders). To test this hypothesis, we used a 10-year, three-colony, individual-based longitudinal data set on breeding success and foraging parameters of a long-lived bird, the Adélie Penguin, Pygoscelis adeliae. Better breeders foraged more efficiently than poorer breeders under harsh environmental conditions and when offspring needs were higher, therefore gaining higher net energy profit to be allocated to reproduction and survival. These results imply that adverse "extrinsic" conditions might select breeding individuals on the basis of their foraging ability. Adélie Penguins show sufficient phenotypic plasticity that at least a portion of the population is capable of surviving and successfully reproducing despite extreme variability in their physical and biological environment, variability that is likely to be associated with climate change and, ultimately, with the species' evolution. This study is the first to demonstrate the importance of "extrinsic" conditions (in terms of environmental conditions and offspring needs) on the relationship between foraging behavior and individual quality.

Trophic cascades in the western Ross Sea, Antarctica: revisited

“…Our research on the foraging of Adélie penguins from Ross Island, using tags that identify geographic position and diving activity (e.g. Lescroël et al 2010, 2014, Ford et al 2014, provides evidence supporting predator-driven tropho-dynamics -facilitated by extensive diet overlap among penguins and cetaceans (Ainley et al 2006, Ballard et al 2012) -though they likely forage differently (see Discussion). By investigating phytoplankton biomass and penguin prey abundance where penguins do and do not forage, we might better understand the spatial and temporal components of the trophic interactions that occur within the pelagic food web.…”

“…Diving data were processed using the program Divesum (v.7.5.5; G. Ballard unpublished software). Divesum classified dives into 3 types: foraging, exploratory, and other by parameterizing several components of each dive (Chappell et al 1993, Schreer et al 2001, Lescroël et al 2010, Ford et al 2014: (1) dive duration (s); (2) maximum depth (m); (3) depth change rate (m s −1 ; calculated as a running average for each 5 s block of the dive duration) in 2 categories: slow, i.e. < 1 m s −1 , or fast, i.e.…”

Seabirds and climate: knowledge, pitfalls, and opportunities

“…In addition, the best predictive models rely on large amounts of high quality demographic data, and sophisticated quantitative approaches. Yet, generating general predictions is difficult because of the inherent ecological variability amongst species, ecosystems (Chambers et al, 2011) and even among individuals (Lescroël et al, 2009(Lescroël et al, , 2010Lescroel et al, 2014) and populations (Tavecchia et al, 2008;Dias et al, 2010). These predictions, if they are local, can also be biased by dispersal processes (e.g., Woehler et al, 2014), because seabirds are very vagile, even species considered as highly philopatric .…”

Diet composition and foraging success in generalist predators: Are specialist individuals better foragers?

“…For example, Lescroël et al (2010) showed recently that in Adélie penguin populations, better breeders were also more efficient foragers than poorer breeders, especially when conditions were challenging. Given that we found a relationship between diet diversity and foraging success, it may be expected that more specialized individuals are also better breeders, particularly those individuals specialized on the most profitable prey in terms of biomass uptake (i.e.…”