Maternally invested carotenoids compensate costly ectoparasitism in the hihi

Abstract

Dietary ingested carotenoid biomolecules have been linked to both improved health and immunity in nestling birds. Here, we test whether maternally invested egg carotenoids can offset the cost of parasitism in developing nestling hihi (Notiomystis cincta) from the bloodsucking mite (Ornithonyssus bursa). Our results reveal clear negative effects of parasitism on nestlings, and that maternally derived carotenoids compensate this cost, resulting in growth parameters and ultimate mass achieved being similar to nonparasitized young. Our results offer an unique example of a direct positive relationship between enhanced maternal investment of carotenoids and an ability to cope with a specific and costly parasite in young birds. As O. bursa infestations reduce population viability in hihi, our findings also highlight the importance of key nutritional resources for endangered bird populations to better cope with common parasite infestations.life history ͉ maternal effects ͉ parasites ͉ stitchbird

Minutes matter: brief hatching asynchrony adversely affects late-hatched hihi nestlings, but not life beyond the nest

“…If brood hierarchies create stressful growth environments for later-hatched 362 nestlings, why did carotenoids not mitigate these effects? We know that our 363 supplementation changed the phenotype of nestlings, as previous analyses of subsets of 364 these data indicate differences in nestlings' body condition (Ewen et al 2009) and 365 tarsus length (Ewen et al 2008) at fledging, and here we find that carotenoid 366 supplementation leads to faster growth (at least for tarsi). Other work with hihi has also 367 shown that increased access to carotenoids influences nestling begging (Ewen et al…”

“…The sample sizes 160 for these analyses were limited by how many nests we were able to collect data on We fitted a standard logistic growth model (Ricklefs, 1968) using the SSlogis function of 179 the "stats" package in R (R Core Team, 2013) to estimate each individual's asymptotic 180 mass (g) and tarsus length (mm), and their growth rates (k). Logistic growth models fit 181 postnatal growth data well in passerines (Starck & Ricklefs, 1998), and have been used 182 to describe growth before in hihi (Ewen et al 2009). Nestlings that died before fledging 183 were excluded.…”

“…During Season 2, 223 some nests included in this dataset (N = 46) were also used in a mite-removal 224 experiment (for methodology see Ewen et al, 2009). We therefore also tested for any 225 interactive effects of hatch order, mite treatment, and carotenoid treatment to 226 determine whether mite treatment had any effect on the relationships we were 227 interested in here.…”

“…This can leave younger, smaller chicks at a disadvantage from 29 sibling competition (Mock & Parker, 1997) if parents feed larger offspring preferentially 30 (Rodriguez-Girones et al 2002), but hatching asynchrony can also be an adaptive 31 strategy if it allows a mother to maximize the overall success of her brood (for example, 32 through brood reduction to match unpredictable environments (Magrath, 1990; 33 Stenning, 1996). While the effects of hatching asynchrony on life within the nest are designed to investigate effects on maternal egg investment , 95 parental provisioning of nestlings (Ewen et al, 2008), and effects of ectoparasites on 96 nestling health (Ewen et al, 2009). Our supplementation regime differed between years, 97 with females in 'Season 1' receiving supplementation from nest building to offspring 98 fledging, whereas in 'Season 2', supplementation was stopped after completion of egg 99 laying (Table 1).…”

Effect of supplementary feeding on reproductive success of hihi (stitchbird, Notiomystis cincta) at a mature forest reintroduction site

“…The inaccessibility of the nests prevented us from determining the cause of nest failure. However, hihi nestling (Armstrong et al 2007;Ewen et al 2009;Rippon 2010). The improved success of feeder-using females is presumably due to supplementary feeding increasing nestling provisioning rates (Makan 2006).…”