Caterpillars benefit from thermal ecosystem engineering by wandering albatrosses on sub-Antarctic Marion Island

Abstract

Wandering albatrosses (Diomedea exulans) nest on Southern Ocean islands, building elevated nests upon which they incubate eggs and raise chicks, and which the chicks occupy through winter. The nests support high invertebrate biomass, including larvae of the flightless moth Pringleophaga marioni. Here we argue that high biomass of P. marioni in the nests is not associated with nutrient loading as previously suspected, but that higher temperatures in the nests increase growth and feeding rate, and decrease deleterious repeated cold exposure, providing fitness advantages for P. marioni. Thus, wandering albatrosses may be serving as thermal engineers, modifying temperature and therefore enabling better resource use by P. marioni.

A global database and “state of the field” review of research into ecosystem engineering by land animals

“…Burrows increased survival and longevity of other burrow users (Bartel, Haddad, & Wright, ). Favourable thermal microclimates inside nests and burrows were often cited as an explanation for these benefits, although few papers empirically tested this hypothesis (Sinclair & Chown, ). Vertebrate burrows also facilitated thermoregulation in shade‐limited habitats (Lane & Shine, ), and this was particularly important in dry/arid habitats, where the majority of studies testing theories related to thermal benefits were conducted (Figure , Appendix S2).…”

“…Greater species diversity in engineered habitats is linked with structural complexity resulting from engineer activity (Romero et al., ). Suggested mechanisms for the increase in diversity include improved ease of escape from predators (Pringle, ); facilitation of foraging for smaller mammal species (Valeix et al., ); and provision of favourable thermal conditions for ectotherms that enable higher rates of feeding and growth (Sinclair & Chown, ). Engineers that altered plant structure accounted for 23% of all studies.…”

“…They contributed to structural complexity in habitats, which generally bolstered animal abundance and diversity, and influenced community structure. In general, nests offered thermal refuge (Sinclair & Chown, ) and the addition of waste products and the physical structure of the nests themselves had impacts on soil nutrients and thus plant growth. This alteration in the structure of plant communities then influenced the survival and abundance of invertebrates (Figure ).…”

The spatial structure of Antarctic biodiversity

“…Albatross nests on sub-Antarctic islands may likewise form localized nutrient sources, though their effects may be complicated by the changes in temperature effected by incubating birds (Joly et al 1987, Sinclair and Chown 2006, Smith and Froneman 2008. Changes in biological community composition and activity in response to the creation of such nutrient sources can be very rapid (Smith 2008, Tiao et al 2012.…”

Variation in nest composition and abundances of ectoparasites between nests in colonially breeding Common EidersSomateria mollissima

“…Furthermore, Eiders have one of the highest incubation constancies of birds, remaining on the nest for about 90-97% of the time, during the 24-27 days long incubation period (Bolduc & Guillemette 2003, Kristjánsson & Jónsson 2011. However, such high and stable nest temperatures during incubation, maintained by high incubation constancy, also favour nest-living ectoparasites (fleas, lice and ticks), as abundances of ectoparasites in the nests have been observed to increase in a favourable thermal microclimate (Sinclair & Chown 2006). Accumulating evidence shows that ectoparasites have substantial negative effects on incubating birds due to loss of blood and increased probabilities of infections (Möller 1993, Oppliger et al 1994, Bush et al 2001, Lesna et al 2009, Clayton et al 2010, Mainwaring et al 2014, Stenkewitz et al 2015.…”