Chemosensory and thermal cue responses in the sub-Antarctic moth Pringleophaga marioni: Do caterpillars choose Wandering Albatross nest proxies?
On the South Indian Ocean Province Islands of the sub-Antarctic, most nutrients are processed through a detritus-based food web. On Marion Island, larvae of the moth Pringleophaga marioni are one of the key decomposers. Abundance of these caterpillars is higher in newly abandoned Wandering Albatross (Diomedea exulans) nests than other habitats, and this observation has been explained by hypotheses regarding the thermal and nutrient advantages of nests. These hypotheses require a mechanism for increasing the abundance of caterpillars, since nests are an ephemeral resource, and here, we determine whether caterpillars respond to chemosensory and thermal cues using a laboratory choice chamber approach. Caterpillars show no significant preference for newly abandoned nest material over no other choice, old nest material, and the common mire moss Sanionia uncinata. Caterpillars that are acclimated to warm (15 °C) conditions do prefer lower (5 °C) to higher (15 °C) temperatures, perhaps reflecting negative effects of prolonged exposure to warm temperatures on growth. Caterpillars also show significant avoidance of conspecifics, possibly because of incidental cannibalism previously reported in this species. Thus, we find no empirical support for nest-finding ability in caterpillars based on chemosensory or thermal cues. It is possible that adult females or very early instar caterpillars show such ability, or high caterpillar density and biomass in nests are an incidental consequence of better conditions in the nests or deposition by the birds during nest construction.
KeywordsAntarctic Ecosystem engineering Habitat choice Chemosensory Thermal preference
We thank Jeremy McNeil for discussions of choice chamber design, Jessica Allen for the technical drawing, and Asanda Phiri, Rina Groenewald, Charlene Janion, Justine Shaw and several members of the Marion Island relief expeditions for assistance with field work, and three anonymous reviewers for their helpful comments. This research was supported by South African National Research Foundation Grant SNA2011110700005.
- Burger AE (1978) Terrestrial invertebrates: a food resource for birds at Marion Island. S Afr J Antarct Res 8:87–99Google Scholar
- Chown SL, McGeoch MA, Marshall DJ (2002) Diversity and conservation of invertebrates on the sub-Antarctic Prince Edward Islands. Afr Entomol 10:67–82Google Scholar
- Cohen J (1988) Statistical power analysis for the behavioural sciences, 2nd edn. Lawrence Erlbaum, New YorkGoogle Scholar
- Crafford JE (1990) Patterns of energy flow in populations of the dominant insect consumers on Marion Island. Dissertation, University of Pretoria, South AfricaGoogle Scholar
- Crafford JE, Scholtz CH, Chown SL (1986) The insects of sub-Antarctic Marion and Prince Edward Islands, with a bibliography of entomology of the Kerguelen biogeographical province. S Afr J Antarct Res 16:42–84Google Scholar
- French DD, Smith VR (1983) A note on the feeding of Pringleophaga marioni Viette larvae at Marion Island. S Afr J Antarct Res 13:45–46Google Scholar
- Gremmen NJM (1981) The vegetation of the subantarctic Islands Marion and Prince Edward. W Junk, The HagueGoogle Scholar
- Lebouvier M, Laparie M, Hullé M, Marais A, Cozie Y, Lalouette L, Vernon P, Candresse T, Frenot Y, Renault D (2011) The significance of the sub-Antarctic Kerguelen Islands for the assessment of the vulnerability of native communities to climate change, alien insect invasions and plant viruses. Biol Invasions 13:1195–1208CrossRefGoogle Scholar
- Pierce NE (1995) Predatory and parasitic Lepidoptera: carnivores living on plants. J Lepidop Soc 49:412–453Google Scholar
- Ronnås C, Larsson S, Pitacco A, Battisti A (2011) Effects of colony size on larval performance in a processionary moth. Ecol Entomol 35:436–445Google Scholar
- Ryan PG, Bester MN (2008) Pelagic predators. In: Chown SL, Froneman PW (eds) The Prince Edward Islands: land–sea interactions in a changing ecosystem. Sun Press, Stellenbosch, pp 121–164Google Scholar
- Smith VR, Avenant NL, Chown SL (2002) The diet and impact of house mice on a sub-Antarctic island. Polar Biol 25:703–715Google Scholar
- Sokal RR, Rohlf FJ (2001) Biometry: the principles and practice of statistics in biological research, 7th edn. WH Freeman, New YorkGoogle Scholar
- R Development Core Team (2013) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, ISBN: 3-900051-07-0. http://www.R-project.org. Accessed 3 Apr 2013