Evol Ecol Res 13: 711-723 (2011)     Full PDF if your library subscribes.

Pathogen- and diet-dependent foraging, nutritional and immune ecology in mealworms

Tamara P. Catalán¹, Matías Barceló¹, Hermann M. Niemeyer², Alexis M. Kalergis³ and Francisco Bozinovic¹

¹Center for Advanced Studies in Ecology and Biodiversity, LINC-Global and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile,  ²Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile and  ³Millenium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas and Departamento de Reumatología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile

Correspondence: F. Bozinovic (
e-mail: fbozinovic@bio.puc.cl), T.P. Catalán (tpcatala@uc.cl) or A.M. Kalergis (akalergis@bio.puc.cl).

ABSTRACT

Background: Feeding habits and dietary nutritional content may play a key role in pathogen-dependent foraging ecology, because mounting an effective immune response is costly for the host.

Hypothesis: Since immune defence is the final line of protection against infective aggression, an adequate provision of dietary macromolecules – through a selective foraging behaviour – is required to maintain immunocompetence in infected hosts.

Goal: We studied dietary switching and its consequences on immune response performance after an immune challenge using mealworms (Tenebrio molitor) as a model host.

Methods: We evaluated diet selection and body mass balance (proxy of fitness) of larvae following a lipopolysaccharide challenge under three experimental nutritional treatments: an isocaloric low-protein/high-carbohydrate or high-protein/low-carbohydrate diet offered either independently (no-choice experiment) or simultaneously (dual-choice experiment). Furthermore, we studied the effect of diet composition on three immune traits: antibacterial activity, phenoloxidase activity, and total haemocyte count.

Results: Immune-challenged larvae ate almost five times more than did control larvae in the dual-choice experiment. In addition, 50.7% of total food intake by immune-challenged larvae corresponded to the high-protein/low-carbohydrate diet, significantly higher than challenged or unchallenged control larvae (3.7% and 2.3% respectively). However, no significant differences in body mass change were observed. In contrast, in the no-choice diet condition, immune-challenged larvae lost body mass compared with naïve mealworms. Furthermore, we found that dietary protein had a positive effect on antibacterial activity and total haemocyte count but not phenoloxidase activity, and that mealworms feeding on a balanced diet did not have a better immune performance.

Conclusions: The immune response activation triggers a compensatory shift in host foraging behaviour that is not necessarily associated with the prevailing physiological state, but can have considerable influence on Darwinian fitness.

Keywords: antibacterial activity, dietary nutrients, ecoimmunology, feeding, haemocytes, phenoloxidase activity, Tenebrio molitor.

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        © 2011 Francisco Bozinovic. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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