phaidra.vetmeduni.ac.at o:1939 DOI 10.1186/s12862-022-02007-8 Eating in a losing cause: limited benefit of modified macronutrient consumption following infection in the oriental cockroach Blatta orientalis Host-pathogen interactions can lead to dramatic changes in host feeding behaviour. One aspect of this includes self-medication, where infected individuals consume substances such as toxins or alter their macronutrient consumption to enhance immune competence. Another widely adopted animal response to infection is illness-induced anorexia, which is thought to assist host immunity directly or by limiting the nutritional resources available to pathogens. Here, we recorded macronutrient preferences of the global pest cockroach, Blatta orientalis to investigate how shifts in host macronutrient dietary preference and quantity of carbohydrate (C) and protein (P) interact with immunity following bacterial infection.We find that B. orientalis avoids diets enriched for P under normal conditions, and that high P diets reduce cockroach survival in the long term. However, following bacterial challenge, cockroaches significantly reduced their overall nutrient intake, particularly of carbohydrates, and increased the relative ratio of protein (P:C) consumed. Surprisingly, these behavioural shifts had a limited effect on cockroach immunity and survival, with minor changes to immune protein abundance and antimicrobial activity between individuals placed on different diets, regardless of infection status.We show that cockroach feeding behaviour can be modulated by a pathogen, resulting in an illness-induced anorexia-like feeding response and a shift from a C-enriched to a more P:C equal diet. However, our results also indicate that such responses do not provide significant immune protection in B. orientalis, suggesting that the host's dietary shift might also result from random rather than directed behaviour. The lack of an apparent benefit of the shift in feeding behaviour highlights a possible reduced importance of diet in immune regulation in these invasive animals, although further investigations employing pathogens with alternative infection strategies are warranted. eng Illness-Induced Anorexia; Self-Medication; Diet Choice; Life-Span; Sickness Behavior; Mormon Crickets; Nutrient Intake; Protein Costs; Trade-Offs; Resistance 2023-08-03T10:04:10.980Z LOMv1.0 Author BEGIN:VCARD VERSION:3.0 N:Sieksmeyer;Thorben; FN:Thorben Sieksmeyer END:VCARD BEGIN:VCARD VERSION:3.0 N:McMahon;Dino P.; FN:Dino P. McMahon X-ORCID:https://orcid.org/0000-0003-1119-5299 END:VCARD BEGIN:VCARD VERSION:3.0 N:Rodríguez-Rojas;Alexandro; FN:Alexandro Rodríguez-Rojas X-ORCID:https://orcid.org/0000-0002-4119-8127 END:VCARD BEGIN:VCARD VERSION:3.0 N:Johnston;Paul R.; FN:Paul R. Johnston END:VCARD BEGIN:VCARD VERSION:3.0 N:Weise;Christoph; FN:Christoph Weise END:VCARD BEGIN:VCARD VERSION:3.0 N:Julseth;Mara Jean; FN:Mara Jean Julseth END:VCARD BEGIN:VCARD VERSION:3.0 N:Banasiak;Ronald; FN:Ronald Banasiak END:VCARD BEGIN:VCARD VERSION:3.0 N:Kuropka;Benno; FN:Benno Kuropka END:VCARD BEGIN:VCARD VERSION:3.0 N:Petrašiūnaitė;Vesta; FN:Vesta Petrašiūnaitė END:VCARD BEGIN:VCARD VERSION:3.0 N:Jiang;Shixiong; FN:Shixiong Jiang END:VCARD BEGIN:VCARD VERSION:3.0 N:Esparza-Mora;M. Alejandra; FN:M. Alejandra Esparza-Mora END:VCARD BEGIN:VCARD VERSION:3.0 N:He;Shulin; FN:Shulin He END:VCARD https://w3id.org/kim/hcrt/scheme https://w3id.org/kim/hcrt/text Textdokument Text LOMv1.0 yes https://creativecommons.org/licenses/by/4.0 application/pdf 1101375 https://phaidra.vetmeduni.ac.at/o:1939 https://phaidra.vetmeduni.ac.at/api/object/o:1939/thumbnail LOMv1.0 discipline