Contrasting patterns of food and macronutrient limitation in the field among co‐existing omnivorous carnivores

TOFT, SØREN; PAVÓN?PELÁEZ, CAMILA; MARTINEZ?VILLAR, MAURO; RENGIFO, LAURA; ARROYAVE, ALEJANDRA; POMPOZZI, GABRIEL; FRANCO, VIVIANA; ALBO, MARIA J.

ECOLOGICAL ENTOMOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2021

0307-6946

1. Carnivores are often food and/or macronutrient limited in their naturalhabitats, but whether they are limited mostly by protein or lipid is still a matter ofcontroversy. As many predators and carnivorous scavengers also include plant materialin their diet (omnivory), carbohydrate limitation is also possible.2. The authors used a recently described double-test procedure to test for foodand macronutrient limitation in five co-existing species of predators and omnivorousscavengers from Uruguay (two crickets: Gryllus sp. and Miogryllus verticalis; twocockroaches: Blatta orientalis and Blaptica dubia and a harvestman: Acanthopachylusaculeatus).3. The authors found that the two crickets and one cockroach were food limited andone cockroach was non-protein (lipid) limited in the field. The harvestman showed adramatic change in food limitation between two dates separated by only 3 weeks, butwasnon-protein (lipid) limited over both dates. From all species, the harvestman showed thehighest self-selected intake of carbohydrates (27%), indicating a high level of omnivory.In contrast, the two cockroaches selected a surprisingly low proportion of carbohydrates(13?14%), while the crickets were intermediate (14?19%). The authors hypothesizethat these omnivores are more carnivorous in the wild than expected from studies oflaboratory populations.4. Though individuals were collected from the same habitats and all speciesself-selected macronutrient ratios characteristic of omnivorous carnivores, they showeddifferent patterns of food and macronutrient limitation, reflecting species? niche segregationand individual differences in foraging success.