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A GRAIN DIET SUPPLEMENTED WITH INSECTS RATHER THAN FRUITS SUPPORTS A MORE ROBUST BODY CONDITION IN AN OMNIVOROUS TROPICAL SONGBIRD
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  • OJODOMO SIMON,
  • Shiiwua Manu,
  • Chima Nwaogu,
  • Taiwo Omotoriogun
OJODOMO SIMON
University of Jos

Corresponding Author:simongodday34@gmail.com

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Shiiwua Manu
University of Jos
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Chima Nwaogu
University of Cape Town
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Taiwo Omotoriogun
Biotechnology Unit, Department of Biological Sciences, Elizade University, P.M.B. 002, Ilara-Mokin, Nigeria
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Abstract

1. Omnivores utilise dietary sources which differ in nutrients, hence dietary restrictions due to environmental change or habitat alteration should cause nutrient limitations; and thus, deterioration of body condition if omnivory is obligate. 2. We investigated how the body condition of the Village weaver Ploceus cucullatus (weavers), which forages predominantly on grains, responds to insects and fruits deprivation. 3. Forty wild-caught weavers held in aviaries were fed a combination of grains and fruits, or grains and insects ad libitum for eight weeks. We confirmed diet preference by recording the number of foragers on each diet option per minute for one hour and the amount of food left-over after 3 hours of foraging. Fortnightly, we assessed indices of body condition including body mass, pectoral muscle, and fat scores, Packed Cell Volume (PCV) and Haemoglobin Concentration (HBC). We modelled the number of foragers, food left-over and body condition as functions of diet, while accounting for time (weeks) and sex effects. 4. We confirmed grains as the preferred diet and found that males ate more fruits and insects than females. Weavers fed on grains and fruits lost body and pectoral muscle mass and accumulated less fat than those fed on grains and insects. This effect was sex-dependent: females deprived of insects lost more pectoral muscle mass than males of the same group and males but not females, deprived of fruits accumulated more fat reserve than those deprived of insects. PCV and HBC did not differ between diets but increased over the eight weeks. 5. Weavers are likely obligate rather than facultative omnivores, with insects as being a more nutritive supplement than fruits. We conclude that nutrient limitation arising from environmental change or habitat alteration can impair body condition and affect physiological response to environmental seasonality in other obligate omnivores like the weavers.
11 Aug 2022Submitted to Ecology and Evolution
12 Aug 2022Assigned to Editor
12 Aug 2022Submission Checks Completed
21 Sep 2022Reviewer(s) Assigned
23 Nov 2022Review(s) Completed, Editorial Evaluation Pending
30 Nov 2022Editorial Decision: Revise Minor