Diet of the Blue-Bellied Poison Frog Andinobates minutus (Anura: Dendrobatidae) in Two Populations from the Colombian Pacific
We studied the effects of sex, body size, and season on the diet of two populations of the Blue-Bellied Poison Frog Andinobates minutus (Anura: Dendrobatidae) along the Pacific coast of Colombia. Andinobates minutus had a specialist diet, with preference for Acari (mites), Formicidae (ants), Collembola (springtails), and Holometabolous larvae. No differences in diet composition were noted between populations or between seasons. However, prey volume was higher in frogs from Bahía Málaga than those from Isla La Palma, and both populations experienced a decrease in the number of prey items in November, caused possibly by the low prey availability in that month. A differential effect of body size on diet was noted between populations. The total volume of prey, the volume and number of ants, and the volume of mites increased with snout–vent length (SVL), whereas the number of springtails decreased with SVL only in the Bahía Málaga population but not in the Isla La Palma population. This differential effect could be caused by the difference in distributions of the individuals' body sizes between populations. A significant effect of sex on diet was noted in both populations. Females from both populations showed higher preference for ants than did males. However, the importance of Formicidae showed temporal fluctuations in both populations. The diet of A. minutus in both populations had an important phylogenetic component, because closely related species have similar diets. Although other factors affected diet, the differential effects observed between populations could be caused by the spatiotemporal dynamic of each population.Abstract
Index of Relative Importance (IRI divided by 100) showing the consumption seasonal pattern of the four main prey categories in the diet of Andinobates minutus, according to sex-population categories. (A) Females from BM. (B) Males from BM. (C) Females from IP. (D) Males from IP. The solid line describes the annual rainfall pattern for the zone, according to historical data provided by Corporación Autónoma Regional del Valle del Cauca (CVC).
Species accumulation curves for prey categories of the diet of A. minutus in Bahia Málaga (A) and Isla La Palma (B).
Total consumption of prey of Andinobates minutus in number (A) and volume (B) in Bahía Málaga and Isla La Palma. The solid line describes the annual rainfall pattern for the zone, according to historical data provided by Corporación Autónoma Regional del Valle del Cauca (CVC).
Relationships between body size and the diet of Andinobates minutus. (A) Total volume of prey. (B) Volume of Formicidae. (C) Volume of Acari. (D) Number of Collembola. Black dots and solid line represent Bahía Málaga population, and grey dots and dotted line represent Isla La Palma population.
Nonmetric multidimensional scaling showing the effect of sex and season in diet composition of Andinobates minutus in Bahía Málaga (BM) and Isla La Palma (IP), based on the Bray-Curtis similarity matrix. “M” represents males and “F” represents females.
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