A breath of fresh air in foraging theory: the importance of wind for food size selection in a central place forager

ALMA, MARINA; ALEJANDRO GUSTAVO FARJI BRENER; ELIZALDE, LUCIANA

AMERICAN NATURALIST

UNIV CHICAGO PRESS

Lugar: Chicago; Año: 2017

0003-0147

Empirical data about food size carried by central-placeforagers do not often fit with the optimum predicted by classical foragingtheory. Traditionally, biotic constraints such as predation riskand competition have been proposed to explain this inconsistency,leaving aside the possible role of abiotic factors. Here we documentedhow wind affects the load size of a central-place forager (leaf-cuttingants) through a mathematical model including the whole foraging process.The model showed that as wind speed at ground level increasedfrom 0 to 2 km/h, load size decreased from 91 to 30 mm2, a predictionthat agreed with empirical data from windy zones, highlighting therelevance of considering abiotic factors to predict foraging behavior.Furthermore, wind reduced the range of load sizes that workers shouldselect to maintain a similar rate of food intake and decreased the foragingrate by ∼70% when wind speed increased 1 km/h. These resultssuggest that wind could reduce the fitness of colonies and limit the geographicdistribution of leaf-cutting ants. The developed model offers acomplementary explanation for why load size in central-place foragersmay not fit theoretical predictions and could serve as a basis to studythe effects of other abiotic factors that influence foraging