![]() Foraging trails vary in the spatial orientation and location ( Kost et al. Finally, leaf-cutting ants travel along a system of foraging trails that they maintain clear of vegetation. 2013) thus, they may be able to decrease the wind interception surface of their loads. Second, ants adjust the area, mass, and shape of their loads depending on the context (e.g., Roces 1994 Lewis et al. Therefore, these loads greatly increase the area of wind interception potentially affecting movement, walking direction, and speed of loaded ants. Typically, workers carry plant fragments that are several times larger than their bodies. First, workers cut and collect plant fragments to use them as substrate to cultivate a mutualistic fungus, the source of food for the larvae. Leaf-cutting ants are good models for analyzing the effect of wind on foraging behavior. If wind can decrease food delivery rate to the colony as it hinders ant movements, we expect ants to show behaviors that reduce the negative effect of wind. However, their results were nonconclusive because they studied the effect of wind on an ant species that forages in tunnels below ground ( Porter and Tschinkel 1987). Although other studies have determined how the wind affects ant movements, only one study quantified the effect of wind on ant foraging activity. ![]() For example, in windy conditions, desert ants wander some distance downwind of the food source, and when they detect the odor stream emanating from the food, they change direction and walk upwind on a slightly zigzag path until they reach the food ( Wolf and Wehner 2000, 2005). In ants, the effect of wind on behavior is notorious wind gusts reduce ant speed and can even blow ants off the foraging trail ( Rudolph and Loudon 1986 Anderson and Jadin 2001 Supplementary MOV. 2000) and spiders modify the size, structure, and orientation of their webs ( Hieber 1984). For example, in windy conditions, cockroaches change their walking direction ( Willis and Avondet 2005) red deer use lower-quality foraging patches ( Conradt et al. The wind may affect the behavior of walking organisms just as it affects flying organisms. However, the effect of wind on foraging of walking organisms is far-less studied. Another abiotic factor that may affect foraging is wind, whose effects have been mostly studied on flying organisms ( Furness and Bryant 1996 Gilchrist et al. Among abiotic factors the effect of temperature on foraging behavior is widely known, influencing activity periods, the type of behavior (risk averse and risk prone), or decreasing walking speed and foraging success ( Avery and Krebs 1984 Caraco et al. The most studied biotic factors are predation risk and competition, which can reduce foraging rate and limit access to food, respectively ( Milinski and Heller 1978 Tran et al. Biotic and abiotic factors may influence the cost-benefit ratio of foraging behaviors. Therefore, foraging behaviors should be selected to maximize benefits and reduce costs. 2012), and sexual selection ( Davies et al. It is known that food quality and quantity affect total egg production, number of offspring, growth rate ( Brett 1993 Kant et al. The fitness and survival of organisms ultimately depend on their feeding. Our work illustrates how short-term behavioral responses can mitigate the negative effect of an understudied environmental factor on ant foraging. This is the first study that quantifies the negative consequences of wind on leaf-cutting ants’ foraging and reports behaviors that can reduce this effect. However, trails showed no particular spatial distribution in relation to wind direction. At the short term, ants reduced the negative effect of wind by selecting smaller, lighter, or more elongated loads. Wind effect increased with area, mass, and shape of loads. However, wind only affected ants walking along trails that were perpendicular to wind direction or parallel upwind. We found that in windy conditions, the speed of loaded ants was reduced by 55%, and ants were blown off the trail 28 times more than in windless conditions. We also tested whether these ants show a short-term response to wind by selecting loads with characteristics that reduce wind interception, and a long-term response, by arranging the spatial design of the trail system in a way that reduces that effect. We quantified the effect of wind on the foraging of leaf-cutting ants and evaluated whether this effect varies with 1) leaf fragment traits, such as area, mass, and shape, and 2) the characteristics of the foraging trail system. ![]() Wind may restrict and modify animal movements increasing the cost of foraging, especially when the animal carries resources that intercept wind. Therefore, foraging behaviors should be selected to maximize cost-benefit ratio.
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