Document Type

Article

Publication Date

2018

Keywords

Pogonomyrmex californicus, invasive species, seed preference, coastal sage scrub, grassland, foraging, disturbance, Phacelia campanularia, Brassica nigra, Bernard Field Station

Abstract

The California Harvester ant, Pogonomyrmex californicus, plays a key ecological role in the coastal sage scrub (CSS) ecosystem as a forager of seeds. Understanding the influence of different environments on food preferences of Harvester ants may indicate how native CSS environments will respond to rising temperatures and human encroachment. We sought to determine the effect of disturbed and undisturbed habitats on Harvester ant seed preference. We predicted that Harvester ants would prefer native seeds, Phacelia campanularia, over non-native seeds, Brassica nigra seeds. Further, we expected that ants in undisturbed habitats will show a stronger preference towards the native seeds than ants in disturbed habitats. By examining three disturbed grassland environments and three in undisturbed CSS environments of the Robert J. Bernard Biological Field Station in Claremont, California, we found that Harvester ants preferred native P. campanularia seeds over non-native B. nigra seeds in both native and non-native habitats. Our results also showed that the grassland habitat ants had less of a preference than the coastal sage scrub ants, which supports our hypothesis that ants in undisturbed habitats would show a stronger preference towards the native seeds than ants in disturbed habitats.

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