Argentine ants displace floral arthropods in a biodiversity hotspot

Lach, Lori (2008) Argentine ants displace floral arthropods in a biodiversity hotspot. Diversity and Distributions, 14 (2). pp. 281-290.

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Argentine ant (Linepithema humile (Mayr)) invasions are often associated with the displacement of ground-dwelling arthropods. Argentine ant invasions can also exert other effects on the community through interactions with plants and their associated arthropods. For example, carbohydrate resources (e.g. floral or extrafloral nectar) may influence foraging behaviour and interactions among ants and other arthropods. In South Africa's Cape Floristic Region, Argentine ants and some native ant species are attracted to the floral nectar of Leucospermum conocarpodendron Rourke (Proteaceae), a native tree that also has extrafloral nectaries (EFNs). Despite having relatively low abundance in pitfall traps, Argentine ants visited inflorescences more frequently and in higher abundance than the most frequently observed native ants, Camponotus spp., though neither native nor Argentine ant floral foraging was influenced by the EFNs. Non-metric multidimensional scaling revealed significant dissimilarity in arthropod communities on inflorescences with Argentine ants compared to inflorescences with native or no ants, with Coleoptera, Diptera, Hymenoptera, Arachnida, Orthoptera, and Blattaria all being underrepresented in inflorescences with Argentine ants compared to ant-excluded inflorescences. Native honeybees (Apis mellifera capensis Eschscholtz) spent 75% less time foraging on inflorescences with Argentine ants than on inflorescences without ants. Neither Argentine ant nor native ant visits to inflorescences had a detectable effect on seed set of Le. conocarpodendron. However, a pollen supplementation experiment revealed that like many other proteas, Le. conocarpodendron is not pollen-limited. Flower predation was negatively associated with increased ant visit frequency to the inflorescences, but did not differ among inflorescences visited by native and Argentine ants. Displacement of arthropods appears to be a consistent consequence of Argentine ant invasions. The displacement of floral arthropods by Argentine ants may have far-reaching consequences for this biodiversity hotspot and other regions that are rich in insect-pollinated plants.

Item ID: 30843
Item Type: Article (Research - C1)
ISSN: 1472-4642
Keywords: biological invasions; extrafloral nectaries; flowers; Leucospermum conocarpodendron; Linepithema humile; nectar; protea
Funders: Cornell University international travel grant, EPA STAR fellowship, National Science Foundation
Projects and Grants: National Science Foundation (grant number 0114923)
Date Deposited: 25 Jun 2014 00:11
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0501 Ecological Applications > 050103 Invasive Species Ecology @ 40%
06 BIOLOGICAL SCIENCES > 0602 Ecology > 060202 Community Ecology (excl Invasive Species Ecology) @ 30%
06 BIOLOGICAL SCIENCES > 0608 Zoology > 060808 Invertebrate Biology @ 30%
SEO Codes: 96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960505 Ecosystem Assessment and Management of Forest and Woodlands Environments @ 50%
96 ENVIRONMENT > 9604 Control of Pests, Diseases and Exotic Species > 960414 Control of Plant Pests, Diseases and Exotic Species in Forest and Woodlands Environments @ 50%
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