Interactions between extrafloral nectaries, aphids and ants: are there competition effects between plant and homopteran sugar sources?

TY - JOUR

T1 - Interactions between extrafloral nectaries, aphids and ants: are there competition effects between plant and homopteran sugar sources?

AU - Engel, V.

AU - Fischer, M.D.

AU - Wäckers, F.L.

AU - Volkl, W.

N1 - Reporting year: 2001 Metis note: 2900; CTE; MTI; file:///L:/Endnotedatabases/NIOOPUB/pdfs/Pdfs2001/Engel_ea_2900.pdf

PY - 2001

Y1 - 2001

N2 - Broad bean (Vicia faba), an annual plant bearing extrafloral nectaries (EFN) at the base of the upper leaves, is regularly infested by two aphid species, Aphis fabae and Acyrthosiphon pisum. EFN and A. fabae are commonly attended by the ant, Lasius niger, while Ac. pisum usually remains uninfested. Sugar concentration and sugar composition of extrafloral nectar did not change significantly after aphid infestation. The sugar concentration was significantly higher in EFN (c. 271 mug mul(- 1)) than in the honeydew of A. fabae (37.5 mug mul(-1)). The presence of small A. fabae colonies had no significant effect on ant attendance of EFN, which remained at the same level as that on plants without A. fabae. Obviously, there was no significant competitive effect between the two sugar sources. We suggest that the high sugar concentration in the extrafloral nectar may outweigh the higher quality (due to the presence of melezitose) and quantity of aphid honeydew. Ants and the presence of EFN influenced aphid colony growth. While A. fabae colonies generally grew better in the presence of ants, Ac. pisum colonies declined on plants with EFN or A. fabae colonies. We conclude that EFN may provide some degree of protection for V. faba against those sucking herbivores that are not able to attract ants. [KEYWORDS: Vicia faba; sugar composition; Aphis fabae Acyrthosiphon pisum; mutualistic interactions Formica-rufa; attendance; mutualisms; parasitism; herbivory; insect; aphidiidae; protection; benefits]

AB - Broad bean (Vicia faba), an annual plant bearing extrafloral nectaries (EFN) at the base of the upper leaves, is regularly infested by two aphid species, Aphis fabae and Acyrthosiphon pisum. EFN and A. fabae are commonly attended by the ant, Lasius niger, while Ac. pisum usually remains uninfested. Sugar concentration and sugar composition of extrafloral nectar did not change significantly after aphid infestation. The sugar concentration was significantly higher in EFN (c. 271 mug mul(- 1)) than in the honeydew of A. fabae (37.5 mug mul(-1)). The presence of small A. fabae colonies had no significant effect on ant attendance of EFN, which remained at the same level as that on plants without A. fabae. Obviously, there was no significant competitive effect between the two sugar sources. We suggest that the high sugar concentration in the extrafloral nectar may outweigh the higher quality (due to the presence of melezitose) and quantity of aphid honeydew. Ants and the presence of EFN influenced aphid colony growth. While A. fabae colonies generally grew better in the presence of ants, Ac. pisum colonies declined on plants with EFN or A. fabae colonies. We conclude that EFN may provide some degree of protection for V. faba against those sucking herbivores that are not able to attract ants. [KEYWORDS: Vicia faba; sugar composition; Aphis fabae Acyrthosiphon pisum; mutualistic interactions Formica-rufa; attendance; mutualisms; parasitism; herbivory; insect; aphidiidae; protection; benefits]

U2 - 10.1007/s004420100765

DO - 10.1007/s004420100765

M3 - Article

SN - 0029-8549

VL - 129

SP - 577

EP - 584

JO - Oecologia

JF - Oecologia

IS - 4

ER -