Extrafloral-nectaries and interspecific aggressiveness regulate day/night turnover of ant species foraging for nectar on Bionia coriacea.
Data
2016
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Resumo
Plants bearing extrafloral nectaries (EFNs) vary the secretion of nectar between day and night, which
creates turnover in the composition of interacting ant species. Daily variation in the composition of ant species
foraging on vegetation is commonly observed, but its mechanisms are poorly understood. We evaluated the daily
variation in nectar availability and interspecific aggressiveness between ants as possible regulatory mechanisms of
the turnover in ant–plant interactions. We hypothesized that (i) plants would interact with more ant species during
periods of higher secretion of nectar and that (ii) aggressive ant species would compete for nectar, creating a
daily turnover of species collecting nectar. We tested this hypothesis by measuring the production of nectar during
the day and night and by experimentally removing EFNs of Bionia coriacea (=Camptosema coriaceum) (Nees &
Mart.) Benth. (Fabaceae: Faboideae) plants in a Brazilian savanna (Cerrado). We then compared the abundance
and composition of ant species between those treatments and during the day. Our results indicate that more ant
workers forage on plants during the day, when nectar was sugary, while more ant species forage at night, when
aggressiveness between ant species was lower. We also detected a day/night turnover in ant species composition.
Ant species foraging for nectar during the day were not the same at night, and this turnover did not occur on
plants without EFNs. Both dominant ant species, diurnal Camponotus crassus (Hymenoptera: Formicidae) and
nocturnal Camponotus rufipes (Hymenoptera: Formicidae), were the most aggressive species, attacking other ants
in their specific periods of forage while also being very aggressive toward each other. However, this aggressiveness
did not occur in the absence of nectar, which allowed non-aggressive nocturnal ant species to forage only
during the daytime, disrupting the turnover. We conclude that extrafloral-nectar presence and interspecific
aggressiveness between ants, along with other environmental factors, are important mechanisms creating turnovers
in ants foraging on plants.
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Brazil, Cerrado, Niche partition, Resource competition
Citação
SILVA, D. V. A. et al. Extrafloral-nectaries and interspecific aggressiveness regulate day/night turnover of ant species foraging for nectar on Bionia coriacea. Austral Ecology, v. 42, p. 317–328, 2016. Disponível em: <http://onlinelibrary.wiley.com/doi/10.1111/aec.12446/full>. Acesso em: 25 ago. 2017.