Extrafloral nectary-mediated ant-plant interactions in the coastal vegetation of Veracruz, Mexico: Richness, occurrence, seasonality, and ant foraging patterns

We studied the extrafloral nectary-mediated ant-plant interactions in the coastal vegetation of Veracruz, Mexico. We surveyed the richness and abundance of interactions, their correlations in both groups, the proportion of associated species and groups, and their temporal and spatial variation. Forty-three plant species (25 families) had extrafloral nectaries, which were more abundant during the wet season. Thirty-one ant species in 18 genera were found in 208 associations with extrafloral nectaries. Sixty-six percent of the nectary-bearing plant species were visited by ants. Eighty-four of the recorded ant species visited nectaries. The proportion of associated species was always higher than that of non-associated species. Ants forage on nectaries day and night, with sympatric species having contrasting foraging schedules. Abundance of nectary-bearing plants differed among seasons, while ant density and richness differed seasonally in specific vegetation types. Abundance of extrafloral nectaries was positively correlated with ant species richness during the rainy season. Seasonal patterns suggest higher nectar availability on vegetative structures during the rainy season and on reproductive structures during the dry season. The high proportion of extrafloral nectary-bearing plants found (14.82%) compared to other surveyed habitats (5-15%) suggests that extrafloral nectary-mediated plant protection by ants is a common feature in coastal communities of Veracruz. Nous avons étudié les interactions qui existent entre les fourmis et les plantes de la végétation côtière de Veracruz, au Mexique, interactions influencées par la présence de nectaires extrafloraux. Nous avons observé la richesse et le nombre des interactions, leurs corrélations dans les deux groupes, ainsi que la proportion et la variation temporelle et spatiale des espèces et des groupes associés. Quarante-trois espèces de plantes, appartenant à 25 familles, ont des nectaires extrafloraux. Elles sont plus abondantes durant la saison humide. Trente-et-une espèces de fourmis provenant de 18 genres forment 208 associations avec des nectaires. Les fourmis visitent 66 % des plantes porteuses de nectaires extrafloraux. Au total, 84 % des espèces de fourmis recensées visitent les nectaires. Il y a toujours une plus grande proportion d'espèces associées que d'espèces non associées. Les fourmis se nourrissent sur les nectaires de jour comme de nuit, les espèces sympatriques ayant des patrons d'activité dif