Ant visitation on cerrado plants in Uberlândia, Minas Gerais, Southeastern Brazil

Samplings were performed in field during the rainy (October 4, 2010 – January 27, 2011) and dry season (April 25 – July 26, 2011

NMDS results obtained for the composition of ant species on Cerrado plants with and without EFNs (N = 10 transects) for both seasons.

<p>The composition of ant fauna did not differ (P > 0.05) between the groups according with ANOSIM tests.</p

Temporal Variation in the Abundance and Richness of Foliage-Dwelling Ants Mediated by Extrafloral Nectar

<div><p>Plants bearing extrafloral nectaries (EFNs) are common in the Brazilian cerrado savanna, where climatic conditions having marked seasonality influence arboreal ant fauna organization. These ant-plant interactions have rarely been studied at community level. Here, we tested whether: 1) EFN-bearing plants are more visited by ants than EFN-lacking plants; 2) ant visitation is higher in the rainy season than in dry season; 3) plants producing young leaves are more visited than those lacking young leaves in the rainy season; 4) during the dry season, plants with old leaves and flowers are more visited than plants with young leaves and bare of leaves or flowers; 5) the composition of visiting ant fauna differs between plants with and without EFNs. Field work was done in a cerrado reserve near Uberlândia, MG State, Brazil, along ten transects (total area 3,000 m²), in the rainy (October-January) and dry seasons (April-July) of 2010–2011. Plants (72 species; 762 individuals) were checked three times per season for ant presence. Results showed that 21 species (29%) and 266 individuals (35%) possessed EFNs. These plants attracted 38 ant species (36 in rainy, 26 in dry season). In the rainy season, plants with EFNs had higher ant abundance/richness than plants without EFNs, but in the dry season, EFN presence did not influence ant visitation. Plant phenology affected ant richness and abundance in different ways: plants with young leaves possessed higher ant richness in the rainy season, but in the dry season ant abundance was higher on plants possessing old leaves or flowers. The species composition of plant-associated ant communities, however, did not differ between plants with and without EFNs in either season. These findings suggest that the effect of EFN presence on a community of plant-visiting ants is context dependent, being conditioned to seasonal variation.</p></div

Number of plants according to phenological state across seasons.

<p>Number of plants according to phenological state across seasons.</p

Percentage of Cerrado plants on which each ant species was found in each season.

<p>Plants were divided according with the presence (N = 266) or absence (N = 496) of EFNs for each season. Figure shows only ant species with ten occurrences or more.</p

Ant visitation patterns on Cerrado plants according to phenological factors.

<p>Plants with and without old leaves according to the seasons (A), plants with and without flowers or floral buds according to the seasons (B). Black horizontal lines represent the median, boxes designate the second and third quartiles, and vertical bars indicate the range of data without outliers. Asterisks indicate significant differences (P < 0.5) between adjacent pairs of categories following contrast procedure.</p

Seasonal ant visitation patterns on Cerrado plants with and without EFNs.

<p>Number of ant species (A) and ant workers (B) per plant. Black horizontal lines represent the median, boxes designate the second and third quartiles, and vertical bars indicate the range of data without outliers. Asterisks indicate significant differences (P < 0.5) between adjacent pairs of categories following contrast procedure.</p

Ecologia comportamental na interface formiga-planta -herbívoro: interações entre formigas e lepidópteros

Ants are one of the most prominent groups of terrestrial organisms in terms of diversity, relative abundance, and biomass. Their importance is due primarily to eusociality combined with complex communication systems, which enable them to recruit nestmates to capture prey and/ or protect profitable resources. Tropical foliage is rich in renewable food sources that promote visitation by ants. Because they are the principle predators among foliage, ants can strongly affect the communities of herbivorous insects and promote trophic cascades with relevant consequences to plants. The presence of ants on foliage can affect herbivores in two ways: (1) ant foragers can decrease the number of herbivores on plants through antagonistic interactions (e.g. aggressiveness, predation), (2) ants can create an enemy-free space for myrmecophilous herbivores (i.e. those living in close association with ants). Here, we discuss the ecological scenario in which these interactions occur, and examine the effects of foliage-dwelling ants on the biology and behavior of lepidopteran larvae.Formigas constituem um dos mais proeminentes grupos de organismos terrestres em termos de diversidade, abundância relativa e biomassa animal. Sua importância se deve principalmente ao comportamento eusocial aliado a complexos sistemas de comunicação, que permitem às formigas recrutar companheiras e defender recursos com grande eficiência. A vegetação de áreas tropicais é rica em fontes de alimentos renováveis que induzem a visitação freqüente de formigas às plantas. Sobre a vegetação, as formigas podem atuar como predadoras e acarretar um forte efeito sobre a comunidade de insetos herbívoros, estruturando redes tróficas e promovendo efeitos em cascata. A presença de formigas sobre plantas pode afetar insetos herbívoros basicamente de duas formas: (1) limitando sua ocorrência na folhagem através de interações antagônicas (ex. agressão, predação) ou (2) propiciando espaços livres de inimigos naturais para herbívoros mirmecófilos (que mantêm associações com formigas). Neste artigo revisamos e discutimos os cenários ecológicos onde estas interações podem ocorrer, com especial atenção aos potenciais efeitos de formigas sobre a biologia e o comportamento de larvas de Lepidoptera.Las hormigas constituyen uno de los grupos de organismos terrestres más relevantes en términos de diversidad, abundancia relativa y biomasa animal. Su importancia se debe, principalmente, al comportamiento eusocial asociado a complejos sistemas de comunicación que permiten a las hormigas reclutar individuos y defender recursos con gran eficiencia. La vegetación de las regiones tropicales es rica en fuentes de alimento renovables, los cuales inducen la visita frecuente de hormigas a las plantas. En la vegetación, las hormigas pueden actuar como depredadores, generando un fuerte efecto sobre las comunidades de insectos herbívoros, estructurando las redes tróficas y promoviendo efectos en cascada. La presencia de hormigas sobre las plantas puede afectar a los insectos herbívoros, básicamente de 2 maneras: (1) limitando su presencia en el follaje a través de interacciones antagónicas (e.g. agresión, depredación) o (2) propiciando espacios libres de enemigos naturales en el caso de los herbívoros mirmecófilos (los cuales mantienen asociaciones con hormigas). En este trabajo, revisamos y discutimos los escenarios ecológicos donde estas interacciones pueden ocurrir, en especial, los efectos potenciales de las hormigas en la biología y el comportamiento de larvas de Lepidoptera

Natural history of a sit-and-wait Dipteran predator that uses extrafloral nectar as prey attractant

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQSit-and-wait predators use different strategies to encounter potential prey. Rhinoleucophenga myrmecophaga Vidal et (Vidal et Vilela; Diptera: Drosophilidae) larvae build sticky shelters on top of extrafloral nectaries (EFNs) of Qualea grandiflora Mart (V47511651172FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ2010/13619-0, 2011/18580–8, 2012/23399-3, 2014/23141-1, 2017/16645-11198-13-0306115/2013-1, 302219/2017-0We thank Luisa Mota and André Tacioli for help in the field, André Freitas and Hélio Soares Jr. for help with the photographs, and Shannon Murphy for comments on the manuscript. M.C.V. was supported by the São Paulo Research Foundation (FAPESP) (2010/136