Navegando por Autor "Claro, Kleber Del"
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Item Effects of the trophobiont herbivore Calloconophora pugionata (Hemiptera) on ant fauna associated with Myrcia obovata (Myrtaceae) in a montane tropical forest.(2012) Souza, Roberth Fagundes de; Claro, Kleber Del; Ribeiro, Sérvio PontesMany studies have investigated the mechanisms behind the structure of arboreal ant assemblages. In this study, the objective was to evaluate the effect of availability of honeydew-producing colonies of Calloconophora pugionata (Membracidae) on the structure of ant assemblages associated with the host plant Myrcia obovata (Myrtaceae) in an Atlantic forest of Minas Gerais (Brazil). Our experiment consisted in a gradual exclusion of hemipteran colonies out of the host plant crown and further record of the ant assemblage response (species richness, composition, and occurrence) to the presence and density of treehopper colonies. The hypothesis was that an increase in the number of trophobiont herbivores results in an increase in tending ant occurrence but a reduction in ant species diversity. Results corroborated ourmain hypothesis: membracids had a positive effect on the occurrence of ants but negative on species richness. Overall insect occurrence was also reduced with increasing in C. pugionata colonies, probably due to strengthening dominant ant species territory sizes and intensification of patrolling.Item Extrafloral-nectaries and interspecific aggressiveness regulate day/night turnover of ant species foraging for nectar on Bionia coriacea.(2016) Silva, Diego Vinícius Anjos; Caserio, Barbara Machado; Rezende, Felipe Teles; Ribeiro, Sérvio Pontes; Claro, Kleber Del; Fagundes, RoberthPlants 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.Item Food source availability and interspecific dominance as structural mechanisms of ant-plant-hemipteran multitrophic networks.(2016) Fagundes, Roberth; Cruz, Wesley Francisco Dáttilo da; Ribeiro, Sérvio Pontes; Gray, Victor Rico; Claro, Kleber DelExtrafloral nectar of plants and honeydew of hemipterans is a food source extensively explored by ants. Although basically a sugary liquid food, nectar and honeydew are composed of different nutrients and offered in distinct ways; thus, ants must interact differently with plants and hemipterans. In this study we assessed the availability and dominance of nectar of extrafloral nectaries and honeydew of sap-sucking hemipterans (i.e., sugarbased resources) as mechanisms regulating interaction frequency and structuring ant-plant-hemipteran networks. We studied 12 plant species (240 shrubs, 20 per species) and 12 hemipteran species (240 aggregations, 20 per species) that interacted with 26 ant species in an area of Rupestrian Fields (Rocky Montane Savannah), Brazil. We observed that the 7 ant species that collected honeydew were a subset of the 25 ant species feeding on nectar, but the highly interacted species Camponotus crassus was the same for both subnetworks. The ant-plant subnetwork exhibited a nested pattern of interaction with a low degree of specialization, while the ant-hemipteran subnetwork exhibited lower nestedness but higher specialization. We found a positive relationship between the offer of EFNs and the number of interactions with ants, probably resulting from reduced competition in plants with high availability of EFNs. However, hemipteran species that were most abundant did not interact with more species of ants, probably because of the numerical dominance of the species tending all hemipteran aggregations, regardless of size. However, segregation between ant species was higher than expected by chance for both plants and hemipterans, con- firming a deterministic factor (i.e., competition between ant species) regulating the frequency of interactions. In summary, the availability of ENFs seems to be an important mechanism regulating ant-plant interactions, while numerical dominance seems to be an important mechanism structuring ant-hemipteran interactions.Item Host life-history traits predict haemosporidian parasite prevalence in tanagers (Aves: Thraupidae).(2022) Penha, Victor Aguiar de Souza; Domingos, Fabricius Maia Chaves Bicalho; Fecchio, Alan; Bell, Jeffrey A.; Weckstein, Jason D.; Ricklefs, Robert E.; Braga, Érika Martins; Moreira, Patrícia de Abreu; Soares, Letícia; Latta, Steven; Pascoli, Graziela Virginia Tolesano; Oliveira, Renata Duarte Alquezar de; Claro, Kleber Del; Manica, Lilian TonelliVector-borne parasites are important ecological drivers influencing life-history evolution in birds by increasing host mortality or susceptibility to new diseases. Therefore, understanding why vulnerability to infection varies within a host clade is a crucial task for conservation biology and for understanding macroecological life-history patterns. Here, we studied the relationship of avian life-history traits and climate on the prevalence of Plasmodium and Parahaemoproteus parasites. We sampled 3569 individual birds belonging to 53 species of the family Thraupidae. Individuals were captured from 2007 to 2018 at 92 locations. We created 2 phylogenetic generalized least-squares models with Plasmodium and Parahaemoproteus prevalence as our response variables, and with the following predictor variables: climate PC1, climate PC2, body size, mixed-species flock participation, incubation period, migration, nest height, foraging height, forest cover, and diet. We found that Parahaemoproteus and Plasmodium prevalence was higher in species inhabiting open habitats. Tanager species with longer incubation periods had higher Parahaemoproteus prevalence as well, and we hypothesize that these longer incubation periods overlap with maximum vector abundances, resulting in a higher probability of infection among adult hosts during their incubation period and among chicks. Lastly, we found that Plasmodium prevalence was higher in species without migratory behaviour, with mixed-species flock participation, and with an omnivorous or animal-derived diet. We discuss the consequences of higher infection prevalence in relation to life-history traits in tanagers.Item Limited effects of fire disturbances on the species diversity and structure of ant-plant interaction networks in Brazilian Cerrado.(2018) Fagundes, Roberth; Lange, Denise; Silva, Diego Vinícius Anjos; Lima, Filipe Paixão de; Oliveira, Larissa Nahas Domingues de; Corro, Erick J.; Silva, Pricila Bonifácio Gomes; Claro, Kleber Del; Ribeiro, Sérvio Pontes; Cruz, Wesley Francisco Dáttilo daFire is one of the main natural disturbances in Tropical Savannas, changing the diversity of species, altering the structure of species interactions, and driving the evolution of adaptations. Here, we investigated the effects of fire disturbance on interactions between ants and plants with extrafloral nectaries in Cerrado (Brazilian Savanna). We carried out the study in two different ecosystems of Brazilian Cerrado 700 km apart; Woody Cerrado and Rupestrian Grasslands. We conducted a Before-After-Control-Impact (BACI) experiment, in which the impact was the disturbance caused by fire. In Woody Cerrado, we found no evidence of fire affecting the diversity and composition of plants or its interactions. Fire also did not affect ant diversity but changed the interaction pattern of its interactions by reorganizing the paired interactions between species (i.e., rewiring). However, this effect did not result in changes on the overall structure of the network. In Rupestrian Grasslands, fire also did not affect the diversity and composition of plant species or its interactions, but it did increase the number of ant species and change its composition, leading to a reorganization of the its paired interactions. However, these fire disturbances in the ant level did not affect the overall structure of the network. Our findings indicate that the structure of ant-plant interaction networks is robust to fire disturbances, more in Woody Cerrado than Rupestrian Grasslands, confirming our hypothesis that ant-plant interactions in Cerrado are adapted to fire disturbances. In sum, our study enhances the understanding of the effects of environmental disturbances and the stability of the ant-plant interactions in fire-adapted ecosystems such as Brazilian Cerrado.Item Tending-ants increase survivorship and reproductive success of Calloconophora pugionata Drietch (Hemiptera, Membracidae), a trophobiont herbivore of Myrcia obovata O. Berg (Myrtales, Myrtaceae).(2013) Souza, Roberth Fagundes de; Ribeiro, Sérvio Pontes; Claro, Kleber DelThe trophic relations between ants and hemipterans are very common in the Neotropical Region, but rarely explored in dry montane ecosystems. Given the diversity of outcomes of this type of interactions influenced by variation in biotic conditions (i.e. seasonality, spatial distribution, identity of species involved), new examples in different ecosystems can provide important data for a more general understanding of their impact in communities. We investigated the outcomes (direct benefits: survivorship and reproduction) of the relationship between the trophobiont herbivore Calloconophora pugionata (Membracidae) and its tending ants. The interaction occurs on Myrcia obovata (Myrtaceae), a common tree in montane forests and rupestrian fields of southeastern Brazil, and has never been studied before. Between 2008 and 2009, we selected and manipulated (ant-exclusion) trees in a pairwise experiment performed on plant branches infested by C. pugionata. This Membracidae laid its eggs peculiarly on the leaf margins, a behaviour that increased egg survival even when ants were absent. All life stages of the hemipteran exhibited higher survival rates (two-fold) and increased fecundity (four-fold higher oviposition rates) when attended by ants. This study shows that this ant-hemipteran interaction occurs in dry montane biomes in a way that is similar to other tropical ecosystems in which ants protect the hemipterans against predators, thus increasing their survival and reproductive fitness.