Temperature Influence on Species Co-Occurrence Patterns in Treefall Gap and Dense Forest Ant Communities in a Terra- Firme Forest of Central Amazon, Brazil

In this study we evaluated the influence of temperature and species co-occurrence on the structure of an ant community of treefall gaps and surrounding dense forests in a terra-firme forest of Central Amazon, Brazil. For this, we collected ants at different hours, and at the time of each collection we measured the temperature of the environment. Even with the difference in the temperature variation and variation throughout the day, there was no difference in the richness and abundance of ants among the environments. Also, the ant species are distributed randomly and independently of one another in both studied environments in accordance with a null model (C-score). However, although not influenced by temperature, the ant composition of treefall gaps was different from the ant community of the surrounding dense forest. Possibly the composition and ant foraging in environments of treefall gaps and surrounding dense forests are not only influenced by temperature, but also by the interaction of this factor with the structural complexity of vegetation in terms of sites available for nesting and feeding, and other microclimatic factors. This generates a difference in ant composition of both environments. In addition, the structuring of ant community in tropical rain forests may actually be stochastic or neutral within each environment

Recolonização de Capoeiras com Diferentes Histórias de uso por Plantas Mirmecófitas e suas Formigas Associadas

In this thesis I studied some factors influencing the re-establishment of myrmecophytes and ants in mature undisturbed forests, and two kinds of secondary forests: post slash-and-burn (thus dominated by Vismia pioneer trees) or post harvesting of pre-existing mature forest trees (thus dominated by Cecropia pioneer trees). Richness and abundance of myrmecophytes were higher in mature forest than in secondary forests, but there were no differences among the two kinds of secondary forests. Myrmecophyte composition was different between mature and secondary forests, as well as between the two types of secondary forest.. In Vismia forests the myrmecophyte composition was strongly associated with the number of recent fire events, while in Cecropia it was related to the age since cutting. There was a strong relationship between the myrmecophyte composition and their ant-associated community within each of the three kinds of forests. However, the proportion of uncolonized plants and the proportion of plants hosting non-specific ants were larger in Vismia forest than in Cecropia or mature forests. The colonization of the myrmecophyte Maieta guianensis, in secondary forests, was limited by the distance to a young queen source (in this case, the mature forest). In both Vismia and Cecropia forests I found a decrease in the number of colonization events and also in the proportion of plants colonized by M. guianensis’ specific partner ant (Pheidole minutula) with increasing distance to the forest. After successfully colonizing a plant in any kind of secondary forest, P. minutula presented normal development and produced workers and alates. Successful colonization and development of the colony in secondary forests were also observed in the Cordia nodosa-Azteca sp.2 plant-ant system, but not in the other common association in Central Amazonia, Hirtella myrmecophila -Allomerus octoarticulatus. In both M. guianensis and C. nodosa the resident ants tend coccids in the domatia. This was not observed in A. octoarticulatus colonies wich have fewer ants per domatia within a plant in secondary forests. Consequently, herbivory of H. myrmecophila was higher in these environments. Herbivory rates were indistinguishable between the two kinds of secondary forest, for any of the three plant species. 17 In the Azteca sp2-C. nodosa system, the predation of ants by Cebus appela monkeys was higher in secondary than in mature forests. This predation occurred almost exclusively in the western part of the study area. This area, which falls on its own hidrografic basin, also presented the largest C. nodosa density. This spatial pattern suggests a density-dependent mechanism for, and/or the existence of a barrier to the dispersal of this feeding behavior tradition. In a preliminary analysis, however, ant predation doesn’t seem to have a relevant impact on plant or ant-plant populations. It sugests that disruptive predation by monkeys does not limit the re-establishment of these systems in secondary forests.Foram estudados alguns fatores que influenciam o re-estabelecimento de plantas mirmecófitas e formigas associadas em capoeiras submetidas a sucessivas queimadas antes do abandono (dominadas por pioneiras do gênero Vismia), capoeiras onde a vegetação foi apenas retirada (dominadas por Cecropia) e áreas de floresta madura e não perturbada. A riqueza e abundância de plantas mirmecófitas foi muito maior em matas do que em capoeiras, porém estes parâmetros não diferiram entre capoeiras com diferentes históricos de uso. A composição de plantas mirmecófitas é diferente entre capoeiras. Enquanto que em capoeiras dominadas por Vismia a composição mudou em função do número de queimas, em capoeiras de Cecropia ela foi relacionada com a idade de abandono. A composição de formigas que usam mirmecófitas foi fortemente relacionada com a composição local de plantas mirmecófitas, independente do tipo de ambiente. Porém, a proporção de plantas desocupadas ou associadas com formigas oportunistas foi maior em capoeiras dominadas por Vismia do que em capoeiras de Cecropia ou matas não perturbadas. A colonização da planta mimecófita Maieta guianensis em florestas secudárias foi limitada pela distância da fonte de rainhas jovens de formigas (neste caso a mata primária). Houve uma diminuição da proporção de plantas colonizadas, assim como na taxa de colonização pela principal espécie de formiga associada a esta planta (Pheidole minutula) em ambos os tipos de capoeira. Uma vez colonizadas por P. minutula, as plantas e formigas se desenvolveram e produziram alados com sucesso. Isto pôde ser observado também no sistema Cordia nodosa–Azteca sp. 2, mas não em Hirtella myrmecophila-Allomerus octoarticulatus, o sistema mais comum na Amazônia Central. Tanto em M. guianensis quanto em C. nodosa, as formigas residentes mantém coccídeos no interior das domáceas. Isto não ocorre em H. myrmecophila, que apresenta menos formigas por domácea e, conseqüentemente, mais herbivoria em capoeiras. Não houve diferença entre diferentes capoeiras para herbivoria para nenhuma das espécies de plantas estudadas

Defining Habitat Use by the Parabiotic Ants Camponotus femoratus (Fabricius, 1804) and Crematogaster levior Longino, 2003

Ant-garden ants have a strong relationship with epiphytes that need light to grow, for these reason, it has been previously documented in forest gaps. Moreover, larger gaps have more available area for nesting and habitats for use as forage. Thus we hypothesize that 1) canopy openness influence the presence of ant´s gardens in gaps, and 2) greater gaps will have more nests, and 3) both openness canopy and area determine the colony size in forest gaps. Furthermore, it is known that parabiotic ants foraging on the ground and in vegetation, the nests are arboreal. So, we also hypothesize that 4) parabiotic ants are more often sampled in arboreal strata and 5) increasing vegetation connectivity and the volume of accumulated litter in the soil increase the foraging of the ants in vegetation and ground, respectively, with the increase in canopy openness increasing the activity of the two species in both strata. Presence, number of Ant-gardens, as colony size, was affected by area and locality, but not by canopy openness. Nevertheless, there was not overall difference in the use of strata by Camponotus femoratus, neither by Crematogaster levior. On the other hand, frequency of C. femoratus on the ground decreases with canopy openness but is not affected by the vegetation connectivity.  Also, C. levior frequency on the ground also decreases with the increase of complexity of vegetation and canopy openness. In addition, neither vegetation connectivity, or canopy openness influence the frequency of foraging of these ants in understory

Amazon Rainforest Ant-Fauna of Parque Estadual do Cristalino: Understory and Ground-Dwelling Ants

Ants are ecologically dominant and have been used as valuable bio-indicators of environmental change or disturbance being used in monitoring inventories.  However, the majority of inventories has concentrated in ground-dwelling ant fauna disregarding the arboreal fauna. This paper aimed to list the ant species collected both on the ground and in the vegetation of the Parque Estadual do Cristalino, an important protected site in the center of the southern Amazon. Moreover, we compared the composition of the ground dwelling and vegetation foraging ants. Was sampled 203 species distributed among 23 genera and eight subfamilies, wherein 35 species had not yet been reported in the literature for Mato Grosso State. As expected, the abundance and richness of ants was higher on the ground than in the understory. Also, the ant assemblages composition was different between these habitats (with only 20% occurring in both). It indicate that complementary methods which include arboreal and terrestrial ants are indicated for efficient inventory. This study provides an inventory of the arboreal and ground ant fauna contributing to the knowledge and conservation of ant fauna of the Amazonian

Postponing the production of ant domatia as a strategy promoting an escape from flooding in an Amazonian myrmecophyte

Background and Aims: Even when adapted to flooding environments, the spatial distribution, growing strategies and anti-herbivore defences of plants face stressful conditions. Here we describe the effects of flooding on carbon allocation on growth, domatia and leaf production, and the herbivory on the myrmecophyte domatia-bearing Tococa coronata Benth. (Melastomataceae) growing along river banks in the Amazon region. Methods: In an area of 80 000 m2 of riparian forest along the Juruena River we actively searched for individuals of T. coronata. In each plant we evaluated the size of the plant when producing the first domatium and determined its best predictor: (1) plant total height; (2) size of plants above flood level; or (3) length of time each plant spent underwater. We also compared the herbivory, internode elongation, foliar asymmetry and specific leaf weight between T. coronata individuals growing above and below the maximum flooding level. The distance to the river and the height of the first domatium produced were compared between T. coronata and its sympatric congener, T. bulifera. Key Results: We found that T. coronata invests in rapid growth in the early ontogenetic stages through an elongation of internodes rather than in constitutive anti-herbivore defences to leaves or domatia to exceed the maximum flooding level. Consequently, its leaf herbivory was higher when compared with those produced above the flooding level. Individuals with leaves above flood levels produce coriaceous leaves and ant-domatias. Thus, flooding seems to trigger changes in growth strategies of the species. Furthermore, T. coronata occurs within the flood level, whereas its congener T. bullifera invariably occurs at sites unreachable by floods. Conclusion: Even in conditions of high stress, T. coronata presents both physiological and adaptive strategies that allow for colonization and establishment within flooded regions. These mechanisms involve an extreme trade-off of postponing adult plant characteristics to rapid growth to escape flooding while minimizing carbon allocation to defence

Hiding from defenders: Localized chemical modification on the leaves of an Amazonian ant-plant induced by a gall-making insect (Diptera: Cecidomyiidae)

Defense against herbivores is considered the main factor influencing the evolution of specialized ant-plant associations. Early studies have demon strated that ants chemically recognize and recruit on host plant leaves due to herbivory simulation. Gall-forming insects are herbivores that are able to manipulate chemical plant properties and thus could change ant responses. The goal of this study was to evaluate recruitment responses of Allomerus octoarticulatus, an ant species associated with the myrmecophyte Hirtella myrmecophila, which is attacked by a gall-forming insect (Cecidomyiidae). We conducted two different experiments to assess whether, octoarticulatus is able to recognize chemical compounds from galled tissues and whether galled and ungalled healthy leaves represent different chemical stimuli to worker ants. We did not observe differences on recruitment between galled and ungalled leaves. However, gall tissue extracts did not induce ant recruitment on H. myrmecophila, while galled leaves extracts resulted in a stimulus to ant recruitment. These results indicate that insect gall tissues on this myrmecophyte probably do not possess compounds which can be detected by the ants. A local change seems to be very helpful to gall-forming insects because they are protected from, and by, ants which deter herbivores

Can Baited Pitfall Traps for Sampling Dung Beetles Replace Conventional Traps for Sampling Ants?

Ants  and  dung  beetles  are  widely  used  in  monitoring  biodiversity  and  are  considered  excellent  environmental  indicators.  Although  the pitfall trap is the most commonly used method to sample dung beetles and ants in ecological studies, beetles are usually sampled using dung‐baited pitfall traps while ants are sampled using un‐baited pitfalls. In the protocol for collecting the beetles it is necessary to have attractive baits in pitfalls. In order to minimize collection effort and costs and to facilitate logistics, it is necessary to determine if there is an effect of the baits on the biodiversity of ants collected in the same traps. Therefore, the objective of this work was to find out whether baited pitfalls could replace conventional pitfalls for the capture of ants. In a total of 42 areas of native habitat, three baited pitfall traps and three without bait were installed, all in the same transect, equidistant ten meters and in activity for 48 hours. In total, 150 species were collected, of which 131 were recorded in non‐baited pitfalls and 107 in baited pitfalls. Traps without bait contributed to 28% of the total number of species captured in this study, whereas pitfalls with bait contributed only to 12% of the total species caught. However, 60% of the total species were captured regardless of the method. In addition to the loss of species among the types of traps, the effect of the method modifies the species composition. We concluded that depending on the type of study, a small decrease in the number of species and change in the composition can influence the results. Thus, we recommend that baited pitfalls should not replace conventional pitfalls.Palavras-chave: Método de coleta; Protocolo de coleta; Desenho da amostra; Esforço de amostragem

Interaction Intimacy Affects Structure and Coevolutionary Dynamics in Mutualistic Networks

The structure of mutualistic networks provides clues to processes shaping biodiversity [1-10]. Among them, interaction intimacy, the degree of biological association between partners, leads to differences in specialization patterns [4, 11] and might affect network organization [12]. Here, we investigated potential consequences of interaction intimacy for the structure and coevolution of mutualistic networks. From observed processes of selection on mutualistic interactions, it is expected that symbiotic interactions (high-interaction intimacy) will form species-poor networks characterized by compartmentalization [12, 13], whereas nonsymbiotic interactions (low intimacy) will lead to species-rich, nested networks in which there is a core of generalists and specialists often interact with generalists [3, 5, 7, 12, 14]. We demonstrated an association between interaction intimacy and structure in 19 ant-plant mutualistic networks. Through numerical simulations, we found that network structure of different forms of mutualism affects evolutionary change in distinct ways. Change in one species affects primarily one mutualistic partner in symbiotic interactions but might affect multiple partners in nonsymbiotic interactions. We hypothesize that coevolution in symbiotic interactions is characterized by frequent reciprocal changes between few partners, but coevolution in nonsymbiotic networks might show rare bursts of changes in which many species respond to evolutionary changes in a single species. © 2007 Elsevier Ltd. All rights reserved

RESPOSTA A LEI Nº 11.861, DE 03 DE AGOSTO DE 2022: CONSEQUÊNCIAS A BIODIVERSIDADE DO PANTANAL

O Pantanal é a maior planície alagada do mundo e berço de grande biodiversidade, porém é constantemente ameaçado por empreendimento humanos. Idealmente, as políticas públicas deveriam se basear em ciência a fim de reconhecer e considerar as particularidades locais a fim de permitir e promover atividades econômicas ao mesmo tempo que protegem sua diversidade e funcionamento. Recentemente foi proposta a lei 11.861/2022, que embora tenha acertos em algumas questões ambientais, permite a pecuária extensiva no Pantanal sem determinar limites para sua implantação. Logo, o objetivo deste estudo é fazer um levantamento de consequências de alguns manejos presentes em manuais básicos de pecuária extensiva sobre a biodiversidade de grupos-chave de animais do Pantanal. A partir da literatura científica global, foram feitas pesquisas padronizadas na plataforma Web of Science para quantificar como o uso de fertilizantes, herbicidas, pesticidas e o fogo afetam a biodiversidade de diferentes grupos de vertebrados e invertebrados que executam importantes funções no ecossistema: Aves, Peixes, Mamíferos, Formigas e Ortópteros. Observamos que literalmente todos esses métodos de manejo poderão causar um decréscimo na biodiversidade destes grupos de forma direta ou indireta. Logo, a implementação da lei permitirá a modificação do ambiente de forma que necessariamente causará impacto negativo a diversos grupos animais no Bioma Pantanal, tendo consequências ambientais e econômicas (pesca, turismo, agricultura de subsistência). Além disso, como essas conversões podem prejudicar as populações humanas tradicionais existentes e outras atividades econômicas que dependem da biodiversidade e das funções do ecossistema. Embora esta lei seja considerada por alguns como um avanço, que atende às demandas de agricultores e proprietários de terras, ela também pode abrir as comportas figurativas para práticas mais desreguladas e catastróficas que já impactam o Pantanal