Efeitos benéficos de formigas para plantas com um escrutínio sobre a proteção contra herbivoria: revisitando o sistema Cecropia-Azteca

Mutualism and herbivory are antagonic ecologic relations. Mutualism is an interaction with mutual benefits for the involved species. Herbivory, on the other hand, is a predation interaction, in which a herbivore species benefits feeding on a usually impaired plant. Both interactions are found in myrmecophytic systems. In such mutualistic systems, plants offer shelter and food to ants, that, in exchange, benefit plants through many mechanisms, being herbivory protection the most evident. In parallel, plants can also use other strategies, like the production of chemical compounds and morphological structures. Moreover, plant physical and physiological responses to herbivory can change throughout its development. Our aim was to investigate all the known potential benefits from ants to plants. In addition, we addressed the effects of herbivory on plant growth along its ontogenetic development. Through an long-term experiment, we monitored Cecropia glaziovii individuals during 54 months. We collected data monthly on plant growth, herbivory, nutrition, investiment in chemical and physical defenses and colonization by ants. We showed here that Azteca muelleri ants benefit their host plants growth via protection against herbivores and pathogens, nutrition and energy saving from other defensive strategies. Moreover, herbivory only impairs plants in the phase after the ant colonization. Here, we conclusively demonstrate the beneficial effects of ants to plants, beyond the classic herbivory protection. In addition, we showed that plant ontogenetic stage is determinant to its response to herbivory.Mutualismo e herbivoria são relações ecológicas com características distintas. Enquanto o mutualismo é uma interação que gera benefícios mútuos para as espécies envolvidas, a herbivoria é uma relação de predação, em que uma espécie herbívora é beneficiada se alimentando da planta. Essas relações são evidentes nos sistemas de plantas mirmecófitas. Nesses sistemas mutualísticos, as plantas oferecem abrigo e alimento para formigas, que, por sua vez, oferecem diversos benefícios às suas hospedeiras, sendo a proteção contra herbivoria a mais evidente. Para se proteger, as plantas ainda possuem outras estratégias, como a produção de compostos químicos e estruturas morfológicas especializadas em proteção. Além disso, as respostas das plantas à herbivoria em suas características físicas e fisiológicas podem mudar ao longo do seu desenvolvimento. Neste trabalho, nosso objetivo foi investigar todos os potenciais benefícios conhecidos das formigas Azteca muelleri para suas plantas hospedeiras, Cecropia glaziovii. Além disso, investigamos os efeitos da herbivoria sobre o crescimento das plantas ao longo do seu desenvolvimento ontogenético. Por meio de um estudo experimental de longo prazo, nós acompanhamos o desenvolvimento de plantas de C. glaziovii por 54 meses. Com coletas mensais, acessamos dados sobre crescimento, herbivoria, nutrição, investimento em defesas químicas e físicas e a colonização das formigas. Demonstramos que as formigas A. muelleri favorecem o crescimento de suas plantas hospedeiras por meio de proteção contra herbívoros e patógenos. As formigas ainda nutre a planta e reduzem gastos energéticos com produção de tricomas. Ademais, a herbivoria só se torna prejudicial para a planta depois que esta é colonizada por formigas. Apresentamos aqui uma definição conclusiva sobre os efeitos benéficos das formigas para as plantas, que vão além da clássica defesa contra herbivoria. Além disso, mostramos que a fase ontogenética da planta parece ser determinante para seu tipo de resposta à herbivoria.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Immediate Effect of dominant species exclusion on structuring bait-visitors ant communities in tropical savannas

A competição é um tema controverso na teoria ecológica. Estudos que tenham envolvido competição e formigas têm demonstrado resultados contraditórios. Assim, trabalhos experimentais são necessários para elucidar a importância da competição sobre a estrutura de comunidades de formigas. Dessa forma, o objetivo desse estudo foi determinar experimentalmente o efeito a curto prazo da exclusão de duas espécies dominantes de formigas sobre a estrutura de comunidades de formigas que forrageiam em iscas. Coletei os dados entre fevereiro e abril de 2007, em Darwin, NT, Austrália, e entre janeiro e fevereiro de 2010, em Uberlândia, MG, Brasil. Nós estabelecemos três grids em cada país, onde nós bloqueamos as espécies dominantes. Os grids eram compostos de 100 iscas espalhadas em 10 linhas de 10 iscas, sempre espaçadas em 3m. As iscas foram feitas de ¼ de papel branco com 30g de sardinha depositada sobre ela. O experimento foi divido em três partes de três dias cada um. A primeira parte foi chamada antes do bloqueio , em que as formigas foram coletadas sem interferência prévia. Na segunda parte, durante o bloqueio , os ninhos das formigas dominantes foram bloqueados com bacias plásticas. Finalmente, depois do bloqueio , quando os ninhos foram desbloqueados. Depois de uma hora da instalação das iscas, nós coletávamos as formigas e anotávamos a sua abundância. Durante o bloqueio na Austrália, a riqueza e a abundância de formigas cresceram significativamente quando comparadas aos demais tratamentos. Além disso, a composição de espécies de formigas nas iscas mudou durante o bloqueio da espécie dominante. No Brasil, houve uma queda desses valores durante e depois do bloqueio, provavelmente devido a uma espécie subdominante (Cephalotes pusillus), que aumentou em abundância e frequência e parece ter tido um efeito negativo maior sobre a comunidade de formigas. Algumas espécies foram coletadas apenas quando as espécies dominantes estavam bloqueadas na Austrália. Nossas análises indicam que existem mudanças importantes sobre a diversidade e a composição de espécies com o bloqueio das espécies dominantes. Na Austrália, as espécies dominantes podem regular a diversidade momentânea, enquanto no Brasil elas podem ter um efeito estabilizador. Isso sugere que a competição pode ser um importante processo na estruturação de comunidades de formigas.Competition is a controversial theme in theoretical ecology. Studies involving competition and ants have demonstrated contradictories results. Thus, experimental work is necessary to elucidate the real importance of competition on structuring ant communities. Then, the aim of this study was to experimentally determinate the immediate effect of exclusion of two dominant ant species on the structure of ants communities which forage on baits. I collected data between February and April of 2007, in Darwin, NT, Australia and between January and February of 2010 in Uberlândia, MG, Brazil. I established three plots in each country where we experimentally removed the two most aggressive ant species. The plots were made of 100 baits spaced in ten lines of ten baits spaced in 3m. The baits were made of ¼ of a paper with 30g of sardine deposited on it. The experiment was divided in three parts of three days each one. The first part was called before exclusion , when the ants were collected without previous interference. In the second part, during exclusion , the dominant ants nests were blocked with plastic bowls. Finally, after exclusion , after we unblock the dominant ants nests. One hour after the baits installation, we collected the ants and noted its abundance. During exclusion in Australia, the richness and abundance of ants increased significantly when compared with others treatments. Furthermore, the ant species composition on baits changed during the dominant species exclusion. In Brazil, there was a decrease of those values during and after exclusion, probably due to a subdominant species (Cephalotes pusillus) that increased in abundance and frequency and may have had a stronger negative effect on ant community. Some species were collected only when the dominant species were blocked in Australia. Our analysis indicates there is an important change in the ant species diversity and composition with the dominant species exclusion. In Australia, dominant species may regulate momentary diversity of ant community while in Brazil it has a buffer effect. This may indicate that competition is a strong factor structuring ant assemblage.Fundação de Amparo a Pesquisa do Estado de Minas Gerai

Multiple effects of mutualistic ants improve the performance of a neotropical ant-plant : a long-term study with the Cecropia-Azteca system

Comprehension of the benefits involved in mutualisms is crucial to disentangle the role of interactions in the structure and functioning of populations, communities and ecosystems. In ant-plant mutualisms, benefits provided by plants to ants are immediately recognizable, but reverse benefits are less obvious, conditional and accumulate over longer time spans. Here we tested the hypothesis that the ant Azteca muelleri simultaneously provides multiple benefits to its host plant (Cecropia glazio-vii), ultimately increasing plant performance. We planted seedlings and experimentally prevented ant colonization for half of them. Over 4.5 years we quantified the effects of ant presence or absence on plant growth, herbivory levels, fungal infection, fertilization via ant debris and changes in defense strategies. Ant colonization increased plant height by 125% compared to ant-free plants. Such an improvement in plant performance can be explained because plants with ants faced less herbivory, lower prevalence of pathogenic fungi, invested less in foliar trichomes and had more foliar nitrogen. We thus confirmed that ant mutu-alists provide cumulative benefits including nutritional benefits, effective defense and lower investment into other defenses -which result in increased plant growth. We highlight the importance of long-term experiments that simultaneously evaluate a multiplicity of potential ant effects to better understand their relative contribution to the performance of the mutualistic partner. (C) 2021 Gesellschaft for Okologie. Published by Elsevier GmbH. All rights reserved

ATLANTIC ANTS: a data set of ants in Atlantic Forests of South America

International audienc

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora