Implications of the Floral Herbivory on Malpighiacea Plant Fitness: Visual Aspect of the Flower affects the attractiveness to Pollinators

The Malpighiaceae family is species-rich and is abundant in Brazil. Malpighiaceae flowers provide oil and pollen to pollinating bees and serve as food for herbivorous insects, which damage the floral structures. Although common in the Cerrado, florivory is still poorly studied. In the present study, we evaluated the effect of florivory in one of the most common genera of Malpighiaceae in the Cerrado (Banisteriopsis) and the impact of florivory on fruiting. The florivory rate was quantified in flowers of B. malifolia belonging to two morphotypes and in flowers of B. variabilis. Additionally, a petal-removal experiment was performed, which simulated the presence of damage in the flowers. The manipulation involved a control group with intact flowers, a group without the standard petal and a group of flowers without common petals. The florivory in the petals (floral area lost) differed between the species, and B. malifolia was the most damaged. The experimental manipulation revealed that intact flowers had a higher fruiting rate compared with the remaining flowers. These results reinforce the concept that florivory renders flowers less attractive to pollinating bees, which negatively affects the fruiting rate and the reproductive success of plants. We suggest that basic studies (such as the present investigation) be extended to further elucidate the effect of interactions between pollinators, plants, and herbivores on the general structure of communities

Ants Visiting the Post-Floral Secretions of Pericarpial Nectaries in Palicourea rigida (Rubiaceae) Provide Protection Against Leaf Herbivores But Not Against Seed Parasites

Pericarpial nectaries (PNs) have frequently been treated in the literature as extrafloral nectaries (EFNs). This treatment is partly justified by their morphological and functional similarities in attracting bodyguard ants to protect the plant against herbivores. Palicourea rigida is a common Neotropical savanna treelet with tubular yellow flowers that are pollinated by hummingbirds. After pollination, the corolla falls, but the sepal ring remains and keeps the nectaries active over the ovarium throughout fruit development stages. Using a standard ant-exclusion experiment, we tested whether these PNs attract ants to protect the developing fruits against seed parasites and the leaves against chewing herbivores. We analyzed the differences between the initial and final leaf area. Before full fruits maturity, they were collected and taken to the laboratory for weighing and to observe wasp emergence. The number of wasps per fruit and per plant was recorded. The results showed that after pollination, the floral nectaries of P. rigida act as EFNs, attracting visiting ants. Ant-tended plants lost significantly less leaf area and had heavier fruits than untended plants. However, the ants did not protect the fruits against seed-parasitic wasps. In P. rigida, the post-floral secretions of PNs play the same role as EFNs, and the ant-plant mutualism is context-dependent based on the type of herbivore and the plant tissue consumed

Effects of ants on pollinator performance in a distylous pericarpial nectary-bearing Rubiaceae in Brazilian Cerrado

Besides the eff ectiveness of floral visitors, to better understand pollination systems is necessary to consider the role of predators. Ants are ubiquitous on the vegetation, especially on plants bearing extrafloral (EFNs) and pericarpial nectaries (PNs). Both EFNs and PNs reward ants which in turn provide to plants effective protection against herbivores. However, ants can also repel pollinators and cause an indirect cost for the plant partner, although the role of ants on pollinators’ performance has rarely been assessed in Neotropics, mainly on PN-bearing plants. Here, our main aim was, through an experimental field study in terms of ant’s presence versus absence, to test the hypothesis that ants dissuade floral visitors by decreasing the time spent during visits on the PN-bearing Declieuxia fruticosa. Additionally, we recorded floral phenology, and quantified and qualified floral visits. We showed that bees were the most frequent pollinators and the presence of ants dissuades them. In ant presence, pollinators were on average 30% faster than without ants. Since D. fruticosa produces fruits mainly after cross-pollination, the role of ants may be profi table to plants as they induce pollinators to do shorter visits and search for other fl owers in conspecifi c plants. Therefore, pollinators avoid stay at longer on plants with ants in order to avoid attacks, which may contribute to plant outcrossing. However, whether positive or negative the effects of ants on D. fruticosa reproduction are, they remain to be studied

Negative effects of ant-plant interaction on pollination: costs of a mutualism

The mutualism of ants and extrafloral nectary (EFN)-bearing plants is known to reduce rates of herbivory. However, ants may have negative impacts on other mutualisms such as pollination, constituting an indirect cost of a facultative mutualism. For instance, when foraging on or close to reproductive plant parts ants might attack pollinators or inhibit their visits. We tested the hypothesis that ants on EFN-bearing plants may negatively influence pollinator behavior, ultimately reducing plant fitness (fruit set). The study was done in a reserve at Brazilian savannah using the EFN-bearing plant Banisteriopsis malifolia (Malpighiaceae). The experimental manipulation was carried out with four groups: control (free visitation of ants), without ants (ant-free branches), artificial ants (isolated branches with artificial ants on flowers) and plastic circles (isolated branches with plastic circles on flowers). We made observations on flower visitors and their interactions, and measured fruit formation as a proxy for plant fitness. Our results showed that pollinators hesitated to visit flowers with artificial ants, negatively affecting pollination, but did not hesitate to visit flowers with plastic circles, suggesting that they recognize the specific morphology of the ants. Pollinators spent more time per flower on the ant-free branches, and the fruiting rate was lower in the group with artificial ants. Our results confirm an indirect cost in this facultative mutualism, where the balance between these negative and positive effects of ants on EFN-bearing plants are not well known

Reproduction Ecology of Myrcia rostrata DC. and Myrcia tomentosa (Aubl.) DC. (Myrtaceae) in Uberlândia, Minas Gerais

Myrtaceae is a very common Neotropical family, its evergreen species and fresh fruits are important food sources for vertebrates and invertebrates, in preserved areas as well as degraded ones, which points out its importance to those ecossistems. We studied the reproductive ecology of two species from one of the biggest genus in this family, Myrcia rostrata DC. and Myrcia tomentosa (Aubl) DC., which are easily found in South American forests and Cerrados. Its small hermafrodite flowers are bee-pollinated, as usual for species of Myrtaceae. Pollen is the sole reward offered to small colonial bees (Trigona, Apis, Augocloropsis). M. rostrata has a “multiple bang” flowering strategy while Myrcia tomentosa has a “pulsed bang” one. The flowering period begins after the first spring rains, a common pattem of many Myrtaceae. Floral buds can remain quiescent for over tliree months waiting for the humidity to increase. Pollination experiments indicated these species are preferencial outcrossing, as many Myrtaceae studied, setting more fruits with outbreeding than with self-pollination. High natural fruit-sets observed for both species denoted adequated pollinating Services at Panga Ecological Reserve. However, the reduced pre-emergent reproductive success values observed mainly for M. tomentosa due to larval herbivory inside floral buds, makes more stuiies necessary to clarify this situation.Dissertação (Mestrado)A família Myrtaceae é bem representada nos Neotrópicos, sendo seus indivíduos sempre verdes e seus frutos camosos uma importante fonte de recursos alimentares para vertebrados e invertebrados, tanto em áreas conservadas quanto em áreas degradadas, o que mostra sua importância para esses ecossistemas. Este estudo enfocou a biologia da reprodução de Myrcia rostrata DC e Myrcia tomentosa (Aubl.) DC, espécies de um dos maiores gêneros da família e amplamente distribuídas nas matas e cerrados lato sensu da América do Sul. Suas flores pequenas e hermafroditas apresentam síndrome de melitofilia, típica para a família. O pólen é o único recurso oferecido para pequenas abelhas sociais (Trigona, Apis e Augocloropsis). A floração de M. rostrata é do tipo “multiple bang” e a de M. tomentosa é do tipo “pulsed bang”, após as chuvas da primavera, padrão semelhante a outras espécies de Myrtaceae. Seus botões florais podem manter-se quiescentes por até 3 meses, à espera do aumento de umidade. As polinizações controladas indicaram que as espécies são xenógamas facultativas, como a maior parte das espécies de Myrtaceae estudadas, com maior frutificação por polinização cruzada do que por autopolinização manual. A alta frutificação natural de M. rostrata e M. tomentosa sugere que a polinização natural na E. E. do Panga foi eficiente para essas espécies, contudo, a predação por larvas no interior de botões florais, principalmente de M. tomentosa, diminuiu seu sucesso reprodutivo pré-emergente. Outros estudos relacionados são necessários para determinar as consequências dessas interações no sucesso reprodutivo dessas espécies

Ecologia comportamental: uma ferramenta para a compreensão das relações animais-plantas

Experimental manipulation and description of behavioral repertoires are just two examples of many different tools used in behavioral ecology to increase the knowledge about plant-animal interactions. Behavioral ecology allows us to evaluate how one behavior can maximize individual fitness and also makes it possible to quantify variations within populations. Behavioral ecology also allows for testing the adaptive value of the behaviors exhibited by distinct members in a food web, providing insights to many aspects of a given community. In this sense, ethological methods associated with modern or traditional techniques in botany, zoology, genetics and computational analysis can be employed in solving ecological questions, many of which are related to consequences of plant-animal interactions. Thus, the ethological tools used in behavioral ecology can help us understand plant-animal interactions in nature, including the ethological roles of species, types of interactions and their results, the structure of the established food web, impacts of selective forces, habitat heterogeneity and geographical variations. We illustrate these methodologies and also discuss their implications for conservation of interaction biodiversity.A manipulação experimental e a descrição de repertórios comportamentais são apenas dois exemplos das muitas ferramentas utilizadas pela ecologia comportamental para incrementar nossa compreensão sobre as interações entre animais e plantas. A ecologia comportamental permite avaliar como um determinado comportamento pode maximizar a aptidão dos indivíduos que o apresentam e possibilita quantificar suas variações na população. Permite também testar o valor adaptativo de comportamentos exibidos por diferentes membros de uma rede trófica, fornecendo uma visão sobre a comunidade. Nesse sentido, os métodos etológicos associados às técnicas clássicas e/ou modernas das áreas de botânica, zoologia, genética e computação, podem ser empregados na solução de questões ecológicas, que se referem principalmente ao significado das interações animais-plantas. Deste modo, as ferramentas etológicas empregadas na ecologia comportamental podem auxiliar na compreensão da natureza das relações animais-plantas, evidenciando o papel ecológico das espécies, os tipos de interações e seus resultados, a estrutura trófica da teia estabelecida, assim como os reflexos da pressão de seleção, a heterogeneidade de habitat e a variação geográfica. Apresentamos exemplos envolvendo o uso dessas metodologias e discutimos suas implicações para a conservação da biodiversidade de interações.La manipulación experimental y la descripción de repertorios de comportamiento son apenas dos ejemplos de las numerosas herramientas utilizadas por la ecología del comportamiento para incrementar nuestra comprensión sobre la interacción entre animales y plantas. La ecología del comportamiento permite evaluar como un determinado comportamiento puede maximizar el éxito de los individuos y permite cuantificar sus variaciones dentro de las poblaciones. Permite también evaluar el valor adaptativo de los comportamientos exhibidos por diferentes miembros de una red trófica, proveyendo una visión sobre diversos aspectos de una comunidad. En este sentido, los métodos etológicos asociados a las técnicas clásicas y/o modernas de las áreas de botánica, zoología, genética y computación, pueden ser empleados para responder a preguntas ecológicas que se refieren principalmente al significado de las interacciones animales-plantas. De este modo las herramientas etológicas empleadas en la ecología del comportamiento pueden ayudar en la comprensión de la naturaleza de las relaciones animales-plantas, evidenciando el papel ecológico de las especies, los tipos de interacciones y sus resultados, la estructura trófica de la red establecida, así como el impacto de la presión de selección, la heterogeneidad del hábitat y la variación geográfica. Presentamos ejemplos incluyendo el uso de estas metodologías y discutimos sus implicaciones para la conservación de la biodiversidad de las interacciones

Characterization of malpighiaceae flower-visitor interactions in a brazilian savannah: how do floral resources and visitor abundance change over time

CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOThe plants of Malpighiaceae are diverse and produce specific floral resources that provide a parameter of habitat quality for oil-collecting bees. We studied three species of Malpighiaceae from the Brazilian savannah, Banisteriopsis campestris, B. malifol234126134CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOsem informação473055/2012-