Estudo comparado sobre a influência de alguns fatores externos e internos no desenvolvimento de colônias de Mischocyttarus cassununga e Mischocyttarus cerberus styx (Hymenoptera, Vespidae, Mischocyttarini)
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Data
2016-08-04
Autores
Biagiotto, Renan Hohendorff [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Mischocyttarus é um gênero de vespas eussociais pertencente à subfamília Polistinae, de importância para estudos como a origem e evolução do comportamento social. Como constroem ninhos desprovidos de envelope, o acompanhamento do desenvolvimento colonial é facilitado, permitindo observar a oviposição, desenvolvimento de ovos, larvas e pupas, assim como a adição de células novas no ninho e eventos de conflitos hierárquicos entre adultos. Mischocyttarus cerberus styx e Mischocyttarus cassununga são espécies representantes de um gênero e tribo que ocorrem apenas nas Américas e estas espécies, por sua vez, ocorrem no município de Rio Claro (SP). Por ser um gênero de vespas de clima tropical e subtropical, colônias em todas as fases de desenvolvimento são encontradas ao longo do ano. Neste sentido, o presente trabalho procurou acompanhar o desenvolvimento colonial e fenologia de ambas espécies, afim de desenvolver um estudo comparado de fatores internos e externos à colônia que interagem com o andamento do ciclo colonial, de forma a verificar se as espécies demonstram perfis similares ou diferenciados entre si. Quatro locais foram escolhidos para representar a amostragem no campus da Universidade Estadual Paulista de Rio Claro, SP. O período de coleta de dados compreendeu abril de 2014 a abril de 2015, com mapeamentos e observações comportamentais semanais de ninhos selecionados, assim como varreduras mensais para detecção de colônias ativas. M. cerberus styx apresentou perfil de produtividade mais inconstante ao longo das estações do ano, apresentando de modo geral os maiores valores para o verão e os menores para o inverno. Já M. cassununga demonstrou um ritmo mais estável, com menor discrepância entre a produtividade exibida dentre as estações, demonstrando melhor desempenho em estações frias, com os maiores valores verificados na primavera e os menores para o outono. A produtividade de todas as formas imaturas de M. cerberus styx apresentou significância estatística em correlação com a temperatura do ar e pluviosidade. Para M. cassununga, a produção de imaturos apresentou correlação significativa com a temperatura e a umidade relativa do ar, exceto para pupas, demonstrando significância estatística para pluviosidade. Ambas espécies apresentaram um padrão similar de duração de estágios imaturos (ovo, larva e pupa) com os menores períodos verificados no verão e os maiores períodos para o inverno. A incidência de oofagia e retirada de larvas dos ninhos coincidiu com estações de maior produtividade, provavelmente ligadas a um conjunto de fatores. Ademais, ninhos em fase de pós-emergência (pós-macho) apresentaram maiores valores de oofagia e retirada de larvas para ambas espécies. Como já constatado em outros estudos, as espécies são assincrônicas em relação às estações do ano e apresentam sinantropismo, nidificando em substrato artificial e natural. Os modelos de Regressão Linear Múltipla indicaram a temperatura do ar como fator preponderante para a oscilação de colônias ativas, porém apenas para colônias em pós-emergência de M. cassununga apresentaram significância estatística. Foram observados parasitoides da família Ichneumonidae em colônias de M. cerberus styx e da família Phoridae em ambas espécies. Foram observados eventos de predação por formigas em M. cassununga, assim como predação por aves, para as duas espécies. Poucos eventos de conflitos hierárquicos foram constatados, apenas indicando influência no andamento do ciclo colonial.
Mischocyttarus is a genus of eusocial wasps belonging to the Polistinae subfamily, of importance to studies such as the origin and evolution of social behavior. They build nests without envelopes, making it easier to take notes and follow the growth of the nest, allowing the observation of oviposition, development of the eggs, larvae and pupae, as well as the addition of new cells to the nest and hierarchical conflicts among adults. Mischocyttarus cerberus styx and Mischocyttarus cassununga are representatives of a genus and tribe that occur only in the Americas and these species happen to occur in the municipality of Rio Claro (SP). Being a wasp genus of tropical and subtropical climates, colonies in all development phases can be found throughout the year. In this sense, the present work aimed to follow the development of colonies and to study the phenology of both species, in order to develop a comparative approach of internal and external factors that interact with the colony cycle, to verify if the species show similar or diverse profiles from each other. Four locations were chosen to represent the sampling at the Universidade Estadual Paulista campus of Rio Claro, SP. The period of data collection ranged from April 2014 to April 2015, with the mapping and behavioral observations of selected colonies, as well as monthly scanning to detect active colonies. M. cerberus styx showed a more irregular profile of productivity along the four seasons, presenting in general the greatest values on summer and the lowest values on winter. M. cassununga, on the other hand, seemed to have a more stable rhythm of productivity, with less discrepancy between seasons, demonstrating a better performance concerning cold seasons, with the greatest productivity values on spring and the lowest values on fall. Productivity of all immature stages of M. cerberus styx showed significant statistical correlation with air temperature and rainfall. For M. cassununga, immature productivity showed significant statistical correlation with air temperature and humidity, except for pupae, showing significant correlation with rainfall. Both species showed a similar pattern of immature development (eggs, larvae and pupae) with the shortest period corresponding to summer and the longest period corresponding to winter. The incidence of oophagy and larvae ejection coincided with the period of greatest productivity, probably linked to other factors. To add, nests in post-emergence (post-male) phase showed greater values of oophagy and larvae ejection for both species. As stated before in other studies, both species are assynchronical in relation to the seasons of the year and showed sinantropism, nesting in artificial and natural substrates. The Multiple Linear Regression models indicated air temperature as a major factor of influence on the variation of active colonies, but only significantly correlated to post-emergent M. cassununga colonies. Parasitoids of the Ichneumonidae family were observed in colonies of M. cerberus styx as well as of the Phoridae family for both species. Predation events by ants were observed for M. cassununga colonies, as well as birds for both species. Only very few events of conflict were observed and stated, being only an indication of influence to the progression of the colony cicle.
Mischocyttarus is a genus of eusocial wasps belonging to the Polistinae subfamily, of importance to studies such as the origin and evolution of social behavior. They build nests without envelopes, making it easier to take notes and follow the growth of the nest, allowing the observation of oviposition, development of the eggs, larvae and pupae, as well as the addition of new cells to the nest and hierarchical conflicts among adults. Mischocyttarus cerberus styx and Mischocyttarus cassununga are representatives of a genus and tribe that occur only in the Americas and these species happen to occur in the municipality of Rio Claro (SP). Being a wasp genus of tropical and subtropical climates, colonies in all development phases can be found throughout the year. In this sense, the present work aimed to follow the development of colonies and to study the phenology of both species, in order to develop a comparative approach of internal and external factors that interact with the colony cycle, to verify if the species show similar or diverse profiles from each other. Four locations were chosen to represent the sampling at the Universidade Estadual Paulista campus of Rio Claro, SP. The period of data collection ranged from April 2014 to April 2015, with the mapping and behavioral observations of selected colonies, as well as monthly scanning to detect active colonies. M. cerberus styx showed a more irregular profile of productivity along the four seasons, presenting in general the greatest values on summer and the lowest values on winter. M. cassununga, on the other hand, seemed to have a more stable rhythm of productivity, with less discrepancy between seasons, demonstrating a better performance concerning cold seasons, with the greatest productivity values on spring and the lowest values on fall. Productivity of all immature stages of M. cerberus styx showed significant statistical correlation with air temperature and rainfall. For M. cassununga, immature productivity showed significant statistical correlation with air temperature and humidity, except for pupae, showing significant correlation with rainfall. Both species showed a similar pattern of immature development (eggs, larvae and pupae) with the shortest period corresponding to summer and the longest period corresponding to winter. The incidence of oophagy and larvae ejection coincided with the period of greatest productivity, probably linked to other factors. To add, nests in post-emergence (post-male) phase showed greater values of oophagy and larvae ejection for both species. As stated before in other studies, both species are assynchronical in relation to the seasons of the year and showed sinantropism, nesting in artificial and natural substrates. The Multiple Linear Regression models indicated air temperature as a major factor of influence on the variation of active colonies, but only significantly correlated to post-emergent M. cassununga colonies. Parasitoids of the Ichneumonidae family were observed in colonies of M. cerberus styx as well as of the Phoridae family for both species. Predation events by ants were observed for M. cassununga colonies, as well as birds for both species. Only very few events of conflict were observed and stated, being only an indication of influence to the progression of the colony cicle.
Descrição
Palavras-chave
Mischocyttarus, Produtividade, Duração de estágios imaturos, Fenologia, Productivity, Duration of immature stages, Phenology