Parasitismo de populações de Anaphes nitens (Hymenoptera: Mymaridae) em Gonipterus platensis (Coleoptera: Curculionidae) e endossimbiontes associados
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Data
2019-01-25
Autores
Ribeiro, Murilo Fonseca
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Universidade Estadual Paulista (Unesp)
Resumo
O setor florestal brasileiro é um dos mais desenvolvidos e competitivos do mundo, sendo líder mundial em produtividade de eucalipto. A presença de grandes maciços florestais favorece a ocorrência de pragas. O gorgulho-do-eucalipto, Gonipterus platensis Marelli (Coleoptera: Curculionidae), é a principal espécie de besouro desfolhador do eucalipto no mundo. As injúrias na planta hospedeira são causadas por adultos e larvas, sendo a última responsável pelas desfolhas mais severas. Os danos podem chegar à redução de 42,8% no incremento médio anual da árvore. O controle biológico por meio do parasitoide de ovos Anaphes nitens Girault (Hymenoptera: Mymaridae) é a principal estratégia de controle de Gonipterus spp., responsável pelo controle populacional da praga desde as primeiras detecções no Brasil na década de 1950. Todavia, surtos de G. platensis têm sido observados em regiões onde ácaros do gênero Pyemotes foram detectados se alimentando de ovos de G. platensis e onde o parasitismo e o estabelecimento do parasitoide caíram. Este trabalho teve como objetivo estudar possíveis fatores bióticos associados ao parasitoide A. nitens, avaliando a capacidade de parasitismo em diferentes populações do parasitoide e realizando prospecção de bactérias simbiontes que possam de alguma maneira interferir no fitness do hospedeiro. Para o parasitismo entre 2 populações de A. nitens, provenientes dos Estados de São Paulo, e Espírito Santo, ambas exibiram resultados de parasitismo, porcentagem de emergência e razão sexual que não diferiram significativamente. Para a prospecção de endossimbiontes secundários em diferentes populações de A. nitens, adultos e ovos de G. platensis e ácaros do gênero Pyemotes, foram realizadas análises moleculares por meio de PCR para a presença de 9 gêneros bacterianos diferentes com a utilização de primers específicos. A bactéria endossimbionte Rickettsia belli e as espécies de bactérias de intestino Yersinia massiliensis, Serratia grimesii e Erwinia amylovora foram encontradas em todas as populações naturais de A. nitens e nas gerações F1 e F2 de laboratório. A espécie Serratia grimesii também foi encontrada em adultos e ovos de G. platensis e em fêmeas de Pyemotes sp. Todas essas detecções representam primeiros relatos para os hospedeiros.
The Brazilian forestry sector is one of the most developed and competitive in the world, being the world leader in eucalyptus productivity. The presence of large forest masses favors the occurrence of pests. The Eucalyptus-snout-beetle, Gonipterus platensis Marelli (Coleoptera: Curculionidae), is the main species of eucalyptus defoliator beetle in the world. Injuries to the host plant are caused by adults and larvae, the latter being responsible for the most severe defoliation. The damages can reach the reduction of 42.8% in the average annual increment of the tree. Biological control through the parasitoid Anaphes nitens Girault (Hymenoptera: Mymaridae) is the main control strategy of Gonipterus spp., responsible for population control of the pest since the first detections in Brazil in the 1950s. However, outbreaks of G. platensis have been observed in regions where Pyemotes mites were detected feeding on G. platensis’s eggs and where parasitism and parasitoid establishment occurred. The objective of this work was to study possible biotic factors associated with the A. nitens parasitoid, evaluating the parasitism capacity in different populations of the parasitoid and conducting prospection of symbiotic bacteria that may interfere in the host 's fitness. For the parasitism between two populations of A. nitens, from the States of São Paulo and Espírito Santo, both showed results of parasitism, emergency percentage and sexual ratio that did not differ significantly. For the prospection of secondary endosymbionts in different populations of A. nitens, adults and G. platensis’s eggs and mites of the genus Pyemotes, molecular analyzes were performed by means of PCR for the presence of 9 different bacterial genera with the use of specific primers. The bacteria endosymbiont Rickettsia belli and the intestinal bacteria species Yersinia massiliensis, Serratia grimesii and Erwinia amylovora were found in all natural populations of A. nitens and in the F1 and F2 generations of the laboratory. The Serratia grimesii species was also found in adults and eggs of G. platensis and in females of Pyemotes sp. All these detections represent first reports to the hosts.
The Brazilian forestry sector is one of the most developed and competitive in the world, being the world leader in eucalyptus productivity. The presence of large forest masses favors the occurrence of pests. The Eucalyptus-snout-beetle, Gonipterus platensis Marelli (Coleoptera: Curculionidae), is the main species of eucalyptus defoliator beetle in the world. Injuries to the host plant are caused by adults and larvae, the latter being responsible for the most severe defoliation. The damages can reach the reduction of 42.8% in the average annual increment of the tree. Biological control through the parasitoid Anaphes nitens Girault (Hymenoptera: Mymaridae) is the main control strategy of Gonipterus spp., responsible for population control of the pest since the first detections in Brazil in the 1950s. However, outbreaks of G. platensis have been observed in regions where Pyemotes mites were detected feeding on G. platensis’s eggs and where parasitism and parasitoid establishment occurred. The objective of this work was to study possible biotic factors associated with the A. nitens parasitoid, evaluating the parasitism capacity in different populations of the parasitoid and conducting prospection of symbiotic bacteria that may interfere in the host 's fitness. For the parasitism between two populations of A. nitens, from the States of São Paulo and Espírito Santo, both showed results of parasitism, emergency percentage and sexual ratio that did not differ significantly. For the prospection of secondary endosymbionts in different populations of A. nitens, adults and G. platensis’s eggs and mites of the genus Pyemotes, molecular analyzes were performed by means of PCR for the presence of 9 different bacterial genera with the use of specific primers. The bacteria endosymbiont Rickettsia belli and the intestinal bacteria species Yersinia massiliensis, Serratia grimesii and Erwinia amylovora were found in all natural populations of A. nitens and in the F1 and F2 generations of the laboratory. The Serratia grimesii species was also found in adults and eggs of G. platensis and in females of Pyemotes sp. All these detections represent first reports to the hosts.
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Controle biológico, Parasitismo, Entomologia molecular, Biological control, Parasitism, Molecular entomology