Impacto da temperatura na manutenção dos simbiontes associados aos cecos gástricos de percevejos.

Abstract: Impacts of climate change may affect population performance directly or indirectly through mediated effects on their mutualists. Recently, my colleagues and I showed that the stink bugs species Nezara viridula, Acrosternum hilare, Murgantia histrionica harbor a dominant caecum-associated symbiont. We detected the symbionts presence in the gastric caecum through PCR (Polymerase chain reaction) by using specific primers and monitored the demographic parameters of the insects rearing them at 25 and 30°C. High temperature (30ºC) eliminated the caeca-associated symbionts of A. hilare and M. histrionica. Mortality of A. hilare was substantially higher at 30°C in the first generation, however M. histrionica only started to show higher mortality at 30°C during second generation. Here I present the data of Prado et al. (2010) which showed that host fitness was potentially mediated by symbiont loss at 30°C, and that climate changes can have influence on the host's development, ecology, and geographic localization

Getting rid of gut microbes: surface sterilization cleans symbionts from the insects'egg masses.

Diverse heteropteran insects that feed on economic important crops, commonly known as stink bugs, are associated with specific gut symbiotic bacteria within their midgut cryptic spaces or the gastric caeca. Recent studies have revealed that the stink bugs Nezara viridula, Acrosternum hilare, Murgantia histrionica, Euschistus heros, Chlorochroa ligata, Chlorochroa sayi, Chlorochroa uhleri, Plautia stali, Thyanta pallidovirens, Dichelops melacanthus, Edessa meditabunda, Loxa deducta, Pellaea stictica, Piezodorus guildinii, Thyanta perditor, (all within Pentatomidae family) carried one major bacterium in their midgut. Phylogenetic tree generated using the 16S rRNA gene sequences obtained from the midgut of these previous species placed all symbionts in a clade with the plant-associated bacteria Erwinia and Pantoea species. In this system, females of stink bug vertically transmit the symbionts by smearing them on the surface of the egg masses. When first instars of nymphs hatch, they probe the egg surface and orally acquire the symbionts. Once ingested, these microbial symbionts will reach the 4th section of the ventriculum (V4), also known as gastric caecum, where they establish. It was hypothesized that nymphs born from surface sterilized eggs do not carry the caeca-associated symbionts. Once ingested these microbial symbionts will reach the 4th section of the ventriculum (V4), also known as gastric caecum, where they establish. It was hypothesized that nymphs born from surface sterilized eggs do not carry the caeca-associated symbionts. Herne, using scanning eletron microscopy (SEM), we are showing that surface sterilized eggs do not carry the surface microbes while eggs from the field of E. heros, D. melacanthus, N. viridula, P. stitica, and Pi. Guildinii carry them. In this unique model of transmission where the symbionts located temporally on the surface of eggs, environment factors may have a great impact on bacterial survival. Additionally, climate change may impact the insect host ecology. This information may lead to design new strategies to control the stink bugs that could used in the integrated pest management

Role of endosymbionts and potential applications on neotropical true bug's management.

Introduction: Insects in the suborder Heteroptera (true bugs) include over 40,000 species worldwide. Insect-microorganism interactions are of great importance and were discovered over 50 years ago. However, mainly due to advances in molecular techniques, only recently has the nature of these associations become clearer. Many important agricultural pests and disease vectors within true bugs are associated with endosymbionts in a close relationship. In this suborder, though symbionts can be found in the insect ?s lumen or within the gastric caeca, the main objective is to elucidate the caeca-associated symbionts. Methods: By using the phylogenetic placement of the gene 16S RNA of the symbionts, it is possible to show that some symbionts have coevolved with true bugs to the scope that host fitness is impacted by the elimination or alteration of their symbiont. Through genetic modification (paratrangenesis) of symbionts it is possible to utilize them for disease control or pest management. Results/Conclusion: Symbionts associated with true bugs of the neotropics including bugs of the families Acanthosomatidae, Alydidae, Coreidae, Pentatomidae, Phyrrocoridae and Scutelleridae will be presented and discussed. Phylogenetic relationships between gut symbionts of heteropteran species will also be presented, as well as, Actinobacteria diversity of 12 genera that inhabit the midgut of pentatomids. With the increasing interest and understanding of the stink bugs/endosymbiont associations, and their ecological and physiological features, it will only be a matter of time before pest/vector control programs utilize this information and technique

Influence of symbionts in the biology of Heteropteran insects.

Although bacterial associations occur within animals and plants, insects are considered to be the largest group that has substantial advantages of these associations. This close relationship between both, microorganisms and insects usually provide innumerous advantages for both. Symbionts can provide some essential nutrients and/or help in the insect digestion, which is really important since insects feed in a poor diet such as many important agricultural pests and disease vectors within Heteroptera. In this suborder, symbionts can be found extracellularly in their midgut. Transmission mechanism of symbionts by the heteropteran insects occurs in different manners (vertical or horizontal routes) within the families, however several families need to be investigated. As many heteropteran symbionts are not cultured outside their hosts, it is being used the phylogenetic placement of the gene 16S RNA of the symbionts to show that some symbionts have coevolved with stink bugs to the point that host fitness is impacted with the elimination or alteration of their symbiont, and others symbionts are more diverse indicating multiple evolutionary origins of the symbiotic associations and/or frequent horizontal transmission of the symbiotic bacteria. The notable collection of the genomic information of the symbionts allied to the recent advanced sequencing methods will facilitate the analysis of the host and symbiont genome which will allow a better understanding of the heteropteran/symbiont associations, and their ecological and physiological features. Additionally, the more we know about the evolutionary and biological aspects of these associations the development of alternative techniques for effective heteropteran pest control will became just a matter of time

Cupins subterrâneos.

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Principais pragas do cafeeiro no contexto do manejo integrado de pragas.

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