Submitted by Gizele Lima (gizele.lima@inpa.gov.br) on 2018-02-28T14:26:11Z No. of bitstreams: 2 dissert_mestr_FA_V_FIN.pdf: 1480902 bytes, checksum: 152e126c204238d63c23b539761bb88d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-28T14:26:11Z (GMT). No. of bitstreams: 2 dissert_mestr_FA_V_FIN.pdf: 1480902 bytes, checksum: 152e126c204238d63c23b539761bb88d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-16 / Fundação de Amparo à Pesquisa do Estado do Amazonas - FAPEAM / Specialized parasites can modify the behavior hosts to increase chances of reproduction. This behavior is considered an example of extension phenotype of the parasite. We study the relationship of the fungus Ophiocordyceps camponoti-atricips, a specialized parasite, with the carpenter ants Camponotus atriceps. Once infected by O. camponotiatricips, the ants dies in places with stable temperature and relative humidity. The reproduction of the parasite is locally increased on these areas. However, light is responsible for controlling the reproduction of several species of free-living fungi, and may play an important role in the terminal phase of parasitic fungal infection. On this work, we evaluate the effect of luminosity in selected sites of dead infected C. atriceps ants. In 10 graveyards (sites near of foraging trails with many infected dead ants), the luminosity was reduced 80% through shading screens in half of the plots area. We identified dead infected C. atriceps using colored marking ribbons over 6 months of fieldwork. The infected ants that died after establishment of the plots were monitored. We measured the number of fruiting bodies, height above ground and the orientation of infected ants in the field. The selected sites of infected C. atriceps shows strong influence by experimental light reduction. The shaded areas received 53 ants (32, 7%) in comparison to the adjacent control area, with 109 (67, 3%) ants. In addition, in the shaded areas only 15 dead ants produced fruiting bodies. In the control areas, 41 dead ants developed fruiting bodies. The infected C.atriceps also died at higher sites in the shaded areas (140 cm) in relation to the control areas (110 cm). Our findings suggest that light may have act in the place death of parasitized C.atriceps ants and therefore play an important role on reproductive cycle of the fungus O. camponoti-atricips. / Parasitas especializados podem modificar o comportamento de seus hospedeiros para aumentar as chances de se reproduzir. Esse comportamento é considerado um exemplo do fenótipo estendido do parasita. Neste trabalho, nós estudamos a relação entre o fungo Ophiocordyceps camponoti-atricips, um parasita especializado, e as formigas carpinteiras Camponotus atriceps. Uma vez infectadas por O. camponoti-atricipis, as formigas morrem em locais onde a temperatura e umidade são mais estáveis. Esses locais aumentam o sucesso reprodutivo do parasita. Entretanto, a luz é responsável por controlar a reprodução de diversas espécies de fungos de vida livre, e pode ter um papel importante na fase terminal da infecção de fungos parasitas. Neste trabalho, nós avaliamos o efeito da luminosidade na seleção dos locais de morte de C. atriceps infectadas. Em 10 cemitérios (locais próximos as trilhas de forrageio de C. atriceps onde são encontradas muitas formigas mortas infectadas), a luminosidade foi reduzida através de telas de sombreamento de 80% em metade da área das parcelas. Nós identificamos os cadáveres de C. atriceps com fitas de marcação coloridas durante 6 meses de trabalho de campo. As formigas infectadas que morreram após o estabelecimento das parcelas foram monitoradas nesse período. O número de cadáveres que produziram corpos de frutificação, a altura em relação ao nível do solo e a orientação das formigas parasitadas foram mensurados. As áreas sombreadas receberam 53 formigas, representando 32,7 % do total, em comparação à área controle adjacente, onde foram encontradas 109 formigas mortas. Além disso, nas áreas sombreadas apenas 15 cadáveres produziram ascomas ou corpos de frutificação. Já nas áreas controle 41 cadáveres desenvolveram os ascomas. As C. atriceps infectadas também morreram em locais mais altos nas áreas sombreadas (140 cm) em relação às áreas controle (110 cm). Nossos resultados sugerem que a luz pode atuar no local da morte das formigas C. atriceps parasitadas e por consequência desempenhar um papel importante no ciclo reprodutivo do fungo O. camponoti-atricipis.

The fungus Ophiocordyceps camponoti-floridani (Ophcf) infects Camponotus floridanus carpenter ants and manipulates them to climb to a high tree branch, bite down on foliage and die. Post ant death, the fungus grows out of the ant and spreads spores for reproduction. I investigated the function of an Ophcf gene product highly activated during the behavioral manipulation of these “zombie ants”; an enterotoxin. I have created an expression vector and heterologously expressed this enterotoxin in Cordyceps bassiana (Cbass), a related fungus that does not normally manipulate behavior. This process includes gene amplification, Golden Gate vector cloning in E. coli, A. tumefaciens-mediated transformation to Cbass, and RT-qPCR to verify heterologous gene expression. This was followed by carpenter ant infections with transgenic Cbass (EntB), wildtype Cbass (infected control), and sham (non-infected control) infected ants. Subsequent behavioral observations using tracking system MARGO (Werkhoven et al., 2019) have detected changes in activity levels of ants infected with both transgenic and WT Cbass compared to sham infected ants. This supports previously qualitative descriptions of increased activity caused during infection with WT Cbass (Trinh, 2020). There is a slight but insignificantly higher activity response from EntB compared to WT infected ants over the course of the trial that may be indicative of Ophcf induced changes that are different from general sickness behavior. Additional replicates are necessary to discern if these findings are statistically robust. Future studies should administer this enterotoxin expressing Cbass to observe inter-social behaviors of Carpenter ants. If the enterotoxin is sufficient to elicit one of the side effects of typical Ophcf infection, this would justify further characterization of the proteins and their functions in altering C. floridanus behavior. This characterization could yield information applicable to other parasite-host relationships as well.

No description available.