Age Polyethism in Atta sexdens (Linnaeus) (Hymenoptera: Formicidae)

This study aimed to verify age polyethism occurrence in medium-sized (cephalic capsule = 2.3 ± 0.21 mm) and small-sized (cc = 1.4 ± 0.10 mm) workers from Atta sexdens (Linnaeus) colonies. Four laboratory colonies were used, and they were maintained at 25 ± 2 °C, with 75 ± 3% relative humidity and a 12-hour photoperiod. Workers from these colonies were marked after their emergence and observed throughout their lifetime to determine which tasks they performed. The number of ants performing each activity was analyzed using linear mixed-effect models (LME), considering the temporal effect and the block design (colonies). We found that fungal garden maintenance tasks were frequent for both sizes, but their occurrence decreased significantly from the ninth week. The foraging activity occurred gradually in both sizes, with stabilization in the number of workers from the fourth week onwards and declined in the last three weeks of lifespan. Waste management tasks occurred throughout life but were more frequent during the first two weeks of life, in both medium and small workers. Therefore, age polyethism may be related to all activities; however, foraging tasks presented a distinct pattern compared to tasks in the fungus garden and refuse dump, where younger ants were more frequently observed

Diversidade florística do estrato arbustivo arbóreo de três áreas de cerrado sensu stricto, Tocantins

The aim of this work was to determine the phytosociological and floristic diversity of the shrub-tree layer of three areas of stricto sensu cerrado. This study was conducted in the city of Gurupi - TO, at the UFT Experimental Farm, Campus of Gurupi, UTM coordinates 11 "46'25 S and 49" 02'54 W and in the city of Aliança do Tocantins - TO on private property Fazenda Nossa Lady Aparecida under its UTM coordinates 11 "46'25 S and 49"02'54 W. Three 20x50m plots were systematically installed in each area, 20m apart from each other, for a total of 3000 m², or 0.3 ha sampling area. Every shrub and individual tree with circumference at breast height (CAP) ? 10 cm was sampled. In the three cerrado fragments evaluated, a total of 138 species, 43 families and 94 genera were found and the distribution between the evaluated areas was as follows. In A1 77 species were sampled, 32 families and 61 genera, in A2 85 species, 37 families and 68 genera were found, and A3 the distribution took place with a total of 67 species, 29 families and 55 genera. The Shannon diversity index (H' = 3.55 3.52 and3.70) and Pielou evenness (J' = 0.81 0.79 and 0.87) respectively demonstrated high richness and diversity in all areas, showing great environmental heterogeneity and low ecological dominance. Keywords: Savanah, Heterogeneity, Ecological DominanceRESUMEN El objetivo de este trabajo fue determinar la diversidad florística y fitosociológico de la capa de arbustos de árboles de tres zonas de bosque cerrado. Este estudio se llevó a cabo en la ciudad de Gurupi - A, en el rancho de la UFT Campus Gurupí bajo las coordenadas UTM 11 "46'25 S y 49" 02'54 W y la ciudad de Aliança do Tocantins - A en la propiedad privada Nuestra Granja Aparecida bajo su coordenadas UTM 11 "S y 49 46'25" 02'54 W. sistemáticamente se instalaron tres porciones de 20 x 50 m en la zona de cada una de ellas espaciadas 20 m de distancia, para un total de 3000 m², o área de la muestra 0,3 ha. Se muestrearon todos los individuos arbusto de madera con la altura del pecho (CAP) ? 10 cm. Ellos fueron verificadas en tres fragmentos de cerrado evaluó un total de 138 especies de 94 géneros y 43 familias y que la distribución entre las áreas se evaluó como sigue. En A1 se muestrearon 77 especies, géneros y 61 familias 32, se encontraron 85 especies A2, 68 géneros y 37 familias, y distribución A3 se produjeron con un total de 67 especies, 55 géneros y 29 familias. El índice de diversidad Shannon (H '= 3,55 3,52 y 3,70) y la uniformidad uniformidad (J' = 0,81 0,79 y 0,87) mostró respectivamente alta riqueza y la diversidad en todas las áreas , mostrando una gran heterogeneidad ambiental y baja dominancia ecológica. Palabras clave: Cerrado, la heterogeneidad, dominio ecológicoO objetivo desse trabalho foi realizar um levantamento fitossociológico e determinar a diversidade florística do estrato arbustivo arbóreo de três áreas de cerrado sensu stricto. Esse estudo foi conduzido na cidade de Gurupi - TO, na Fazenda Experimental da UFT Campus de Gurupi sob as coordenadas UTM 11”46’25 S e 49”02’54 W e na cidade de Aliança do Tocantins – TO na propriedade particular Fazenda Nossa Senhora Aparecida sob as respectivas coordenadas UTM 11”46’25 S e 49”02’54 W. Foram instaladas sistematicamente três parcelas de 20 x 50 m em cada área, sendo distanciadas 20 m entre si, perfazendo um total de 3000 m², ou 0,3 ha de área amostral. Foram amostrados todos os indivíduos arbustivo arbóreos com circunferência altura do peito (CAP) ? 10 cm. Foram verificados nos três fragmentos de cerrado sensu stricto avaliados um total de 138 espécies, 43 famílias e 94 gêneros sendo que a distribuição entre as áreas avaliadas ocorreu da seguinte maneira. Na A1foram amostradas 77 espécies, 32 famílias e 61 gêneros, na A2 foram encontradas 85 espécies, 37 famílias e 68 gêneros, e na A3 a distribuição ocorreu com um total de 67 espécies, 29 famílias e 55 gêneros. Os índices de diversidade de Shannon (H’= 3,55 3,52 e 3,70) e equabilidade de Pielou (J’= 0,81 0,79 e 0,87) demostraram respectivamente alta riqueza e diversidade em todas as áreas, evidenciando grande heterogeneidade ambiental e baixa dominância ecológica

Simarouba versicolor (Simaroubaceae) Dispersal by the Leaf-Cutter Ant Atta sexdens

The importance of Simarouba versicolor St. Hil. fruit dispersal by the leaf-cutting ant Atta sexdens (L.) was studied in the Cerrado, Tocantins, Brazil. The trees and nests were located between a forest area and a Brachiaria decumbens Stapf pasture. Seeds were collected in October 2015 along foraging trails and on the anthill of an A. sexdens colony. Germination of three groups of seeds was tested: (1) seeds with the tegument removed by the ants; (2) seeds without tegument, cleaned manually, and (3) seeds with tegument. The germination rates for the three treatments were similar; however, it was verified that the seeds cleaned by ants germinated faster. In addition, it was verified that the ants dispersed the seeds by at least 20 meters in the study area. Simarouba versicolor is a plant studied for its insecticidal properties, and this is the first study to our knowledge reporting its dispersal by ants

Bacterial Communities in the Midgut of Ponerine Ants (Hymenoptera: Formicidae: Ponerinae)

Symbiotic microorganisms are directly related to the ecological success of host insects, influencing many aspects of their biology. The present study is the first to investigate the microbiota associated with ants of the subfamily Ponerinae and aims to identify the bacterial midgut communities of Dinoponera lucida, Pachycondyla curvinodis, Pachycondyla striata, Odontomachus brunneus and Odontomachus bauri. After dissecting the midguts of these ants, DNA was extracted, and the bacterial 16S rRNA gene was amplified via PCR using the universal primers pair 27F/1492R. The obtained PCR products were cloned and sequenced using an ABI 3500 automated sequencer. The sequences were grouped into operational taxonomic units (OTUs) based on a 97% similarity criterion using MOTHUR. The greatest species richness was observed in O. bauri, with 15 OTUs, followed by D. lucida with five OTUs, O. brunneus, with four OTUs, and P. curvinodis and P. striata, both with three OTUs. There were representatives of the phyla Actinobacteria, Proteobacteria, Tenericutes and Firmicutes, including the genera Bartonella, Mesoplasma, Mesorhizobium, Spiroplasma, Wolbachia and Serratia in the guts of the studied Ponerine ants. The low microbial diversity observed given the predatory trophic habits of the species studied suggests that there is selection for these microorganisms, predominantly preserving symbionts with functional roles that are able to colonize this environment. It is also valid to infer that the identified bacteria are predominant in the gut and exhibit mutualistic functions that are important for immunity, reproduction and nutrition; moreover, a subset may be parasites that have considerable impacts on the studied ants

ATRIBUTOS DE SATISFAÇÃO DO CONSUMIDOR EM UM HOTEL DE MÉDIO PORTE EM QUIXADÁ-CE

Este trabalho tem como objetivo verificar a satisfação dos hóspedes por faixa etária de idade de quatro décadas entre homens e mulheres, por meio da averiguação de construtos em relação aos serviços de hotelaria

Suscetibilidade de operárias de Atta sexdens tratadas com o imunossupressor Sandimmun Neoral a Metarhizium anisopliae

The objective of this work was to evaluate if the immunosuppressant Sandimmun Neoral enhances the activity of Metarhizium anisopliae against the leaf-cutting ant Atta sexdens. The vulnerability to the pathogen was measured by comparing the mortality rate of worker ants subjected to the following treatments: immunosuppressant+control, immunosuppressant+M. anisopliae, excipient+control, excipient+M. anisopliae, control+M. anisopliae, and control. Worker ants treated with immunosuppressant+M. anisopliae showed the highest mortality rate in comparison with those subjected to all other treatments. The use of the immunosuppressant together with entomopathogenic fungus controlled leaf-cutting ants in laboratory conditions.O objetivo deste trabalho foi avaliar se o imunossupressor Sandimmun Neoral favorece a atividade de Metarhizium anisopliae contra a formiga cortadeira Atta sexdens. A vulnerabilidade ao patógeno foi medida ao se comparar a mortalidade de operárias expostas aos seguintes tratamentos: imunossupressor+controle, imunossupressor+M. anisopliae, excipiente+controle, excipiente+M. anisopliae, controle+M. anisopliae e controle. Operárias tratadas com imunossupressor+M. anisopliae apresentaram a maior taxa de mortalidade em comparação às submetidas a todos os outros tratamentos. O uso do imunossupressor juntamente com fungo entomopatogênico controlou as formigas cortadeiras em condições de laboratório

Social behaviour and immune responses in the ant Camponotus fellah : implications of the bacterial endosymbiont Blochmannia

La vie en société présente des avantages écologiques et évolutifs, mais augmente les risques de transmission de pathogènes. Pour faire face à ce problème, les insectes sociaux ont développé plusieurs mécanismes de défenses comportementales et physiologiques, et en plus utilisé la protection fournie par des organismes tiers. C’est ainsi que des abeilles et des fourmis se servent de substances antimicrobiennes d’origine végétale ou des fourmis possèdent des bactéries productrices d’antibiotiques. La fourmi est un insecte qui, par définition, ne peut vivre que dans sa société avec des congénères avec lesquels elle entretient des relations nombreuses comme des léchages interindividuels et des échanges en bouche à bouche (appelés trophallaxies). Dans la première partie de la thèse, nous avons étudié les altérations comportementales des ouvrières de la fourmi Camponotus fellah après le déclenchement d’une réaction immunitaire. Nous avons posé l’hypothèse que si les relations sociales sont aussi coûteuses que les défenses immunitaires physiologiques, l’individu devrait être confronté à un choix : où investir son énergie ? Au contraire, suite à une réaction immunitaire les fourmis ont augmenté leur taux de trophallaxie et aucun signe d’isolement de l’ouvrière malade ne fut observé. Ce résultat met en évidence l’importance des relations sociales pour la guérison de l’individu et qui peuvent même avoir une fonction prophylactique. La deuxième partie a été consacrée à l’étude d’un endosymbiote primaire de C. fellah, une bactérie du genre Blochmannia. Cet endosymbiote a un rôle nutritif qui a été déjà montré chez d’autres espèces de Camponotus. Nous avons envisagé qu’il ait aussi d’autres fonctions comme : favoriser le système immunitaire de la fourmi, favoriser le développement des nouvelles colonies et participer à la formation d’odeur coloniale. Nous avons d’abord décrit cette nouvelle bactérie par des techniques de biologie moléculaire. Ensuite, nous avons pu montrer qu’elle favorise la réponse immunitaire des fourmis en augmentant l’encapsulation de particules étrangères. Elle contribue à une plus grande production de larves, aboutissant à une plus grande quantité d’ouvrières. Nous n’avons pas mis en évidence de lien entre la quantité de bactéries et celle d’hydrocarbures cuticulaires, bien que leur élimination par un antibiotique entraînait une surproduction de ces hydrocarbures, probablement une réponse liée au stress. Plus généralement, ces travaux montrent de nouvelles fonctions des endosymbiotes, qui ont probablement contribué au succès écologique de ce groupe de fourmis hautement diversifié et très répandu.The colonial lifestyle has ecological and evolutionary advantages, but it increases the risks of pathogen transmission. To minimize this problem, social insects have developed several behavioural and physiological defence mechanisms, including using protection provided by other organisms. Bees and ants utilize antimicrobial substances of vegetable origin and ants harbour antibiotics-producing bacteria to control parasites. Ants are insects that cannot live without their nestmates with which they maintain many interactions, such as grooming and trophallaxis. In the first part of this thesis, we studied the behavioural alterations in workers of the ant Camponotus fellah after mounting an immune response. We hypothesized that if social interactions and physiological immune responses are expensive, individual workers should be forced to choose where to invest energy. In fact, after mounting an immune response, the workers increased their trophallaxis rate and no sign of avoidance by nestmates was observed. This result highlights the importance of social relations for individual cure and prophylactic mechanisms. In the second part, we studied the primary endosymbiont of C. fellah, a bacterium of Blochmannia genus. This bacterium plays a role in ant nutrition, a function already demonstrated in other Camponotus species. We considered the possibility that the importance of this association is not exclusively nutritional. The bacterium might improve the host immune system and increase the development rate of incipient colonies. Indeed, it might be involved in colony odour formation. The first step was to describe formally this new bacterium with molecular biology techniques. Next, we showed that it improves the host immune response by increasing the encapsulation rate against foreign particles. It increases host larvae production and the number of adult workers. Though we did not find a relation between the number of bacteria and the amount of cuticular hydrocarbons, when the bacteria was eliminated with antibiotics, cuticular hydrocarbons were overproduced, which could be interpreted as a stress response. This work highlights new functions of Blochmannia endosymbionts in their association with the ants. The bacterium likely contributed to the ecological success of Camponotus ants, a globally widespread genus

Discrimination and survival of workers in monoginic and poliginic colonies of Acromyrmex subterraneus molestans (Hymenoptera: Formicidae)

A poliginia dentro de uma colônia de inseto social pode ser primária ou secundária. A poliginia primária ocorre quando várias rainhas se juntam para iniciar uma nova colônia. Também, colônias monogínicas podem aceitar novas rainhas fecundadas, tornando-se assim poligínicas secundariamente. A poliginia diminui o grau de parentesco entre as operárias companheiras de ninho e, com isso, os benefícios de se ajudar indivíduos mais próximos geneticamente também se reduzem. Estudos acerca do reconhecimento entre companheiras de ninho e da adoção de rainhas são imprescindíveis para esclarecer como o número de rainhas é regulado, bem como as causas da variação nesse número. Neste trabalho, escolheu-se como objeto de estudo Acromyrmex subterraneus molestans Santschi, 1925, uma subespécie de formiga cortadeira bastante comum na região de Viçosa, MG. Numa mesma região são encontradas colônias monogínicas e poligínicas dessa subespécie, o que a torna ideal em estudos dos processos que regulam o número de rainhas em colônias de Formicidae. Estudos conduzidos em laboratório mostraram que colônias monogínicas de Ac. subterraneus molestans podem se tornar poligínicas pelo mecanismo de adoção de rainhas de outras colônias. Operárias da maioria das colônias estudadas não foram capazes de discriminar entre rainhas de outras colônias da sua própria. A ausência de comportamento discriminatório também foi verificada quando se realizaram encontros de operárias de diferentes colônias. Análises químicas mostraram que não existem diferenças qualitativas no perfil químico cuticular das colônias, quer sejam elas monogínicas ou poligínicas. Finalmente, avaliou-se a possibilidade de haver sobrevivência diferencial entre operárias de colônias poligínicas e monogínicas, quando essas eram mantidas em contato com o lixo da própria colônia. Os testes de sobrevivência mostraram que operárias dos dois tipos de colônia morriam a taxas estatisticamente iguais. Vantagens da poliginia e da ausência de comportamento discriminatório são discutidas nesta dissertação.Polygyny within a colony of social insects can be primary or secondary. Primary polygyny may occur when several queens jointly initiate a new colony. Monogynous colonies can also accept newly mated queens and become secondarily polygynous. Polygyny reduces kinship among nestmate workers and, consequently, reduces the benefits of helping genetically close individuals. Studies on nestmate recognition and on queen adoption are essential to elucidate how the number of queens is regulated, as well as the causes of the variation in this number. In this research, Acromyrmex subterraneus molestans Santschi, 1925 was chosen because it is a very common leaf-cutting ant in the region of Viçosa, Minas Gerais State where the Federal University of Viçosa is located. Additionally in this region monogynous and polygynous colonies of this subspecies occur naturally, which makes them ideal for studying regulation in queen number in Formicidae. Laboratory studies demonstrated that monogynous colonies of Ac. subterraneus molestans may become polygynous by the mechanism of queen adoption from other colonies. Workers of most of the studied colonies were not able to discriminate among queens from other colonies and their own. The lack of discriminatory behavior was also observed when encounters from different colonies were induced. Chemical analyzes showed no qualitative differences in the cuticular chemical profile of either polygynous or monogynous colonies. Finally, the possibility of differential survival among workers from these colonies when maintained in contact with colony refuse was evaluated. Survival tests revealed that workers from either monogynous or polygynous colonies died at equal rates in contact with refuse. Advantages of polygynous and of the lack of discriminatory behavior among workers are discussed in this thesis.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Occurrence and feeding preference of Diabrotica speciosa Germar and Cerotoma arcuata (Olivier) for different cultivars of cowpea Vigna unguiculata (Linnaeus) Walpers

Chrysomelid pests are not only known as leaf-feeding in beans but as vectors of viruses too. Chemical control is most commonly used but has high economic and environmental costs. This study aimed to report the occurrence of chrysomelid pests on cowpea area in the State of Tocantins and compare the feeding preference of the species collected in different cowpea cultivars. Weekly monitoring was carried out in cowpea stand at the experimental station of the Federal University of Tocantins, in Gurupi-TO. Insect feeding preference was evaluated under laboratory conditions (25 ± 2 °C, 60 ± 5% R.H.). A total of 1,542 adults of two species of chrysomelid pests was recorded: Cerotoma arcuata (Olivier) presented 71.49% and Diabrotica speciosa Germar, 28.51%. Leaf discs of the cultivars BRS "Tumucumaque"," BRS "Nova Era", BRS "Sempre Verde", and "Pingo de Ouro", were offered to adult beetles. It was observed a significant difference in no-choice leaf disc assays and four-choice leaf disc assays for the D. speciosa species, being BRS "Tumucumaque" the most consumed. In the no-choice leaf disc assay "Pingo de Ouro" was less consumed and showed non-preference type resistance. In the four-choice leaf disc assay, BRS Sempre Verde was more resistant to D. speciosa consumption. In both tests, C. arcuata did not show a significant difference among the tested cultivars, but mathematically, BRS "Nova Era" was the most consumed, while "Pingo de Ouro" the lowest consumed and showed non-preferred resistance in both tests. Cerotoma arcuata stood out as greater defoliant than D. speciosa in all cultivars tested.Crisomelídeos pragas não são apenas desfolhadores do feijoeiro, mas atuam também como vetores de viroses. O método de controle mais utilizado é o químico, o que acarreta altos custos econômicos e ambientais. Este trabalho objetivou registrar a ocorrência de crisomelídeos pragas em cultivo de feijão-caupi no estado do Tocantins, bem como comparar a preferência alimentar das espécies coletadas por diferentes cultivares. Foi realizado monitoramento semanal na área de feijão-caupi da estação experimental da Universidade Federal do Tocantins em Gurupi-TO. Foram registrados 1.542 adultos de duas espécies de crisomelídeos pragas: Cerotoma arcuata (Olivier)apresentou 71,49% e Diabrotica speciosa Germar, 28,51%. Em condições de laboratório, discos foliares das cultivares BRS "Tumucumaque", BRS "Nova Era", BRS "Sempre Verde" e "Pingo de Ouro" foram oferecidos a insetos adultos para testar sua preferência alimentar. Foi observada diferença significativa nos ensaios sem chance e com chance de escolha para espécie de D. speciosa, sendo o BRS "Tumucumaque" o mais consumido. Nos ensaios sem chance de escolha, "Pingo de Ouro" foi menos consumido e apresentou resistência do tipo não preferência. Nos ensaios com chance de escolha, o cultivar BRS "Sempre Verde" foi mais resistente ao consumo de D. speciosa. Em ambos os testes, C. arcuata não apresentou diferença significativa na preferência pelos quatro cultivares, embora BRS "Nova Era" tenha sido mais consumido em valores absolutos, enquanto "Pingo de Ouro" foi menos desfolhado apresentando resistência de tipo não preferência nos dois testes. Cerotoma arcuata destacou-se como maior desfolhador do que D. speciosa em todas os cultivares testados