Danival de Souza | Universidade Federal do Tocantins (original) (raw)

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Papers by Danival de Souza

Comptes Rendus Biologies, 2011

Carpenter ants (genus Camponotus) have mutualistic, endosymbiotic bacteria of the genus Blochmann... more Carpenter ants (genus Camponotus) have mutualistic, endosymbiotic bacteria of the genus Blochmannia whose main contribution to their hosts is alimentary. It was also recently demonstrated that they play a role in improving immune function as well. In this study, we show that treatment with an antibiotic produces a physiological response inducing an increase in both the quantity of cuticular hydrocarbons and in the melanization of the cuticle probably due to a nutritive and immunological deficit. We suggest that this is because it enhances the protection the cuticle provides from desiccation and also from invasions by pathogens and parasites. Nevertheless, the cuticular hydrocarbon profile is not modified by the antibiotic treatment, which indicates that nestmate recognition is not modified.Les fourmis charpentières (du genre Camponotus) possèdent des bactéries endosymbiotiques mutualistes du genre Blochmannia qui contribuent à l’alimentation de leurs hôtes. Il a été démontré récemment qu’elles peuvent aussi favoriser les réponses immunitaires. Dans cette étude, nous montrons qu’à la suite d’un traitement antibiotique, les fourmis ont une réponse physiologique induisant la production de plus d’hydrocarbures cuticulaires et une cuticule plus mélanisée. Cela doit permettre une protection contre la perte d’eau et prévenir mieux contre l’intrusion de pathogènes et parasites. Néanmoins, le profil d’hydrocarbures cuticulaires n’est pas modifié par le traitement antibiotique, ce qui permet le maintien de la reconnaissance des congénères du nid.

Sociality is associated with many benefits that have favoured its evolution in social insects. Ho... more Sociality is associated with many benefits that have favoured its evolution in social insects. However, sociability also presents disadvantages like crowding of large numbers of individuals, which may favour the spread of infections within colonies. Adaptations allowing social insects to prevent and/or control pathogen infections range from behavioural responses to physiological ones including their immune systems. In a state of infection, social interactions with nestmates should be altered in a way which might prevent its spreading. We simulated a microbial infection in workers of the ant Camponotus fellah by the administration of peptidoglycan (PGN) and then quantified their immune response and social interactions. PGN injections as well as control injections of Ringer solution elicited similar production of antibacterial compounds, during 1-4 days after. However, injections of PGN reduced the ability of encapsulation of a nylon implant compared to Ringer controls. The immune challenged workers did not decrease the level of interactions with their nestmates. On the contrary, they devoted more time to trophallaxis. These results are discussed in relation to ant life history traits.

Brazilian Archives of Biology and Technology, 2006

Behavioral assays were conducted with individuals from monogynous and polygynous colonies of Acro... more Behavioral assays were conducted with individuals from monogynous and polygynous colonies of Acromyrmex subterraneus molestans to evaluate the discriminatory ability of ant workers. These bioassays showed that this subspecies could not discriminate among non-nestmates or nestmate workers. However, nestmates of these same colonies did discriminate among workers of another subspecies Ac. subterraneus subterraneus. When discrimation occurred there were no differences in the response of workers from either monogynous or polygynous colonies. Similarities or differences in the chemical profile of both subspecies explained the absence or occurence of aggressiveness among workers. The chemical profile of colonies of the same subspecies was very similar among them, although distinct among subspecies. The number of queens did not influence the cuticular chemical composition of the workers or their behavior.

Italian Journal of Zoology, 2011

Nuptial flight is a critical phase in the reproduction of most ant species. Here, we describe the... more Nuptial flight is a critical phase in the reproduction of most ant species. Here, we describe the nuptial flight and mating behaviour of Acromyrmex ameliae, a leaf-cutting ant social parasite. We observed a nuptial flight of this parasite in a parasitized colony of Acromyrmex subterraneus subterraneus – known as a host of the social parasite in nature – and we registered the initial and final times of copula as well as the time the male dispended attempting to mate. Mating flight occurred after the beginning of the light phase in the laboratory. Agitation of host workers preceded the nuptial flight, without aggression between host workers and sexuals. Alates were attracted to the light bulbs of the room and formed couples that dropped to the ground immediately after their formation. Copula lasted on the average 1.6 ± 0.6 min. During mating attempts, the male put his forelegs on the female's abdomen while she remained walking on the ground. Copula normally occurred when the female stopped or slowed her movement. No attempt at remating was observed. Dealate females were offered to colonies of Acromyrmex subterraneus molestans, a taxon not known as a host of the social parasite in nature, and were promptly accepted by these colonies. The sex ratio value (males:females) was 1:1.83, another factor suggesting that females mate with only one male.

Fuel and Energy Abstracts, 2005

Bioassays were conducted in both laboratory and the field to determine if monogynous colonies of ... more Bioassays were conducted in both laboratory and the field to determine if monogynous colonies of Acromyrmex subterraneus molestans (Myrmicinae, Attini) adopt queens from other colonies of the same subspecies. The results suggest that the adoption of fertilized queens is a possible mechanism to explain the occurrence of colonies with multiple queens in this subspecies. Only minor workers were able to discriminate queens from other colonies and were aggressive toward them. Therefore, queen recognition differs among subcastes.

Ciencia Rural, 2003

1Financiado pelo Convênio CAPES-COFECUB, N°244-1998-2000 2Biólogo, Mestrando em Entomologia , Dep... more 1Financiado pelo Convênio CAPES-COFECUB, N°244-1998-2000 2Biólogo, Mestrando em Entomologia , Departamento de Biologia Animal (DBA), Centro de Ciências Biológicas e da Saúde (CCB), Universidade Federal de Viçosa (UFV). 3Biólogo, Professor Titular, Doutor, ...

Insect Science, 2007

Abstract The fungus-growing ants (Tribe Attini) are a New World group of > 200 species, all oblig... more Abstract The fungus-growing ants (Tribe Attini) are a New World group of > 200 species, all obligate symbionts with a fungus they use for food. Four attine taxa are known to be social parasites of other attines. Acromyrmex (Pseudoatta) argentina argentina and Acromyrmex (Pseudoatta) argentina platensis (parasites of Acromyrmex lundi), and Acromyrmex sp. (a parasite of Acromyrmex rugosus) produce no worker caste. In contrast, the recently discovered Acromyrmex insinuator (a parasite of Acromyrmex echinatior) does produce workers. Here, we describe a new species, Acromyrmex ameliae, a social parasite of Acromyrmex subterraneus subterraneus and Acromyrmex subterraneus brunneus in Minas Gerais, Brasil. Like A. insinuator, it produces workers and appears to be closely related to its hosts. Similar social parasites may be fairly common in the fungus-growing ants, but overlooked due to the close resemblance between parasite and host workers.

Ciencia Rural, 2004

Polygyny denotes the coexistence of two or more mated and fertile queens in the colony. A colony ... more Polygyny denotes the coexistence of two or more mated and fertile queens in the colony. A colony of Acromyrmex subterraneus molestans Santschi containing 14 queens was collected on campus of the Universidade Federal de Viçosa, Brazil, aiming to verify if they were all egg-layers and fertile . The volume of the fungus garden in the nest was about 500 ml

PLEOMETROTIC COLONY FOUNDATION BY SOLENOPSIS SAEVISSIMA (HYMENOPTERA: FORMICIDAE) UNDER LABORATOR... more PLEOMETROTIC COLONY FOUNDATION BY SOLENOPSIS SAEVISSIMA (HYMENOPTERA: FORMICIDAE) UNDER LABORATORY CONDITIONS. The objective of this study was to investigate the preference of Solenopsis saevissima (Fr. Smith, 1855) queens for pre-existing soil cavities as compared to soil holes excavated by themselves. It also aimed to verify if there was competition between these queens for this resource under laboratory conditions. When two queens were placed on artificial arenas in plastic recipients, they did not compete for the single pre-existing hole. They simply occupied this hole simultaneously. The number of queens present on each recipient was checked when foraging activity was verified. In 15 out of 21 plastic recipients there were two queens. In the others one queen was left with remnants of the exoskeleton of the other. All females oviposited within 72 hours while they were in the plastic recipients. However, there was always a queen of the associated pair which laid a significantly higher number of eggs than the other.

Animal Biology, 2010

Th e exocrine metapleural gland is unique for ants and is characterized by antibiotic production.... more Th e exocrine metapleural gland is unique for ants and is characterized by antibiotic production. Th is work aimed at comparing (1) the volume of the metapleural gland, (2) the nucleus-cytoplasm relation of the secretory cells and (3) the surface area of the bulla which corresponds to the external part of the gland in workers of Atta sexdens rubropilosa Forel, 1908 . Th e measurements were conducted in medium-sized workers of the following groups: waste processors (workers that manipulated waste), waste removers (workers that transported the waste fragment), foragers and workers inside the fungus garden. We show that the volume of the metapleural gland reservoir is larger in groups that are more exposed to infections.