Actinomycetes bacteria associated with leafcutter ants produce secondary metabolites with antimicrobial properties against Escovopsis, a fungus specialized in attacking the gardens of fungus-growing ants, which denies the ants their food source. Because previous studies have used fungi isolated from fungus gardens but not from ant integument, the aims of the present study were to isolate actinomycetes associated with the cuticle of the Acromyrmex spp. and to quantify their inhibition abilities against the filamentous fungal species carried by these ants. The results demonstrated that actinomycetes had varied strain-dependent effects on several filamentous fungal species in addition to antagonistic activity against Escovopsis. The strain isolated from Acromyrmex balzani was identified as a Streptomyces species, whereas the remaining isolates were identified as different strains belonging to the genus Pseudonocardia. These findings corroborate the hypothesis that actinomycetes do not act specifically against Escovopsis mycoparasites and may have the ability to inhibit other species of pathogenic fungi.

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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.

Ants are important components of food webs in several ecosystems. In anthropic areas, they can be used as bioindicators of the environmental impacts caused by many factors or in the evaluation of the dynamics of the recovery of an area after a certain disturbance. In this context, ants can be used as bioindicators in studies on the evaluation of environmental disturbances caused by pesticide use. Thus, the present work investigated the environmental impacts caused by the application of the insecticides chlorpyriphos and thiamethoxam and the herbicide metsulfuron-methyl in the community of ants in wheat crop (Triticum aestivum L.). The data were collected by pitfall traps and Berlese funnels. A Principal Response Curve was used for a relative abundance analysis. In addition, diversity index and richness were calculated for ant communities. The presence of six families, 11 tribes, 15 genera, and 19 morphospecies of ants belonging to the guilds of fungivorous, omnivorous, and predaceous ants were observed in the soil of the wheat crop. The insecticides chlorpyriphos and thiamethoxam reduced the richness, diversity, and relative abundance of ants of all the guilds on the surface and inside the soil. The effect of the herbicide metsulfuron-methyl on the community of ants was lower than the impact of the insecticides on these insects.

Understanding the environmental influences on insect pests and predator dynamics is essential for the development of integrated pest management strategies for common bean plants. This study aimed to determine the effects of the planting system, plant age, climatic variables, and predator populations on common bean pests under field conditions. Planting systems, plant age, climatic variables, and the abundance of insect pests and predators were evaluated under field conditions over two years in three planting seasons per year. A generalized linear mixed model (GLMM) was adjusted to quasi-Poisson and negative binomial distributions. Model selection was based on the Akaike information criterion. According to the selected model, chewing, sap-sucking, cell content-sucking, and boring insects were influenced by plant age, planting system, air temperature, rainfall, and relative humidity. Additionally, predators including spiders, beetles, ants, pirate bugs, and ladybugs were influenced by plant age, air temperature, rainfall, relative humidity, and abundance of insect pests on common bean plants. This information is essential for conservation biology programs and integrated pest management.