Colony-colony interactions between highly invasive ants

Among invasive species, ants are a particularly prominent group with enormous impacts on native biodiversity and ecosystem functioning. Globalization and on-going climate change are likely to increase the rate of ant invasions in the future, leading to simultaneous introductions of several highly invasive species within the same area, Here, we investigate pairwise interactions among four highly invasive species, Linepithema humile,Lashis neglectus, Pheidole megacephala and Wasmannia auropunctata, at the whole colony level, using a laboratory set-up. :Each colony consisted of 300 workers and one queen. The number of surviving workers in the competing colonies was recorded daily over 7 weeks. We modelled the survival of each colony during pairwise colony interactions, using a nonlinear model characterizing the survival dynamics of each colony individually. The least dominant species was P. megacephala, which always went extinct. Interactions among the three other species showed more complex dynamics, rendering the outcome of the interactions less predictable. Overall, W auropunctata and L neglectus were the most dominant species. This study shows the importance of scaling up to the colony level in order to gain realism in predicting the outcome of multiple invasions.

Nesting architecture and population structure of the fungus-growing ant Cyphomyrmex transversus (Formicidae: Myrmicinae: Attini) in the Brazilian coastal zone of Ilheus, Bahia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Susceptibility of the ant-cultivated fungus Leucoagaricus gongylophorus (Agaricales : Basidiomycota) towards microfungi

The aim of this study was to select virulent strains of microfungi against Leucoagaricus gongylophorus, a symbiotic fungus cultivated by leaf-cutting ants. The results from in vitro assays showed that microfungal strains had a variable and significant impact on the colony development of L. gongylophorus. Specifically, Trichoderma harzianum, Escovopsis weberi CBS 810.71 and E. weberi A088 were more effective, inhibiting the L. gongylophorus colonies by 75, 68 and 67%, respectively (P < 0.05) after 15 days. Strain E. weberi A086 and Acremonium kiliense were less effective: 43 and 26%, respectively (P < 0.05). In spite of the current negative perspective of a microbiological control approach for these ants, the present work discusses the possibility of using mycopathogenic fungi for the control of these insects, and points out the importance of encouraging more studies in this area.

The functional morphology of the metapleural gland of the leaf-cutting ant Atta laevigata (Formicidae: Attini)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Proteomic View of the Venom from the Fire Ant Solenopsis invicta Buren

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Post-Embryonic Development of Larvae of the Weaver Ant Camponotus textor (Hymenoptera: Formicidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ultrastructural profile of metapleural gland cells of the ant Atta laevigata (F. Smith, 1858) (Formicidae: Attini)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morphological Organization of the Dorsal Protuberance of Linepithema humile (Mayr, 1868) Ant's Larvae (Hymenoptera, Formicidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Description of the immatures of the ant, Myrmelachista catharinae

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nest architecture and population dynamics of the Ponerinae ant, Ectatomma opaciventre Roger (Hymenoptera : Formicidae)

Eleven nests of Ectatomma opaciventre were collected from January to December, 1994, in Rio Claro, SP, southeastern Brazil. This species excavates their nests up to 68 cm deep, containing 3, 4 or 5 chambers. The hole of entrance has a chimney-like rigid structure, with up to 2/5 cm high. The most numerous colonies were found in January and February, with 47 and 62 adult ants, respectively. The quantity of individuals decreased from March, being observed colonies with only 9 adult ants in June and July. The colony population increased again since September. Reproductive forms (winged ants) were observed between October and February. We did not observed immature stages in July, but they were numerous between September and March. There was a significant correlation between the number of colony individuals and temperature, but not between the number of colony individuals and relative humidity and rainfall. E. opaciventre is a species of hunter ants which have not an efficient recruitment system for food collecting, consequently their colonies are small due to the scarcity of food resources during the colder and dry months.

Nest defense behavior against ant attacks in post-emergent colonies of wasp Mischocyttarus cerberus (Hymenoptera, Vespidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Colony defense behavior of the primitively eusocial wasp, Mischocyttarus cerberus is related to age

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

LARVAL INSTARS AND IMMATURE DEVELOPMENT OF A BRAZILIAN POPULATION OF PHARAOHS ANT, MONOMORIUM-PHARAONIS (L) (HYM, FORMICIDAE)

The immature development of pharaoh's ant, Monomorium pharaonis, workers was s died in a naturally collected Brazilian population. Three larval instars were confirmed by measuring maximal cephalic widths in cohorts of known age. Minimum egg to adult duration was 25 days, while the maximum duration was 54 days, both of which are larger than those reported for European populations. Larval instar development is cyclical at the colony level, suggesting reproductive bursts followed by lower reproductive activity of the queens.

SOLENOPSIS (HYMENOPTERA, FORMICIDAE) FIRE ANT REACTIONS TO ATTACKS OF PSEUDACTERON FLIES (DIPTERA, PHORIDAE) IN SOUTHEASTERN BRAZIL

We studied the responses of Solenopsis fire ants to Pseudacteon phorid fly attacks in southeastern Brazil. The presence of these phorid parasites triggered a suite of phorid-specific defense responses including reduced foraging, bait guarding, a curled defensive posture, and general colony immobility. The existence of these phorid-specific defenses indicates that Pseudacteon phorids exert substantial evolutionary pressure on South American fire ant populations.

Ant Group Effects on the Insecticide and Dye Flow Among Atta sexdens rubropilosa (Hymenoptera: Formicidae) Workers

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)