
In fights between groups of social animals, willingness of an individual to fight increases with group size. To better understand how individuals assess numerical state and coordinate group behaviour, I investigated how individual ants, Formica xerophila collect information about group size prior to a competitive encounter, and how this information affects F. xerophila behaviour towards a closely related competitor, F. integroides. To determine how F. xerophila collect information regarding numerical state, I performed aggression bioassays between F. xerophila and F. integroides in which F. xerophila individuals were experimentally exposed to isolated communication...
The ultrastructural study on the fat body of gynes (virgin queens) of the basal ant species Cyphomyrmex rimosus and Mycetarotes parallelus and the derived Acromyrmex disciger and Atta laevigata queens showed vesicular rough endoplasmic reticulum, Golgi complex, and mitochondria in trophocytes, suggesting the involvement of these cells in protein synthesis, in addition to digestive vacuoles associated with the digestion of endocytosed compounds or rejected cell organelles. Oenocytes, another cell type present in the fat body of these species exhibit mitochondria, digestive vacuoles, and vesicles, indicating a mobilization of compounds by these cells. In
Yeasts and filamentous fungi carried by the gynes of leaf-cutting ants.
Antonie Van Leeuwenhoek. 2008 Jul 30;
Authors: Pagnocca FC, Rodrigues A, Nagamoto NS, Bacci M
Insect-associated microbes exhibit a wide range of interactions with their hosts. One example of such interactions is the insect-driven dispersal of microorganisms, which plays an essential role in the ecology of several microbes. To study dispersal of microorganisms by leaf-cutting ants (Formicidae: Attini), we applied culture-dependent methods to identify the filamentous fungi and yeasts found in two different body parts of leaf-cutting ant gynes: the exoskeleton and the infrabuccal pocket. The gynes use the latter structure to store a pellet of the ants' symbiotic fungus during nest founding. Many filamentous fungi (n = 142) and yeasts (n = 19) were isolated from the gynes' exoskeleton. In contrast, only seven filamentous fungi and three yeasts isolates were recovered from the infrabuccal pellets, suggesting an efficient mechanism utilized by the gynes to prevent contamination of the symbiotic fungus inoculum. The genus Cladosporium prevailed (78%) among filamentous fungi whereas Aureobasidium, Candida and Cryptococcus prevailed among yeasts associated with gynes. Interestingly, Escovopsis, a specialized fungal pathogen of the leaf-cutting ant-fungus symbiosis, was not isolated from the body parts or from infrabuccal pellets of any gynes sampled. Our results suggest that gynes of the leaf-cutter ants Atta laevigata and A. capiguara do not vertically transmit any particular species of yeasts or filamentous fungi during the foundation of a new nest. Instead, fungi found in association with gynes have a cosmopolitan distribution, suggesting they are probably acquired from the environment and passively dispersed during nest foundation. The possible role of these fungi for the attine ant-microbial symbiosis is discussed.
PMID: 18665453 [PubMed - as supplied by publisher]
The reproductive biology of social Hymenoptera is characterized by lifelong sperm storage by queens and sperm limitation in males. Both sexes are therefore expected to be especially choosy about their mating partners. In particular, sexuals should avoid sibmating because of the resulting risk of producing sterile diploid male offspring. Colonies of the ant Leptothorax gredleri are specialists of patchy habitats and often live in subpopulations of fewer than a few dozen colonies with restricted gene flow between patches. Sexuals therefore have a high probability of mating with a related partner. Using gas chromatography and mass spectrometry, we found...