Tuesday, December 30, 2003

Korner and Schmid-Hempel show for the bumble-bee (Bombus terrestris) an influence of the male genotype on the longevity of females. They show that insemination with sperm of certain patrilinies can reduce the survival of queens. This effect is not caused by accessory gland products like for e.g. the case in Drosophila, as they additonally inseminated some queens artificially with the content of these glands only. This seems surprising as bumble-bees generally are singly mated and therefore male and female interests should be more convergent. However, a genetic incompatibility effect is considered to be unlikely as no support for a patriline x matriline interaction effect was found. Somatic-genetic incompatibilites as immune reactions, cryptic diseases or other substance might contribute to their findings.

Monday, December 29, 2003

Different Evolutionary Conditions for Worker and Soldier Castes: Genetic Systems Explaining Caste Distribution among Eusocial Insects

According to N. Yamamura, the differences between worker and soldier castes of social insects have not been addressed sufficiently. He suggests that the evolution of worker and soldier castes must be considered in terms of different trade-offs, “specifically, the different relations between benefits and costs of sterility.” According to this, an individual becomes a sterile helping worker if there is a higher genetic gain for growing its siblings than the costs of losing its own offspring. Soldiers (also sterile) should occur if the sacrifice of their own life is connected with the survival of related family members, and therefore “genetically compensated”. According to Yamamura’s theory is the distribution of castes in eusocial insects explainable by differences in their genetic systems, when applying these different conditions for evolution of sterility (aphids, parasitic wasps: asexual and therefore with only soldiers; termites: diploidy and therefore dominantly soldiers; ants, wasps and bees: male-haploidy and therefore with mainly workers).

Thursday, December 18, 2003

ScienceDirect - Australian Journal of Entomology : Carbon dioxide concentrations in the nests of the mud-dwelling mangrove ant Polyrhachis sokolova Forel (Hymenoptera: Formicidae)

ScienceDirect - Journal of Invertebrate Pathology : Use of ribosomal DNA sequence data to characterize and detect a neogregarine pathogen of Solenopsis invicta (Hymenoptera: Formicidae)

ScienceDirect - African Entomology : Diversity of Hymenoptera and other insects in the Late Cretaceous (Turonian) deposits at Orapa, Botswana: A preliminary review: "108 specimens (>68 species) of Hymenoptera : 20%Chalcidoidea, 12% Formicidae, 12% Sphecidae s.l., Megalyridae, 9% Braconidae, 9% Bethylidae, 7% Scelionidae, 6% Gasteruptiidae and 5% Ichneumonidae. "

ScienceDirect - Sociobiology : A New Gnamptogenys of the striatula Group from Bolivia, (Hymenoptera: Formicidae): " Description of new ant species from Bolivia, named "Gnamptogenys aspera" (striatula group), found in leaf litter of a montane evergreen forest: mahogany with red appendages, fine punctures on its costulate sculpture. Inclusion of a modified key to the species."

ScienceDirect - Sociobiology : The interaction among workers of the Genera Atta and Acromyrmex (Hymenoptera: Formicidae) and seeds of Mabea fistulifera (Euphorbiaceae), a pioneer tree species in Brazil: "This laboratory shows interactions among workers of Atta sexdens rubropilosa and Acromyrmex subterraneus subterraneus and the seeds of Mabea fistulifera and interactions effects on seed germination: both species manipulated the seeds, carrying them into the nest and discrading them after elaiosome removal. Indication of importance for M. fistulifera seed transportation, with Atta being more important."

ScienceDirect - Sociobiology : Non-Specific Interaction between Ants (Hymenoptera; Formicidae) and Fruits of Syagrus romanzoffiana (Arecaceae) in an Area of the Brazilian Atlantic Forest

ScienceDirect - Sociobiology : Biodiversity of Ants (Hymenoptera: Formicidae) in Golf Course and Lawn Turf Habitats in Kentucky: "Ants are relatively well adapted to golf course habitats. Management practices that conserve ant species diversity and abundance may contribute to stability of turfgrass ecosystems. "

ScienceDirect - Sociobiology : Queen of the Army Ant Aenictus pachycerus (Hymenoptera, Formicidae, Aenictinae): "description + illustrations"

ScienceDirect - Sociobiology : Foraging Behavior and Subtask Hierarchical Structure in Acromyrmex spp. (Hymenoptera: Formicidae): "Compared with Acromyrmex rugosus, A. balzani, a grass-cutting ant species, shows a behavioral repertoire composed of more variable subtasks during foraging. "

ScienceDirect - Sociobiology : Trends in Karyotype Evolution in the Ant Genus Camponotus (Hymenoptera: Formicidae): "The result agrees with the paraphyletism of Camponotus, found in phylogenetic information using molecular biology resources. "

ScienceDirect - Fenxi Huaxue : Cell Component Identification for Dufour Glands of Harvester Ant Genus Pogonomyrmex by Gas Chromatography/Mass Spectrometry

Monday, December 15, 2003

Ecological Entomology, Vol 28, Issue 6, pp. 651-658a>: "Effects of experimental small-scale grassland fragmentation on spatial distribution, density, and persistence of ant nests. Persistence time of nests of Lasius paralienus (most abundant species) decreases with fragmentation of experimental plots."

Friday, December 12, 2003

ScienceDirect - Sociobiology : A morphometric analysis of intercastes of the slave-making ant Polyergus rufescens (Hymenoptera: Formicidae): "Intercastes of Polyergus rufescens show morphometrical, diagnositc differences to queens and workers castes."

ScienceDirect - Italian Journal of Zoology: The mandibular glands as a source of sexual pheromones in virgin queens of Polyergus rufescens (Hymenoptera, Formicidae):
"Grasso et al. show that the role of the mandibular glands of winged females is demonstrated to be a source of sexual pheromones"

Friday, December 05, 2003

Significant reproductive skew in the facultatively polygynous ant Pheidole pallidula - Mol Ecol, Vol 13, Issue 1, pp. 203-210 (Abstract): "Fournier et al. (2004) show a trade-off in the relative contribution of nestmate queens to gyne and worker production. The queens contributing more to gyne production contributed significantly less to worker production."

Fungal farming in a snail (PNAS Online): "Silliman and Newell show that Littoraria irrorata snails, which graze fungus-infected wounds on live marsh grass, primarily do so not to feed but to prepare substrate for fungal growth and consume invasive fungi. These results provide a case of fungus farming in the marine environment and outside the class Insecta with its known three terrestrial lineages."