1. Sperm length, sperm storage and mating system characteristics in bumblebees

   • B. Baer
   • P. Schmid-Hempel
   • J. J. Boomsma

   Research Article Pages: 101 - 108

2. Spatial differences in worker policing facilitate social parasitism of Cape honeybee workers (Apis mellifera capensis Esch.) in queenright host colonies

   • P. Neumann
   • C. W. W. Pirk
   • R. F. A. Moritz

   Research Article Pages: 109 - 112

3. Lack of patriline-specific differences in chemical composition of the metapleural gland secretion in Acromyrmex octospinosus

   • D. Ortius-Lechner
   • R. Maile
   • J. J. Boomsma

   Research Article Pages: 113 - 119

4. Spatial patterns of seed predation by harvester ants (Messor Forel) in Mediterranean grassland and scrubland

   • F. M. Azcárate
   • B. Peco

   Research Article Pages: 120 - 126

5. The organisation of larval feeding in bumblebees (Hymenoptera, Apidae) and its significance to caste differentiation

   • J. J. M. Pereboom
   • H. H. W. Velthuis
   • M. J. Duchateau

   Research Article Pages: 127 - 133

6. Reproductive decisions by honey bee colonies: tuning investment in male production in relation to success in energy acquisition

   • T. D. Seeley
   • A. S. Mikheyev

   Research Article Pages: 134 - 138

7. Sociobiology of hypogaeic army ants: characterization of two sympatric Dorylus species on Borneo and their colony conflicts

   • S. M. Berghoff
   • J. Gadau
   • U. Maschwitz

   Research Article Pages: 139 - 147

8. The first record among Dolichoderinae (Formicidae) of parasitism by Strepsiptera

   • D. P. Hughes
   • G. Moya-Raygoza
   • J. Kathirithamby

   Research Article Pages: 148 - 150

9. Nestmate discrimination in ants: effect of bioassay on aggressive behavior

   • T. H. Roulston
   • G. Buczkowski
   • J. Silverman

   Research Article Pages: 151 - 159

10. Annual and multi-year nests of the western yellowjacket, Vespula pensylvanica, in California

    • P. K. Visscher
    • R. S. Vetter

    Research Article Pages: 160 - 166

11. Altruistic defenders in a gall-forming aphid of the tribe Hormaphidini (Homoptera, Aphididae, Hormaphidinae) on its primary host

    • H. Shibao
    • T. Fukatsu

    Research Article Pages: 167 - 173

12. Collective and individual nursing investment in the queen and in young and old honeybee larvae during foraging and non-foraging periods

    • T. Schmickl
    • B. Blaschon
    • K. Crailsheim

    Research Article Pages: 174 - 184

13. Mitochondrial DNA and AFLP markers support species status of Apis nigrocincta

    • D. R. Smith
    • M. R. Palmer
    • M. Damus

    Research Article Pages: 185 - 190

14. Finding its place in a competitive ant community: leaf fidelity of Camponotus sericeus

    • K. Mody
    • K. E. Linsenmair

    Research Article Pages: 191 - 198

15. Identification of polygyne and monogyne fire ant colonies (Solenopsis invicta) by multiplex PCR of Gp-9 alleles

    • S. M. Valles
    • S. D. Porter

    Short communication Pages: 199 - 200