In nest environment modulates nestmate recognition in the ant Camponotus fellah

Multiple behavioral and chemical studies indicate that ant nestmate recognition cues are low-volatile substances, in particular hydrocarbons (HCs) located on the cuticular surface. We tested the hypothesis that in the ant Camponotus fellah, nest environment, in particular nest volatile odors, can modulate nestmate-recognition-mediated aggression. Workers were individually confined within their own nest in small cages having either a single mesh (SM = limited physical contact permitted) or a double mesh (DM = exposed to nest volatiles only) screen. Individual workers completely isolated outside their nest (CI) served as control. When reintroduced into a group of 50 nestmates, the CI workers were attacked as alien ants after only 2 weeks of separation, whereas the SM workers were treated as nestmates even after 2 months of separation. Aggression towards DM ants depended on the period of isolation. Only DM workers isolated for over 2 months were aggressed by their nestmates, which did not significantly differ from the CI nestmates. Cuticular HC analyses revealed that the profile of the non-isolated ants (NI) was clearly distinct from that of CI, SM and DM ants. Profile differences matched the aggressive response in the case of CI ants but were uncorrelated in the case of SM or DM ants. This suggests that keeping the ants within the nest environment affected nestmate recognition in additional ways than merely altering their HC profile. Nest environment thus appears to affect label-template mismatch by modulating aggressive behavior, as well as the direction at which cuticular HCs diverged during the separation period. © Springer-Verlag 2004.Peer Reviewe

Pheromone-sensitive glomeruli in the primary olfactory centre of ants

Tremendous evolutional success and the ecological dominance of social insects, including ants, termites and social bees, are due to their efficient social organizations and their underlying communication systems. Functional division into reproductive and sterile castes, cooperation in defending the nest, rearing the young and gathering food are all regulated by communication by means of various kinds of pheromones. No brain structures specifically involved in the processing of non-sexual pheromone have been physiologically identified in any social insects. By use of intracellular recording and staining techniques, we studied responses of projection neurons of the antennal lobe (primary olfactory centre) of ants to alarm pheromone, which plays predominant roles in colony defence. Among 23 alarm pheromone-sensitive projection neurons recorded and stained in this study, eight were uniglomerular projection neurons with dendrites in one glomerulus, a structural unit of the antennal lobe, and the remaining 15 were multiglomerular projection neurons with dendrites in multiple glomeruli. Notably, all alarm pheromone-sensitive uniglomerular projection neurons had dendrites in one of five ‘alarm pheromone-sensitive (AS)’ glomeruli that form a cluster in the dorsalmost part of the antennal lobe. All alarm pheromone-sensitive multiglomerular projection neurons had dendrites in some of the AS glomeruli as well as in glomeruli in the anterodorsal area of the antennal lobe. The results suggest that components of alarm pheromone are processed in a specific cluster of glomeruli in the antennal lobe of ants

Increased genetic diversity as a defence against parasites is undermined by social parasites: Microdon mutabilis hoverflies infesting Formica lemani ant colonies

Genetic diversity can benefit social insects by providing variability in immune defences against parasites and pathogens. However, social parasites of ants infest colonies and not individuals, and for them a different relationship between genetic diversity and resistance may exist. Here, we investigate the genetic variation, assessed using up to 12 microsatellite loci, of workers in 91 Formica lemani colonies in relation to their infestation by the specialist social parasite Microdon mutabilis. At the main study site, workers in infested colonies exhibited lower relatedness and higher estimated queen numbers, on average, than uninfested ones. Additionally, estimated queen numbers were negatively correlated with estimated average numbers of mates per queen within infested colonies. At another site, infested colonies also exhibited significantly lower worker relatedness, and estimated queen numbers were comparable in trend. In contrast, in two populations of F. lemani where M. mutabilis was absent, relatedness within colonies was high (40 and 90% with RO0.6). While high genetic variation can benefit social insects by increasing their resistance to pathogens, there may be a cost in the increased likelihood of infiltration by social parasites owing to greater variation in nestmate recognition cues. This study provides the first empirical test of this hypothesis

Role of hydrocarbons in egg recognition in the honeybee

Despite worker-laid and queen-laid honeybee eggs having significantly different hydrocarbon profiles, bioassays and chemical supplementation studies show that changing the hydrocarbon profile does not affect egg identity. Furthermore, full-sized eggs that are tested just before being laid or just after being laid have similar hydrocarbon patterns but are treated differently in egg-discrimination bioassays with only the laid eggs surviving. This suggests that hydrocarbons play no role in the egg-recognition system in honeybees

The War Housing Program and Its Future

SCOPUS: cp.kinfo:eu-repo/semantics/publishe