A. Lenoir

Individual geographical and experimental variation of cuticular hydrocarbons of the ant Cataglyphis cursor (Hymenoptera: Formicidae): their use in nest and subspecies recognition.

Abstract The cuticular hydrocarbons of Cataglyphis cursor (Fonsc.) adults have been identified and quantified. Comparison of the proportion of hydrocarbons in various locations shows a variation between populations from each side of the Rhǒne river and an isolated population in the mountains near Madrid. In the studied area (not including Italy and eastern places) at least three subspecies have been found. Ethological analyses show that colony recognition, as indicated by aggressive behavior and the possibilities of adoption in an allen society, is correlated with the composition of cuticular hydrocarbons. Callows can be adopted in an allen colony, they can live in two colonies where the adults do not tolerate each other. These adopted callows have a hydrocarbon pattern intermediate between the patterns of the another colony and the adoptive colony.

Social closure, aggressive behavior, and cuticular hydrocarbon profiles in the polydomous antCataglyphis iberica (hymenoptera, Formicidae)

Nestmate recognition was studied in the polydomous antCataglyphis iberica (Formicinae) in the laboratory. The study examined six colonies collected from two different populations 600 km apart in the Iberian peninsula (Barcelona and Murcia). Introduction of an alien worker into an allocolonial arena always ended in death to the intruder, demonstrating that in this species societies are extremely closed. Dyadic encounters composed of individuals from different colonies in a neutral arena confirmed the existence of high aggression between allocolonial individuals. We also investigated variability in the composition of the major cuticular hydrocarbons between the colonies used in the behaviorial tests. There were marked quantitative differences between the profiles of ants from the two populations, suggesting that the populations are completely segregated. Cuticular profiles within a population tended to be more similar, but were nevertheless colony specific. The degree of colony closure inC. iberica seemed to be independent of geographic distance since aggression between the colonies was always at its maximum, irrespective of their population origin.

Chemical mimicry between parasitic ants of the genus Formicoxenus and their host Myrmica (hymenoptera, Formicidae)

Abstract Ants of the genus Formicoxenus are called xenobiotic ants because they live in close association with their Myrmica host; they cannot live independently of the host but they keep their brood apart. They forage in the hosts galleries and obtain food from it through trophallaxies. They also very frequently lick the Myrmica workers and for that reason are called “shampoo ants”. The chemical basis of the integration of the parasite into the host society is studied. In the two host-parasite pairs F. provancheri/M. incompleta and F. quebecensis/M. alaskensis , chemical mimicry in the cuticular hydrocarbons was found. With adoption experiments it is shown that this mimicry was not innate but is acquired during the first days of adult life.

Preimaginal induction of adult behaviour in insects

This review illustrates the role of preimaginal experiences in four main aspects of insect life: feeding, habitat choice, host selection, and social relationships. After an illustration of the two former aspects with examples taken from various species, special attention is paid to the two latter aspects. First, an experiment is described, which demonstrates the existence of preimaginal induction involved in host selection by the solitary parasitoid wasp Dinarmus basalis (Hymenoptera: Pteromalidae). Then, a review of preimaginal induction in ants behaviour is presented; orientation of social behaviour, particularly altruism, is mainly determined by preimaginal imprinting. All the examples developed in this review clearly show that insects can no longer be considered as strictly, rigidly “pre-programmed” beings. Their complex behavioural development and plasticity is clearly documented.

Age-related changes in aggression in ant cataglyphis cursor (hymenoptera, formicidae): influence on intercolonial relationships.

Cataglyphis cursor forms monogynous societies which may however accept some foreign viduals. The factors influencing the degree of aggressiveness of the workers have been studied as follows. We have shown that the aggressive behaviour is expressed mainly by the foragers, the nurses are very little. aggressive. We observe therefore an evolution in the reactivity of the workers to a foreign odour in terms of age-related changes. However the closing of the society still depends on the behaviour of the foragers. Among the socia insects young workers are generally adopted by foreign colonies even if these colonies are completely closed to any other adult ants. Experiments allowed us to specify that young workers are recognized- as foreigners by another colony after the 4th day of age. Afterwards the adopted young ants were put back at different ages into their original colony, where they were recognized and accepted ty their sisters. The discussion is based on the origin of the colony odour. If this odour is formed from cuticular substances, in C. cursor their origin is probably endogenous, and predominant in comparison with the odours ac4uired from the environment (including that of the adoptive colony). Such an individualistic recognition system is known in only one other social insect species, the sweat bee.

Social organization in some primitive Australian ants. I.Nothomyrmecia macrops Clark

SummaryResults of laboratory-based ethological studies on twoNothomyrmecia macrops colonies with individually marked workers are reported. Interactive behavioural acts constituted less than 1% of all those recorded, revealing a strong tendency by the ants not to engage in social contact. Very few workers performed queen-directed acts. They stayed near the queen, though seldom in direct contact. Division of labour was otherwise barely apparent, except that some individuals showed a propensity to guard the nest entrance. No exchange of food was observed between workers, workers and queen, or adults and larvae (apart from worker placement of prey items with larvae). A queen fed from aDrosophila carcass retrieved from the nest floor, without assistance from workers. Systematic scanned observations confirmed levels of inactivity higher than previously observed in ants (comprising almost 2/3 of recorded behavioural acts). The time budget for activities directed toward the immature stages was the same in both colonies, and fluctuated during the circadian period. Non-nestmate larvae added to worker groups were more frequently licked than nestmate larvae, but this might not involve the particular recognition of nestmateversus non-nestmate brood. These observations support the hypothesis thatNothomyrmecia is primitively eusocial, and of special significance in myrmecology.

Reproductive competition and colony fragmentation in the guest-ant,Formicoxenus provancheri

Aggressive reproductive conflicts and dominance interactions among queens are involved in establishing functional monogyny in the ant,Formicoxenus provancheri. Competition among potential reproductives may lead to the founding of new societies by budding or colony fragmentation.

Semi-claustral colony foundation in the formicine ants of the genusPolyrhachis (Hymenoptera: Formicidae)

SummaryPolyrhachis laboriosa andP. militaris are two tree-inhabiting ant species, belonging to the subgenusMyrma common in Cameroon forest. WhileP. laboriosa live on pioneer trees on the edge of forest tracks,P. militaris inhabit dense equatorial forest. Foundation of societies is independent in these two species. Founding queens ofP. laboriosa made small cells under leaves, while foundresses ofP. militaris made cells in soil, hollowed dead branches, or old termitaria. The queens left their cells daily to forage. They collected water, sugared juices, and prey. They were also observed “grazing” the surface of leaves.P. laboriosa queens also collected vegetal matter which was then used to build their founding cells under leaves. This behavior was observed in both the field and the laboratory. This article is the first description of semi-claustral foundation in a formicine ant. It may be related to the fact that these ants are protected from predators by mandrels (hooks) on the thorax and the petiole. Bright yellow coloration of the gaster may also serve as an aposematic warning signal for potential predators. Prey capture was studied in the two species by offering both small (isolated or in group) and large prey to the foundresses. Hunting behavior ofPolyrhachis queens was similar to that of workers, and was identical in the two species.

Relations between the parasite ant Formicoxenus provancheri and its host Myrmica incompleta. Biological and ethological data (Hym. Formicidae).

RésuméLa biologie et le comportement deFormicoxenus provancheri, fourmi parasite de Myrmica incompleta, sont précisées. Cette espèce forme de grandes sociétés polycaliques où chaque unité conserve une certaine autonomie (mise en évidence par le faible taux de passage dune unité à lautre et la discrimination du couvain de chaque unité). Ladoption desFormicoxenus par lesMyrmica est facile et nentraîne quune mortalité très faible parmi les parasites, même lorsquil sagit deMyrmica totalement indemnes de parasites. Nous décrivons deux comportements importants dans les interactions entre les deux espèces: le léchage de lhôte et le comportement dapaisement envers lhôte. Les larves deFormicoxenus sont consommées par lhôteMyrmica, ce qui explique la nécessité pour lesFormicoxenus de garder leur couvain à lécart de lhôte. Il est probable que la formation des supercolonies seffectue par bouturage dune gyne (ou dune ergate fécondée) accompagnée dergates, qui va fonder une nouvelle calie à la périphérie de la société hôte. Le problème de la dissémination du parasite est posé: les gynes après fécondation sont fortement agressées si on tente de les introduire dans une société étrangère.SummaryInformation on the biology and the behaviour ofFormicoxenus provancheri, a parasite ofMyrmica incompleta, is presented.F. provancheri forms large polycalic societies whith each unit maintaining some independance: movements from one unit to another are not frequent and there is brood discrimination between different units. Adoption ofFormicoxenus ergates byMyrmica societies is easy, the mortality is very low among the parasites, even if the adoptiveMyrmica were previously completely parasite free. The larvae ofFormicoxenus can be eaten by the host Myrmica, this explains the necessity for theFormicoxenus to keep their brood apart from the host. Grooming of the host is very frequent. This might enable the parasite to acquire the species-specific odour of the host colony. Grooming might also be a way of obtaining some nutricious substances from the host body. Appeasement behaviour presented by theFormicoxenus is described. New small units of colonies, at the periphery of the host society, are probably founded by budding of any fecundated female leaving the nest with some ergates. This leads to the formation of super-societies by the parasite. The probleme of how the parasite spreads is not answered by this study because it was shown that newly fecundated gynes suffer strong aggression when they enter an alien host society.

Relations entre la fourmi parasiteFormicoxenus provancheri et son hôteMyrmica incompleta. Données biologiques et éthologiques (Hym. Formicidae)

RésuméLa biologie et le comportement deFormicoxenus provancheri, fourmi parasite de Myrmica incompleta, sont précisées. Cette espèce forme de grandes sociétés polycaliques où chaque unité conserve une certaine autonomie (mise en évidence par le faible taux de passage dune unité à lautre et la discrimination du couvain de chaque unité). Ladoption desFormicoxenus par lesMyrmica est facile et nentraîne quune mortalité très faible parmi les parasites, même lorsquil sagit deMyrmica totalement indemnes de parasites. Nous décrivons deux comportements importants dans les interactions entre les deux espèces: le léchage de lhôte et le comportement dapaisement envers lhôte. Les larves deFormicoxenus sont consommées par lhôteMyrmica, ce qui explique la nécessité pour lesFormicoxenus de garder leur couvain à lécart de lhôte. Il est probable que la formation des supercolonies seffectue par bouturage dune gyne (ou dune ergate fécondée) accompagnée dergates, qui va fonder une nouvelle calie à la périphérie de la société hôte. Le problème de la dissémination du parasite est posé: les gynes après fécondation sont fortement agressées si on tente de les introduire dans une société étrangère.SummaryInformation on the biology and the behaviour ofFormicoxenus provancheri, a parasite ofMyrmica incompleta, is presented.F. provancheri forms large polycalic societies whith each unit maintaining some independance: movements from one unit to another are not frequent and there is brood discrimination between different units. Adoption ofFormicoxenus ergates byMyrmica societies is easy, the mortality is very low among the parasites, even if the adoptiveMyrmica were previously completely parasite free. The larvae ofFormicoxenus can be eaten by the host Myrmica, this explains the necessity for theFormicoxenus to keep their brood apart from the host. Grooming of the host is very frequent. This might enable the parasite to acquire the species-specific odour of the host colony. Grooming might also be a way of obtaining some nutricious substances from the host body. Appeasement behaviour presented by theFormicoxenus is described. New small units of colonies, at the periphery of the host society, are probably founded by budding of any fecundated female leaving the nest with some ergates. This leads to the formation of super-societies by the parasite. The probleme of how the parasite spreads is not answered by this study because it was shown that newly fecundated gynes suffer strong aggression when they enter an alien host society.