Social insect nests provide a safe and favourable shelter to many guests and parasites. In Aphaenogaster senilis nests many guests are tolerated. Among them we studied the chemical integration of two myrmecophile beetles, Sternocoelis hispanus (Coleoptera: Histeridae) and Chitosa nigrita (Coleoptera: Staphylinidae), and a silverfish. Silverfishes bear low quantities of the host hydrocarbons (chemical insignificance), acquired probably passively, and they do not match the colony odour. Both beetle species use chemical mimicry to be accepted; they have the same specific cuticular hydrocarbon profile as their host. They also match the ant colony odour, but they keep some specificity and can be recognised by the ants as a different element. Sternocoelis are always adopted in other conspecific colonies of A. senilis with different delays. They are adopted in the twin species A. iberica but never in A. simonellii or A. subterranea. They are readopted easily into their mother colony after an isolation of different durations until one month. After isolation they keep their hydrocarbons quantity, showing that they are able to synthesize them. Nevertheless, their profile diverges from the host colony, indicating that they adjust it in contact with the hosts. This had never been demonstrated before in myrmecophile beetles. We suggest that the chemical mimicry of Sternocoelis is the result of a coevolution with A. senilis with a possible cleaning symbiosis.

Ants are important consumers in most terrestrial ecosystems. They show a great diversity of diets and foraging strategies. Here, we analyzed how circannual variation in resource use by the Mediterranean species Aphaenogaster senilis is related to colony life cycle and resource availability. In southwestern Spain, this species is active almost yearround, but foraging intensity decreases 10fold between March and November, following larval production. In the summer, ants refrain from foraging at midday to avoid high temperatures. We hypothesized that diet and foraging plasticity could also explain the ecological success of this species. There are several techniques for assessing the diet of ants. Combining isotope analyses with conventional methods can provide better taxonomic resolution of resource utilization. Using a combination of classic and isotopic analyses, we found that 1) the proportion of plant and animalderived items collected by foragers did not vary significantly from March to November, and 2) isotope analyses indicated a decrease in the trophic level of A. senilis between June and September, suggesting a difference between collected material and items assimilated. Interestingly, most animal prey were collected by individual ants, and many were retrieved alive. Therefore, A. senilis is not only a scavenger, but also a nonnegligible predator, particularly of aphids. The abundance of the most common animalderived items in the diet was proportional to their abundance in the study area. We conclude that A. senilis is an opportunistic species that is able to feed on a variety of resources, which may be key to its ecological success.Résumé : Les fourmis sont des consommateurs importants dans la plupart des écosystèmes terrestres. Elles montrent une grande diversité de stratégies de recherche de nourriture et de régimes alimentaires. Nous avons analysé comment la variation circannuelle de l'utilisation des ressources par l'espèce méditerranéenne Aphaenogaster senilis est reliée au cycle de vie de la colonie et à la disponibilité des ressources. Au sudouest de l'Espagne, cette espèce est active presque toute l'année, mais l'intensité de sa quête alimentaire est réduite d'un facteur 10 entre mars et novembre après la production de larves. En été, les fourmis s'abstiennent de fourrager au milieu de la journée pour éviter les températures trop élevées. Nous avons formulé l'hypothèse que la plasticité du régime et de la quête alimentaires pourrait aussi expliquer le succès écologique de cette espèce. Il y a plusieurs techniques pour déterminer le régime alimentaire des fourmis; la combinaison d'analyses isotopiques et de méthodes classiques peut fournir une meilleure résolution taxonomique de l'utilisation des ressources. En combinant des analyses classiques et isotopiques, nous avons trouvé : 1) que la proportion de plantes et d'éléments d'origine animale récoltés par les fourmis fourrageuses ne variait pas significativement entre mars et novembre; et 2) les analyses isotopiques ont indiqué une diminution du nive...

In contrast to other plant-animal mutualisms, seed dispersal interactions, and particularly seed dispersal by ants, are generally considered asymmetric, non-specialized relationships in which dispersers depend less on plants than vice versa. Although myrmecochory is well understood in many terrestrial ecosystems, dispersal of non-elaiosomebearing seeds by ants has barely been studied outside the Neotropics. Aphaenogaster senilis, a common ant in Southern Spain, collects a great variety of non-myrmecochorous diaspores along with insect prey. At our study site, fleshy fruits of Arum italicum, Phillyrea angustifolia and Pistacia lentiscus represent up to one-fourth of the items collected by A. senilis from June to November. However, they are mostly ignored by other ants. In the laboratory, the addition of A. italicum fruits to A. senilis insect-based diet increased male production and both worker and queen pupae size. Seeds were transported up to 8 m away from the mother plant and deposited in a favorable habitat allowing a relatively high proportion of germination. Given important differences in seed production between species, our data suggest that A. senilis removes virtually all seeds of A. italicum, but a negligible fraction of P. lentiscus seeds. We conclude that in contrast to the common view, dispersal of non-myrmecochorous Mediterranean plants by ants might be an important phenomenon. Keystone disperser ants like A. senilis probably obtain an important fitness advantage from non-myrmecochorous diaspore collection. However, plant benefit may vary greatly according to the amount of seeds per individual plant and the existence of alternative dispersal agents.

Dispersal is an important step in animal's life cycle, one consequence of which is reducing local mate and resource competition. Dispersal is often achieved during one unique special movement, from the birthplace to a new appropriate area where to settle and reproduce. However, in species in which this special movement is limited by life history tradeoffs, we may expect dispersal to be promoted also by routine movements occurring throughout the animal's life and stimulated by other activities like foraging or the search of nesting conditions. Here we employ a multidisciplinary approach consisting of computer simulations, mark-recapture and genetic data to better understand the role of colony relocations as dispersal strategy in the gypsy ant Aphaenogaster senilis. Contrary to expectations, our results show that colony relocations do not result in effective dispersal as evidenced by mark-recapture and genetic data. Furthermore, simulations showed that successive colony relocations did not follow a constant direction, but occurred either in a randomly changing direction or followed a circular trajectory, indicating limited effective dispersal. We also found a general lack of inbreeding and significant population viscosity between neighbouring colonies suggesting that relocations may act as a balancing strategy between these two processes. We discuss the results in terms of their evolutionary and ecological significance, and highlight future directions of research towards the understanding of dispersal strategies in colonial species.

Pollen is a product originating from the anthers of flowers. Members of the Apidae group feed on this floristic product, which is metabolized and stored in the hives. It is known that the pollen metabolized by stingless and stingless bees has medicinal and nutritional characteristics. This study aimed to evaluate the physicochemical and microbiological quality of pollen collected by Tetragonisca angustula, Melipona quadrifasciata and Apis mellifera. Pollen was collected between January 2021 and January 2023 in a conservation area in Goiás, Brazil. The pollen was characterized by physicalchemical analysis for moisture, ash, proteins, lipids, total sugars and pH, and microbiological analysis on Escherichia coli and Salmonella spp. The obtained results characterize the pollens of indigenous bees as suitable for consumption, since they presented good physicochemical characteristics for most of the analyzed parameters and free of pathogens.