Altered feeding behavior and immune competence in paper wasps: A case of parasite manipulation?

Paper wasps (Polistes dominula), parasitized by the strepsipteran Xenos vesparum, are castrated and desert the colony to gather on plants where the parasite mates and releases primary larvae, thus completing its lifecycle. One of these plants is the trumpet creeper Campsis radicans: in a previous study the majority of all wasps collected from this plant were parasitized and focused their foraging activity on C. radicans buds. The unexpected prevalence and unusual feeding strategy prompted us to investigate the influence of this plant on wasp behavior and physiology through a multidisciplinary approach. First, in a series of laboratory bioassays, we observed that parasitized wasps spent more time than non-parasitized ones on fresh C. radicans buds, rich of extra-floral nectaries (EFNs), while the same wasps ignored treated buds that lacked nectar drops. Then, we described the structure and ultra-structure of EFNs secreting cells, compatible with the synthesis of phenolic compounds. Subsequently, we analysed extracts from different bud tissues by HPLC-DAD-MS and found that verbascoside was the most abundant bioactive molecule in those tissues rich in EFNs. Finally, we tested the immune-stimulant properties of verbascoside, as the biochemical nature of this compound indicates it might function as an antibacterial and antioxidant. We measured bacterial clearance in wasps, as a proxy for overall immune competence, and observed that it was enhanced after administration of verbascoside—even more so if the wasp was parasitized. We hypothesize that the parasite manipulates wasp behavior to preferentially feed on C. radicans EFNs, since the bioactive properties of verbascoside likely increase host survival and thus the parasite own fitness.

Kick Out The Ants: A Novel and Striking Behavior in Ant-Wasp Interactions

Trophobiosis between ants and homopterans is widely known. Nevertheless, this interaction can also happen between treehoppers and other animals in a non-mutualistic way. For instance, here we observed the wasp Pseudopolybia vespiceps (Hymenoptera: Vespidae) collecting honeydew flickered by Aethalion reticulatum (Hemiptera: Cicadomorpha) as an alternative food resource. Fieldwork was conducted during three consecutive days, when we made ad libitum behavioral observations using video footage. We noted the behavior of P. vespiceps when collecting honeydew from A. reticulatum. Strikingly, our observations resulted in the description of novel wasp behavior. The wasps compete with ants for access to treehoppers by kicking them out of the plant. Studies like this contribute to the understanding of trophic nets that depend on hemipteran honeydew.

Wasps, Termites, and Waspmites: Distinguishing Competence from Performance in Collective Construction

We introduce a distinction between algorithm performance and algorithm competence and argue that bio-inspired computing should characterize the former rather than the latter. To exemplify this, we explore and extend a bio-inspired algorithm for collective construction influenced by paper wasp behavior. Despite its being provably general in its competence, we demonstrate limitations on the algorithm's performance. We explain these limitations, and extend the algorithm to include pheromone-mediated behavior typical of termites. The resulting hybrid waspmite algorithm shares the generality of the original wasp algorithm, but exhibits improved performance and scalability.