Ants use various communication channels to regulate their social organisation. The main channel that drives almost all the ants’ activities and behaviours is the chemical one, but it is long acknowledged that the acoustic channel also plays an important role. However, very little is known regarding exploitation of the acoustical channel by myrmecophile parasites to infiltrate the ant society. Among social parasites, the ant nest beetles (Paussus) are obligate myrmecophiles able to move throughout the colony at will and prey on the ants, surprisingly never eliciting aggression from the colonies. It has been recently postulated that stridulatory organs in Paussus might be evolved as an acoustic mechanism to interact with ants. Here, we survey the role of acoustic signals employed in the Paussus beetle-Pheidole ant system. Ants parasitised by Paussus beetles produce caste-specific stridulations. We found that Paussus can “speak” three different “languages”, each similar to sounds produced by different ant castes (workers, soldiers, queen). Playback experiments were used to test how host ants respond to the sounds emitted by Paussus. Our data suggest that, by mimicking the stridulations of the queen, Paussus is able to dupe the workers of its host and to be treated as royalty. This is the first report of acoustic mimicry in a beetle parasite of ants.

Stingless bees (Hymenoptera: Meliponini) are among the most important pollinators of tropical forests. Peru is considered a hotspot of biodiversity of Meliponini, but many areas of this country (e.g., Peruvian Amazon) remain unexplored. We aimed to produce a first inventory of stingless bee species dwelling in humid and seasonally dry forests of northern Peru by combining traditional (morphologically-based) taxonomy and DNA barcoding. Specimens were collected in 2020 at five sites located in San Martin and Piura regions. We identified 12 genera of Meliponini. Among those, Trigona and Plebeia were the most abundant (45.9% and 12.8% respectively), whereas Nannotrigona and Scaura were the least represented ones (2.3%). We assigned a reliable species identification to about 30% of specimens (Trigona amazonensis, T. muzoensis, T. williana, Partamona testacea, Scaura tenuis, Tetragona goettei, and Tetragonisca angustula). Yet, more than a half of the specimens received a provisional identification (e.g., Geotrigona cf. fulvohirta, T. cf. amalthea, T. cf. fuscipennis, T. cf. hypogea, Melipona cf. cramptoni, Partamona cf. epiphytophila, Ptilotrigona cf. perenae, Scaura cf. latitarsis, Tetragona cf. clavipes, Trigonisca cf. atomaria). We also highlighted an extensive polyphyly that affected a number of currently recognized species (e.g., T. fulviventris, T. guianae, Plebeia franki, P. frontalis, M. eburnea, M. illota), whose members were split into various clades. Finally, 16% of individuals failed to be identified at the species level (Trigona sp. 1, T. sp. 2, Nannotrigona sp., Partamona sp., Scaptotrigona sp. 1, S. sp. 2, Trigonisca sp. 1, and Trigonisca sp. 2). We discuss our findings according to the current faunistic and biogeographic knowledge of Meliponini in Peru and the Neotropical region. We also remark on the importance of conducting a taxonomic revision of stingless bees and improving both their morphology-based identification keys and BOLD repository. Finally, we claim that integrative taxonomy shall be strongly implemented to truly assess the biodiversity of Neotropical stingless bees, allowing conserving these important pollinators and the associated traditional meliponiculture in an effective manner.

Several studies have highlighted the global decline of pollinator insects, with Lepidoptera being particularly affected in large parts of Europe in recent decades. Given the important biogeographic and conservation implications from faunal studies on the large Mediterranean islands, we focused on assessing butterfly diversity within the Culuccia Peninsula in north-eastern Sardinia (Italy). This area, characterized by an environmental mosaic largely untouched by human activities over the last century, is still unknown in terms of flora and fauna. For this reason, we compiled the first butterfly checklist of the Culuccia Peninsula and produced a detailed land cover map of the area to investigate the influence of the land use classes on Lepidoptera communities across seasons. The butterflies were sampled in five sessions from April to October 2022, along seven fixed transects selected to cover land use classes representative of natural and human-exploited areas for agriculture and grazing. Despite the small size of the study area, 23 of the 56 species present in Sardinia were recorded. The butterfly communities presented high dissimilarity across the different land use classes, which was driven primarily by species turnover. Significant differences in Lepidoptera diversity were observed between land cover classes with sparse vegetation and dense maquis, with higher species richness observed in the former. Shrub-dominated land use classes were associated with cooler butterfly communities compared to open environments, suggesting that they could serve as refugia in response to predicted climate change.

The concentration of nanoplastics (NPs) is expected to increase in aquatic environments thus potentially threatening freshwater organisms through interactions with plastic particles that variously float, circulate in the water column or sink into the benthos. Studies into the mechanisms of any NP effects are still scarce, particularly with respect to the regenerative ability of biota for which there is no recognised model organism. The present study therefore aimed to investigate behavioural and regeneration responses of the freshwater planarian Girardia tigrina after 10 days exposed to along a gradient 0.01-10 mg/L of poly (styrene-co-methyl methacrylate) NPs (∼426 ± 175 nm). Exposure to NPs induced a significant reduction in planarian feeding rate even at low concentrations (LOEC of 0.01 mg/L), while head regeneration was delayed in a clear dose response way (LOEC of 0.1 mg/L for blastema length). Planaria locomotion assessed was not affected. Our results highlight the potential adverse effects of exposure to poly (styrene-co-methyl methacrylate) NPs and show that feeding behaviour and regeneration of a freshwater benthic organism can be indicators of the resulting toxicity. Planarians are becoming widely used model organisms in ecotoxicology and can help to address potential effects of plastic polymers on regeneration.

As disease worsens in patients with cystic fibrosis (CF), Pseudomonas aeruginosa (PA) colonizes the lungs, causing pulmonary failure and mortality. Progressively, PA forms typical biofilms, and antibiotic treatments determine multidrug-resistant (MDR) PA strains. To advance new therapies against MDR PA, research has reappraised bacteriophages (phages), viruses naturally infecting bacteria. Because few in vitro studies have tested phages on CF PA biofilms, general reliability remains unclear. This study aimed to test in vitro newly isolated environmental phage activity against PA isolates from patients with CF at Bambino Gesù Children’s Hospital (OBG), Rome, Italy. After testing in vitro phage activities, we combined phages with amikacin, meropenem, and tobramycin against CF PA pre-formed biofilms. We also investigated new emerging morphotypes and bacterial regrowth. We obtained 22 newly isolated phages from various environments, including OBG. In about 94% of 32 CF PA isolates tested, these phages showed in vitro PA lysis. Despite poor efficacy against chronic CF PA, five selected-lytic-phages (Φ4_ZP1, Φ9_ZP2, Φ14_OBG, Φ17_OBG, and Φ19_OBG) showed wide host activity. The Φ4_ZP1-meropenem and Φ14_OBG-tobramycin combinations significantly reduced CF PA biofilms (p < 0.001). To advance potential combined phage-antibiotic therapy, we envisage further in vitro test combinations with newly isolated phages, including those from hospital environments, against CF PA biofilms from early and chronic infections.