Public Engagement Provides First Insights on Po Plain Ant Communities and Reveals the Ubiquity of the Cryptic Species Tetramorium immigrans (Hymenoptera, Formicidae)

Ants are considered a useful model for biodiversity monitoring and several of their characteristics make them promising for citizen science (CS) projects. Involving a wide range of public figures into collecting valuable data on the effect of human impact on ant biodiversity, the School of Ants (SoA) project represents one of the very few attempts to explore the potential of these insects in CS. Through the collaboration with the "BioBlitz Lombardia" project, we tested the SoA protocol on 12 Northern Italy parks, ranging from urban green to subalpine protected sites. As a result, we obtained some of the very first quantitative data characterizing the ants of this region, recording 30 species and highlighting some interesting ecological patterns. These data revealed the ubiquitous presence of the recently taxonomically defined cryptic species Tetramorium immigrans, which appears to be probably introduced in the region. We also discuss advantages and criticisms encountered applying the SoA protocol, originally intended for schools, to new categories of volunteers, from BioBlitz participants to park operators, suggesting best practices based on our experience

A new exception to the dominance-discovery trade-off rule in ant communities

Interspecific competition is one of the main factor shaping ant community structure. The “dominance-discovery trade-off’’, an inverse relationship between interference and exploitative competitive ability, is thought to be a fundamental mechanism facilitating coexistence of ants. Despite its widely acceptance in literature, this trade-off appears to be broken in several cases and needs further investigations. Thus, the aim of the present study was to detect the presence/absence of the dominance-discovery trade-off in Mediterranean ant communities. Samplings were conducted inside the Presidential Estate of Castelporziano (Rome, Italy) and seven sampling sites were selected according to their vegetation structure. In each site, baiting was conducted to assess two behavioural indices for each species: the monopolization index and the discovery ability index. Correlation analyses showed no evidence for the existence of a dominance-discovery trade-off. Furthermore, a positive correlation between the two indices was detected in some of the sampling sites. The dominance-discovery trade-off seems therefore to be just one of the possible mechanisms facilitating species coexistence in ant communities

Ergatandromorphism in the Ant Myrmica lobulicornis Nylander, 1857 (Formicidae: Myrmicinae)

Ergatandromorphism is the result of an aberrant development in which part of the body of a social insect shows the traits of the worker caste, while the other resembles a male. It is considered a specific case of gynandromorphism. Specimens with these characteristics have rarely been collected in different ant lineages across the world. Here, we provide the first description of ergatandromorphism in the ant Myrmica lobulicornis Nylander, 1857: an ergatandromorphous specimen was recovered during an arthropod sampling campaign across altitudinal and ecological gradients on the Italian Alps (Stelvio National Park), together with 480 workers and 4 queens of the same species, which expressed the normal phenotype

Social Parasite Ants in the Alps: a New Site of the Vulnerable Myrmica myrmicoxena and New Uppermost Altitudinal Limit for M. microrubra

We conducted a survey on the Alpine fauna of one of the largest Natural Park of the Italian Alps (Stelvio National Park) in the framework of a broad ecological monitoring of Alpine biodiversity. A two-years standardized sampling employing pitfall traps along a 1200 m altitudinal gradient led to the discovery of two interesting inquiline social parasite ants of the genus Myrmica: M. myrmicoxena Forel, 1895 and M. microrubra Seifert, 1993. Myrmica myrmicoxena, which is classified as Vulnerable according to the IUCN Red List, was so far known from only three sites across a narrow geographic range between Italy and Switzerland. Our data support the previous hypothesis over its ecology and host association. Myrmica microrubra is considered an incipient species of high evolutionary interest, sometimes regarded as an intraspecific form of M. rubra. While having a wide distribution in Europe, its presence in Italy was hitherto known only from a single site, and our record extends its altitudinal distribution limit in Europe upwards by about 600 m

The role of interspecific behavioural dominance in the analysis of ant community structure

La mirmecofauna (Hymenoptera, Formicidae) riveste un ruolo critico all’interno del proprio ecosistema, in quanto è presente a vari livelli trofici. Ciò significa che il taxon dei formicidi comprende numerose specie keystone: esse si relazionano con tutte le componenti di un ecosistema ed intervengono nel regolare gli equilibri alla base di una comunità. Le formiche agiscono, inoltre, come ingegneri ecologici nel modellare la struttura e la composizione del suolo. Di conseguenza, è possibile affermare che le formiche rappresentano, sotto alcuni aspetti, il proprio ecosistema e che lo studio della struttura di comunità si rivela un valido strumento, insieme ad altri, per descrivere lo stato dell’ecosistema stesso. In ambienti caratterizzati da un livello moderato di stress e di disturbo, il fattore cruciale che regola la struttura di comunità è la competizione interspecifica, che si risolve con la formazione di gerarchie di dominanza alimentare. In particolare, la dominanza si distingue in numerica e comportamentale; stimata con valori di abbondanza e frequenza, la prima è ampiamente descritta in letteratura, poiché richiede metodologie di più rapido e semplice impiego, mentre la seconda è più difficilmente misurabile, visto che necessita la stima di diversi parametri e l’uso di una metodologia attiva, che prevede l’osservazione diretta delle interazioni comportamentali. Poiché, attualmente, la documentazione sull’etoecologia delle formiche italiane è assai scarsa, questo progetto di ricerca si propone di analizzare la struttura di comunità della mirmecofauna in Italia. In particolare, lo scopo principale è quello di misurare in modo standardizzato le due componenti della dominanza in tre varietà distinte di ecosistema: montano, urbano e mediterraneo. L’applicazione di un protocollo sperimentale ad hoc si propone di evidenziare il ruolo della dominanza comportamentale nel descrivere la struttura di comunità. Inoltre, è stato valutato l’effetto del gradiente altitudinale associato allo stress ambientale (I anno), del disturbo associato allo sfruttamento antropico (II anno) e della competizione da parte di una specie invasiva (III anno) sulla struttura di comunità. I risultati hanno mostrato che l’analisi della sola dominanza numerica non esaurisce la spiegazione dei meccanismi alla base della struttura di comunità. Al contrario la stima della dominanza comportamentale mette in luce aspetti diversi delle abilità competitive delle varie specie. Inoltre, i modelli ambientali scelti si sono rivelati adeguati per rispondere alle domande sperimentali. Sono, infine, emersi spunti interessanti per la progettazione di ulteriori studi sull’etoecologia di comunità dei formicidi.Ant-fauna (Hymenoptera, Formicidae) plays an important role in its ecosystem, being present at different trophic levels. This taxon includes several keystone species: they are related to each component of an ecosystem and they rule community mechanisms. Moreover, ants are defined as “ecological engineers” because they contribute to shape soil structure and composition. As a consequence, ants are considered to represent their own ecosystem and the study of ant community structure may become a useful tool to describe the ecosystem conditions. In environments characterized by low levels of stress and disturbance, the main factor structuring ant community is interspecific competition that results in the development of dominance hierarchies. In particular, dominance can be divided in two components: numerical and behavioural dominance. The former is widely used in literature employing easier and faster methods of measurement, while the latter is more difficult to be measured depending on the assessment of different variables and on techniques that require spending a lot of time observing behavioural interactions. At present the knowledge on the behavioural ecology of Italian ants is very poor and so the aim of this research was to analyse the structure of the ant-fauna in Italy. In particular, I focused on standardizing the measure of the two components of dominance in three different types of ecosystem: mountain, urban and Mediterranean environments. Moreover, an experimental protocol ad hoc was used to underline the role of behavioural dominance in describing ant community structure. Finally, I evaluated the effect of an altitudinal gradient related to environmental stress (year I), of anthropogenic exploitation (year II) and of the competition by an invasive species (year III) on ant community structure. Results showed that the analysis of numerical dominance was not sufficient to explain the mechanisms structuring ant communities. On the other hand, the assessment of behavioural dominance pointed out several aspects of species competitive abilities. Furthermore, the selected environmental models resulted suitable to answer to the experimental questions. Finally, results gave rise to interesting suggestions for other projects on the behavioural ecology of ants

Daily activity patterns and food preferences in an alpine ant community

Species may reduce competitive interactions by temporal separation in activity times. Similarly to other animals, ants also partition their niches by being active during specific periods of the year or at specific times of the day. However, if several species share the same temporal niches, interspecific competition may give rise to behavioural dominance hierarchies, territoriality or spatial mosaics. Thus, our first aim was to study daily activity patterns of alpine communities to investigate their temporal dynamics at both general and specific levels. Due to short distances among different ecosystems, montane systems are ideal models to study the effect of geographic variation on community structure. On the other hand, ants represent an excellent model to analyze beta-diversity because they are one of the most ecologically significant components of many ecosystems. Nevertheless, there is a lack of ecological studies on ant communities in Italy and, in particular, on alpine ants. Therefore, the second aim of this work was to study ant species richness and distribution in order to update information on alpine ant fauna. As ants can simultaneously exhibit multiple trophic roles, assessing the feeding habits of an ant community may help to clarify how these insects can influence their ecosystem. Thus, the third aim of this research was to evaluate ant food preferences in alpine environments. Samplings were conducted in Soana Valley, inside the Gran Paradiso National Park, during summer 2011: pitfall traps and food baits were placed in order to collect data on species richness, abundances and food preferences. The acquired results on activity patterns showed that ants were more active in the late morning. The analysis of food preferences revealed that sugary solutions were the favourite resources. Finally, concerning species spatial distribution, there was a higher level of biodiversity at intermediate elevations, probably due to an increase of temperature and spatial heterogeneity