Chiara Natali

Drivers of Population Structure of the Bottlenose Dolphin ( Tursiops truncatus ) in the Eastern Mediterranean Sea

The drivers of population differentiation in oceanic high dispersal organisms, have been crucial for research in evolutionary biology. Adaptation to different environments is commonly invoked as a driver of differentiation in the oceans, in alternative to geographic isolation. In this study, we investigate the population structure and phylogeography of the bottlenose dolphin (Tursiops truncatus) in the Mediterranean Sea, using microsatellite loci and the entire mtDNA control region. By further comparing the Mediterranean populations with the well described Atlantic populations, we addressed the following hypotheses: (1) bottlenose dolphins show population structure within the environmentally complex Eastern Mediterranean Sea; (2) population structure was gained locally or otherwise results from chance distribution of pre-existing genetic structure; (3) strong demographic variations within the Mediterranean basin have affected genetic variation sufficiently to bias detected patterns of population structure. Our results suggest that bottlenose dolphin exhibits population structures that correspond well to the main Mediterranean oceanographic basins. Furthermore, we found evidence for fine scale population division within the Adriatic and the Levantine seas. We further describe for the first time, a distinction between populations inhabiting pelagic and coastal regions within the Mediterranean. Phylogeographic analysis suggests that current genetic structure, results mostly from stochastic distribution of Atlantic genetic variation, during a recent post-glacial expansion. Comparison with Atlantic mtDNA haplotypes, further suggest the existence of a metapopulation across North Atlantic/Mediterranean, with pelagic regions acting as source for coastal environments.

Characterization of 13 polymorphic microsatellite loci in the European pine marten Martes martes

A set of 13 polymorphic microsatellite markers were isolated and characterized from a genomic library enriched for dinucleotide repeats in the European pine marten Martes martes. Microsatellite loci amplification was tested on a panel of 12 tissue samples and 9 distinct hair samples collected from either road-killed or trapped animals in Tuscany, Italy. Allelic diversity was 6 and the number of alleles per locus ranged from 2 to 10. Mean observed and expected heterozygosity were 0.610 (range: 0.238–0.905) and 0.698 (range: 0.400–0.856), respectively. This novel set of microsatellite loci will be particularly useful for non-invasive genetic studies to assess population distribution and patterns of population structure and dispersal of M. martes in woodlands and fragmented habitats.

The Rules of Aggression: How Genetic, Chemical and Spatial Factors Affect Intercolony Fights in a Dominant Species, the Mediterranean Acrobat Ant Crematogaster scutellaris

Nest-mate recognition plays a key role in the biology of ants. Although individuals coming from a foreign nest are, in most cases, promptly rejected, the degree of aggressiveness towards non nest-mates may be highly variable among species and relies on genetic, chemical and environmental factors. We analyzed intraspecific relationships among neighboring colonies of the dominant Mediterranean acrobat ant Crematogaster scutellaris integrating genetic, chemical and behavioral analyses. Colony structure, parental relationships between nests, cuticular hydrocarbons profiles (CHCs) and aggressive behavior against non nest-mates were studied in 34 nests located in olive tree trunks. Bayesian clustering analysis of allelic variation at nine species-specific microsatellite DNA markers pooled nests into 14 distinct clusters, each representing a single colony, confirming a polydomous arrangement of nests in this species. A marked genetic separation among colonies was also detected, probably due to long distance dispersion of queens and males during nuptial flights. CHCs profiles varied significantly among colonies and between nests of the same colony. No relationship between CHCs profiles and genetic distances was detected. The level of aggressiveness between colonies was inversely related to chemical and spatial distance, suggesting a ‘nasty neighbor’ effect. Our findings also suggest that CHCs profiles in C. scutellaris may be linked to external environmental factors rather than genetic relationships.

Characterization of microsatellite loci in the European pond turtle Emys orbicularis

A set of eight highly polymorphic microsatellite markers was isolated and characterized from a genomic library enriched for dinucleotide repeats in the European pond turtle, Emys orbicularis. The markers were tested for polymorphism in a total of 33 turtles sampled in two natural ponds in the nature reserve of Kerkini, northern Greece. Number of alleles varied from 10 to 18, and expected heterozygosity ranged between 0.738 and 0.921. This novel set of loci will be particularly useful to assess fine‐scale population structure and for parentage analysis in E. orbicularis.

Development of a multiplex PCR assay for fine-scale population genetic analysis of the Komodo monitor Varanus komodoensis based on 18 polymorphic microsatellite loci

Multiplex PCR assays for the coamplification of microsatellite loci allow rapid and cost‐effective genetic analyses and the production of efficient screening protocols for international breeding programs. We constructed a partial genomic library enriched for di‐nucleotide repeats and characterized 14 new microsatellite loci for the Komodo monitor (or Komodo dragon, Varanus komodoensis). Using these novel microsatellites and four previously described loci, we developed multiplex PCR assays that may be loaded on a genetic analyser in three separate panels. We tested the novel set of microsatellites for polymorphism using 69 individuals from three island populations and evaluated the resolving power of the entire panel of 18 loci by conducting (i) a preliminary assignment test to determine population(s) of origin and (ii) a parentage analysis for 43 captive Komodo monitors. This panel of polymorphic loci proved useful for both purposes and thus can be exploited for fine‐scale population genetic analyses and as part of international captive breeding programs directed at maintaining genetically viable ex situ populations and reintroductions.

Characterization of polymorphic microsatellite loci in the ant Crematogaster scutellaris

Nine polymorphic microsatellite loci were isolated and characterized in the ant Crematogaster scutellaris from Italy. Allelic variation was tested for individuals collected from 26 nests in an olive grove in Tuscany, where ant–homopteran mutualistic interactions are under study to control damages to the olive crop. Allelic diversity was 12.4 and the number of alleles per locus ranged from 8 to 17. Mean observed and expected heterozygosity were 0.826 (range, 0.760–0.923) and 0.829 (range, 0.736–0.869), respectively. This novel set of loci will be used to assess population structure, dispersal strategies and mating system of C. scutellaris, and in particular to determine genetic relationships among individuals engaged in intraspecific conflicts.

Molecular identification of imported red wood ant populations in the Campigna Biogenetic Nature Reserve (Foreste Casentinesi National Park, Italy)

During the second half of the XIX century, several species of red wood ants (Formica rufa group) were used as biological control agents and introduced to the Italian Apennine mountains where they were formerly absent. Among these, Formica lugubris was the most widely introduced alien species. In 1996, however, a taxonomic revision defined two sibling species, F. lugubris and F. paralugubris, each with distinct ecological and behavioural characteristics that differently affect their spatial distribution. The first one can be both monodomous and polydomous with a low number of interlinked nests, and it is obliged to mate by nuptial flight. Conversely, F. paralugubris is usually unicolonial, with a considerable portion of intranest mates. Discrimination between the two species using morphological characters is possible but requires considerable taxonomic expertise. Restriction analysis, whereby presence/absence of a BamHI site in the mitochondrial DNA COI gene results in different restriction profiles, provides an alternative efficient method to unambiguously distinguish F. lugubris from F. paralugubris. We applied this method to identify ant species introduced to several locations in the Campigna Forest of the Foreste Casentinesi, Monte Falterona and Campigna National Park, one of the Italian locations mostly affected by alien ant introductions. This area has considerable ecological relevance. Given the potential impact of ants on native arthropod communities, it is of the most importance to identify which species has been introduced. Contrary to previous assumptions, results of our analysis clearly show that only F. paralugubris is present in the National park.