Distribution of mobile organisms on near-continent islands is mainly shaped by factors operating over ecological rather geological time. However, the phylogeography of single species has the potential to expose historical factors at work. In the present study, West Mediterranean populations of the butterfly Maniola jurtina are studied using geometric morphometrics. The distribution of the two well established lineages (Maniola jurtina jurtina in the Atlanto-Mediterranean area and Maniola jurtina janira in the Central-Eastern-Mediterranean area) on 12 islands and the adjoining continents are compared. The south-western lineage unexpectedly occurs on islands close to shores occupied by the eastern lineage. We have modelled the distribution of the lineages using three different hypotheses: (1) a contemporary isolation model, which predicts lineage occupancy of islands is linked to relative distances from neighbouring continental areas; (2) a refugial hypothesis, which predicts one lineage to be the ancestral one for the whole region studied, and then successively replaced over part of it; (3) a changing geography hypothesis, which predicts the two lineages to have evolved in their currently occupied areas, continuously sourcing islands subsequent to the Würm maximum glaciation. Of the three models, the refugial hypothesis is most highly correlated with the observed pattern, suggesting that Mediterranean islands may function as refugia during cold periods, much as the three mainland peninsulas of Iberia, Italy and Greece are known to have done. Thereafter, hybridization on the nearest and smallest islands has occurred, with the entire process supporting the notion of the joint influence of factors in ecological and geological time.

The poor survival rate of immature northern bald ibises Geronticus eremita during their first years spent outside the natal site is driving the last known wild colony of the migratory eastern population to extinction. To inform emergency conservation action for this Critically Endangered species we investigated the distribution range and behaviour of immature birds in passage and wintering areas, and the threats to which they are subject. We integrated recent satellite telemetry data with visual observations spanning 130 years. We assessed threats across the range, using satellite tracking and field surveys. Our results show that during the years before they return to the natal site in Syria, immature northern bald ibises reside away from the recently identified adult wintering site in the central Ethiopian highlands. They occur mainly across the northernmost 70-80% of the adult migratory range. Historical records suggest that immature birds spend more time along the western Arabian Peninsula now than in the past. This range shift exposes them for longer periods to threats, such as hunting and electrocution on power lines, which are absent from the wintering site used by adult birds. We suggest that other threatened and declining bird species sharing the same flyway probably face the same threats during migration.

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Honeybee disappearance is one of the major environmental and economic challenges this century has to face. The ecto-parasitic mite Varroa destructor represents one of the main causes of the worldwide beehive losses. Although halting mite transmission among beehives is of primary importance to save honeybee colonies from further decline, the natural route used by mites to abandon a collapsing colony has not been extensively investigated so far. Here, we explored whether, with increasing mite abundance within the colony, mites change their behaviour to maximize the chances of leaving a highly infested colony. We show that, at low mite abundance, mites remain within the colony and promote their reproduction by riding nurses that they distinguish from foragers by different chemical cuticular signatures. When mite abundance increases, the chemical profile of nurses and foragers tends to overlap, promoting mite departure from exploited colonies by riding pollen foragers.

Aim  Distinct insular populations are generally considered important units for conservation. In island–mainland situations, unidirectional introgressive gene flow from the most abundant, typically continental, populations into the smaller island populations can erase native insular genetic units. As an indication of threat, the concept of phenetic slope is developed, a measure proportional to differentiation and to geographical proximity. Location  The Western Mediterranean, including the following islands: Sardinia, Sicily, Corsica, Balearics, circum‐Italian, circum‐Sicilian and circum‐Sardo‐Corsican archipelagos. Eastern Europe is included for comparison. Methods  Geometric morphometrics was applied to 2392 male genitalia of seven butterfly species groups. Geographic Information System techniques were used to depict the pattern in the distribution of morphotypes. The slope of variation in genital shape was computed to highlight geographical areas showing abrupt morphological changes. Correlation analyses were performed between the mean slope values across sea straits separating islands and nearest sources and ecological traits of the species that underlie their colonization and migration capacity. Results  Phenetic slope analysis has revealed that the strait of Messina and the northern Tyrrhenian Sea support particularly contrasting populations. In these areas, mean slopes for species also correlated with certain ecological traits of the species. Sardinia emerges as the most stable refugium for ancestral mediterranean populations. Main conclusions  There is strong support for the hypothesis that Italy has experienced invasion by populations from Eastern Europe with postglacial expansion of these populations across Italy. However, propagules are impeded from invading islands by the expanse of sea straits. Even so, sea straits are not invariably barriers. Our results suggest that wind direction in combination with habitat occupancy may have maintained ancestral insular populations in key locations distinguished by phenetic compression. We conclude that native insular populations acting as barriers to introgression in the areas showing particularly steep phenetic slopes deserve attention in conservation programmes.