The findings of a project funded by the Research Committee of the University of Malta in 2010, titled “Investigating the compartmentalisation of local pocket beach macrofaunal assemblages through the quantification of intraspecific genetic variation within Phaleria acuminata and Phaleria bimaculata” and led by Alan Deidun, have been published in the scientific publication, Bulletin of Insectology.
The research, conducted jointly by the University of Malta and the Dipartimento di Biologia Animale of the University of Palermo, sampled almost 50 sandy beaches around Malta, Sicily, the Pelagian Islands (Lampedusa and Linosa), the Egadian Islands (Favignana) and the Aeolian Islands (Vulcano and Lipari) for two different species of a tenebrionid (darkling beetle) – Phaleria acuminata and Phaleria bimaculata – by means of pitfall trap constellations. The two beetles are restricted to a sand environment and are thus termed psammaphiles.
To identify any possible morphological differences between the various beetle populations sampled, the elytra and the pronotum (two body parts) of 10 beetles from each population were used, within what is known as the geometric morphometrics technique.
Positions on the two body parts, known as ‘landmarks’ and ‘semi-landmarks’, were identified and their co-ordinates recorded. Multivariate statistical analysis techniques were used to identify any possible differences between the co-ordinates of these points between the different popula-tions sampled.
Such techniques showed a high degree of morphological differentiation between the different beetle populations, with three main clusters being identified – individuals from Vulcano, from Sicily and other islands around it, and from the Maltese Islands.
The research shows that no beach insect community is expendable and that populations of the same species, when living in isolation over a protracted period, show different development. This mechanism, which sees the rise of new species from geographically-isolated populations, is an example of speciation.
The head and forelegs of the P. bimaculata individuals used were dissected from the specimens to be used for future genetic and molecular analyses, which is the subject of a separate ongoing research project, also led by Dr Deidun, which is intended to confirm the outcome of the morphological project.