Les Drosophilidae (Diptera) de l‘Ile de La Réunion et de l‘Ile Maurice. III. Biologie et origine des espèces.

30 Drosophiliden-Arten sind gegenwärtig von den Maskarene-Inseln bekannt. Auf Reunion ist die dominante Art Drosophila simulans (mehr als 30% aller gesammelten Arten), während diese auf Mauritius zu fehlen scheint und dort durch die endemische vikariante Drosophila mauritiana ersetzt wird. In Reunion sind die Höhe und zu einem geringeren Grade die Niederschlagsmenge die beiden hauptsächlichen Faktoren, durch die die Verbreitung der Arten bestimmt wird. Auf den Maskarene-Inseln gibt es etwa 30% endemische und eben so viele kosmopolitische Arten. Der Rest der Fauna setzt sich aus orientalischen und aethiopischen Arten zusammen. Die Zahl der endemischen Arten beweist, dass die Einwanderung der Fliegen ein sehr altes Ereignis ist, das vor der Besiedlung durch den Menschen stattfand. Eine analoge Schlußfolgerung trifft wahrscheinlich auch auf einige kosmopolitische Arten zu. Die Rolle des Menschen bei der Verbreitung der Drosophiliden ist offenbar von weit geringerer Bedeutung als gewöhnlich angenommen wird.30 Drosophilid species are now recorded from Maskarene Islands. In Reunion the dominant species is Drosophila simulans (more than 30% of the collected flies), while it seems to be absent from Mauritius, being replaced there by the endemic vicariant Drosophila mauritiana. In Reunion altitude and to a lesser degree pluviometry are the two decisive factors determining the repartition of the different species. Maskarene Islands contain about 30% of endemic and the same proportion of cosmopolitan species. The remainder of the fauna consists of Etiopian and Oriental elements. The number of endemic species proves that in many cases the introduction of flies was a very old event, much before human colonization. The same conclusion may probably apply to some cosmopolitan species. The role of man in the dispersion of drosophilid flies is probably far less important than usually admitted

Evolutionary Genomics of Genes Involved in Olfactory Behavior in the Drosophila melanogaster Species Group

Previous comparative genomic studies of genes involved in olfactory behavior in Drosophila focused only on particular gene families such as odorant receptor and/or odorant binding proteins. However, olfactory behavior has a complex genetic architecture that is orchestrated by many interacting genes. In this paper, we present a comparative genomic study of olfactory behavior in Drosophila including an extended set of genes known to affect olfactory behavior. We took advantage of the recent burst of whole genome sequences and the development of powerful statistical tools to analyze genomic data and test evolutionary and functional hypotheses of olfactory genes in the six species of the Drosophila melanogaster species group for which whole genome sequences are available. Our study reveals widespread purifying selection and limited incidence of positive selection on olfactory genes. We show that the pace of evolution of olfactory genes is mostly independent of the life cycle stage, and of the number of life cycle stages, in which they participate in olfaction. However, we detected a relationship between evolutionary rates and the position that the gene products occupy in the olfactory system, genes occupying central positions tend to be more constrained than peripheral genes. Finally, we demonstrate that specialization to one host does not seem to be associated with bursts of adaptive evolution in olfactory genes in D. sechellia and D. erecta, the two specialists species analyzed, but rather different lineages have idiosyncratic evolutionary histories in which both historical and ecological factors have been involved

Phenetic distances in the Drosophila melanogaster-subgroup species and oviposition-site preference for food components

Oviposition-site preferences (O.S.P.) have been investigated in females of six sibling species of the Drosophila melanogaster subgroup. O.S.P. were determined for standard food components and yeast genotypes. Females of all species showed a strong preference for complete medium and avoidance of pure agar as an egg-deposition site.\ud \ud Ecological trees of the species on the basis of rank correlations were constructed. In ‘no-choice’ situations they agree with phylogenetic trees obtained by different means but in ‘choice’ situations they do not agree too well.\ud \ud All species showed a high egg production on live yeast compared with standard medium (with killed yeast) and D. erecta females demonstrated discrimination between yeast genotypes. Niche breadth calculated from survival on the sterol mutant yeasts correlated fairly well with phylogenetic trees

Sur quelques Diptères de l'Ile Majorque

En septembre 1958, j'ai en l'occasion d'effectuer une récolte de Diptères aux environs du village Valldemosa de l'Ile de Majorque (Baleares). Le résultat de cette récolte est assez maigre en ce qui concerne le nombre d'espèces récoltées. Cela n'est pas étonnant si l'on considère la saison tardive et la longue période de sécheresse, quatre mois de suite sans la moindre pluie. La végétation armuelle était absolument sèche, voire bralée. Elle ne persistait que près de deux petites sources et d'un petit réservoir d'eau et c'est lä précisément que j'ai pu récolter quelques Diptères. Dans les oliveraies environnant le village je n'ai pas pu trouver méme le Da cus oleae malgré que sur quelques olives on voyait des piqüres d'ovoposition.Peer reviewe

Un Hoplopheromerus Becker nouveau de la Malaisie [Dipt. Asilidae]

Tsacas Léonidas. Un Hoplopheromerus Becker nouveau de la Malaisie [Dipt. Asilidae]. In: Bulletin de la Société entomologique de France, volume 74 (5-6), Mai-juin 1969. pp. 132-136