M. D. Ochando

Fitness of wild-caught Drosophila melanogaster females: Allozyme variants of GPDH, ADH, PGM, and EST

We have collected several hundred Drosophila melanogaster flies (near Davis, California), isolated them individually, without anesthesia, at the collecting site, and estimated the fitness components of the wild‐caught females under different environmental conditions. The fitness parameters measured are fecundity, oviposition rate, and productivity (egg‐to‐adult viability, development rate, and number of progeny). The environmental variables are two temperatures (22°C and 28°C) and two densities (‘scant’ and ‘crowded’). After the fitness measurements are completed for each individual female, its genotype is determined at four loci encoding enzymes: GPDH and ADH, located on chromosome II and PGM and EST‐C, located on chromosome III. Density has a large significant effect on productivity; temperature has significant effects on fecundity, oviposition rate, and development rate. The experiments show that allozyme polymorphisms are associated with selection effects. Fitness differences between allozyme genotypes occur for all fitness components, except oviposition rate. But which genotype is superior depends on the environmental conditions; heterozygotes exhibit higher fitness than homozygotes in a number of cases, but inferior in others. A unique feature of the present experiments is that the experimental flies are wild‐caught females rather than laboratory‐bred individuals.

Genetic polymorphism at the cytochrome oxidase I gene in mediterranean populations of Batrocera Oleae (Diptera: Tephritidae)

The tephritid Bactrocera oleae (Gmelin) is a harmful pest of olive crops that cause important agricultural and economic losses in the Mediterranean area where 90% of the world olive trees are cultivated. The knowledge of the genetic diversity in insect pest species populations is critical for decisions concerning appropriate control management strategies. In the present work, the genetic variability within and among 7 populations ‐five from Spain, one from Italy and one from Tunisia‐, was assessed by sequencing 1151 bp of the COI gene. A total of 21 haplotypes were observed. The intraspecific diversity was high, particularly in the Spanish populations (haplotype and nucleotide diversity 0.84 and 0.00137, respectively). However, the genetic differentiation among the populations was low in the case of Spanish ones (Fst between 0 and 0.041), and higher –and statistically significant– when comparing with the Italian and Tunisian samples. The haplotypes distribution and the PCoA analysis show three clear groups of populations: Spanish, Italian and Tunisian. The results might indicate the length of time elapsed since B. oleae became established in the Mediterranean region, the large effective sizes expected of its populations and the high gene flow among Iberian populations. The information could be relevant for integrated control programmes coordination.

GENETIC DIFFERENTIATION IN SPANISH POPULATIONS OF CERATITIS CAPITATA AS REVEALED BY ABUNDANT SOLUBLE PROTEIN ANALYSIS

Ceratitis capitata is one of the most important pest species in the tropical and temperate regions of the world, however, genetic knowledge of this species is still very limited. In the present study, we have attempted for the first time an analysis of the genetic variability in seven natural populations of C. capitata by means of abundant soluble proteins, combining high resolution techniques such as polyacrylamide gel electrophoresis and silver staining methods. A total of 66 polypeptides have been analyzed. The results show the existence of a decreasing trend in the ‘levels’ of polymorphism from the southern areas to the northern that is correlated with the latitude of the sampling areas, most probably due to the colonization process of the Iberian Peninsula. On the other hand, and with relation to the ‘pattern’ of the variability, a geographic differentiation (not strictly latitudinal) is detected when an UPGMA clustering method was applied to the data. Moreover, principal component anaysis has revealed that a part of this differentiation could be explained in relation with environmental factors such as annual rainfall and minimum temperature in winter months. This is suggesting that selection (added to the historical process) could be playing an important role in the process of geographic differentiation, ‘shaping’ the pattern of that variability. No host-related differentiation has been observed in these samples.

Update of genetic information for the white-clawed crayfish in Spain, with new insights into its population genetics and origin

The white-clawed crayfish is endemic to western and southern Europe and its populations have decreased over recent decades. Spanish populations are generally poorly represented in scientific reports and are usually studied only with a single molecular marker. Here, we use two mitochondrial markers (cytochrome oxidase subunit I and rDNA 16S genes) to examine levels and patterns of genetic structure across the range of the species’ distribution in Spain. Data reveal the existence of two main genetic groups of white-clawed crayfish in Spain with the Ebro basin as a possible contact zone. Processes occurred in historical and recent times, such as genetic drift and translocations, contribute greatly to this genetic structure. Levels of genetic variability and genetic structure of Spanish populations together with demographic inferences suggest that the species established in the Iberian Peninsula, at least since the Late Pleistocene. Knowing the true origin of the Spanish populations is crucial when deciding upon the management policies that should be followed. Given the lack of any clear evidence against its indigenous status, we propose that current protection and conservation measures should be maintained. From a management point of view, we suggest that Spanish population should be considered as a single evolutionary significant unit (ESU) with two management units (MUs) corresponding with the genetic clusters detected in the present study.

Mating behaviour and analysis of eye pigmentation of several mutants of Drosophila melanogaster

Mating in the dark between individuals carrying different eye color mutants extracted from the same natural population is shown to be random. (Previous experiments had shown that darker-eye males mate more successfully under alternating light-dark conditions). Extraction of pigments and quantitative analysis by absorption curves show that all mutants have less pigmentation than wild-type individuals; unexpectedly, darker-eye mutants do not resemble the wild-type level of pigmentation any more than light-eye single mutants. The results suggest that (1) eye pigmentation is not neccessarily related to visual ability; (2) some kind of pleiotropic effect affecting the central nervous system may be involved in the sexual behaviour of male mutants.

The white-clawed crayfish in Spain—reply to Clavero and Centeno-Cuadros

This short communication is only intended to point out briefly and objectively some of the comments, appreciations, and sometimes misinterpretations made by Clavero and CentenoCuadros in their criticism to our article on the phylogeography of the white-clawed crayfish in Spain, recently published in this journal. For those skilled in the discipline of phylogeography, it is well known to be a multidisciplinary science. Therefore, we disagree with the argument of monodisciplinary approach given by these authors. The work of Matallanas et al. 2016, as all our previous ones, has no intention, no bias, or directionality. It clearly aims what the title synthesizes, an update of genetic information for the white-clawed crayfish in Spain. To achieve this, we have been the first to use two mitochondrial markers, the longest so far used, in a wide and representative sample of Iberian crayfish. A sample of crayfish fromNorthern Italy was just used as outgroup. The design is, therefore, very suitable and appropriate for the question posed.