Search

Across altitudinal and latitudinal gradients, the proportion of suitable habitats varies, influencing the individual dispersal that ultimately can produce differentiation among populations. The natterjack toad (Bufo calamita) is distributed across a wide geographic range that qualifies the species as interesting for a geographic analysis of its genetic variability. Five populations of B. calamita in the Sierra de Gredos (Spain) were studied in an altitudinal gradient ranging from 750 to 2270 m using microsatellite markers. In addition, we analyzed the latitudinal genetic variation in B. calamita within a global European distribution using genetic diversity parameters (mean number of alleles per locus [M-a] and expected heterozygosity [H-E]) obtained from our results and those published in the literature. The low level of genetic differentiation found between populations of B. calamita (F-st ranging from 0.0115 to 0.1018) and the decreases in genetic diversity with altitude (M-a from 13.6 to 8.3, H-E from 0.82 to 0.74) can be interpreted by the combined effects of discontinuous habitat, produced mainly by the high slopes barriers and geographic distance. In the latitudinal gradient, genetic diversity decreases from south to north as a consequence of the colonization of the species from the Pleistocene refugium. We conclude that the genetic variability in B. calamita along its wide altitudinal and latitudinal geographic distribution mainly reflects the colonization history of the species after the last glacial period.

The adult body size of the Mediterranean fruit ßy, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), varies in natural conditions. Body size is an important Þtness indicator in the Mediterranean fruit ßy;largerindividuals are more competitive at mating and have a greater dispersion capacity and fertility. Both temperature during larval development and host fruit quality have been cited as possible causes for this variation.We studied the inßuence of host fruit and temperature during larval development on adult body size (wing area) in the laboratory, and determined body size variation in Þeld populations of the Mediterannean fruit ßy in eastern Spain. Field ßies measured had two origins: 1) ßies periodically collected throughout the year in Þeld traps from 32 citrus groves, during the period 2003Ð2007; and 2) ßies evolved from different fruit species collected between June and December in 2003 and 2004. In the lab, wing area of male and female adults varied signiÞcantly with temperature during larval development, being larger at the lowest temperature. Adult size also was signiÞcantly different depending on the host fruit in which larvae developed. The size of the ßies captured at the Þeld, either from traps or from fruits, varied seasonally showing a gradual pattern of change along the year. The largest individuals were obtained during winter and early spring and the smallest during late summer. In Þeld conditions, the size of the adult Mediterannean fruit ßy seems apparently more related with air temperature than with host fruit. The implications of this adult size pattern on the biology ofC. capitata and on the application of the sterile insect technique are discussed.

The adult body size of the Mediterranean fruit ßy, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), varies in natural conditions. Body size is an important Þtness indicator in the Mediterranean fruit ßy;largerindividuals are more competitive at mating and have a greater dispersion capacity and fertility. Both temperature during larval development and host fruit quality have been cited as possible causes for this variation.We studied the inßuence of host fruit and temperature during larval development on adult body size (wing area) in the laboratory, and determined body size variation in Þeld populations of the Mediterannean fruit ßy in eastern Spain. Field ßies measured had two origins: 1) ßies periodically collected throughout the year in Þeld traps from 32 citrus groves, during the period 2003Ð2007; and 2) ßies evolved from different fruit species collected between June and December in 2003 and 2004. In the lab, wing area of male and female adults varied signiÞcantly with temperature during larval development, being larger at the lowest temperature. Adult size also was signiÞcantly different depending on the host fruit in which larvae developed. The size of the ßies captured at the Þeld, either from traps or from fruits, varied seasonally showing a gradual pattern of change along the year. The largest individuals were obtained during winter and early spring and the smallest during late summer. In Þeld conditions, the size of the adult Mediterannean fruit ßy seems apparently more related with air temperature than with host fruit. The implications of this adult size pattern on the biology ofC. capitata and on the application of the sterile insect technique are discussed.

[EN] Seasonal and annual trends in Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) populations were analyzed to determine the factors that influence population fluctuations in the field. Adult flies were monitored along 2003-07 in two citrus areas in eastern Spain with similar climate, Valencia and Tarragona. Adults were present throughout the study period, even in winter. The initial annual population increase was related to previous winter and spring temperatures. Captures started to increase in April-May and usually reached a peak in July. This peak corresponded to the maximum capture period in Valencia, but not in Tarragona, where there was usually a second peak in autumn, with capture levels similar to the first peak. Gravid females were found throughout the year, even in overwintering populations of medfly. The availability of other host fruit species in the vicinity of the citrus groves may explain the differences in annual abundance and distribution of captures between the two areas studied., [ES] Se analizó la evolución estacional de las poblaciones de Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) para determinar los factores que influencian sus fluctuaciones poblacionales en campo. Se muestreó la población de adultos entre 2003 y 2007 en dos áreas citrícolas del este de España con clima similar, Valencia y Tarragona. Se encontraron adultos a lo largo de todo el periodo de estudio, incluso en invierno. El primer incremento anual de la población estuvo relacionado con las temperaturas previas del invierno y la primavera. Las capturas comenzaron a incrementarse en abril-mayo y generalmente alcanzaron un máximo en julio. Este máximo correspondió al máximo periodo de capturas en Valencia, pero no en Tarragona, donde hubo generalmente un segundo máximo en otoño, con niveles de captura similares al primer máximo. Se encontraron hembras grávidas a lo largo de todo el año, incluso en las poblaciones invernantes de mosca de la fruta. La disponibilidad de otras especies de frutales hospedantes cercanas a las parcelas de cítricos puede explicar las diferencias en abundancia anual y distribución estacional de capturas entre las dos áreas estudiadas.