The first record of European catfish Silurus glanis (Siluridae) in the Alcantara reservoir (Tagus basin) is reported. A specimen (TL= 331 mm) was caught in a trammel net on June 2008.
Se hace referencia a la primera observación de Neoscona byzanthina (Pavesi, 1876) (Araneae, Araneidae) de la Península Ibérica. El ejemplar fue capturado en octubre de 2018 en un encinar adehesado (Extremadura, España).
The genus Cerambyx Linnaeus, 1758 in Extremadura (SW Iberian Peninsula) (Coleoptera, Cerambycidae) In Extremadura (SW Iberian Peninsula) the plagues attributed to Cerambyx species are serious and frequent. One of these species (C. cerdo) is protected to international level. The purpose of this study was to determine the distributions of the Cerambyx species in Extremadura. Cerambyx spp. were sampled during late spring and summer 2005 in 65 sampling sites in Extremadura (SW Iberian Peninsula). Cerambyx cerdo was found in three localities in the north-east part of Extremadura. C. welensii is the one that presents greater distribution with 21 known localities. Finally, C. scopolii only appears in two localities.
Abstract The introduced population of Gambusia holbrooki in the River Guadiana, Iberian Peninsula, was studied for 12 months, focusing on the reproductive ecology. Two main cohorts were identified (2001 and 2002). Females outnumbered males, the average female/male ratio being 1.36. Maximum ages were 2+ in females and 1+ in males. Growth commenced in March and continued until September. Females reached greater sizes, grew faster, and lived longer than males. The largest sizes found were 49.16 mm in females and 31.5 mm in males. Reproducing females were significantly larger in the 2001 cohort (31.10 ± 3.57 SD mm) than in the 2002 one (26.69 ± 4.52 SD mm). Multiple spawning occurred throughout the reproductive cycle (from April to September). The average brood size per female reached its maximum in July in both cohorts (32.95 embryos/female in the 2001 cohort and 30.69 embryos/female in the 2002 one). Potential fecundity was significantly higher than real fecundity in both cohorts. The mean dry weight of intra‐ovarian embryos decreased to a minimum immediately before birth. Mean dry weight of full‐term embryos was significantly higher in the 2001 cohort than in the 2002 one. Fecundity was size dependent throughout the reproductive season. Relative reproductive mass was related to somatic condition in both cohorts. The population completed two generations each year (spring and summer).
Growth parameters in pikeperch may be affected by several factors. The purpose of this study was to investigate the growth and length–weight of pikeperch in a reservoir in south-western Spain and compare the results with previous published data. Age and growth are described for Sander lucioperca from the Alcántara Reservoir (south-western Spain) from March to October 2009. A total of 285 fish were examined; the ratio of males to females was estimated as 0.78:1 and age ranges as 1–5 years. Total lengths ranged from 16.1 to 52.5 cm. The length–weight relationships were described as W = 0.00 462 TL3.09 (r = 0.9865) for males and W = 0.00279 TL3.16 (r = 0.9921) for females. Growth was expressed in length and the von Bertalanffy growth parameters were estimated as L∞ = 92.14 cm, k = 0.09, t0 = −1.05 for males and L∞ = 107.72 cm, k = 0.08, t0 = −1.16 for females. Growth performance indexes were also estimated as Φ' = 2.88 for males and Φ' = 2.96 for females. Differences in growth and length–weight relationships between sexes were not found.
Social wasps of the genus Polistes Latreille, 1802 abound in urban environments, where they use diverse anthropic structures to locate their colonies during the late spring and summer period. This direct contact with the population gives rise to a general feeling of fear or rejection towards these vespids due to the possibility of receiving stings. The aim of this study was to reveal the social perception towards these social wasps in a small urban area in the southwest of the Iberian Peninsula. The results showed that 90.44% of 272 respondents reported to have been stung by these species, of which more than 50% admit having suffered five or more attacks in their lifetime. The possible causes of these stings have been classified, as well as the type of reaction by the inhabitants towards the existence of wasps’ nests in their domestic environment. Finally, it is important to mention that most of the respondents recognize the biological importance of these hymenopterans, despite the general fear they show towards them.