Abstract. An outbreak of the livestock viral disease bluetongue (BT) was detected during September and October 2000 in the Balearic Islands, Spain. Due to the lack of information about the species of Culicoides (Diptera: Ceratopogonidae) reported in the affected area, six farms in Majorca, four in Minorca and one in Ibiza were selected to carry out surveillance of Culicoides adults using light traps. Here, for the first time, we report the presence in the Balearic Islands of Culicoides imicola Keiffer, the main vector of BT, and the Culicoides obsoletus Meigen group.

The abundance and sexual maturity of piangua Anadara similis in La Plata Archipelago, Bahía Málaga, Pacific coast of Colombia, was analyzed between September 2009 and August 2010. Sexual maturity of these organisms was studied at macroscopic level using fresh samples and at microscopic level using standard histological techniques. The mean density was estimated in 0.130 ± 0.098 ind/m2 and the mean size was 42.30 ± 5.00 mm. Months with the presence of the highest densities of piangua were May (0.295 ind/m2) and August (0.195 ind/m2). The mean sexual maturity size was estimated in 41.8 ± 4.5 mm, while the size at which at least 50% of the population of A. similis have had its first spawn was estimated in 41 mm. Reproductive activity of the species was present year-round with higher peaks in March (83.33%) and April (75.00%). 4.30% of organisms analyzed showed signs of hermaphroditism, being this the first record of this kind for the species. Higher density, larger mean size, higher meat yield in females as well as the presence of more female reproductive tissue, suggest a process of sexual reversion in the species, which have to be further studied. Low capture and sexual maturity sizes, as well as the low density of organisms found during the present work, might be the product of high fishery pressure, habitat modifications, and pollution processes in the area, factors that have to be studied in detail in order to implement management strategies for the species.

The hermaphrodite condition of the cockles Anadara tuberculosa and Anadara similis, gonochoric species living in mangroves of the Pacific coast of Colombia, are described in this paper. The gonads of 290 individuals of A. tuberculosa and 336 individuals of A. similis collected in five localities of the Colombian Pacific coast were analyzed using histological methods. Our results exposed that 3.1 % of A. tuberculosa and 3.0 % of A. similis analyzed showed signs of both ovules and spermatozoids, as well as simultaneous sexual maturation. Based on this frequency of occurrence of hermaphrodite individuals and the fact that hermaphrodite organisms were present in most of the sampling sites, we conclude that hermaphroditism is a normal rather than casual condition of these two species. We suggest that future studies in the hermaphroditism of these organisms center on the determination of factors potentially affecting this condition.

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The problem of scheduling production in job shop environments has been approached by different authors who have developed diverse alternatives for solutions. Only a small number of these alternatives, however, has been implemented by SMEs in the graphic arts industry because of their high complexity, the strong assumptions involved, and the informal nature of this industry. This article presents a methodological proposal that begins by grouping process factors, applying group technology and later determining both installed and required capacity. It ends with a proposal for scheduling production based on the exploitation of bottlenecks, which allows establishing delivery dates.