F. Torres

Nesting behavior of Oxybelus lamellatus Olivier (Hymenoptera: Sphecidae).

Abstract In a study carried out on Oxybelus lamellatus Olivier in eastern Spain, males emerge before females, patrolling the potential nesting area; they form mating balls and construct sleeping burrows. Females nest during the summer in dense aggregations on flat, sandy soils with almost no vegetation. They construct their nests mainly early in the morning. When excavating the nest, they push and rake soil, including the tumulus, which is leveled before provisioning begins. After the nest has been built, females orient by engaging in circular and figure-8 flights. The nest consists of an oblique main burrow with a single cell, although females may add cells later to an established nest. The prey (males and females of Diptera: Brachycera) are carried in pedal and abdominal transport. Pedal carriage was used for lighter prey, whereas abdominal carriage (sting-carrying) was used for those of greater weight; for prey weight/wasp width ratios between 3.10 and 3.40, both types of carriage were observed. Thirty-five species included in 9 families were caught as prey. Eggs are laid in a Crabro-type (sensu Iwata 1942) position.

Updated list of bumblebees (Hymenoptera: Apidae) from the Spanish Pyrenees with notes on their decline and conservation status

The Pyrenees, where Euro-Siberian, Mediterranean and alpine faunas join together, have a large biodiversity of bumblebees. We compiled historical literature records of bumblebee species from the Spanish Pyrenees, and then compared these to contemporary surveys to assess trends in elevational distribution. Twenty-eight species (including thirty-five subspecies) were found in the contemporary survey. Nine species and two subspecies previously present were not detected, some included on the Spanish Red List. With the exception of a few species, a reduction of the altitudinal range and an orophilous tendency was observed at both upper and lower elevational levels, suggesting an upward trend towards better-preserved high areas. Our results reinforce the need to develop new protection programs and more restrictive conservation measures for bumblebee populations, species and their habitats.

Analysis of the diversity of Megachilidae bees on the northern subplateau of the Iberian Peninsula

Abstract In the western Mediterranean, 772 species of bees in the family Megachilidae have been reported. Special emphasis has been placed on the Iberian Peninsula, where to date 218 species are known. However, few intensive studies providing information about communities of Megachilidae have been carried out. Two earlier works cite 70 species; almost one third of those known on the Peninsula. With an aim of gaining insight into the structure of the communities of Megachilidae and the factors influencing them, an analysis was made of the alpha and beta diversity of different localities in the northern subplateau. Malaise traps (black and white) were used, and 559 specimens belonging to 55 species were identified of which most exhibited a nest-holder-type nesting habit. Abundance and richness were higher for white traps, although a considerable degree of complementarity was observed with the black traps. In the study zone, diversity can be considered medium-high with a phylogenetic diversity corresponding to stable populations. Regarding the composition of the Megachilidae communities, the influence of the landscape structure, of the microhabitat, and of the colour of the trap used to collect the specimens was detected. The following are recommended: (1) the use of both black and white traps, since they show high complementarity and offer different information about community structure, (2) homogenization of the samples in comparisons among communities, owing to the influence of the color of the trap, which masks the importance of ecological factors in community structuring, and (3) the collection of samples from at least two years previous, in view of the elevated “replacement” of species observed with species richness estimators.