Passaloecus
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| Shuckard , 1837 |
Passaloecus is a genus of digger wasps (Spheciformes) from the Crabronidae family. The genus is distributed holarctic , 15 species are represented in Europe.
features
The small, maximal 6.5 millimeters long digger wasps have a black body with a sessile abdomen. They are similar to the closely related genera Diodontus and Polemistus , but differ from them in their slimmer build, the lamella of the labrum protruding at an acute angle, and the thorny splints ( tibia ) of the hind legs. The pleura of the mesonotum bears a single, sometimes double vertical row of dots. In the females there is no pygidial field on the last segment of the abdomen, in the males the end of the abdomen is drawn out in a spike-like, upwardly directed appendage. The mandibles of the females are covered with a layer of wax, expanded distally and provided with a cavity on the inside, which is surrounded by strong bristles.
Way of life
The females lay their nests in dried out, mostly medullary twigs, straw or reeds, drill holes in wood and bark or plant galls. It is not uncommon to find the nests in nesting aids. A Central European species, Passaloecus pictus , is known to build its nest in sandy soils. The brood is supplied with aphids . These are killed with the mandibles or presumably anaesthetized with the sting in flight. The cell partitions and the nest closure are made either with resin from conifers, or earth or sand mixed with resin. The females can process the resin through their modified mandibles, which they presumably obtain from pine needles. In some species, females steal prey from both conspecifics and other species.
In Central Europe, two generations often develop each year. The adults of several species are flower visitors, but also eat honeydew . Parasitoids are from the parasitic wasps , jewel wasps and wasps known.
Courtship behavior
In some species the males have developed a special courtship behavior. The female is observed with antennae pointing forward and then suddenly jumped at. On the back of the female, they hold on to the thorax with their front and middle legs with a little space between them and stretch their hind legs backwards. The female tries to escape at first, but calms down after a while. The male then moves the body forward and swings the front body three to four times to the side and lowers the antennae almost parallel between those of the female. Gradually the sideways pendulum changes into an up and down movement of the front body and drum the antennae ends downwards at high frequency, into the air, against the ground or even against the face of the female. The male also touches the forehead or the vertex of the female with the mouth with the mandibles open. As the front body swings upward, the basal limbs of the female antennae are gripped and quickly pulled upward, causing the antennae to slide through the mandibles. The female follows the up and down movements of the male. After several ups and downs, there is sometimes a pause in which the wings are whirring. The male then spreads his antennae further apart and swings them outwards to encircle the antennae of the female in a tight loop. The loops are then passed up over the antennae tips of the female. Copulation then takes place. After it begins, the male immediately turns sideways away from the female and assumes a position of end of abdomen to end of abdomen. Mating takes 10 to 30 minutes, during which the male moves his body convulsively several times. In the end, the male abruptly runs away. After mating, both partners clean themselves extensively and the female can bend the end of her abdomen to the top of the thorax and head.
Species (Europe)
- Passaloecus australis Merisuo, 1976
- Passaloecus borealis Dahlbom, 1844
- Passaloecus brevilabris Wolf, 1958
- Passaloecus clypealis Faester , 1947
- Passaloecus corniger Shuckard, 1837
- Passaloecus eremita Kohl, 1893
- Passaloecus gracilis Curtis, 1834
- Passaloecus insignis (Vander Linden, 1829)
- Passaloecus longiceps Merisuo, 1973
- Passaloecus monilicornis Dahlbom, 1842
- Passaloecus pictus Ribaut, 1952
- Passaloecus ribauti Merisuo, 1974
- Passaloecus singularis Dahlbom, 1844
- Passaloecus turionum Dahlbom, 1844
- Passaloecus vandeli Ribaut, 1952
supporting documents
Individual evidence
- ↑ a b c d e Manfred Blösch: The digger wasps in Germany: way of life, behavior, distribution . 1st edition. Goecke & Evers, 2000, ISBN 3-931374-26-2 , pp. 180 ff .
- ^ Passaloecus. Fauna Europaea, accessed July 25, 2010 .
literature
- Manfred Blösch: The digger wasps in Germany: way of life, behavior, distribution . 1st edition. Goecke & Evers, 2000, ISBN 3-931374-26-2 .
