10.000 holletjes in zandpad bij Fochteloerveen gem

Gestart door characea, mei 12, 2007, 22:34:30 PM

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characea

Hoi,

Een maand geleden zaten in het pad naar het Fochteloerveen tienduizenden gaatjes (lengte 300 meter, per meter een paar honderd holletjes) waarbij een soort bijtjes bezig waren met het maken van holletjes.
Wat zijn dit ?

Grijze zandbij Adrena vaga

CiteerKind name:   Andrena vaga tanks 1799
Synonymously:   German: “Pasture sand bee”
Characteristics:   11-15 mm; black with grey-white behaartem of head and thorax, male clearly smaller.
Spreading:   Europe between the 42° and 66° n. Width.
Habitat:   Flussauen, dams, sand, gravel and Lehmgruben; Nests on more or less even surfaces.
Reproduction:  self-dug earth nests, small to very large aggregations.
Kuckuck:   Wasp bee Nomada lathburiana, probably also Sphecodes giving bus.
Food,
Nest provisions:   specialized in pastures (Salicaceae, Salix) (oligolektisch).
Flying time:   a generation in the year (univoltin): M.: End to February end of April; W.: In the middle of March end of May. Hibernation as Imago.

Citeernglish Title: Foraging strategy and pollen preferences of Andrena vaga (Panzer) and Colletes cunicularius (L.) (Hymenoptera: Apidae).
Personal Authors: Bischoff, I., Feltgen, K., Breckner, D.
Author Affiliation: Zoologisches Forschungsinstitut und Museum Alexander Koenig, Adenauerallee 160, D-53113 Bonn, Germany.
Document Title: Journal of Hymenoptera Research, 2003 (Vol. 12) (No. 2) 220-237

Abstract:

Andrena vaga and Colletes cunicularius, both vernal ground nesting bees, were studied from 1996 to 1999 in a lowbush heath near Cologne, western Germany. Both species are solitarily but nest gregariously and sometimes form large aggregations with thousands of nests. They are reported to feed strictly oligolectic on the genus Salix. We observed the daily foraging rhythms of both species and compared their foraging strategies. C. cunicularius started provisioning trips earlier in the morning, made more trips per day than Andrena vaga, and finished nest provisioning later in the evening. C. cunicularius burrowed even in the dark after 20.00 h. Andrena vaga collected pollen and nectar on different days. One pollen day included 1 to 5 pollen trips. There was no clear correlation between the number of pollen trips and the occurrence of a subsequent nectar day. We also found no correlation between the occurrence of nectar-provisioning trips and weather conditions. Pollen loads of both species were analysed qualitatively and quantitatively with a cell counter and 2 different hand-counting systems. Andrena vaga collected nearly twice as much pollen as C. cunicularius during one foraging trip. Cells and pollen loads of C. cunicularius contained large portions of other pollen types, mostly Rosaceae such as Prunus, Sorbus and Pyrus or Acer, Quercus and Ilex. Thus, C. cunicularius is not oligolectic as described in the literature. The percentage of pollen types other than Salix increased at the end of the flowering period of Salix, which indicates a resource restriction at the end of the season. The reproductive success of C. cunicularius measured by nest provisionment exceeded that of Andrena vaga because of longer activity per day and digging activity in the evening.










xenion

Lijkt mij de Grijze Zandbij (Andrena vaga), op de foto's heb je het mannetje staan.
Groeten,
Martin

leo custers

[size=8]LEO CUSTERS[/size]