The Sweat bee Lasioglossum sexstrigatum is a permanent resident of the garden.
This is a common bee in the Netherlands with the exception for the northern provinces and Zuid-limburg in the south where it is less common.
The species is active from the end of March until October.
The bee nests in sand and can occur in gardens in the spaces between the tiles [1, 2], something that I haven’t observed in the garden myself.
The bee is common on [1, 2]:
- Common dandelion (Taraxacum officinale)
- Alder buckthorn (Rhamnus frangula)
- Willow (Salix)
In the garden the species is observed foraging on:
- Firethorn (Pyracantha)
- Meadow buttercup (Ranunculus acris)
- Marsh-marigold (Caltha palustris)
In Dutch Sweat bees are called ‘Groove bees’ due to the characteristic groove feature on the female sixth tergite at the tip of the abdomen. The english name is due the behaviour that these bees are apparently attracted by sweat.
The bee is a small species measuring 5 – 7 mm.
It is recogniseable using the following characteristics [1, 2, 3]:
- Black body 
- Back edge tergites II – IV (topsode abdomen segment) transparent brown colored 
- Thorax with fine punctuation, sides wrinkly 
- Vertex (topside head) punctuated with clear spaces in between 
- Inner backthy with 2 to 3 thorns (thorn with microscopic sawteeth, which distinguishes this species from L. sabulosum) 
- Antennae with 12 segments
- Abdomen with 6 segments, segment VI with characteristic groove edged with hairs
- Backside tergites with white hairbands [1, 2]
- Mesonotum (topside thorax) matt 
- Head wider than long [2, 3]
- Antennae with 13 segments
- Abdomen with 7 segments
- Base tergite II sunken 
- Light yellow white color on mandibles, clypeus (front face) and labrum (lip above mouth) 
- Sternite II (underside segment abdomen) not noticably long or dencely haired 
- Temple usually with corner pointing down or a tooth [2, 3]
These cleptoparasites have been observed in the garden:
References1 Peeters, T.M.J., H. Nieuwenhuijsen, J. Smit, F. van der Meer, I.P. Raemakers, W.R.B. Heitmans, C. van Achterberg, M. Kwak, A.J. Loonstra, J. de Rond, M. Roos & M. Reemer 2012. De Nederlands bijen (Hymennoptera: Apidae s.l.). - Natuur van Nederland 11, Naturalis Biodiversity Center & European Invertebrate Survey - Nederland, Leiden.
2 wildebijen.nl, "De Nederlandse bijen en hun relaties, overzicht van in Nederland en Vlaanderen voorkomende solitaire en sociale bijen (Apidea s.l.)"
3 HERRMANN, M.; DOCZKAL, D. Schlüssel zur Trennung der Zwillingsarten Lasioglossum sexstrigatum (SCHENCK, 1870) und Lasioglossum sabulosum (WARNCKE, 1986)(Hym., Apidae). Bzzz/HymenoVaria, 1999, 10.1: 33-40.