Six-banded Sweat Bee

Halictus sexcinctus is a species of ground-nesting bees, previously thought to only exhibit solitary behavior. They are relatively large compared to other sweat bees. They are 14–16 mm in length, and have white felt bands on their abdomens. Workers are typically smaller than foundresses, while foundresses will usually be the largest and most worn individuals in the nest. Sterile and reproductive workers do not differ in size.

Sexual dimorphism. As is typical among sweat bees, females are larger than males. Males also have slimmer bodies than females and their antennae are longer with a slightly different coloration. H. sexcinctus looks very similar to Halictus scabiosae, so the two are easily confused. Both have ring-like bands on their tergites, with females having anterior and posterior buff-colored bands on tergites 2-4, while males have whitish posterior bands on tergites 2-6. H. sexcinctus differs from H. scabiosae in that males have longer, reddish antennae, and females lack the basal hair bands on tergites 2-4.

Social description. In eusocial nests, queens show aggressive behavior, and a fight to the death can occur if another female tries to usurp the foundress. However, in communal nests, aggression between females is little to non-existent, and foundresses will continuously join the colony during the founding period from late May to early June. …

Halictus sexcinctus are commonly found across Europe, and can be found as far north as southern Sweden and as far east as Turkey and Iraq. They are solitary in the northern part of the range and social in their southern range. They live in very large aggregations in central Europe, despite being solitary in this part of their range. H. sexcinctus prefers to nest in sandy or loamy soil. They use their mandibles to dig nests in the ground or even on vertical substrates if it is made of earth. Their nests consist of a main tunnel dug diagonally into the ground, with several short side chambers off of it leading to brood cells, and a small tumulus around the nest entrance. One egg is laid per cell on top of a nectar-pollen mixture. Females tend to forage in plant species with wide-open flowers, therefore they primarily collect pollen from plants of the family Asteraceae such as asters, daisies, and sunflowers.