Lasioglossum malachurum

Species of bee

Lasioglossum malachurum, the sharp collared furrow bee, is a small European halictid bee. This species is obligately eusocial, with queens and workers, though the differences between the castes are not nearly as extreme as in honey bees. Early taxonomists mistakenly assigned the worker females to a different species from the queens. They are small (about 1 cm), shiny, mostly black bees with off white hair bands at the bases of the abdominal segments.

L. malachurum was described by the entomologist William Kirby in 1802. This species of bees fall within the genus Lasioglossum, which is the largest bee genus. L. malachurum falls within the order Hymenoptera, a large order of generally winged insects containing wasps, bees, and ants. One species of lasioglossum that is closely related to the L. malachurum is L. hemichalceum.

Physical size is a major distinguishing feature between queens and gynes versus female worker bees. Queens consistently are larger in body size than workers. Queens also tend to have worn wings and worn mandibles as a result of higher activity, in addition to greater ovarian development correlating with the reproductive capacity of queens. Queens also generally have abundant fat stores. Nest entrances are frequently concealed using scattered foliage. For L. malachurum, thousands of nests can be found located within a small region in nesting aggregations, which suggests that the bees likely have some sort of identification mechanism for conspecific nests. In fact, nest entrances and brood cell linings are both impregnated with secretions from the Dufour's gland of the bees, which plays a role in nest orientation. Nests are dug into hard, compact soil and can be sealed from within by the queen using her abdomen. Because nests are dug into hard soil, construction of a nest represents a significant energy expense to a queen, which explains why gynes frequently usurp other nests rather than founding one of their own. L. malachurum is a Western Palaearctic species and nests can be found across Southern England and the Channel Islands, most of continental Europe, and North Africa.

L. malachurum is found across England, continental Europe, and northern Africa, so is capable of inhabiting a broad range of habitats and climates. Differences in the climes of the various habitats can frequently impact the social behavior of L. malachurum within that habitat. The length of summer, for example, can affect the length of the breeding season and thereby impact the number of broods a queen may have. The longer breeding seasons in Southern Europe can also lead to reproductive capacity in worker bees, making L. malachurum in those regions not purely eusocial.

The queens of L. malachurum, following fertilization the previous year, begin to appear in the spring, when food sources are plentiful to sustain them after the long overwintering period. Although several females usually outwinter in the same burrow with little conflict, they start to act aggressively until a single female is left in possession of the burrow, leaving the evicted females to obtain or excavate burrows of their own. She then goes on to construct more, similar cells containing eggs and pollen masses.

Nestmates are able to identify other nestmates using olfactory cues, as well. Chemical similarities, specifically in nonvolatile alkenes and alkanes, provide this cue. Notably, the component of discrimination is not based on kinship, but on shared nesting site, and individual bees of L. malachurum do not behave differently toward related nestmates and unrelated nestmates. In a given nest, the many different compounds mix together to form a gestalt odor that marks all of the members of the nest. This form of scent blending is found commonly among other members of Hymenoptera including certain bees, wasps, and ants. The gestalt bouquet of odors differs significantly in terms of chemical composition between different nests.

Queens frequently can be usurped by intraspecific gynes, because the creation of a new nest is a significant energy investment for gynes. Males are attracted during mating by a mix of olfactory cues produced in multiple glandular sources from the female. Males seek out unrelated, unmated females; because females are only receptive for a short period following their emergence, males must seek out and find an unmated gyne before the large number of other males.

L. malachurum bees are polylectic, meaning that they collect pollen from a broad range of unrelated plant species. Although L. malachurum displays opportunism when selecting flowers from which to extract pollen, they will generally narrow their selection of pollen during a given collection period. The species demonstrates floral consistency, and generally only collects from one pollen source during a given pollen flight. The pollination behavior of L. malachurum may be useful for humans to cultivate and develop, because the bee has been implicated in pollinating species of plants that are commonly used by humans for food and for medication.

L. malachurum colonies are parasitized by the kleptoparasitic species of the genus Sphecodes. The bees of this genus have developed a strategy for invading the nest of host species that involves avoiding interaction with any host individuals. The parasites generally parasitize L. malachurum nests during the early spring when the foundress queens need to leave their nests unattended to forage. Other species enter guarded nests during the second brood cycle and kill the guard, as well all other present host individuals, before laying eggs in the brood cells. After oviposition, the parasite closes the brood cells to prevent the host female from returning and replacing the parasite eggs. Because the parasites in the genus Sphecodes parasitize a broad range of other bee species, few adaptations to the specific L. malachurum bee colonies exist.