Bumblebee larvae are the immature, developing stage of a bumblebee. These small, white, grub-like creatures represent the future generation of a colony. Their development from egg to adult is a complex process essential for the colony’s survival and growth.
From Egg to Adult: The Larval Journey
Bumblebee larvae hatch from eggs four to six days after being laid by the queen. They appear as pale, legless, grub-like organisms, often described as resembling maggots. These larvae grow rapidly, developing through several stages called instars, periods between molts where they shed their skin to grow. Bumblebees undergo four or five instars during their larval phase.
The larval stage lasts around 14 days, during which they feed and grow. After this feeding period, the larvae spin silken cocoons around themselves. Inside these cocoons, they enter the pupal stage, transforming into adult bumblebees through metamorphosis. The pupae initially appear white and transparent, but gradually develop the colors and features of an adult bee before emerging from their cocoons. The entire journey from egg to adult takes between four to five weeks.
Nourishment and Nurturing in the Nest
Adult worker bumblebees care for and feed the larvae in the nest. The diet for the larvae consists of a mix of pollen and nectar. Pollen provides protein and nutrients for growth, while nectar supplies carbohydrates for energy.
Workers deliver nectar to the larvae by regurgitating it directly into the brood cell. Pollen is given in two main ways: “pocket-making” species create pollen pockets at the base of the brood-cell clump, while “pollen-storing” species keep pollen in separate wax pots and feed it to the larvae. Consistent feeding is important for larval growth, with some larvae consuming up to 1,300 meals a day.
The Larvae’s Place in the Colony
Bumblebee larvae are central to the colony, as they become the future workforce and reproductive members. The first batches of eggs laid by the queen develop into female workers, who take over foraging, nest maintenance, and brood care. The queen’s ability to focus on egg-laying once workers emerge allows the colony to expand.
Later in the season, the queen lays unfertilized eggs that develop into males (drones), and some fertilized larvae are reared into new queens. The successful development and health of these larvae directly influence the colony’s eventual size and its ability to produce new queens and males, which are necessary for the continuation of the species. New queens, for example, are fed up to three times more pollen as larvae, contributing to their larger size.
Dangers Facing Young Bumblebees
Bumblebee larvae face threats that impact their survival and colony health. Natural predators, such as badgers, may dig up and consume entire nests. Parasites, like mites, can infest bumblebee nests, and internal parasites, such as Crithidia bombi, can affect colony growth and queen fitness.
Diseases, including chalkbrood, can also cause larval mortality. Environmental factors also pose dangers; pesticide use can directly poison larvae or reduce the availability of flowering plants needed for their survival. Habitat loss and fragmentation, often due to development and agriculture, diminish resources for colonies, impacting larval survival and colony success.