Question

The evolution of bumblebee hibernation. We are wondering whether the hibernation period of a particular species will be able to adapt to the sifting climate (earlier spring snow melt) what factors must be in place in order for their species to adapt its hibernation to shift according to climate change ?

Answer 1

Bumble bees are eusocial insects whose population sizes rely

on continuous floral resource availability (abundance of flow-

ers used by bees) for successive life stages during the flight

season: overwintered queens start colonies in the spring, over-

lapping worker cohorts forage during mid-season, and repro-

ductive males and queens are produced late in the season.

Bumble bee populations often increase with floral abundance

and colony growth may be impeded by aspects of floral

phenology, such as gaps in floral availability and

season length. Flowering is strongly responsive

to climate, and there are widespread reports of shifting

phenologies and floral abundance declines over time or with

climate extremes.

Over the last four decades, there has been documented

earlier spring snowmelt, warmer spring and summer tempera-

tures, are more frequent damaging spring frosts.

Simultaneously, the flowering season is shifting earlier and

extending and a mid-season floral decline

is expanding. Climate variation affects

the abundance of bumble bee species indirectly by alter-

ing the temporal distribution of floral resources. Hence,

climate-driven alterations in floral resource phenology can

play a critical role in governing bee population responses to

global change.

Now, researchers have found that two bumblebee species have responded to this decline in flowering due to warming temperatures by evolving shorter tongues. Results suggest that some bumblebee species may be able to adapt to environmental challenges.

For this species the cycle begins in February, reproduction starts in July or August, and ends in the winter months. The queen remains in hibernation until spring of the following year in order to optimize conditions to search for a nest.

Flowering snowdrops were common throughout December.

The large queens appear in the first days of spring and go in search of pollen for their newly hatching brood.

In early summer they live in a nest made up of a queen bee and female worker bees. As summer progresses, the queen lays eggs which produce a new generation of queen bees and male bees.

The colony eventually leaves the nest and mates, with the young queens gorging on nectar and pollen to build up fat in their bodies. Eventually, the new queens hibernate alone underground, with their vital fat stores helping them survive through the winter.

The rest of the nest - including the old queen, the male bees and the female worker bees - falls away with the leaves, dying out through autumn.

Come the spring, the warmer temperatures wake the queens from their hibernation and they’ll seek nectar to feed on before finding a suitable nest site for the year. Having already mated before they hibernated, they will lay their first brood of eggs in early summer, which will produce female worker bees. The lifecycle is complete.

Because spring temperatures influence when hibernating bees wake up, it makes them a good species to observe for Nature’s Calendar.

Hope this answer helps.