Queens, Workers and Royal Jelly

Use honeybee data to explain how food and genes affect growth.

Answer Key

Three kinds of bees

Read the passage and Table 1, then answer the questions.

A Week at Bee Camp

1Soraya Petrakis, a sixth grader, spent a week at a summer bee camp run by a university's research apiary. Campers wore veils and gloves and stood back while bee scientist Dr. Ezekiel Thornbury opened the hives. The camp, the people and the numbers here are made up, but they are based on real honeybee studies.

2A honeybee colony has one queen, thousands of female workers and, in summer, a few hundred male drones. The queen lays all the eggs. A fertilized egg can become either a worker or a queen. An egg that is not fertilized becomes a drone, so a drone gets genes from his mother only. Each egg is laid in a wax cell. In a healthy hive, the queen lays fertilized eggs in small worker cells and unfertilized eggs in larger drone cells. When the colony raises a new queen, workers build a big, cup-shaped queen cell around a young larva.

3After an egg hatches, the larva is fed by young workers called nurse bees. For about its first three days, every larva gets royal jelly, a rich food made in glands in the nurse bees' heads. After that, nurse bees switch worker larvae to a plainer mix that includes pollen and honey. A larva in a queen cell keeps getting plenty of royal jelly for its whole time as a larva. Drone larvae in drone cells also switch to the plainer mix but are given more of it.

4Beekeepers raise queens by grafting. They lift very young larvae out of worker cells with a tiny brush and set each one in a plastic queen cup. A colony with no queen then feeds the larvae in the cups as queens. Dr. Thornbury grafted 20 larvae of each age, counted in days since hatching. He also marked 20 one-day-old larvae that he left in their worker cells. He weighed every adult on the day it came out of its cell. Last, he showed the campers a frame from a hive whose old queen had stopped fertilizing her eggs, so drones were growing in small worker cells.

Table 1. Adults From the Camp's Hives (averages)
Bee	Egg	Cell	Days, egg to adult	Mass (mg)
Worker	Fertilized	Worker cell	21	100
Queen	Fertilized	Queen cell	16	200
Drone	Not fertilized	Drone cell	24	230
Drone from the frame	Not fertilized	Worker cell	24	150

Use Table 1.

A queen takes 5 fewer days than a worker to develop from egg to adult, and she weighs 2 times as much.

Queens and workers both come from fertilized eggs laid by the same queen. Which explanation of the differences between them fits paragraphs 2 and 3 best?

A. Workers start out as small queens and lose mass after they come out of their cells.
B. Queen larvae are fed by the old queen herself, while worker larvae feed themselves.
C. Queen larvae get plenty of royal jelly the whole time, while worker larvae switch to a plainer mix.
D. Queen eggs are larger than worker eggs and hold more stored food for the larva.

Which two rows of Table 1 best show the effect of the kind of egg (genes) when the kind of cell is the same?

A. Worker and Drone from the frame
B. Queen and Drone
C. Worker and Queen
D. Drone and Drone from the frame

The drones from the frame were still males that took 24 days to develop, but they weighed much less than drones from drone cells. What does this show best?

A. The small worker cells turned some of the unfertilized eggs into female bees.
B. The drones from the frame were workers that grew larger than usual.
C. A drone's mass is set by his genes, since both kinds of drones took 24 days.
D. The egg set whether each bee was male, while the small cell limited his size.

The grafting test

Use Table 2 and paragraphs 3 and 4.

Table 2. Dr. Thornbury's Grafting Test
Larvae used	Larvae	Became queens	Mean adult mass (mg)
1 day old, left in worker cells	20	0	100
1 day old, moved to queen cups	20	18	205
2 days old, moved to queen cups	20	17	200
3 days old, moved to queen cups	20	15	185
4 days old, moved to queen cups	20	9	150

All 20 larvae left in worker cells became workers, so their mass is the mass of workers. In every other row, the mass is the mean mass of the queens.

Use Table 2.

Of the larvae moved at 1 day old, 90% became queens. Of the larvae moved at 4 days old, 45% became queens.

Which statement describes the rows for larvae moved to queen cups best?

A. Larva age changed how many queens formed, but queen mass stayed near 190 mg.
B. The older the larvae were when moved, the fewer became queens and the lighter the queens were.
C. Queen mass rose by about 15 mg for each day older the larvae were when moved.
D. Larvae moved at 2 days old grew into the heaviest queens of the four groups.

Why did larvae moved at 4 days old grow into lighter queens than larvae moved at 1 day old?

A. Royal jelly made the older larvae lose mass because they digested it too fast.
B. They had already been fed the plainer worker mix for about a day.
C. They had hatched from unfertilized eggs, which grow into smaller bees.
D. Their genes changed from queen genes to worker genes on their third day.

Why did Dr. Thornbury leave 20 one-day-old larvae in their worker cells?

A. To keep the nurse bees from leaving the hive
B. To count how many eggs the queen laid that day
C. To see what the same larvae become without the move
D. To find out which of the larvae were drones

Sort each difference by what most likely caused it.

A bee from an unfertilized egg develops as a male.A 1-day-old larva moved to a queen cup becomes a queen, not a worker.A drone raised in a worker cell is lighter than one raised in a drone cell.A queen from a 1-day-old larva is heavier than a queen from a 4-day-old larva.A fertilized egg and an unfertilized egg laid in the same size of cell become a worker and a drone.

Mostly genes	Mostly the environment
A bee from an unfertilized egg develops as a male. A fertilized egg and an unfertilized egg laid in the same size of cell become a worker and a drone.	A 1-day-old larva moved to a queen cup becomes a queen, not a worker. A drone raised in a worker cell is lighter than one raised in a drone cell. A queen from a 1-day-old larva is heavier than a queen from a 4-day-old larva.

10.

When a hive suddenly loses its queen, workers build queen cells around some larvae already in worker cells and feed them royal jelly. Based on Table 2, which larvae would most likely give the heaviest new queen?

A. Larvae about 1 day old, since they have had royal jelly all along
B. Larvae about 4 days old, since they are already the largest
C. Larvae in drone cells, since drones are the heaviest bees
D. Larvae about 3 days old, since they are halfway to adults

11.

Dr. Thornbury wants to raise heavy queens for 10 new hives next spring. Write a plan for him. Make a claim about which larvae to use and how they should be raised, give evidence from both tables, and explain how genes and the environment each affect how a honeybee grows.

Claim: he should graft larvae from worker cells when they are about 1 day old and give them to a colony with no queen, so they are fed royal jelly the whole time. Evidence: in Table 2, 18 of 20 larvae moved at 1 day old became queens with a mean mass of 205 mg, but only 9 of 20 moved at 4 days old became queens, and they averaged 150 mg. Larvae of the same age left in worker cells became 100 mg workers. Reasoning: genes from a fertilized egg make a female bee, which can become a queen or a worker, while an unfertilized egg becomes a drone (Table 1). Which female she becomes and how big she grows depend mostly on her environment: the kind of cell and how much royal jelly she gets. Older larvae have already eaten the plainer worker mix, so they grow into lighter queens. He should use fertilized eggs (from worker cells), not drone cells, and move them as young as possible.