ENT 119- Apiculture Midterm 1

Example of clearly domesticated insect

Bombyx mori (silk moth)

kept for 5,000 years, domesticated in china

cannot live without humans and cannot fly

Why is it difficult to conduct artificial selection in honey bees

queens mate with 12 random males

takes expensive equipment to control mating

example of an animal that is kept but not domesticated

Asian elephant

captured from the wild and trained

What is beekeeping?

based on knowledge of bee biology and behavior

find out triggers of aggression and avoid them

figure out what makes bees swarm and avoid it

figure out what hakes bees make more honey and do it

Langstroth hive

removable combs allows for less destruction to bees, less wasted wax, less aggressive bees

What is domestication?

May be domination: humans select for useful traits; animals change to meet our needs

May be mutualism: humans and animals rely on each other; both change to accommodate

(in contemporary evolution theory it is mutualism)

Argument for honey bee domestification

kept for thousands of years in artificial hives

selected for gentleness and other traits

insect domestication is possible (silkworms)

argument against honey bee domestification

Bees are not dependent on humans; they go wild all the time

Most apis mellifera are wild bc they live in africa where beekeeping is not common

We cannot artificially select bees because it is hard to artificially breed them

Cues

information left passively in the environment by an animal

can be used by anyone

eg tracks, odors, sounds

Signals

Information intentionally sent by one animal to another (usually within species)

can be used by others (eavesdropping)

How do signals evolve from cues

signals= exaggerated cues

For example, threat signals evolve from the moment preceding an attack

selection works to increase both the production of the cue and the sensitivity of the receiver

How did the waggle dance evolve

In a hypothetical ancestor, inactive workers can use nest activity as a cue for how much foraging is occurring. Over time, workers learn to exaggerate the cue after finding food

How do we tell what a signal means?

observe the context in which it is produced (is a predator present?)

Observe the receiver and what is their response (prey of that predator responds by running)

Example of a complex signal (birds)

Bird mating signals can have different meanings for males and females

For males, it may indicate territoriality

for females, it may act as a mating call

Complex signal

a signal that can have multiple meanings for different individuals

this is common in social insects

Types of honey bee communication signals

Chemical (pheromones):

• fertility

• alarm

• flower visitation

• colony membership

• mate attraction

Mechanical / acoustical:

• dances

• other buzzing/shaking/vibrating type signals

What two types of signals do foragers produce

• signals with info about food sources (received by other foragers; telling them to go collect nectar)

• signals to coordinate activity (received by middle age bees; telling them to help process nectar)

Spectrum of color vision in humans compared to bees

Bees can see a lower wavelength of light than us, they see UV but not red

Distance experimental design (waggle dance)

Food source was moved different distances in the same direction. As the food source got farther away, the “waggle” part of the dance got longer

Direction Experimental design (waggle dance)

Food source was moved the same distance but in different directions. As the angle of the feeder changed, the angle of the dance changed.

How do bees communicate the quality of a food patch?

The number of waggle dances the bee performs correlates to the quality of the food

How do bees determine site quality?

Bees use energy gain as metric for site quality

a combination of distance from nest and nectar concentration

via what sensory modalities is the waggle dance communicated?

• releasing pheromones (a blend of hydrocarbons)

• send sound, motion, and vibrations

How do bees measure distance?

optic flow: the rate of image flow across the retina

Optic flow experiment

make foragers fly down a narrow tube to a feeder

narrow tube increases optic flow, but not time or energy used

Results: recruits of bees that flew down tunnel flew significantly further, indicating the original bee communicated a farther distance

Bees radiated when ______ radiated

Flowering plants

What makes bees the major insect pollinator

hairy bodies adapted to moving pollen

specialists on using pollen as a protein source

minor pollinators include:

birds, flies, butterflies, other insects

Most Hymenoptera are _____

parasitoids: laying the egg in the body of another organism

Aculeates

all Hymenoptera with stingers

Why can male aculeates not sting?

the stinger is a modified ovipositor in hymenoptera, meaning males do not have one

Families of bees (must know bolded ones)

• stenoritidae

• collectidae

• halictidae

• andrenidae

• malittidae

• megachilidae

• apidae

solitary bee life history

1- adult female mates

2- a cell is constructed from leaves, wood, soil, etc

3- nectar and pollen are collected to make a provision ball which is placed in the cell

4- egg is laid on pollen ball

5- cell is sealed

6- process repeats

*females make as many cells as they can before they die or the season runs out

Halictidae (sweat bees)

• very common

• often small and metallic

• diverse biology: solitary, parasites, primitively social

How are alkali bees used commercially?

Used for pollination of alfalfa, mostly in the pacific northwest

pros and cons of using alkali bees (halictids) commercially

Pros:

• can build up a large permanent population and provide all pollination services

cons:

• takes time to build up population

• can be wiped out by disease or pests

• needs particular soil and habitat

Megachilidae (Mason and leafcutter bees)

• a large group of robust bees

• show typical life history patterns

• build cells out of leaves or soil and provision each with pollen

• inefficient pollen collectors makes them good pollinators (no pollen basket)

Alfalfa leafcutter bee (megachilid)

Introduced to US in 1930s

separates cells with cut leaves

used for alfalfa pollination mostly in PNW, Canada, and west coast

Pros and cons of alfalfa leafcutter bee

Pros:

• can be purchsed in large number

• reliable pollinators

cons:

• many pests and diseases can become a problem

Blue mason bee (megachilid)

• used for pollination of tree fruit

• separates nest cells with mud

• moves row to row in orchards (honey bees move down rows)

• not yet used on a large scale

Apidae

• large and diverse group of bees

• some have scopae (hairy legs for pollen transfer)

• some have pollen baskets (curved depression on hind leg)

Orchid bees

• often large and long lived

• males collect odors from flowers

• females prefer males with more complex odors

Bumble bee life cycle

1- fertilized queen overwinters as adult

2- in the spring they find a new nest and start a colony (often mouse burrow)

3- Queen stops foraging when first brood develops

4- workers produced early in season

5- new queens and males produced late in season

In what situation are bumblebees used as pollinators?

bumblebees are used in greenhouses for commercial pollination

bumblebees perform buzz pollination, which is necessary for pollination of nightshades

honeybees dont do well indoors

Bumble bee behavior

• colonies only get to be a couple hundred strong

• queens and workers have similar physiology

• weak division of labor

• workers can communicate the presence of food but not location

• Queen incubated egg with thoracic shivering

Carpenter bees vs bumble bees

Bumble bees

• form small colonies

• nest in soil

• pollen basket

• more closely related to honey bees than carpenter bees

• usually hairy all over

Carpenter bees

• usually solitary

• nest in wood

• scopae

• No hair on abdomen

Nectar robbing

• Stealing nectar from flowers without pollinating

• carpenter bees use their strong jaws to cut into the side of the flower to steal nectar

• honey bees cannot cut the flower themselves but they can use slits cut by carpenter bees

carpenter bee biology

• nest in dead wood (can bore nest hole in a day)

• line nest with glandular secretions

• show parental care (mother guards nest)

Aggregation

• clustering and working together in a simple way

• Sawflies: form tight aggregations that move together and exhibit group defense (possibly thermoregulation and group feeding)

• Sawflies use toxic secondary compounds they sequester for group defense

• living in groups causes higher exposure to pathogens, being easier to find by predators

Parental care

• Any help beyond host site selection and egg laying

• starting point for the evolution of sociality

• rare in all orders of insects except earwigs; although there are examples from many orders

Incipiently eusocial behavior

• simplest social groups

• social groups are family groups

• Found in aphids, thrips, ambrosia beetles

social aphids

• all aphids in a gall are clones

• some become clones with sword-like appendages; may be venomous

Simplest eusocial pattern

• alternation of tasks

• colony typically 2-6 individuals

• Dominant: reproduction, guarding, building

• Subordinate: foraging, building

• subordinate have a high probability of taking over or leaving

Team-like societies

• dozens to hundreds of workers

• queen lays eggs and stays in nest

• queen has physiological specialization

• simple communication: pheromones and mechanical signals

• flexible workers; no true castes

• bumble bees, paper wasps

Factory like society

• thousands to millions of individuals

• permanent dimorphism between queen and workers

• inflexible castes (physical or temporal)

• elaborate communication systems

• honey bees, army ants, leafcutter ants, swarm founding wasps

Trends in eusocial behavior

Social evolution is characterized by:

• more division of labor in larger societies

• more communication in larger societies

Superorganism concept

A society of cells (organism) acts as a society of individuals (superorganism) due to convergent evolution

Organization:

• organism: anatomy (organs and tissues)

• superorganism: castes (age-based and physical)

Coordination:

• organism: physiology (hormones, nerve cells)

• superorganism: communication (pheromones, acoustics, mechanical signals)

Teams vs factory society analogy

Team like society = small business

• everyone is flexible

• someone may need to fill in for others

• individuals broadly trained

• uncertainty handled by flexible individuals

Factory like society = corporation

• everyone is specialized

• never fill in for others outside your group

• uncertainty handled through plans and procedures

Major social lineages

Social Wasps, Social bees, ants, termites

Social wasps

paper wasps:

• team like society

• similar to bumblebees

Swarm founding wasps:

• factory like society

• similar to honeybees

Social bees

Incipiently eusocial

• Halictids

• alodapine bees

Primitively eusocial

• bumblebees

• some halictids

advanced eusocial

• honey bees

• stingless bees

Ants (social groups)

• all highly social

ponerines

• team like society of large hunting ants

• bullet ants, meat ants, bulldog ants, etc

• painful stings

Large colony ants

• many kinds

• harvester ants, fire ants, argentine ants, wood ants

Termites (social groups)

• all highly social

• much convergence in colony design with ants (soldiers, fungus gardening)

• Hemimetabolous (many moults, can be very complex)

Social classes of termites

Lower termites

• simple organization similar to paper wasps or bumble bees

Higher termites

• mound builders, etc

• live in large colonies

• some grow fungus

• soldiers

• complicated and poorly understood

What is a temporal caste?

Bees of different ages specialize on different task sets

physiology changes to specialize bees for their tasks

bees go through 3 puberties

“regular” adult development

Juvenile form: play behavior, incomplete muscular development

Adult form: secondary sexual characteristics develop, behavior changes

Hormones change to facilitate different forms

Honey bee temporal castes

Days 1-4 Newly emerged

Days 4-12 Nurses

Days 12-21 Middle age bees

Day 21+ Forager

Newly emerged bees

• clean cells

• continue to develop (exoskeleton hardens)

Nurse bees

• feed the queen and young

• provide protein to all bees

• can feed queen more or less to determine egg output

Middle age bees

• process food

• build and guard nest

• remove dead

• Store pollen as “bee bread” (mix of pollen and honey)

Foragers

• collect food

• defend nest?

Are task sets discretized in honey bees(is there overlap)?

Any overlap in task sets is due to variability in the time spent in each caste. Marking bees by caste and not age shows this separation of tasks

Worker flexibility test

• remove foragers from two colonies

• give 1 group a week to recover

• record foraging rates

• hive with recovery time had higher foraging rates

scan sampling

periodic snap shots of collective behavior

Focal animal observations

continuous monitoring of animal behavior in time and place

Stop signal

high pitched piping sound and head butting

• produced after harassment at a feeder

• received by forager dancing for that site (identified by odor)

• respnds by stoping dancing

Tremble dance

looks like waggle dance with no figure 8

tells other bees to increase effort toward nectar unloading

• produced by foragers after difficulty unloadding nectar

• received by other bees

• response: head toward dance floor and help unload nectar

Shaking signal

bee grabs another bee and shakes it

“work bell”: tells others to stop or start work

• produced at start of foraging or night

• produced by foragers

• received by everyone

• response: start working or stop working

brood pheromone

• complex signal

• induces brood food production in nurses

• increases rate of foraging in foragers

• interacts with queen pheromone to control activation of worker ovaries and production of new queens

Worker pheromones

Defense

foraging

control division of labor

reproductive biology

division of labor hormone

• ethyl oleate

• produced mainly by foragers

• delays growth rate from middle age to forager

• more Ethyl oleate results in slower development (more foragers present)

alarm pheromone

• isopentyl acetate

• released when bee stings

• excites other bees to sting

• encourages adult bees to attack while young bees retreat (complex signal)

Nasonov pheromone

• used in aggregation (foraging, finding new home, swarming)

• made by nasnov gland

Flower signals

• bees mark visited flowers with a pheromone

• marked (depleted) flowers avoided for at least an hour

Bees collect 4 things

• nectar

• pollen

• water

• propolis (tree resin)

How do bees determine site quality?

• sugar concentration

• distance to flowers

• time of year (food availability)

• state of the nest (how much food they already have)

How do bees confer site quality using waggle dance?

bees perform more repetitions of the dance to recruit more foragers to the site

Do bees compare waggle dances?

No, recruits follow the first dance they see

The number of recruits to each site matches the number of dance repetitions

the allocation of bees to each patch matches the bees quality assessment of that patch

Scouting behavior

Scouting bees don’t follow waggle dances

they consistently look for new sources of food

during dearths they are the only bees foraging

consistently monitoring; may find better sources

Collective decision making

Each bee only knows her piece of information

With all bees contributing their information, the colony contains all of the information

total allocation of recruits matches the number of dances performed matches the distribution of quality

Pollen collection

Bees only collect how much pollen they need

foragers unload pollen directly (unlike nectar where they get help)

colony maintains a stable supply of pollen

Middle age bees collect protein in their bodies so there is a buffer when pollen stores run low

How do foragers know how much pollen the colony has?

• direct assessment: go around and count how much pollen is stored

• indirectly sense lack of pollen through hunger in their own body

has been shown NOT to be indirect sense; disrupting digestion in bees had no effect on pollen foraging rate

Heat stress- effect on brood development

Too high of temperatures can cause abnormalities in brood development

too low of temperatures slow the rate of development

Thermoregulatory behavior

When colony was heated, these behaviors increased:

• trophallaxis

• wing flapping (fan)

• tongue lash (collecting water in mouth and spreading it around colony)

• evacuate (all bees not actively working evacuated)

bees formed long chain of wing flapping to provide cooling

bees create evaporative cooling by putting water around hive and flapping wings

How do bees gauge water need?

not known

possibly the amount of time it takes to unload water; if there is high demand for water they will be more likely to get more and recruit others to water sources

Swarming

splitting of the colony into 2 or more pieces

typically occurs in spring, sometimes a second peak in fall

old queen leaves with the swarm while new queen takes over nest

Swarm composition (who is in the swarm?)

old queen and about 70% of youngest bees in the nest

each worker carries about 40% of body weight in honey

remaining colony after swarming

about 40% of original bees

mostly older bees

lots of emerging brood

15-20 closed queen cells

Queen duels

colonies often produce more queens than needed

1st queen emerges and kills all other queens in their cells

if they are not killed in cells, they will fight to the death after emergence

worker interference (queen duels)

workers drag queen away before she can kill other queen cells

workers do not try to help full sisters win over half sisters