VL 12

Question 1

Associative/conditioned learning

Answer 1

Change behaviour in repeatable way as result of experience

Learning curve - gradual change increasing with each experience

Change in behaviour gradually lost if experience less frequent

Question 2

How does learning occur in insects?

Answer 2

Learning abilities are related to the size of mushroom bodies

Mushroom bodies encode memory formation and complex decision making in the brains of arthropods

These are largest in eusocial insects

Increase in size with experience

Question 3

Central learning categories in a model system

Answer 3

• Feeding
• Danger avoidance
• Mating
• Aggression
• Navigation

Question 4

Feeding

Answer 4

Drosophila
* Associative learning of food presence/quality with novel odours and colours

Ecological relevance:
* Most useful for species that feed on multiple food sources – learn strength of reward. Specialists have strong innate preferences

Question 5

Danger avoidance

Answer 5

Drosophila
* Can associate novel odours or odour intensity with a shock or predator presence, will then avoid as larvae and adults
* Specific visual patterns with high heat -> avoidance

Ecological relevance:
* Associate food containing toxins/bad taste with odours/colour (eg. aposematism)
* Food aversion learning mainly found in generalists

Question 6

Mating

Answer 6

Drosophila
* Sexual cues – will learn odours for virgin and mated females and inter vs intra specific
* Males will attempt to mate with mated females and females of another species. If experience courtship and rejection, modify attraction
* If females are immobilised, males don’t learn

Question 7

Aggression/individual recognition

Answer 7

Drosophila
* Competition for mating territory
* Males will establish a dominance hierachy when fighting
* If a male loses a conflict, will avoid males they have previously fought for mates

Question 8

Navigation

Answer 8

Drosophila
* Will learn location of cool spot in an arena based on visual cues
* Can then navigate more swiftly to the tile even when position changes, as long as there are coupled visual cues

Ecological relevance:
* Memorisation of and swift retracing to nesting sites, territory boundaries, shelter, food sources

Question 9

Host preference: mosquitoes

Answer 9

Mosquitoes are more likely to try and bite a species or individual they have successfully fed on – visual and odour cues (unless the first host was non-optimal, then may lose preference)

They can learn to avoid the smell of aggressive hosts – dopamine pathway

Question 10

Individual recognition: paper wasps

Answer 10

Polistes fuscatus paper wasps have co-foundress queens that establish relative dominance – recognition is important for social structure

Only the most dominant female starts to produce a chemical signal

They visually recognise the face and abdominal markings of individual nestmates, and can re-learn them if they alter

Question 11

Navigation: honey bee orientation flights

Answer 11

Several orientation flights before starting as a forager

Learn spatial geography around the hive - landmarks

Don’t collect nectar or pollen – only purpose is learning hive location

Question 12

Navigation: ants

Answer 12

Cataglyphis desert ants associate directional information with landmarks

Foraging trips may exceed 1500m, up to 350m away from nest

Learning walks

Integration – directional compass and distance information

Always return to nest by the shortest route – straight line

Question 13

Flower rewards: bees

Answer 13

Visit a small patch of flowers repeatedly to learn which individual flowers provide best rewards (nectar and pollen)

Complex hierarchical trait learning, ie. odor>color>shape for floral characteristics for honeybees

Question 14

Flower handling: bees

Answer 14

Gradual increase in food-delivery rate, until proficient at 7-10 days as a forager

by repeated visits bees gradually find out, how to get the nectar

Question 15

Social learning

Answer 15

Shown in social Hymenoptera (bees, wasps, ants)

Recruits learn and apply information - fast spread of
novel behaviours

Example from social insect lecture: Waggle dance (honey bees)

What are the negatives?

Inexperienced insects more likely to ‘follow

Question 16

Social learning: Tandem running (Ants)

Answer 16

An ant leads a follower to a food source or potential new nest site, keeping antennal contact

They move slower so that the follower can learn the route

The follower can then return to the nest to recruit others

Question 17

Social learning: Oviposition sites (Drosophila)

Answer 17

Demonstrator flies were trained to avoid either strawberry or banana flavoured media (aversive shaking)

Observer flies could mingle with or watch them, then were found to copy their oviposition choices after separation

If had previous, personal experience, observers less likely to copy

Question 18

Social learning: Flower copying (Bees)

Answer 18

Inexperienced bumblebees will copy the flower choices of experienced bees

When inexperienced, will use the presence of conspecifics to identify unfamiliar food types, but once experienced, will ignore choices of other bees

Question 19

Social learning: Nectar robbing (Bees)

Answer 19

Bumblebees learn nectar robbing strategies from each other, including ‘handedness’ (which side)

Secondary nectar robbing leads to primary robbing – more likely to create successful holes themselves

Cross species social learning - Bombus wurflenii and Bombus lucorum

Question 20

Social learning: Novel skills (Bees)

Answer 20

Novel skills for food access

Can be taught new behaviours and will then pass them on

Question 21

Mosquitoes: resisting repellents

Answer 21

Mosquitoes can become desensitised and learn to ignore repellents

Implications for personal repellent efficacy in high-use areas

Question 22

Mosquitoes: oviposition and repellency

Answer 22

Aedes aegypti will return to oviposit in water with similar odour cues to where hatched - imprinting

Even if that water contains mosquito repellents (citronella and neem oil)

Implications for dengue vector surveillance and larval control

Question 23

Parasitoid wasps: host seeking

Answer 23

Herbivore hosts are are under selection to be inconspicuous (hard to detect)

Plants under attack produce highly detectable signals, but these can be variable/suppressed

Parasitoids have no innate response to environmental cues, but learn over oviposition attempts

Odour, visual, pattern cues related to environment where host currently found – ie host plants, substrate

Associative training before wasp release could increase effectiveness – specific crop types/HIPVs

Question 24

Bees: pesticides

Answer 24

In bees, direct link between cognitive ability and foraging efficacy: which flower species are currently rewarding, where are they, how to handle them, how to travel to and from nest

Neonicotinoid exposure results in longer learning times or bees never returning from foraging

Potential mechanisms: decreased neural cell development; sublethal doses of neonicotinoids in honeybees impair development and function of mushroom bodies

Uncertain how much can extrapolate from lab studies. Effect on wild bees little studied