Week 9

Question 1

What are the phylogenetic breakdown of insects?

Answer 1

Phylum- Arthropoda
Clade - Mandibulata
Sybphylum - Hexapoda
Class - Insecta

Question 2

What trait means insects are apart of the phylum Arthropoda?

Answer 2

Hardened chitinous exoskeleton that moults

Question 3

What trait means insects are apart of the clade Mandibulata?

Answer 3

Antennae and body divded into head, thorax and abdomen

Question 4

What trait means insects are apart of the subphylum Hexapoda?

Answer 4

3 pairs of jointed legs

Question 5

What trait means insects are apart of the class Insecta?

Answer 5

2 pairs of wings (can be secondarily lost)
1 pairs of antennae

Question 6

How many species are insects?

Answer 6

> 1 million species compared to all other animals ~650,000 species (40%)

Question 7

How many species of beetles are there?

Answer 7

Approximately 380,000 (23% of all species)

Question 8

Why are insects important?

Answer 8

Important for ecosystem services such as:
Pollination
Dung removal
Pest control
Carrion breakdown
Food

Question 9

How important are insects economically?

Answer 9

> 57 billion annually in the US

Question 10

How have insect populations been over last 50 years?

Answer 10

Up to 75% decline in the past 50 years

Question 11

What traits in insects are being used as inspiration?

Answer 11

Dragonflies flight
Be uncrushable
Bees effective communication
Termintes building nest that are air conditioned

Question 12

What is biometrics?

Answer 12

The tranfer of ideas and analogues from biology to technology

Question 13

What is an example of a biometric?

Answer 13

Tribots, inspired by trapjaw ants

Question 14

What are examples of the cultural significance of insects?

Answer 14

1338 BCE, commemorative Egyptian scarab
Pet cricket & gourd container watercolor byQi Baishi(1864–1957)
The song Flight of the Bumblebee

Question 15

What is an overview of monarch butterfly navigation?

Answer 15

Up to 3000 km travelled
No single individual completes the trip
4 generations in the complete annual cycle

Question 16

What is an overview of learning and memory in bumblebees?

Answer 16

Bees have to navigate complex spatial environments - need to remember floral resources
Bees can be taught simple tasks in the lab And can learn by watching other bees (or bee-shaped models)
Seen being able to play simple football and pull string to get to reward

Question 17

What is an example of rentention of memory in moths?

Answer 17

Retention of moth memory through metamorphosis
Tobacco hornworm caterpillars were trained to avoid the scent of ethyl acetate
77% of adults still avoided it once they had undergone metamorphosis

Question 18

What is an exmaple of parentla care in burying beetles?

Answer 18

Both parents care for offspring
But also sometimes eat them, or desert them - unkown why they choose which behaviour

Question 19

What is the goal of behavioural ecology?

Answer 19

“explain the survival and reproductive value (i.e. the evolutionary significance) of behavioural traits

Question 20

Why are studying insect useful?

Answer 20

Many fascinating behaviours
Useful tractable models in behavioural ecology
Many offspring produced
Can measure lifespan and lifetime reproduction
Large sample size

Question 21

What is aggresion and weaponry in behaviour?

Answer 21

Sexually selected traits constitute some of the most eye catching morphologies
In lots of species, one sex (typically but not always the male) invests in weapons which are used in contests

Question 22

What are examples of insects investing in weapons for mating?

Answer 22

Stalk eyed flies
Coreids (leaf-footed bugs) - large rear legs with spikes

Question 23

What is an example of fighiting being costly?

Answer 23

Thasus neocalifornicus (Coreid) - wing tears
Wing tears increase resting metabolic rate and decrease flight ability
Bigger tear bigger difference

Question 24

How did scientists manipulate the outcome of Thasus neocalifornicus fights?

Answer 24

Giving bugs more defensive armour increases their likelihood of winning contests
Armoured bugs on area damaged meant 1.6x more likely to win

Question 25

What is an example of different species of same species fighting with similar but different methods?

Answer 25

Rhinoceros beetles Trypoxylus dichotomus - prob then twist to wrestle rival Dynastes hercules - Scissor motion Golofa porteri - Stabby motion

Question 26

What are the evolutionary pressures meant to decrease injury in rhinoceros beetles?

Answer 26

Trypoxylus dichotomus - resistant to downwards, sideways and twisting motion Dynastes hercules - resistant to downwards and sideways but vulnerable to twisting motion Golofa porteri - resistant to downwards and sideways but vulnerable to twisting motion

Question 27

How likely is injury in rhinoceros beetles when fighting for mates?

Answer 27

17% injured 4% severly injured

Question 28

What can cause males to fight for females when risks present?

Answer 28

Males must weigh up the costs and benefits of engaging Fight escalation is more likely when males are similar in size And when females are present (i.e. payoff is greater) And if they’ve won before (the winner-loser effect)

Question 29

What is the winning effect?

Answer 29

Winning fights induces short term hyperaggression, seen in crickets Time limited effect

Question 30

What mediates the winner effect?

Answer 30

Mediated via the action of octopamine (equivalent role to noradrenaline in mammals), nitric oxide and serotonin

Question 31

What happens during the winner effect?

Answer 31

Winning releases octopamine Acts as a reward therefore more likely to fight

Question 32

What is the balance found in insenct males for weapons for fighting other males?

Answer 32

Big weapons help males win fights but also increase the risk of predators

Question 33

What is a common antipredator strategy in insects?

Answer 33

Autotomy

Question 34

What is autotomy?

Answer 34

‘The self‐controlled loss of a body part at a predetermined breakage location’

Question 35

What are other examples of animals that can undergo autotomy?

Answer 35

Nematoida Platyhelminthes Mollusca Craniata

Question 36

What can vary with autosomy?

Answer 36

Autotomize is widespread across hemipterans Some species drop their legs faster than others

Question 37

How common can autosomy be found?

Answer 37

It’s common to find individuals missing one (or more!) limbs in the wild

Question 38

What is a secondary advantage of autosamy?

Answer 38

Autotomy not just enables escape but also increases survival after injury - seen in experiment with species of coreids, automy survival was 85% compared to 60% when injured and 72% in control

Question 39

How does autotomy impact males fighting competition?

Answer 39

Autotomy doesn’t affect how likely males are to engage in fighting But it does increase the likelihood they lose

Question 40

If males cant fight, how can they produce offspring?

Answer 40

Invest in sperm production rather than weaponary - more competitively sucessful when matings do arise Seen in dung beetles

Question 41

Is there a trade-off between weapons and testes?

Answer 41

Autotomy during the fourth instar associated with 15-39% greater adult testes mass Seen in coreids

Question 42

How was the tradeoff between weapons and testes investigated?

Answer 42

We can use autotomy (a natural antipredator behaviour) as a way to look for trade-offs by removing weapon

Question 43

What is the relationship between weapon autosomy and testes investment?

Answer 43

The earlier autotomy limb loss occurs, the bigger a male’s testes are Seen in coreids

Question 44

What behaviour can autosomy impact with mating?

Answer 44

Autotomy induces an increase in average mating duration Seen in coreids

Question 45

How can behaviour and morphology interact?

Answer 45

Morphology - decrease in reallocation after adulthood as resources avaliable decrease as well as developmental flexability Behaviour - potentially maximase the pay off of larger testes Seen in coreids

Question 46

What are examples of plasticity of reproduction allocation in insects?

Answer 46

Adjust ejaculate size based on female mating status, fecundity, and age (Lupold et al. 2010) Produce more sperm produced in response to the presence of rivals (Moatt et al. 2014) Grow bigger testes if reared at high larval densities (Stockley & Seal 2001) Grow bigger testes if hear adult males (Bailey et al. 2010)

Question 47

What tradeoffs are there in reproduction?

Answer 47

When should they fight? How much should they invest in weapons vs testes? How much should they risk predation for mating opportunities? How many risks should they take?