special reading - 1 - The adaptiveness of defence behaviour

Question 1

what were the hypotheses tested?

Answer 1

• a combination of eyes spots and sound (hissing) are more effective than either trait alone in the peacock butterflies predator defence

Question 2

who wrote the paper?

Answer 2

Vallin et al (2005)

Question 3

describe the treatment methods?

Answer 3

• 6 different treatments (3 treatment, 3 controls)
• treatment 1 - eye spots removed using marker pen ( control = marking parts of wing without eyespots)
• treatment 2 -hissing was removed by cutting lower edge of forewing (control = cut away lower edge of hindwing)
• treatment 3 - removed both (control = both)

Question 4

How were the butterflies presented to the birds?

Answer 4

• presented in a small room with natural light to blue tits
• one on one
• studied 54 presentations
• bird discovered butterfly in all

Question 5

what was the name of the butterfly and bird used in the experiment?

Answer 5

• peacock butterfly

- blue tit

Question 6

what were the results of the study?

Answer 6

• eyespots significantly reduced predation risk - 9/9 survived vs 5/10 without eyespots
• hissing had no significant effect against blue tits
• 1/34 with eyespots were killed compared to 13/20 of those without

Question 7

what do the results mean in reference to the hypothesis?

Answer 7

• for blue tits hissing isn’t useful however it may be a useful predator defence strategy against other predators

Question 8

describe the results of this test in context of other studies

Answer 8

• butterflies are exploiting the blue tits fear of large predators using eyespots
• dishonest signalling
• hissing whilst not effective has no costs

Question 9

when undisturbed the butterflies adopt a cryptic position imitating a fallen leaf, however after being discovered and reacting(flicking wings open) they adopt one of 3 behaviours what are these?

Answer 9

1) keep eye spots visible
2) continue to flick wings in direction of bird
3) return to cryptic position

Question 10

examples of anti predation techniques

Answer 10

• parents remove egg shells from nest
• dilution effect
• cryptic colouration e.g. dark moth (tested by operant conditioning in blue jays) e.g. decorator crab
• stotting (honest signalling)
• selfish herds