2-4 Eacock et al 2019

Question 1

Caterpillars with completely obscured ocelli remained capable of what and what?

Answer 1

Caterpillars with completely obscured ocelli remained capable of enhancing their crypsis by changing colour and choosing to rest on colour-matching twigs.

Question 2

what is dermal photoreception?

Answer 2

the ability to perceive photic information through the skin independently of eyes

Question 3

what is dermal photoreception best known for?

Answer 3

It is best known for its involvement in shadow reflexes, phototaxis, and orientation in response to light

Question 4

what else is dermal photoreception referred to as?

Answer 4

extraocular photoreception

Question 5

Slow (morphological) colour change, occurring over ____ to ____, is common in arthropods

Answer 5

Slow (morphological) colour change, occurring over hours to weeks, is common in arthropods

Question 6

Several studies have demonstrated that ______ _____ and the ______ __ ______ influence pupal colour in a variety of butterfly species14, on the assumption that they use their eyes to perceive the colour stimuli.

Answer 6

Several studies have demonstrated that substrate characteristics12 and the wavelength of light13 influence pupal colour in a variety of butterfly species14, on the assumption that they use their eyes to perceive the colour stimuli.

Question 7

whose experiments were the first to provide evidence for extraocular photoreception in colour-changing arthropods?

Answer 7

Edward Bagnall Poulton on the control of pupal colour in the small tortoiseshell butterfly

Question 8

what has been only recently revisited by researchers?

Answer 8

the possibility that extraocular photoreception is involved in slow colour change of arthopods

Question 9

The peppered moth (Biston betularia) has evolved to be highly cryptic to ____ ___, both in the ____and ____stages

Answer 9

The peppered moth (Biston betularia) has evolved to be highly cryptic to visual predators, both in the adult and larval stages

Question 10

how is crypsis achieved?

Answer 10

Crypsis is achieved through contrasting mechanisms in each stage (adult and larval)

Question 11

how is the adult colour pattern polymorphism (melanism) determined?

Answer 11

genetically

Question 12

how is larvae camouflage determined?

Answer 12

through a combination of twig-mimicking masquerade19 and colour plasticity

Question 13

Colour change in these polyphagous larvae is a continuous reaction norm in response to what?

Answer 13

Colour change in these polyphagous larvae is a continuous reaction norm in response to colour cues from the twigs in the larvae’s immediate surroundings rather than the leaves they eat

Question 14

The precision of this colour and pattern response is at odds with what and what?.

Answer 14

The precision of this colour and pattern response is at odds with the simple larval ocelli21, and the distal position of the head relative to the twig when larvae are in the resting pose.

Question 15

what animal was used in this research?

Answer 15

The peppered moth (Biston betularia)

Question 16

how many larvae did they rear?

Answer 16

321

Question 17

We reared ___larvae from __ families in replicated groups of __ individuals

Answer 17

We reared 321 larvae from 4 families in replicated groups of 25 individuals

Question 18

what was inside the boxes holding the moths?

Answer 18

inside transparent plastic boxes containing inter-crossing artificial twigs (painted dowels), on stalkless fresh leaves of the grey willow, Salix cinere

Question 19

what did they do to the caterpillars ocelli?

Answer 19

We painted over the caterpillars’ ocelli with black acrylic paint with the aid of a microscope

Question 20

When was the obstruction to ocular vision or ‘blindfolding’ started?

Answer 20

This obstruction to ocular vision or ‘blindfolding’ started at late second to early third instar

Question 21

This obstruction to ocular vision or ‘blindfolding’ started at late second to early third instar

which is what?

Answer 21

This obstruction to ocular vision or ‘blindfolding’ started at late second to early third instar, which is the earliest stage at which larvae can be effectively blindfolded, and is prior to a strong colour response.

Question 22

how did they overcome the problem of caterpillars shedding the blindfold in the process of molting between instars?

Answer 22

we checked caterpillars twice daily for early signs of head capsule slippage

Question 23

Head capsule slippage takes ~__–__h to complete

Answer 23

Head capsule slippage takes ~12–18 h to complete

Question 24

Head capsule slippage takes ~12–18 h to complete, during which time we did what?

Answer 24

Head capsule slippage takes ~12–18 h to complete, during which time we held these individuals separately and singly overnight in opaque white boxes without any dowels

Question 25

what were the different dowel colours?

Answer 25

We used four different dowel colours, with one colour per enclosure: brown, green, black, and white

Question 26

We used four different dowel colours, with one colour per enclosure: brown, green, black, and white (see ‘Methods’). The first pair of colours differed in ____ and _____; the second pair differed only in _____

Answer 26

We used four different dowel colours, with one colour per enclosure: brown, green, black, and white (see ‘Methods’). The first pair of colours differed in chroma and luminance; the second pair differed only in luminance

Question 27

The spectral reflectance of each caterpillar’s integument was measured at the ___ (___) instar using a ______

Answer 27

The spectral reflectance of each caterpillar’s integument was measured at the final (sixth) instar using a spectrophotometer

Question 28

We used a computational model of visual perception to quantify what?

Answer 28

We used a computational model of visual perception to quantify larval colour and luminance as it would be perceived by a visually hunting avian predator, the blue tit, Cyanistes caeruleus

Question 29

We used a computational model of visual perception to quantify larval colour and luminance as it would be perceived by a visually hunting avian predator, the ___ ___

Answer 29

We used a computational model of visual perception to quantify larval colour and luminance as it would be perceived by a visually hunting avian predator, the blue tit, Cyanistes caeruleus

Question 30

We calculated how green the caterpillars appeared to a predator as the ratio of what?

Answer 30

We calculated how green the caterpillars appeared to a predator as the ratio of the medium and long wavelength cone responses

Question 31

We found a striking whole-body colour change in the absence of visual information from the eyes, whereby caterpillars not only changed colour to resemble the dowel colour in their enclosure, but they did so to the same degree as what?

Answer 31

We found a striking whole-body colour change in the absence of visual information from the eyes, whereby caterpillars not only changed colour to resemble the dowel colour in their enclosure, but they did so to the same degree as non-blindfolded controls.

Question 32

We found a striking whole-body colour change in the absence of visual information from the eyes, whereby caterpillars not only changed colour to resemble the dowel colour in their enclosure, but they did so to the same degree as non-blindfolded controls.

This is evident to the ___ ____, and is also apparent by comparison of _________________

Answer 32

This is evident to the human eye (Fig. 2a, d), and is also apparent by comparison of the spectral reflectance curves in the visible wavelength range

Question 33

viewed through this lens, B. betularia larvae reared in white dowel enclosures were significantly ____ than those reared on ____dowels, when measured as the double cone responses of the avian retina

Answer 33

viewed through this lens, B. betularia larvae reared in white dowel enclosures were significantly brighter than those reared on black dowels, when measured as the double cone responses of the avian retina

Question 34

there was no significant effect of blindfolding on the _____of larvae from black or white treatments

Answer 34

there was no significant effect of blindfolding on the luminance of larvae from black or white treatments

Question 35

Larvae reared in green dowel enclosures were significantly ____to an avian predator than larvae from ____treatments

Answer 35

Larvae reared in green dowel enclosures were significantly greener to an avian predator than larvae from brown treatments

Question 36

blindfolding had no significant effect on the greenness of larvae in the ____ or ____treatments

Answer 36

blindfolding had no significant effect on the greenness of larvae in the green or brown treatments

Question 37

blindfolding had no significant effect on the greenness of larvae in the green or brown treatments (F1,169 = 0.67, P = 0.4), and the distribution of greenness was what?

Answer 37

blindfolding had no significant effect on the greenness of larvae in the green or brown treatments (F1,169 = 0.67, P = 0.4), and the distribution of greenness was similar between blindfolded and control larvae across both treatments

Question 38

we find that birds would not be able to discriminate between what and what?

Answer 38

we find that birds would not be able to discriminate between blindfolded and control larvae,

Question 39

we find that birds would not be able to discriminate between blindfolded and control larvae, whether reared on ____or _____dowels

Answer 39

we find that birds would not be able to discriminate between blindfolded and control larvae, whether reared on achromatic or chromatic dowels

Question 40

To further evaluate the capacity of B. betularia caterpillars for extraocular colour perception, what did they test?

Answer 40

To further evaluate the capacity of B. betularia caterpillars for extraocular colour perception, we tested background choice behaviour using two designs of background choice arena

Question 41

To further evaluate the capacity of B. betularia caterpillars for extraocular colour perception, we tested background choice behaviour using two designs of background choice arena

what were they

Answer 41

a transparent plastic cube containing two diagonally crossing dowels, each painted with a single colour (bright green vs dark brown); and a transparent horizontal tube with a single horizontally suspended dowel, one half painted green, and the other brown

Question 42

a transparent plastic cube containing two diagonally crossing dowels, each painted with a single colour (bright green vs dark brown); and a transparent horizontal tube with a single horizontally suspended dowel, one half painted green, and the other brown

what did these designs allow them to test?

Answer 42

the consistency of background choice in different contexts

Question 43

For each trial, final instar larvae from blindfolded and control groups of the green and brown treatments were placed _____from ___ ____ ___

Answer 43

For each trial, final instar larvae from blindfolded and control groups of the green and brown treatments were placed equidistantly from each dowel colour.

Question 44

Because predation risk increases the likelihood of behavioural background matching, we simulated predation by doing what?

Answer 44

Because predation risk increases the likelihood of behavioural background matching, we simulated predation by gently poking larvae on the dorsal surface with tweezers

Question 45

For horizontal dowel chambers, to eliminate any positional preferences, ___trials were conducted per larva

Answer 45

For horizontal dowel chambers, to eliminate any positional preferences, two trials were conducted per larva

Question 46

In one trial, the brown end of the dowel was at the far end of the ______; in the other trial, the direction of the dowel was ______

Answer 46

In one trial, the brown end of the dowel was at the far end of the chamber; in the other trial, the direction of the dowel was reversed

Question 47

ndividual larvae were left for __h (_-h dark, _-h light), after which the dowel colour that each caterpillar was resting on was recorded.

Answer 47

ndividual larvae were left for 12 h (7-h dark, 5-h light), after which the dowel colour that each caterpillar was resting on was recorded.

Question 48

In both types of arena (and both dowel orientations in the horizontal arena), larvae were able to maximise camouflage by doing what?

Answer 48

In both types of arena (and both dowel orientations in the horizontal arena), larvae were able to maximise camouflage by selecting dowel colours that more closely matched their own body colours

Question 49

__-___% of brown larvae chose to rest on a brown dowel,

Answer 49

75–80% of brown larvae chose to rest on a brown dowel,

Question 50

__-__% of green larvae chose to rest on a green dowel

Answer 50

70–80% of green larvae chose to rest on a green dowel

Question 51

In the diagonal chamber design, there was no effect of ______ (Z = −0.22, P = 0.83) or ___ ___ (Z = −0.87, P = 0.39) on matching success.

Answer 51

In the diagonal chamber design, there was no effect of blindfolding (Z = −0.22, P = 0.83) or larval colour (Z = −0.87, P = 0.39) on matching success.

Question 52

In the horizontal chamber, there was also no effect of ____(Z = −1.24, P = 0.21), ___ ____ (Z = 0.82, P = 0.41), or ____ ____ (Z = −1.72, P = 0.08) on matching success.

Answer 52

In the horizontal chamber, there was also no effect of blindfolding (Z = −1.24, P = 0.21), larval colour (Z = 0.82, P = 0.41), or dowel position (Z = −1.72, P = 0.08) on matching success.

Question 53

To investigate the molecular basis of the morphological and behavioural responses, we analysed what?

Answer 53

To investigate the molecular basis of the morphological and behavioural responses, we analysed the expression of key genes involved in visual perception in head (including eyes) and dermal tissue of B. betularia larvae and adults.

Question 54

what are opsins?

Answer 54

Opsins are light-sensitive proteins that mediate the conversion of a photon of light into an electrochemical signal, necessary for vision and photoreception

Question 55

We identified opsins sensitive to ____ , _____ , ___ _____ and _____

Answer 55

We identified opsins sensitive to ultraviolet (two splice variants UVA and UVB), blue (two splice variants BlA and BlB), long wavelength (two gene copies LW1 and LW2), and melanopsin

Question 56

Dermal tissue expression for all genes, averaged across all three body segments, is _____across larvae and adults

Answer 56

Dermal tissue expression for all genes, averaged across all three body segments, is similar across larvae and adults

Question 57

The ratio of gene expression in the epidermis to that in the head provides a measure what?

Answer 57

The ratio of gene expression in the epidermis to that in the head provides a measure of the contribution of putative photoreceptors in the larval epidermis to the total light-sensing capacity of a caterpillar.

Question 58

In larvae, expression of ___, ___, and ___is upregulated in dermal tissue to similar levels of that in the head.

Answer 58

In larvae, expression of RDB, BlB, and LW1 is upregulated in dermal tissue to similar levels of that in the head.

Question 59

The strongest contrast in relative dermal expression between larvae and adults is for ___, ___, ___ and __ ___ ___ copy one

Answer 59

The strongest contrast in relative dermal expression between larvae and adults is for Arr-1, BlB, MelB, and long wavelength copy one

Question 60

Biston betularia larvae that were prevented from receiving light input through their ocelli changed colour in response to luminance and colour cues, and also maximised the benefits of this plastic masquerade by activelydoing what?

Answer 60

Biston betularia larvae that were prevented from receiving light input through their ocelli changed colour in response to luminance and colour cues, and also maximised the benefits of this plastic masquerade by actively selecting twigs of similar colour.

Question 61

Experimental and control larvae were equally able to ___ ____ and choose the appropriate ___ ___

Answer 61

Experimental and control larvae were equally able to change appearance and choose the appropriate resting background

Question 62

Experimental and control larvae were equally able to change appearance and choose the appropriate resting background

what does this demonstrate

Answer 62

demonstrating that they are capable of spectrally sensitive extraocular photoreception, and implying that the ocelli play a secondary role in these responses

Question 63

Our results ____ those of similar blindfolding experiments in other arthropods, where the characteristics of the blindfolding paint, rather than the background colour, did what

Answer 63

Our results contrast those of similar blindfolding experiments in other arthropods10,28, where the characteristics of the blindfolding paint, rather than the background colour, affected colour change.

Question 64

The necessity for extraocular photoreception in B. betularia may relate to what?

Answer 64

The necessity for extraocular photoreception in B. betularia may relate to the angled twig posture of the larvae during the daytime, which places the ocelli away from the twig perch

Question 65

The necessity for extraocular photoreception in B. betularia may relate to the angled twig posture of the larvae during the daytime, which places the ocelli away from the twig perch

In this position, as well as during feeding on leaves, photoreceptors across the larval skin may receive more accurate what?

Answer 65

In this position, as well as during feeding on leaves, photoreceptors across the larval skin may receive more accurate colour and pattern information about the resting twig than the ocelli.

Question 66

The potential role of extraocular photoreceptors in colour change via pigment production was first suggested by _____, working on the determination of pupal colour in __ _____.

Answer 66

The potential role of extraocular photoreceptors in colour change via pigment production was first suggested by Poulton15,29, working on the determination of pupal colour in A. urticae.

Question 67

what did poulton show

Answer 67

By means of individual partitioned chambers (i.e., not occluding or destroying the ocelli), in which the head end of a larva and the remainder of the body were exposed to contrasting coloursy, he showed that the resulting pupal colour was determined by the background colour to which the greatest surface area of skin had been exposed.

Question 68

Kato et al.30 showed what?

Answer 68

Kato et al.30 showed that the pupal greenness of the Japanese oak silkmoth, Antheraea yamamai, was determined by the intensity of white light and was unaffected by cauterization of the larval ocelli

Question 69

The ability to choose a colour-matching background could be considered ____ in colour-changing animals, such as peppered moth caterpillars, which gain additional protection from predation by _____ __ ___

Answer 69

The ability to choose a colour-matching background could be considered redundant in colour-changing animals, such as peppered moth caterpillars, which gain additional protection from predation by masquerading as twigs

Question 70

However, as colour change in B. betularia is a slow process, and the twig colour environment inhabited by these caterpillars is often what?

Answer 70

However, as colour change in B. betularia is a slow process, and the twig colour environment inhabited by these caterpillars is often heterogeneous

Question 71

The equivalent strategy of choosing to rest on matching backgrounds in visually heterogeneous environments in species that are also capable of colour change has evolved in ___, ___ ___ & _____

Answer 71

The equivalent strategy of choosing to rest on matching backgrounds in visually heterogeneous environments in species that are also capable of colour change has evolved in flatfish, larval newts, and salamander

Question 72

Epidermal opsin expression associated with achromatic light perception has been reported in ______, ______, _______, and _______

Answer 72

Epidermal opsin expression associated with achromatic light perception has been reported in cnidarians36, cephalopods37, arthropods38, and vertebrates

Question 73

Given what is known about their primary function, and the energetic cost of gene expression39, the relatively high abundance of a whole suite of phototransduction gene transcripts in the larval epidermis suggests what?

Answer 73

Given what is known about their primary function, and the energetic cost of gene expression39, the relatively high abundance of a whole suite of phototransduction gene transcripts in the larval epidermis suggests that they constitute part of the extraocular photoreceptor machinery.

Question 74

To our knowledge, our study provides the first evidence for what?

Answer 74

To our knowledge, our study provides the first evidence for extraocular opsin expression potentially capable of detecting colour in an arthropod, linked to functional changes in appearance and behaviour.

Question 75

Extraocular photoreceptors, resembling light-sensitive phaosome cells in earthworm skin, have been described in the _____ of swallowtail butterflies and proposed to aid in mate choice and oviposition

Answer 75

xtraocular photoreceptors, resembling light-sensitive phaosome cells in earthworm skin, have been described in the genitalia of swallowtail butterflies and proposed to aid in mate choice and oviposition

Question 76

hilst the colour response of blindfolded B. betularia larvae could, in principle, be produced by a highly compartmentalised physiological mechanism, the background matching behaviour suggests what?

Answer 76

hilst the colour response of blindfolded B. betularia larvae could, in principle, be produced by a highly compartmentalised physiological mechanism, the background matching behaviour suggests the integration of diffuse information from the epidermis, not only about the twig colours but also resemblance to self. I

Question 77

It is therefore likely that the ____ and ____systems have a combined role in the colour and background choice responses.

Answer 77

It is therefore likely that the nervous and endocrine systems have a combined role in the colour and background choice responses.

Question 78

The expression profiles of visual genes in B. betularia, combined with morphological and behavioural evidence, lead us to propose that larvae of B. betularia possess photoreceptors distributed throughout the _____.

Answer 78

The expression profiles of visual genes in B. betularia, combined with morphological and behavioural evidence, lead us to propose that larvae of B. betularia possess photoreceptors distributed throughout the epidermis.

Question 79

Biston betularia were reared from what?

Answer 79

Biston betularia were reared from eggs

Question 80

Partial removal of the blindfold was observed only ____ out of a total of ____checks across all experiments; these individuals were removed from the experiment.

Answer 80

Partial removal of the blindfold was observed only twice out of a total of 11,480 checks across all experiments; these individuals were removed from the experiment.

Question 81

Larvae were cooled in a ____ for __-__ min prior to measurement to reduce movement.

Answer 81

Larvae were cooled in a fridge for 2–10 min prior to measurement to reduce movement.

Question 82

Out of 137 individuals, __(~__%) alternated their colour choice between trials.

Answer 82

Out of 137 individuals, 34 (~25%) alternated their colour choice between trials.