SR2: Deal et al 2017 - filial cannibalism

Question 1

what is the main species studied and which sex shows the parental care?

Answer 1

sand goby (P.minutus)
paternal

Question 2

what did they look at the exposure and absence of?

Answer 2

predator- perch

P.fluviatilis

Question 3

when did the number of eggs eaten not depend on predation threat?

Answer 3

when males consumed only some of their eggs

Question 4

what could partial clutch consumption be considered to be motivated by?

Answer 4

benefits of existing young

Question 5

what is one of the strongest predictors of total cannibalism ?

Answer 5

small clutch size - more likely

Question 6

when is total cannibalism less common?

Answer 6

with predator exposure

Question 7

which males built larger nest entrances and why?

Answer 7

those consuming the entire brood

perhaps as predator avoidance

Question 8

is the cannibalism related to sustaining nest building?

Answer 8

no

Question 9

why may parents not wish to care for their young?

Answer 9

costly
time consuming
energetically demanding
exposure to disease and predators

Question 10

what investment may parents trade off?

Answer 10

existing young with future reproduction investment

Question 11

what does cannibalism prevent and what does it provide?

Answer 11

prevent cost of parental care from affecting future young

provides energy and nutrition

Question 12

what is the benefit of partial cannibalism?

Answer 12

will nutritionally support and improve the body condition of the parent caring for the surviving young

Question 13

what does the level of predation pressure likely influence?

Answer 13

future reproduction

courtship and spawning restricted

Question 14

what are gobies perceiving high predation risk less likely to do?

Answer 14

engage in total cannibalism and if partial will eat fewer

Question 15

what was the experimental set up? (8)

Answer 15

• MF pair added to experimental aquarium
• one nesting and one exposure compartment
• flowerpot with acetate sheet for eggs to attach to in nesting compartment
• males piled sand and made nest chamber
• female removed after eggs laid
• males exposed to control or predator
• measured nest entrance
• counted eggs eaten

Question 16

how many males engaged in total cannibalism?

Answer 16

18/64

Question 17

all males consumed eggs, what was the min?

Answer 17

12

Question 18

by what % was likelihood of total clutch cannibalism affected in perch exposed and unexposed?

Answer 18

exposed: 21% decrease

unexposed 35% decrease

Question 19

in terms of the nest what was exposure to perch associated with?

Answer 19

taller and wider nest entrances

Question 20

for total cannibals what was consuming more eggs associated with?

Answer 20

piling less sand

Question 21

was partial cannibalism influenced by perch?

Answer 21

no

Question 22

when is total cannibalism only adaptive?

Answer 22

when parents can survive to reproduce again

Question 23

when may parents exploit young for food?

Answer 23

when predation threat restricts ability to forage

Question 24

what will males engaging in partial cannibalism do about their nests?

Answer 24

wont compromise care or nest entrance even if it affects their own survival

Question 25

what does the fact that partial clutch cannibalism wasn’t affected by predator exposure suggest?

Answer 25

that they are largely motivated by the benefits of existing young

Question 26

if there are more abundant opportunities to breed in the future then how are costs of current reproduction reduced?

Answer 26

consume their young

Question 27

why may more sand be piled on a nest?

Answer 27

attractive to females and may provide better protection

Question 28

how many predator treatments and how many control?

Answer 28

33 predator

31 control

Question 29

what did the study highlight the importance of considering?

Answer 29

the effect of adult predation risk on parental effort decisions