SR2: Deal et al 2017 - filial cannibalism Flashcards
what is the main species studied and which sex shows the parental care?
sand goby (P.minutus) paternal
what did they look at the exposure and absence of?
predator- perch
P.fluviatilis
when did the number of eggs eaten not depend on predation threat?
when males consumed only some of their eggs
what could partial clutch consumption be considered to be motivated by?
benefits of existing young
what is one of the strongest predictors of total cannibalism ?
small clutch size - more likely
when is total cannibalism less common?
with predator exposure
which males built larger nest entrances and why?
those consuming the entire brood
perhaps as predator avoidance
is the cannibalism related to sustaining nest building?
no
why may parents not wish to care for their young?
costly
time consuming
energetically demanding
exposure to disease and predators
what investment may parents trade off?
existing young with future reproduction investment
what does cannibalism prevent and what does it provide?
prevent cost of parental care from affecting future young
provides energy and nutrition
what is the benefit of partial cannibalism?
will nutritionally support and improve the body condition of the parent caring for the surviving young
what does the level of predation pressure likely influence?
future reproduction
courtship and spawning restricted
what are gobies perceiving high predation risk less likely to do?
engage in total cannibalism and if partial will eat fewer
what was the experimental set up? (8)
- 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
how many males engaged in total cannibalism?
18/64
all males consumed eggs, what was the min?
12
by what % was likelihood of total clutch cannibalism affected in perch exposed and unexposed?
exposed: 21% decrease
unexposed 35% decrease
in terms of the nest what was exposure to perch associated with?
taller and wider nest entrances
for total cannibals what was consuming more eggs associated with?
piling less sand
was partial cannibalism influenced by perch?
no
when is total cannibalism only adaptive?
when parents can survive to reproduce again
when may parents exploit young for food?
when predation threat restricts ability to forage
what will males engaging in partial cannibalism do about their nests?
wont compromise care or nest entrance even if it affects their own survival
what does the fact that partial clutch cannibalism wasn’t affected by predator exposure suggest?
that they are largely motivated by the benefits of existing young
if there are more abundant opportunities to breed in the future then how are costs of current reproduction reduced?
consume their young
why may more sand be piled on a nest?
attractive to females and may provide better protection
how many predator treatments and how many control?
33 predator
31 control
what did the study highlight the importance of considering?
the effect of adult predation risk on parental effort decisions
