The long term effects of family conflict in birds
Lead Research Organisation:
Lancaster University
Department Name: Biological Sciences
Abstract
Family conflicts are widespread and play an important role in the evolution of many behaviours and traits. In birds, for example, sexual conflict, parent-offspring conflict and sibling rivalry are all important components of within-family interactions that can influence survival and reproductive success. So far, most studies have focussed on the costs and benefits to the parents of parent-offspring conflict, whereas the effects on offspring, and especially the longer term effects, have received little attention. In this project using zebra finches, we will experimentally manipulate competition within broods by creating synchronous and asynchronously hatching broods, and so broods where chicks are similar, or differ, in size. Chick size is an important determinant in the outcome of competition for food delivered by parents and as hatching synchrony is under parental control it is a component of parent-offspring conflict. This will be the first experimental study: 1) to quantify the effects of parent-offspring conflict on variation in offspring growth strategies while controlling for genetic differences between families, and 2) to quantify the longer term effects of this conflict on traits that influence offspring fecundity. This will add an important dimension to our understanding of the far reaching effects of family conflict and the measurement of fitness.
Organisations
People |
ORCID iD |
| Ian Russell Hartley (Principal Investigator) |
Publications
Mainwaring M
(2011)
Parentally biased favouritism in relation to offspring sex in zebra finches
in Behavioral Ecology and Sociobiology
MAINWARING M
(2012)
Hatching asynchrony can have long-term consequences for offspring fitness in zebra finches under captive conditions HATCHING ASYNCHRONY AND NESTLING FITNESS
in Biological Journal of the Linnean Society
MAINWARING M
(2010)
Hatching asynchrony and growth trade-offs within domesticated and wild zebra finch, Taeniopygia guttata, broods DEVELOPMENT OF ZEBRA FINCHES
in Biological Journal of the Linnean Society
Mainwaring M
(2016)
Local weather conditions have complex effects on the growth of blue tit nestlings
in Journal of Thermal Biology
Mainwaring M
(2013)
Hatching asynchrony and offspring sex influence the subsequent exploratory behaviour of zebra finches
in Animal Behaviour
Mainwaring MC
(2010)
Environmental and not maternal effects determine variation in offspring phenotypes in a passerine bird.
in Journal of evolutionary biology
Mainwaring MC
(2011)
Zebra finches are bolder in an asocial, rather than social, context.
in Behavioural processes
Mainwaring MC
(2009)
Experimental evidence for state-dependent nest weight in the blue tit, Cyanistes caeruleus.
in Behavioural processes
| Description | The original aims of the project were: 1) to quantify the effects of parent-offspring conflict on variation in offspring growth strategies while controlling for genetic differences between families, and 2) to quantify the longer term effects of this conflict on traits that influence offspring fecundity. I feel that the project has successfully met its aims and the findings will be of general interest to evolutionary biologists when the papers are published. Parent birds are normally in control of hatching synchrony, which is a potential source of parent-offspring conflict. We used experimentally manipulated hatching asynchrony to simulate parent-offspring conflict of high and low levels. Pairs of zebra finches were allowed to breed twice: once with a synchronously hatching brood, where chicks were of similar competitive ability, and once with a brood that hatched one egg per day, which delivered a brood of variable competitive ability. We were subsequently able to compare siblings raised under different conflict regimes. We looked at individual growth curves for siblings raised by the same parents, but under different hatching regimes. Growth data for skeletal, body-mass and feather growth were recorded and a summarised in Table 1. The analysis shows that while final sizes for the body components are not affected by rearing regime, the way that they grow is affected; chicks grow their feathers faster in synchronous broods. Feathers grown quickly are often weaker and more prone to damage than slowly grown feathers, so we have identified a previously unknown cost that is due to hatching synchrony and, therefore, parent-offspring conflict. It is likely that such a cost is short-term for the offspring, because they moult a few months after fledging, and is likely to reflect a shunting of resources into priority structures such as the skeleton and muscle, both of which are important in determining the outcome of sibling competition. We compared mature sibling zebra finches raised under different rearing regimes. For females, there was no significant effect of rearing regime on their subsequent clutch size, egg mass, egg volume, yolk size, yolk total carotenoid concentration, or concentrations of tocopherol components within the yolk (GLMM; n = 15 females. P values range from 0.13 to 0.97). For females, therefore, there appear to be no long-term affects of parent-offspring conflict that influence their own reproductive success parameters. For males, there was no significant effect of rearing regime on their subsequent attractiveness to a series of unrelated, mature females. In choice chamber tests, females showed no preference for siblings raised in synchronous versus asynchronous broods (Paired t-test, P=0.79). The lack of a longer term cost makes sense following the finding above, that nestlings pay for the costs of parent-offspring conflict by shunting resources out of feather development. By the time they moult out of their low quality juvenile feathers, the pressures of sibling competition and parent-offspring conflict are removed. |
| Exploitation Route | Our findings suggest strong links between early growth conditions and final quality of individuals as adults. They also suggest that the competitive environment for early development is important for this process. This is of interest to academic studies of the effects of environment on development, but could also have applications in agriculture and animal rearing. |
| Sectors | Agriculture, Food and Drink,Education,Environment,Healthcare |
| Description | The publications have been cited in the research of others. |
| First Year Of Impact | 2011 |
| Sector | Education |