The ecology and evolution of sibling cannibalism in the wild


Cannibalism is remarkably widespread across animals. As such, ecologists and evolutionary biologists are interested in the ecological and evolutionary causes and consequences of eating members of one’s own species. Ecologically, cannibalism may arise opportunistically when resources are limited, and this can include the crucial early stages of an animal’s life. So called “sibling cannibalism” is a specific instance of cannibalism, an extreme form of sibling rivalry when related individuals in a brood kill and eat each other. Sibling cannibalism is particularly interesting from an evolutionary perspective: in this case, the puzzle is why individuals should be selected to eat close relatives, when effectively one is eating one’s own genes (i.e. a route to gain inclusive fitness benefits that you are instead eating). Moreover, sib cannibalism may shape parent-offspring conflicts, and influence female reproductive investment and oviposition behaviour. Ecologically, sibling cannibalism can influence ecological success – including when invading novel environments – and shape intra- and inter-specific patterns of competition. There is still much we do not understand however about the role early-stage cannibalism plays in both within-species conflicts and between-species competition.

In this project, the student will explore intra- and inter-specific patterns of sibling cannibalism in species of true bugs and ladybirds, in both the field and laboratory. The project will involve measuring the costs and benefits of egg cannibalism in terms of both parents and offspring, as well as exploring the extent to which competition between different species is influenced by the cannibalistic interactions of young. The project will provide the opportunity for novel tests of evolutionary and ecological theory and also – for the mathematically inclined candidate – provide the opportunity to develop new theory. In addition, we will use molecular genetic techniques to assess patterns of parentage and relatedness in the groups of juvenile bugs and beetles in the wild, combining behaviour and genetics in the field and the laboratory.

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The project will involve behavioural, ecological and molecular genetic experimental approaches, with the opportunity for development of new evolutionary or ecological theory pertaining to the causes and consequences of sibling cannibalism.

Project Timeline

Year 1

Introduction to the study systems and laboratory experiments: costs and benefits of sib cannibalism in seed bugs. Fieldwork: within- and between-species cannibalism in wild populations of seed bugs. Molecular analysis of field-samples. Identification of relevant training requirements and course attendance.

Year 2

Laboratory experiments: experimental manipulation of cannibalism. Fieldwork: within- and between-species cannibalism in wild populations of seed bugs. Fieldwork: sibling cannibalism in wild ladybird populations. Molecular analysis of field-samples. Manuscript preparation.

Year 3

Final year of laboratory experiments on seed bugs and ladybirds. Fieldwork: sibling cannibalism in wild ladybird populations. Molecular analysis of field-samples. Manuscript and thesis preparation.

Year 3.5

Manuscript and thesis preparation.

& Skills

The project will provide a number of key training opportunities for the successful candidate: (1) training in experimental design and behavioural techniques, in both the field and the laboratory; (2) molecular ecological genetic techniques; (3) quantitative skills, from data management through to statistical analysis; (4) communication skills, in terms of presenting work to both academic and non-technical audiences through a variety of media. Experience of fieldwork and the ability to drive would be useful for the project.

References & further reading

Further Information

For further details of the work in the Insect Behavioural Ecology lab, please visit our website: You are strongly encouraged to make informal enquiries before applying, so please also email Dr David Shuker at:

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