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Bose APH. Parent-offspring cannibalism throughout the animal kingdom: a review of adaptive hypotheses. Biol Rev Camb Philos Soc 2022; 97:1868-1885. [PMID: 35748275 DOI: 10.1111/brv.12868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 05/03/2022] [Accepted: 05/05/2022] [Indexed: 12/01/2022]
Abstract
Parents that kill and consume their offspring often appear to be acting against their own reproductive interests. Yet parent-offspring cannibalism is common and taxonomically widespread across the animal kingdom. In this review, I provide an overview of our current understanding of parent-offspring cannibalism, which has seen a proliferation in adaptive hypotheses over the past 20 years for why parents consume their own young. I review over four decades of research into this perplexing behaviour, drawing from work conducted on fishes, reptiles, insects, birds, and mammals among other taxa. Many factors have been hypothesised to explain parent-offspring cannibalism in nature, including poor parental energy reserves, small or large brood sizes, low or uncertain parentage, and high brood densities, and additional factors are still being uncovered. Parent-offspring cannibalism does not appear to have a single predominant explanation; rather, the factor, or set of factors, that govern its expression is largely taxon specific. Parents may either consume all offspring under their care (full-brood cannibalism) or consume a fraction of their offspring (partial brood cannibalism). These forms of cannibalism are thought to provide adaptive benefits to cannibals under a range of circumstances, primarily by allowing parents to allocate parental efforts more optimally - energy from eating (some of) one's current offspring can be redirected to other offspring, or to parental growth, survival, and ultimately to other future reproductive endeavours. Thus, parent-offspring cannibalism is a phenotypically plastic trait that responds to changing environmental, social, and physiological conditions. The expression of parent-offspring cannibalism in any given system is intimately linked to the reproductive value of current young relative to parents' expectations for future reproduction, and also to whether parental care is predominantly depreciable or non-depreciable. Furthermore, parent-offspring cannibalism has the potential to generate conflict between the sexes, and I briefly discuss some consequences of this conflict on patterns of mate choice. Finally, there still remain many aspects of this behaviour where our understanding is poor, and I highlight these topics to help guide future research.
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Affiliation(s)
- Aneesh P H Bose
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences (SLU), Skogmarksgränd, 90183, Umeå.,Department of Collective Behaviour, Max Planck Institute of Animal Behavior, University of Konstanz, Universitaetsstraße 10, 78464, Konstanz, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Universitaetsstraße 10, 78464, Konstanz, Germany.,Department of Biology, University of Konstanz, Universitaetsstraße 10, 78464, Konstanz, Germany
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Zimmermann H, Fritzsche K, Henshaw JM, Katongo C, Banda T, Makasa L, Sefc KM, Bose APH. Nest defense in the face of cuckoldry: evolutionary rather than facultative adaptation to chronic paternity loss. BMC Evol Biol 2019; 19:200. [PMID: 31684856 PMCID: PMC6829816 DOI: 10.1186/s12862-019-1528-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 10/17/2019] [Indexed: 12/02/2022] Open
Abstract
Background Raising unrelated offspring is typically wasteful of parental resources and so individuals are expected to reduce or maintain low levels of parental effort when their parentage is low. This can involve facultative, flexible adjustments of parental care to cues of lost parentage in the current brood, stabilizing selection for a low level of paternal investment, or an evolutionary reduction in parental investment in response to chronically low parentage. Results We studied parental care in Variabilichromis moorii, a socially monogamous, biparental cichlid fish, whose mating system is characterized by frequent cuckoldry and whose primary form of parental care is offspring defense. We combine field observations with genetic parentage analyses to show that while both parents defend their nest against intruding con- and hetero-specifics, males and females may do so for different reasons. Males in the study group (30 breeding pairs) sired 0–100% (median 83%) of the fry in their nests. Males defended less against immediate threats to the offspring, and more against threats to their territories, which are essential for the males’ future reproductive success. Males also showed no clear relationship between their share of defense and their paternity of the brood. Females, on the other hand, were related to nearly all the offspring under their care, and defended almost equally against all types of threats. Conclusion Overall, males contributed less to defense than females and we suggest that this asymmetry is the result of an evolutionary response by males to chronically high paternity loss in this species. Although most males in the current study group achieved high parentage in their nests, the average paternity in V. moorii, sampled across multiple seasons, is only about 55%. We highlight the importance and complexity of studying nest defense as a form of parental care in systems where defense may serve not only to protect current offspring, but also to ensure future reproductive success by maintaining a territory.
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Affiliation(s)
- Holger Zimmermann
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010, Graz, Austria
| | - Karoline Fritzsche
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010, Graz, Austria.,Department of Biological Sciences, University of Idaho, 875 Perimeter MS, Moscow, ID, 3051, USA
| | - Jonathan M Henshaw
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010, Graz, Austria.,Department of Biological Sciences, University of Idaho, 875 Perimeter MS, Moscow, ID, 3051, USA
| | - Cyprian Katongo
- Department of Biological Sciences, University of Zambia, Great East Road Campus, P.O. Box 32379, Lusaka, Zambia
| | - Taylor Banda
- Lake Tanganyika Research Unit, Department of Fisheries, Ministry of Fisheries and Livestock, P. O. Box 420055, Mpulungu, Zambia
| | - Lawrence Makasa
- Lake Tanganyika Research Unit, Department of Fisheries, Ministry of Fisheries and Livestock, P. O. Box 420055, Mpulungu, Zambia
| | - Kristina M Sefc
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010, Graz, Austria.
| | - Aneesh P H Bose
- Institute of Biology, University of Graz, Universitätsplatz 2, 8010, Graz, Austria. .,Present address: Department of Collective Behaviour, Max Planck Institute for Ornithology, Universitätsstraße 10, 78464, Konstanz, Germany.
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Cheng YR, Rubenstein DR, Shen SF. Nest predation predicts infanticide in a cooperatively breeding bird. Biol Lett 2019; 15:20190314. [PMID: 31387470 DOI: 10.1098/rsbl.2019.0314] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In cooperatively breeding species, social conflict is typically assumed to underlie destructive behaviours like infanticide. However, an untested alternative hypothesis in birds is that infanticide in the form of egg tossing may simply be a parental response to partial nest predation representing a life-history trade-off. We examined egg tossing behaviour in the colonial and cooperatively breeding grey-capped social weaver (Pseudonigrita arnaudi), a plural breeder in which pairs nest separately, often in the same tree. Using infrared nest cameras, we found that 78% of the tossing events from 2012 to 2017 were committed by parents, suggesting that social conflict is unlikely to be the main reason underlying egg tossing in this species. Instead, reductions in clutch size due to both natural and experimentally simulated predation induced parental egg tossing. Our study suggests that destructive behaviour in cooperatively breeding birds can be shaped by a variety of mechanisms beyond social conflict and that alternative hypotheses must be considered when studying the adaptive significance of infanticide in group-living species.
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Affiliation(s)
- Yi-Ru Cheng
- Biodiversity Research Center, Academia Sinica, Taipei, 115 Taiwan, Republic of China.,Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY 10027, USA
| | - Dustin R Rubenstein
- Department of Ecology, Evolution and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY 10027, USA
| | - Sheng-Feng Shen
- Biodiversity Research Center, Academia Sinica, Taipei, 115 Taiwan, Republic of China
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