Influence of ecology and social interactions on the early evolution of family life.
Sensory and Behavioural Biology
Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
Final Report Abstract
A long-lasting problem in evolutionary biology is to understand why some animals live in families, whereas others prefer solitary life. In this context, a major issue concerns which factors promote the emergence and maintenance of family interactions. In this project, we aimed at addressing this question by testing how resource availability and sibling interactions shape the early evolution of family life in the European earwig "Forficula auricularia". The first part of the project specifically focused on the short- and long-term effects of low resource availability on family interactions. Our results produced four published manuscripts, in which we showed that (1) food restrictions entails a competition between mothers and offspring that can reduce offspring survival, (2) parental condition affects the behaviors that juveniles express toward their siblings and parents during family interactions, (3) variation in resource availability have limited effects on the expression of maternal care under natural conditions and (4) inter-individual variation in body conditions (driven by resource availability) shapes the outcome of investment trade-off between reproduction and care in earwig females, The second part of this project explored putative forms of cooperative behaviors between siblings and investigated to what extend the benefits of sibling cooperation could promote the early evolution of family life. This second part lead to three published manuscripts demonstrating that (5) juveniles do not only compete but may also exchange food during family life, (6) this food exchange may compensate for low levels of maternal care and that (7) this food exchange stops when offspring reach adulthood. In addition to these two parts, we were also interested in taking broader perspectives on the topic of this project and produced 3 additional published manuscripts. Specifically, we (8) wrote a review to discuss the important controversy between kin selection and multilevel selection in the evolution of social life in nature, (9) investigated the short and long-term effects of maternal deprivation in flexible social systems and finally (10) the role of maternal care on the chemical signatures of offspring and the expression of nepotistic behaviors. Overall, our projects tested predictions of a novel and major hypothesis stating that good rather than harsh ecological conditions favor switch from solitary to family life, and more generally provided novel and key insights on the importance of environmental quality and within-group interactions on the early evolution of family life.
Publications
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(2017) When earwig mothers do not care to share: Parent–offspring competition and the evolution of family life. Funct Ecol (Functional Ecology) 31 (11) 2098–2107
Kramer, Jos; Körner, Maximilian; Diehl, Janina M. C.; Scheiner, Christine; Yüksel‐Dadak, Aytül; Christl, Teresa; Kohlmeier, Philip; Meunier, Joël
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2014. Influences of relatedness, food deprivation, and sex on adult behaviors in the group-living insect Forficula auricularia. Ethology 120: 923–932
Weiß, C., Kramer, J., Holländer, K. & Meunier, J.
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2014. Mother and offspring fitness in an insect with maternal care: phenotypic trade-offs between egg number, egg mass and egg care. BMC Evol. Biol. 14: 125
Koch, L.K. & Meunier, J.
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2014. Paternal signature in kin recognition cues of a social insect: concealed in juveniles, revealed in adults. Proc. R. Soc. B Biol. Sci. 281: 20141236
Wong, J.W.Y., Meunier, J., Lucas, C. & Kölliker, M.
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2014. Sibling cooperation in earwig families provides insights into the early evolution of social life. Am. Nat. 183: 547–557
Falk, J., Wong, J.W.Y., Kölliker, M. & Meunier, J.
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2015. Negative association between parental care and sibling cooperation in earwigs: a new perspective on the early evolution of family life? J. Evol. Biol. 28: 1299–1308
Kramer, J., Thesing, J. & Meunier, J.
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2015. Short-term benefits, but transgenerational costs of maternal loss in an insect with facultative maternal care. Proc. R. Soc. B Biol. Sci. 282: 20151617
Thesing, J., Kramer, J., Koch, L.K. & Meunier, J.
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2016. Kin and multilevel selection in social evolution: a never-ending controversy? F1000Research 5: 776
Kramer, J. & Meunier, J.
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2016. Maternal condition determines offspring behavior toward family members in the European earwig. Behav. Ecol. 27: 494–500
Kramer, J. & Meunier, J.
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2016. The population determines whether and how life-history traits vary between reproductive events in an insect with maternal care. Oecologia 182: 443–452
Ratz, T., Kramer, J., Veuille, M. & Meunier, J.
