Search results for "Forficula auricularia"

Paternal signature in kin recognition cues of a social insect: concealed in juveniles, revealed in adults

2014

Kin recognition is a key mechanism to direct social behaviours towards related individuals or avoid inbreeding depression. In insects, recognition is generally mediated by cuticular hydrocarbon (CHC) compounds, which are partly inherited from parents. However, in social insects, potential nepotistic conflicts between group members from different patrilines are predicted to select against the expression of patriline-specific signatures in CHC profiles. Whereas this key prediction in the evolution of insect signalling received empirical support in eusocial insects, it remains unclear whether it can be generalized beyond eusociality to less-derived forms of social life. Here, we addressed this…

Sibling cooperation in earwig families provides insights into the early evolution of social life.

2014

The evolutionary transition from solitary to social life is driven by direct and indirect fitness benefits of social interactions. Understanding the conditions promoting the early evolution of social life therefore requires identification of these benefits in nonderived social systems, such as animal families where offspring are mobile and able to disperse and will survive independently. Family life is well known to provide benefits to offspring through parental care, but research on sibling interactions generally focused on fitness costs to offspring due to competitive behaviors. Here we show experimentally that sibling interactions also reflect cooperative behaviors in the form of food sh…

Matters of scale: positive allometry and the evolution of male dimorphisms

2005

J.L.T. was funded by a Biotechnology and Biological Sciences Research Council research fellowship, J.S.K. by the Academy of Finland, and N.R.L. by a Natural Environment Research Council research fellowship. The developmental independence of alternative phenotypes is key to evolutionary theories of phenotypic plasticity and the origins of diversity. Male dimorphisms associated with alternative reproductive tactics are widely cited examples of such facultative expression of divergent fitness optima. Current models for the evolution of male dimorphisms invoke a size-dependent threshold at which the phenotype is reprogrammed. We use predictions derived from allometric modeling to test for the e…

Negative association between parental care and sibling cooperation in earwigs: a new perspective on the early evolution of family life?

2015

International audience; The evolution of family life requires net fitness benefits for offspring, which are commonly assumed to mainly derive from parental care. However, an additional source of benefits for offspring is often overlooked: cooperative interactions among juvenile siblings. In this study, we examined how sibling cooperation and parental care could jointly contribute to the early evolution of family life. Specifically, we tested whether the level of food transferred among siblings (sibling cooperation) in the European earwig F orficula auricularia (1) depends on the level of maternal food provisioning (parental care) and (2) is translated into offspring survival, as well as fem…

2014

Oviparous females have three main options to increase their reproductive success: investing into egg number, egg mass and/or egg care. Although allocating resources to either of these three components is known to shape offspring number and size, potential trade-offs among them may have key impacts on maternal and offspring fitness. Here, we tested the occurrence of phenotypic trade-offs between egg number, egg mass and maternal expenditure on egg care in the European earwig, Forficula auricularia, an insect with pre- and post-hatching forms of maternal care. In particular, we used a series of laboratory observations and experiments to investigate whether these three components non-additivel…

Forceps size and immune function in the earwig Forficula auricularia L.

2007

Females of many species select their mates on the basis of the size or intensity of sexual ornaments, and it has been suggested that these provide reliable signals of a male’s ability to resist parasites and pathogens. European earwigs, Forficula auricularia, are sexually dimorphic in forceps shape and length. Male forceps are used as weapons in male contests for access to females, but recent findings suggest that females also choose males on the basis of their forceps length. In the present study, we tested the hypotheses that in the European earwig, F. auricularia, the size of forceps is correlated with immune function and that immune function differs between the sexes. We found that enca…

Influences of Relatedness, Food Deprivation, and Sex on Adult Behaviors in the Group-living Insect Forficula auricularia

2014

The evolution of group living is generally associated with the emergence of social behaviors that ensure fitness benefits to group members. However, the expression of these behaviors may depend on group composition, which can vary over time with respect to sex, starvation status, and relatedness. Here, we investigated (1) whether adults of the group-living European earwig, Forficula auricularia, show cooperative behaviors toward conspecifics and (2) whether sex, food availability, and relatedness shape the nature and frequency of these behaviors. We conducted a full-factorial experiment using 108 unisexual pairs of adults, in which we manipulated these three factors and video-recorded the e…

Age, pathogen exposure, but not maternal care shape offspring immunity in an insect with facultative family life

2017

International audience; Background: To optimize their resistance against pathogen infection, individuals are expected to find the right balance between investing into the immune system and other life history traits. In vertebrates, several factors were shown to critically affect the direction of this balance, such as the developmental stage of an individual, its current risk of infection and/or its access to external help such as parental care. However, the independent and/or interactive effects of these factors on immunity remain poorly studied in insects.Results: Here, we manipulated maternal presence and pathogen exposure in families of the European earwig Forficula auricularia to measur…

Data from: Survival after pathogen exposure in group-living insects: don’t forget the stress of social isolation!

2016

A major cost of group-living is its inherent risk of pathogen infection. To limit this risk, many group-living animals have developed the capability to prophylactically boost their immune system in the presence of group members and/or to mount collective defenses against pathogens. These two phenomena, called density dependent prophylaxis and social immunity, respectively, are often used to explain why, in group-living species, individuals survive better in groups than in isolation. However, this survival difference may also reflect an alternative and often overlooked process: a cost of social isolation on individuals’ capability to fight against infections. Here, we disentangled the effect…

Data from: Growing up with feces: benefits of allo-coprophagy in families of the European earwig

2016

An important issue in the evolution of group living is the risk of pathogen and predator exposure entailed by the inherent accumulation of feces within a nesting site. While many group living species limit this risk by cleaning the nest, others do not, raising questions about the benefits of maintaining feces in the nest and their importance in social evolution. Here, we investigated whether one of these benefits could be mediated by coprophagy in families of the European earwig, Forficula auricularia. In this insect species, mothers and mobile juveniles (nymphs) line their nests with feces and consume them. In a first experiment, we tested whether access to feces produced by either nymphs …