Exposure to predator models during the fertile period leads to higher levels of extra‐pair paternity in blue tits

Abstract

The perceived risk of predation can affect breeding behaviour and reduce reproductive success in prey species. Individuals exposed to predators may also adopt different mating tactics with potential consequences for the distribution of paternity in socially monogamous species that engage in extra‐pair copulations. We experimentally increased perceived predation risk during the fertile period in blue tits Cyanistes caeruleus. Every morning between nest completion and the onset of egg laying, we presented a model of either a predator or a non‐predator (control) near active nestboxes. Broods from pairs exposed to predators had higher levels of extra‐pair paternity than control broods. This mainly resulted from a higher proportion of extra‐pair offspring in broods with at least one extra‐pair young. Females exposed to predators first emerged from the nestbox later in the morning, stayed away from the nestbox for longer and were less likely to be visited at the nest by their social mate, but we detected no behavioural differences once the model was removed. Our results suggest that the higher rates of extra‐pair paternity resulted from the disruption of morning routines, which may have inhibited within‐pair copulations or increased opportunities for females to engage in extra‐pair copulations. We conclude that the perceived risk of predation can have substantial effects on levels of extra‐pair paternity.

Imminent risk of predation reduces the relative strength of postcopulatory sexual selection in the guppy

“…The effect of these interactions on the operation of sexual selection may not be easy to predict. For example, a recent study on the socially monogamous passerine Cyanistes cyaneus [42] found that predation cues significantly increased the frequency of extrapair paternity (and hence, possibly, the relative strength of postcopulatory selection) through disruptions of morning routines, either inhibiting within-pair copulations or increasing opportunities for females to engage in extra-pair copulations.…”

The effects of season, sex, age and weather on population‐level variation in the timing of activity in Eurasian Blue Tits Cyanistes caeruleus

“…This also confirms anecdotes described by Kluijver (1950), who studied breeding Great Tits and mentioned 'two inexplicable cases in which she (the Great Tit female) became active very late'. Why some individuals sometimes leave their nestbox so late remains unexplained but might be associated with the presence of a predator nearby (Santema et al 2019).…”

“…For further analyses, we discarded two types of data. We excluded all data from replacement clutches and from clutches where the start of activity was experimentally manipulated (some clutches in 2012-13, Schlicht et al (2014) and some in 2017, Santema et al (2019)). Second, we visually inspected whether fitted models fulfilled the assumptions of homoscedasticity and normal distribution of residuals.…”

“…Other variables that may influence patterns of activity are latitude (Amlaner & Ball 1983, predation risk (Amlaner & Ball 1983, Santema et al 2019, noise (Arroyo-Sol ıs et al 2013; but see , the lunar phase (York et al 2018) and the risk of territorial intrusions (Foote et al 2011; but see Amrhein & Erne 2006).…”

Sight of parasitoid wasps accelerates sexual behavior and upregulates a micropeptide gene in Drosophila

“…Taken together, our results extend the effect of parasitoid wasps to another domain of Drosophila behavior: mating. The presence of predators has been found to affect sexual behaviors in other species, including courtship, mate choice, and nest-building in fish [36][37][38], calling behavior in tree frogs [39], and mating behavior in birds [40]. We have examined the effect of exposure to parasitoids, an enormously abundant class of organism, and above all we have studied the effect in Drosophila, a species that allows incisive analysis of its underlying molecular, cellular, and circuit basis.…”