Contrasting Patterns of Phenotypic Plasticity in Reproductive Traits in Two Great Tit (Parus Major) Populations

Abstract

Phenotypic plasticity is an important mechanism via which populations can respond to changing environmental conditions, but we know very little about how natural populations vary with respect to plasticity. Here we use random-regression animal models to understand the multivariate phenotypic and genetic patterns of plasticity variation in two key life-history traits, laying date and clutch size, using data from long-term studies of great tits in The Netherlands (Hoge Veluwe [HV]) and UK (Wytham Woods [WW]).We show that, while population-level responses of laying date and clutch size to temperature were similar in the two populations, between-individual variation in plasticity differed markedly. Both populations showed significant variation in phenotypic plasticity (IxE) for laying date, but IxE was significantly higher in HV than in WW. There were no significant genotype-by-environment interactions (GxE) for laying date, yet differences in GxE were marginally nonsignificant between HV and WW. For clutch size, we only found significant IxE and GxE in WW but no significant difference between populations. From a multivariate perspective, plasticity in laying date was not correlated with plasticity in clutch size in either population. Our results suggest that generalizations about the form and cause of any response to changing environmental conditions across populations may be difficult.

Multiple pathways mediate the effects of climate change on maternal reproductive traits in a red deer population

“…This approach has been widely used across a range of study systems (e.g., Estrella et al 2007, Brommer et al 2008, Husby et al 2010, Phillimore et al 2013, and provides an easily implemented and easily interpreted means of assessing the impact of climate at different time points. However, it also clearly has some limitations, firstly because it assumes that all days within a critical window exert equal influence on the trait, and secondly because the arbitrary nature of the cutoff points used (for example, the start and end of a week, as used here) may not be biologically realistic (Sims et al 2007, van de Pol andCockburn 2011).…”

“…Identification of critical time window of climatic variation.-To find the key weather variables determining trait expression, we used associative modeling, specifically a sliding-window approach (Estrella et al 2007, Brommer et al 2008, Husby et al 2010. In this approach, the mean of a particular weather variable (or, in the case of rainfall, the sum) is calculated across a given time period (window) and then tested for the strength of association with the trait of interest.…”

“…1998, Post andForchhammer 2008), However, it should be noted that in the case of Great Tits, although females with high levels of individual mismatch recruited fewer offspring, across years the relationship between annual average measures of fitness and population-level mismatch was weak or absent . Finally, the effects of climate change on fitness may vary within species, particularly if there is variation in the extent to which individuals are plastic in their response to changing environmental cues (Visser et al 2003, Visser et al 2004, Charmantier et al 2008, Husby et al 2010. Currently, the majority of phenological responses to climate change have been documented in birds (Berteaux and , Parmesan 2006, Thackeray et al 2010, although an increasing number of studies have found evidence of phenological changes in mammal populations (Re´ale et al 2003, Berteaux and Stenseth 2006, Post and Forchhammer 2008, Ozgul et al 2010, Burthe et al 2011, Moyes et al 2011, Lane et al 2012.…”

Avian ecologists and physiologists have different sexual preferences

“…Photoperiod is still considered as the major environmental cue containing long-term predictive information about the optimal period for initiating and terminating breeding [29,100,133], and is therefore one of the most studied topics in avian physiology. In comparison, heritability studies have become common in evolutionary ecology over recent decades, because of the development of computational resources and statistical methods such as the "animal model", now allowing us to analyze multigenerational pedigrees and reliably estimate the additive variance that underlies heritability [50,60,124]. Finally, heritability studies on physiological mechanisms in birds are still extremely rare [54,115,but see 35,87], so the keyword "heritability" almost never refers to physiological studies which might contaminate the results.…”

Geographic Variation in Air Temperature Leads to Intraspecific Variability in the Behavior and Productivity of a Eusocial Insect

“…Nevertheless, sometimes different climate regimes also generate trait differences among individuals or populations belonging to the same 55 species (e.g., Husby et al 2010;Oliveira et al 2013). Understanding the effects that climate has on the ecology and phenology of a species, as well as determining the ability of a species to adapt to different climate regimes, is essential because it gives us the ability to foreseen how ecosystems will react to climate changes in the long-term (Somero 2010).…”