Intraspecific priority effects modify compensatory responses to changes in hatching phenology in an amphibian

Abstract

Summary1. In seasonal environments, modifications in the phenology of life-history events can alter the strength of time constraints experienced by organisms. Offspring can compensate for a change in timing of hatching by modifying their growth and development trajectories. However, intra-and interspecific interactions may affect these compensatory responses, in particular if differences in phenology between cohorts lead to significant priority effects (i.e. the competitive advantage that early-hatching individuals have over late-hatching ones). 2. Here, we conducted a factorial experiment to determine whether intraspecific priority effects can alter compensatory phenotypic responses to hatching delay in a synchronic breeder by rearing moor frog (Rana arvalis) tadpoles in different combinations of phenological delay and food abundance. 3. Tadpoles compensated for the hatching delay by speeding up their development, but only when reared in groups of individuals with identical hatching phenology. In mixed phenology groups, strong competitive effects by non-delayed tadpoles prevented the compensatory responses and delayed larvae metamorphosed later than in single phenology treatments. Nondelayed individuals gained advantage from developing with delayed larvae by increasing their developmental and growth rates as compared to single phenology groups. 4. Food shortage prolonged larval period and reduced mass at metamorphosis in all treatments, but it did not prevent compensatory developmental responses in larvae reared in single phenology groups. 5. This study demonstrates that strong intraspecific priority effects can constrain the compensatory growth and developmental responses to phenological change, and that priority effects can be an important factor explaining the maintenance of synchronic life histories (i.e. explosive breeding) in seasonal environments.

The role of seasonal timing and phenological shifts for species coexistence

“…Furthermore, phenologies vary naturally across years and sites leading to interannual variation in relative timing of species interactions (Høye & Forchhammer 2008;Thackeray et al 2016;Rudolf 2018) and this variation is likely to increase with climate change (Pearse et al 2017). Recent studies indicate that even small changes in the timing of species interactions can result in substantial changes in the outcome of species interactions (Stier et al 2013;Godoy & Levine 2014;Rasmussen et al 2014;Cleland et al 2015;Young et al 2015;Murillo-Rinc on et al 2017;Rudolf 2018;Alexander and Levine, 2019). This implies that per-capita interaction strengths are typically not constant, but instead naturally change over time with shifts in the relative phenologies of interacting species within and across years (e.g., Fig.…”

Stage-mediated priority effects and season lengths shape long-term competition dynamics

“…Miller and Rudolf 2011; Rasmussen 2013a, 2013b;Rudolf et al 2014;Murillo-Rincón et al 2017). We report specific methods and results of the latter scenario in Supporting Information, Section 1 as it did not change our general conclusions.…”

Impacts of phenological variability in a predatory larval salamander on pond food webs

“…One of the hypothesized mechanisms that induce body size asymmetries is variability in the timing of breeding, which could occur between species (fall‐ vs. spring‐breeding species) (Urban, ) or within a species (multiple breeding cohorts) (Petranka & Thomas, ; Murillo‐Rincón et al , ). We found partial support for this hypothesis.…”

“…Changes in the timing of ontogenetic events, or phenological shifts, can affect both population and community dynamics (Miller‐Rushing et al , ; Yang & Rudolf, ; Nakazawa & Doi, ). Variation in these dynamics occurs in part when phenological shifts impact the outcome of species interactions through processes such as match–mismatch scenarios (Cushing, ; Durant et al , ) or monopolization of resources by earlier arriving individuals or species, that is priority effects (Connell & Slatyer, ; Rasmussen, Van Allen & Rudolf, ; Murillo‐Rincón et al , ). Understanding the consequences of phenological shifts has become imperative, as the timing of key life history events of many taxa is changing worldwide in response to climate change (Parmesan, ).…”

“…Adults rely on temperature and rainfall cues to initiate breeding migrations (Todd & Winne, ), but vary in their relative timing both within and between species. Thus, interaction strengths among larval stages of amphibians can strongly depend on species timing and arrival order to ponds (Alford & Wilbur, ; Lawler & Morin, ; Petranka & Thomas, ; Boone, Scott & Niewiarowski, ; Eitam, Blaustein & Mangel, ; Segev & Blaustein, ; Murillo‐Rincón et al , ). This occurs largely due to body size asymmetries that develop between early and later breeders: larger larvae from earlier breeding adults outcompete and prey on smaller larvae from later breeding adults of the same or different species.…”