Biology subjects

Niemela, P. T.

Publications and source records attributed to Niemela, P. T..

3 recordsLinked to original sources

bioRxiv2026

Social foragers rely more on dynamic cues than prior beliefs in unpredictable natural environments

Foraging is a prime example of adaptive decision-making in uncertain and changing environments. Foragers need to continuously integrate their direct experiences and observations of what others are doing with what they already know about the distribution of prey. Yet little is known about the importance of prior knowledge relative to dynamically sampled information in social foraging settings. Here, we investigated the role of prior beliefs in five large-scale ice-fishing competitions involving 49--53 highly experienced ice-fishers in 251 foraging trips. To quantify their prior spatial beliefs, participants marked areas they believed to have high resource abundance on topographic maps containing isoclines (i.e., depth curves) before each competition. GPS devices and headcams tracked behavioural states and foraging success. We found that prior beliefs about the fish distribution are to a large extent driven by lake topography and therefore converge across individuals. However, these prior beliefs were not systematically linked to foraging success. While prior beliefs predicted spot choices, especially in the beginning of competitions, they were heavily outweighed by dynamic personal and social information sources. Exploring how the use of prior beliefs differed between foraging trips, we found that high reliance on prior beliefs was associated with reduced avoidance of unsuccessful locations which resulted in limited spatial exploration. We conclude that dynamic information sampling and accumulation are key processes in social foraging decisions, with prior spatial beliefs playing only a minor role in natural environments where resources are hard to predict in advance.

animal behavior and cognition↗

bioRxiv2021

Life-history genotype explains variation in migration activity in Atlantic salmon (Salmo salar).

One of the most important life-history continuums is the fast-slow axis, where "fast" individuals mature earlier than "slow" individuals. "Fast" individuals are predicted to be more active than "slow" individuals; high activity is required to maintain a fast life-history strategy. Recent meta-analyses revealed mixed evidence for such integration. Here, we test whether known life-history genotypes differ in activity expression by using Atlantic salmon (Salmo salar) as a model. In salmon, variation in Vgll3, a transcription co-factor, explains [~]40% of variation in maturation timing. We predicted that the allele related to early maturation (vgll3*E) would be associated with increased activity. We used an automated surveillance system to follow [~]1900 juveniles including both migrants and non-migrants (i.e. smolt and parr fish, respectively) in semi-natural conditions over 31 days ([~]580 000 activity measurements). Against our prediction, vgll3 did not explain variation in activity in pooled migrant and non-migrant data. However, in migrants, vgll3 explained variation in activity according to our prediction in a sex-dependent manner. Specifically, in females the vgll3*E allele was related to increasing activity, whereas in males the vgll3*L allele (later maturation allele) was related to increasing activity. These sex-dependent effects might be a mechanism maintaining within-population genetic life-history variation.

evolutionary biology↗

bioRxiv2019

Density-dependent costs and benefits of male mating success in a wild insect

O_LISocial environments are important determinant of fitness, particularly when same-sex local densities shape both mating success and survival costs.\nC_LIO_LIWe studied how mating success varied across a range of naturally occurring local male densities in wild field cricket males, Gryllus campestris, monitored by using fully automated RFID-surveillance system. We predicted that mating success as a function of local density follow a concave pattern predicted by the Allee-effect theory. As increasing density should reduce per capita predation and parasitism risk, we predicted that males generally having high mating success in low (versus high) local density live less long. Finally, we predicted that males on average occurred in local densities where their mating success is highest.\nC_LIO_LIMale mating success followed a density-dependent pattern predicted by the Allee-effect theory. Males also differed in the local density where their mating success was highest. This variation explained longevity and total fitness: males with high mating success in low local density lived longer and had higher total mating success. Finally, we found no evidence of males occupying local densities in which their mating success is highest.\nC_LIO_LIOur study suggest that density-dependent plasticity in mating success is under selection: males having high mating success in low density, but low mating success in high density, lived longer and had higher overall mating success. We thus provide novel insights, with unseen detail, about individual differences in density-dependent mating success and, costs and benefits related to variation in mating success in the wild. Finally, our study also highlights that specific statistical approaches are needed to firmly study the costs and benefits associated with the traits that are repeatedly expressed across range of environments.\nC_LI

evolutionary biology↗