Biology subjects

Reeve, H. K.

Publications and source records attributed to Reeve, H. K..

4 recordsLinked to original sources

bioRxiv2026

Testing a Mates Brain: Courtship signals may reveal signaler decision-making capacity

IIt has been suggested that courtship signals reflect a potential mate's learning ability or nervous system competence. However, there is no rigorous theory that explains how features of sexual signals represent a nervous system's "quality". Such a theory may provide a mechanism for mate assessment via sexual signals and offer an explanation for why courtship signals are rhythmic and stereotypic. In our paper, first we use a general model of optimal neural decision-making to show that variance in an organism's solution time for a given fitness problem lowers the fitness gain rate; more specifically, in well-supported "competing accumulator" models of decision making, we show that noise in the slope of spike rate increase in evidence accumulators increases both reaction time and the probability of a sub-optimal decision. In conclusion, higher timing regularity leads to quicker and better decisions. This finding accords with extensive human study data showing that variance in reaction times is negatively associated with various measures of motor and cognitive performance. Thus, selection should favor individuals that require potential mates to advertise courtship signal regularity to indicate their nervous system's general timing consistency (the timing-consistency signaling theory). The focus on signal consistency (rather than on signal duration or power) may account for why courtship signals are typically rhythmic, are often multi-modal, and why rhythmic signals are also employed in territorial contests. One of the model's several predictions is that individuals should favor potential mates with lower noise in courtship signal features such as inter-pulse intervals.

animal behavior and cognition↗

bioRxiv2024

Maternal Care Leads to the Evolution of Long, Slow Lives

Animals, and mammals in particular, vary widely in their "pace of life," with some species living long lives and reproducing infrequently (slow life histories) and others living short lives and reproducing often (fast life histories). These species also vary in the importance of maternal care in offspring fitness: in some species, offspring are fully independent of their mothers following a brief period of nutritional input, while others display a long period of continued dependence on mothers well after nutritional dependence. Here we hypothesize that these two axes of variation are causally related to each other, such that extended dependence of offspring on maternal presence leads to the evolution of longer lives at the expense of reproduction. We use a combination of deterministic modeling and stochastic agent-based modeling to explore how empirically-observed links between maternal survival and offspring fitness are likely to shape the evolution of mortality and fertility. Each of our modelling approaches leads to the same conclusion: when maternal survival has strong impacts on the survival of offspring and grandoffspring, populations evolve longer lives with less frequent reproduction. Our results suggest the slow life histories of humans and other primates as well as other long-lived, highly social animals such as hyenas, whales, and elephants, are partially the result of the strong maternal care that these animals display. We have designed our models to be readily parameterized with demographic data that is routinely collected by long-term researchers, which will facilitate more thorough testing of our hypothesis. Significance StatementHumans and other primates live longer lives and reproduce less often than other mammals of similar body mass. What is the cause of these long lives? Here we add to existing hypotheses, including the Mother and Grandmother hypotheses, by arguing that these increased lifespans are partially explained by the intense maternal care that many primates express. Using a combination of deterministic and stochastic modeling approaches, informed by empirical data, we show that stronger connections between maternal survival and offspring fitness leads to selection for longer lives and slower reproduction. Our models suggest that the importance of the mother-offspring relationship, which defines much of human and non-human primate lives, lies at the core of the evolution of our long lives.

evolutionary biology↗

bioRxiv2021

Acoustic and postural displays in a miniature and transparent teleost fish, Danionella dracula

Acoustic communication is widespread across vertebrates, including among fishes. We report robust acoustic displays during aggressive interactions for a laboratory colony of Danionella dracula, a relatively recently discovered miniature and transparent species of teleost fish closely related to zebrafish (Danio rerio). Males produce bursts of pulsatile, click-like sounds and a distinct postural display, extension of a hypertrophied lower jaw, during aggressive but not courtship interactions. Females lack a hypertrophied lower jaw and show no evidence of sound production or jaw extension in such contexts. Novel pairs of size-matched or -mismatched males were combined in resident-intruder assays where sound production and jaw extension could be linked to individuals. Resident males produce significantly more sound pulses and extend their jaw more often than intruders in both dyad contexts, and relatively larger males are significantly more sonic and exhibit more jaw extensions in size-mismatched pairs. The majority of highest sound producers in both contexts also show increased jaw extension during periods of heightened sonic activity. These studies firmly establish D. dracula as a sound-producing species that modulates both acoustic and postural displays during aggressive interactions based on either residency or body size, providing a foundation for further investigating the role of multimodal displays in a new model clade for neurogenomic studies of aggression, courtship, and other social interactions.

animal behavior and cognition↗

bioRxiv2018

Evolutionary dynamics of recent selection for enhanced social cognition

Cognitive abilities can vary dramatically among species though little is known about the dynamics of cognitive evolution. Here we demonstrate that recent evolution of visual individual recognition in the paper wasp Polistes fuscatus is the target of arguably the strongest positive selective pressure in the species recent history. The most extreme selective sweeps in P. fuscatus are associated with genes known to be involved in long-term memory formation, mushroom body development and visual processing - all traits that have recently evolved in association with individual recognition. Cognitive evolution appears to have been driven initially by selection on standing variation in perceptual traits followed by both hard and soft sweeps on learning and memory. Evolutionary modeling reveals that intense selection as observed in P. fuscatus is likely the norm during the early stages of cognitive evolution. These data provide insight into the dynamics of cognition evolution demonstrating that social selection for increased intelligence can lead to rapid multi-genic adaptation of enhanced recognition abilities.

animal behavior and cognition↗