Assessing wild turkey productivity before and after a 14-day delay in the start date of the spring hunting season in Tennessee.

Ten state wildlife management agencies in the United States, including six within the Southeast, have delayed their spring wild turkey (Meleagris gallopavo) hunting seasons since 2017 by five or more days to address concerns related to the potential effects of hunting on wild turkey seasonal productivity. One hypothesis posits that if the spring hunting season is too early, there may be insufficient time for males to breed hens before being harvested, thus leading to reduced seasonal productivity. We conducted an experiment to determine whether delaying the wild turkey hunting season by 2 weeks in south-middle Tennessee would affect various reproductive rates. In 2021 and 2022, the Tennessee Fish and Wildlife Commission experimentally delayed the spring hunting season to open 14 days later than the traditional date (the Saturday closest to 1 April) in Giles, Lawrence, and Wayne counties. We monitored reproductive rates from 2017 to 2022 in these three counties as well as two adjacent counties, Bedford and Maury, that were not delayed. We used a Before-After-Control-Impact design to analyze the proportion of hens nesting, clutch size, hatchability, nest success, poult survival and hen survival with linear mixed-effect models and AIC model selection to detect relationships between the 14-day delay and reproductive parameters. We detected no relationship (p > .05) between the 14-day delay and any individual reproductive parameter. In addition, recruitment (hen poults per hen that survived until the next breeding season) was very low (<0.5) and did not increase because of the 14-day delay. The traditional Tennessee start date had been in place since 1986 while the turkey harvest increased markedly until about 2006 and more recently stabilized. Our data indicate that moving the start of the hunting season from a period just prior to peak nest initiation to 2 weeks later, to coincide with a period just prior to peak nest incubation initiation, resulted in no change to productivity or populations in wild turkey flocks in south-middle Tennessee.

Substrate Prediction for RiPP Biosynthetic Enzymes via Masked Language Modeling and Transfer Learning.

Ribosomally synthesized and post-translationally modified peptide (RiPP) biosynthetic enzymes often exhibit promiscuous substrate preferences that cannot be reduced to simple rules. Large language models are promising tools for predicting such peptide fitness landscapes. However, state-of-the-art protein language models are trained on relatively few peptide sequences. A previous study comprehensively profiled the peptide substrate preferences of LazBF (a two-component serine dehydratase) and LazDEF (a three-component azole synthetase) from the lactazole biosynthetic pathway. We demonstrated that masked language modeling of LazBF substrate preferences produced language model embeddings that improved downstream classification models of both LazBF and LazDEF substrates. Similarly, masked language modelling of LazDEF substrate preferences produced embeddings that improved the performance of classification models of both LazBF and LazDEF substrates. Our results suggest that the models learned functional forms that are transferable between distinct enzymatic transformations that act within the same biosynthetic pathway. Our transfer learning method improved performance and data efficiency in data-scarce scenarios. We then fine-tuned models on each data set and showed that the fine-tuned models provided interpretable insight that we anticipate will facilitate the design of substrate libraries that are compatible with desired RiPP biosynthetic pathways.

Complexity of postural sway affects affordance perception of reachability in virtual reality.

Visual perception of whether an object is within reach while standing in different postures was investigated. Participants viewed a three-dimensional (3D) virtual reality (VR) environment with a stimulus object (red ball) placed at different egocentric distances. Participants reported whether the object was reachable while in a standard pose as well as in two separate active balance poses (yoga tree pose and toe-to-heel pose). Feedback on accuracy was not provided, and participants were not allowed to attempt to reach. Response time, affordance judgements (reachable and not reachable), and head movements were recorded on each trial. Consistent with recent research on perception of reaching ability, the perceived boundary occurred at approximately 120% of arm length, indicating overestimation of perceived reaching ability. Response times increased with distance, and were shortest for the most difficult pose-the yoga tree pose. Head movement amplitude increased with increases in balance demands. Unexpectedly, the coefficient of variation was comparable in the two active balance poses, and was more extreme in the standard control pose for the shortest and longest distances. More complex descriptors of postural sway (i.e., effort-to-compress) were predictive of perception while in the tree pose and the toe-to-heel pose, as compared with control stance. This demonstrates that standard measures of central tendency are not sufficient for describing multiscale interactions of postural dynamics in functional tasks.

Comparison of two psychophysical methods across visual and haptic perception of stand-on-ability.

Recent research (Hajnal et al. in Perception 45(7):768-786, 2016) found apparent differences between haptic and visual perception of the affordance of stand-on-ability. One reason for this discrepancy might be the imprecision of the measurement method. We compared the psychophysical method of adjustment with a dynamic staircase method of stimulus presentation in an affordance task. Three groups of participants either visually inspected a flat sturdy sloped ramp, placed one foot onto the ramp occluded from view, or placed one foot on the ramp while allowed to look at it, in the visual, haptic, or multimodal condition, respectively. Each trial was presented by moving the ramp up or down until the participant perceived the action boundary, i.e., the steepest slope that still afforded upright stance. After perceptual trials, we measured the actual action boundaries by allowing participants to attempt to stand on the ramp. The action boundary was the average between the lowest false alarm and steepest hit within a 1.5° margin of difference. Visual perception was found to be equivalent with haptic perception. Perceptual and action boundaries were indistinguishable, but only when employing the more precise staircase method. The results support the postulate of equivalence among perceptual systems proposed by Gibson (The senses considered as perceptual systems. Houghton Mifflin Company, Boston, 1966), and the idea of correspondence between perception and action which is the cornerstone of affordance theory.

Multifractality of posture modulates multisensory perception of stand-on-ability.

By definition, perception is a multisensory process that unfolds in time as a complex sequence of exploratory activities of the organism. In such a system perception and action are integrated, and multiple energy arrays are available simultaneously. Perception of affordances interweaves sensory and motor activities into meaningful behavior given task constraints. The present contribution offers insight into the manner in which perception and action usher the organism through competent functional apprehension of its surroundings. We propose that the tensegrity structure of the body, manifested via multifractality of exploratory bodily movements informs perception of affordances. The affordance of stand-on-ability of ground surfaces served as the experimental paradigm. Observers viewed a surface set to a discrete angle and attempted to match it haptically with a continuously adjustable surface occluded by a curtain, or felt an occluded surface set to a discrete angle then matched it visually with a continuously adjustable visible surface. The complex intertwining of perception and action was demonstrated by the interactions of multifractality of postural sway with multiple energy arrays, responses, and changing geometric task demands.

Fractality of body movements predicts perception of affordances: Evidence from stand-on-ability judgments about slopes.

We recorded head motion with one wireless marker attached to the back of the head during quiet stance as participants visually inspected a sloped ramp in order to perceive whether they might be able to stand on the surface. Participants responded with "yes" or "no" without attempting to stand on the ramp. As has been found in dynamic touch (Palatinus, Kelty-Stephen, Kinsella-Shaw, Carello, & Turvey, 2014), we hypothesized that multiscale fluctuation patterns in bodily movement during visual observation would predict perceptual judgments. Mixed-effects logistic regression predicted binary affordance judgments as a function of geographical slant angle, head-motion standard deviation, and multifractal spectrum width (Ihlen, 2012). Multifractal spectrum width was the strongest predictor of affordance judgments. Specifically, increased spectrum width predicted decreased odds of a "yes" answer. Interestingly, standard deviation was not a significant predictor, reinforcing our prediction that traditional measures of variability fail to account for what fractal measures of multiscale interactions can predict about information pickup in perception-action systems. (PsycINFO Database Record

Estimating population extinction thresholds with categorical classification trees for Louisiana black bears.

Monitoring vulnerable species is critical for their conservation. Thresholds or tipping points are commonly used to indicate when populations become vulnerable to extinction and to trigger changes in conservation actions. However, quantitative methods to determine such thresholds have not been well explored. The Louisiana black bear (Ursus americanus luteolus) was removed from the list of threatened and endangered species under the U.S. Endangered Species Act in 2016 and our objectives were to determine the most appropriate parameters and thresholds for monitoring and management action. Capture mark recapture (CMR) data from 2006 to 2012 were used to estimate population parameters and variances. We used stochastic population simulations and conditional classification trees to identify demographic rates for monitoring that would be most indicative of heighted extinction risk. We then identified thresholds that would be reliable predictors of population viability. Conditional classification trees indicated that annual apparent survival rates for adult females averaged over 5 years ([Formula: see text]) was the best predictor of population persistence. Specifically, population persistence was estimated to be ≥95% over 100 years when [Formula: see text], suggesting that this statistic can be used as threshold to trigger management intervention. Our evaluation produced monitoring protocols that reliably predicted population persistence and was cost-effective. We conclude that population projections and conditional classification trees can be valuable tools for identifying extinction thresholds used in monitoring programs.

Perception of Stand-on-ability: Do Geographical Slants Feel Steeper Than They Look?

Past research has shown that haptically perceived surface slant by foot is matched with visually perceived slant by a factor of 0.81. Slopes perceived visually appear shallower than when stood on without looking. We sought to identify the sources of this discrepancy by asking participants to judge whether they would be able to stand on an inclined ramp. In the first experiment, visual perception was compared to pedal perception in which participants took half a step with one foot onto an occluded ramp. Visual perception closely matched the actual maximal slope angle that one could stand on, whereas pedal perception underestimated it. Participants may have been less stable in the pedal condition while taking half a step onto the ramp. We controlled for this by having participants hold onto a sturdy tripod in the pedal condition (Experiment 2). This did not eliminate the difference between visual and haptic perception, but repeating the task while sitting on a chair did (Experiment 3). Beyond balance requirements, pedal perception may also be constrained by the limited range of motion at the ankle and knee joints while standing. Indeed, when we restricted range of motion by wearing an ankle brace pedal perception underestimated the affordance (Experiment 4). Implications for ecological theory were offered by discussing the notion of functional equivalence and the role of exploration in perception.