Harris Hawks Optimization with Multi-Strategy Search and Application

The probability of the basic HHO algorithm in choosing different search methods is symmetric: about 0.5 in the interval from 0 to 1. The optimal solution from the previous iteration of the algorithm affects the current solution, the search for prey in a linear way led to a single search result, and the overall number of updates of the optimal position was low. These factors limit Harris Hawks optimization algorithm. For example, an ease of falling into a local optimum and the efficiency of convergence is low. Inspired by the prey hunting behavior of Harris’s hawk, a multi-strategy search Harris Hawks optimization algorithm is proposed, and the least squares support vector machine (LSSVM) optimized by the proposed algorithm was used to model the reactive power output of the synchronous condenser. Firstly, we select the best Gauss chaotic mapping method from seven commonly used chaotic mapping population initialization methods to improve the accuracy. Secondly, the optimal neighborhood perturbation mechanism is introduced to avoid premature maturity of the algorithm. Simultaneously, the adaptive weight and variable spiral search strategy are designed to simulate the prey hunting behavior of Harris hawk to improve the convergence speed of the improved algorithm and enhance the global search ability of the improved algorithm. A numerical experiment is tested with the classical 23 test functions and the CEC2017 test function set. The results show that the proposed algorithm outperforms the Harris Hawks optimization algorithm and other intelligent optimization algorithms in terms of convergence speed, solution accuracy and robustness, and the model of synchronous condenser reactive power output established by the improved algorithm optimized LSSVM has good accuracy and generalization ability.

Hunter Concerns and Intention to Hunt in Forested Areas Affected by Wildlife Disease

Deer hunting is a major forest-based recreation activity in the US South. However, the recent discovery of chronic wasting disease (CWD) threatens deer hunting in the region. Stakeholders are interested in understanding how hunters perceive the risk and change their hunting behavior. This study found a significant change in hunters’ concerns after the first deer season since the discovery of CWD in Tennessee, USA. Results also showed that hunters’ short- and long-term intentions to hunt deer in the region were positively related to previous experience of hunting in CWD-affected areas, beliefs in the effectiveness of herd reduction to control CWD, concerns regarding potential decline in deer quality and changes in hunting regulations due to CWD, and trust in wildlife agency action. Hunters who hunt on public land and were concerned with deer and human health risk were less likely to hunt in the CWD region. These results are useful in understanding hunter behavior in response to wildlife disease and identifying variables that may help project immediate as well as long-term change in hunting demand in affected regions. Study Implications As two-thirds of forestlands in the USA are under private ownership and public hunting lands are limited or crowded in many regions, deer hunting occurs mostly on private lands. Managers of private and public forestlands that provide recreation access for hunting benefit from a better understanding of how wildlife diseases affect user perception and demand for deer hunting on their lands. One such disease issue that has threatened the hunting industry in the nation is chronic wasting disease in white-tailed deer. Results from this study inform on how hunters perceive the risk of disease, how their relative tolerance changes over time, and what factors determine their intention to hunt in forests with diseased deer. These findings are useful in understanding hunter’s behavior in response to wildlife disease in forest lands and highlight variables that may determine hunting demand in affected regions both in the short- and long-term.

A biomechanical model to assess the injury risk of leopards (Panthera pardus) hunting by free falling from trees

Leopards have been observed to ambush prey by jumping down on it from trees. There are both anecdotal reports and video recordings of this hunting behavior. Here we conducted a biomechanical analysis of this technique to assess the degree of risk for the predator in such cases. We concluded that the risk of suffering severe injuries seems to be too high for this technique to be a usual way of predation on horned mammals such as male impalas. Our results can be useful in discussing proposed paleobiological hunting scenarios and living predators’ strategies of managing risks.

Periaqueductal gray neurons encode the sequential motor program in hunting behavior of mice

Sequential encoding of motor programs is essential for behavior generation. However, whether it is critical for instinctive behavior is still largely unknown. Mouse hunting behavior typically contains a sequential motor program, including the prey search, chase, attack, and consumption. Here, we reveal that the neuronal activity in the lateral periaqueductal gray (LPAG) follows a sequential pattern and is time-locked to different hunting actions. Optrode recordings and photoinhibition demonstrate that LPAGVgat neurons are required for the prey detection, chase and attack, while LPAGVglut2 neurons are selectively required for the attack. Ablation of inputs that could trigger hunting, including the central amygdala, the lateral hypothalamus, and the zona incerta, interrupts the activity sequence pattern and substantially impairs hunting actions. Therefore, our findings reveal that periaqueductal gray neuronal ensembles encode the sequential hunting motor program, which might provide a framework for decoding complex instinctive behaviors.

Flight rapidly modulates body temperature in freely behaving bats

Background Bats are remarkable in their dynamic control over body temperature, showing both hypothermia with torpor and hyperthermia during flight. Despite considerable research in understanding bats’ thermoregulation mechanisms, knowledge on the relationship between flight and body temperature in bats remains limited, possibly due to technological restraints. Results We used onboard dataloggers including a temperature sensor and an inertial sensor (accelerometers) and continuously recorded the flight behavior and skin temperature (Tsk) subcutaneously of a perch-hunting bat, Hipposideros armiger, both in the laboratory and in the field. We provide evidence that flight increases the body temperature of bats. The median of the maximum increase in the Tsk caused by flight bouts was 3.4 °C (between 1.9 and 5.3 °C for different individuals) in the laboratory. The maximum Tsk for the bats was narrowly centered around 40 °C (between 38.5 and 40.9 °C). Moreover, we found that the faster the Tsk rises, the greater the maximum increase in Tsk. Interestingly, bats can slow down the Tsk rises with intermittent fights, during which they perch after brief flight bouts to allow the body temperature to drop rapidly. Similar data were collected from field recordings in free-ranging bats. Conclusions We suggest that perch-hunting behavior observed in approximately 200 species of bats that results in intermittent flights may function as a thermoregulatory strategy, in addition to optimizing energy efficiency as demonstrated by previous studies.

Fractional Order Filter Discretization With Marine Predators Algorithm

In this study, discrete time models of continuous time fractional order filters are obtained by using the Marine Predators Algorithm (MPA). Marine Predators optimization algorithm is a population-based heuristic method. This method is inspired by the hunting behavior of marine predators. The algorithm works on three basic phases. These phases occur according to the difference or equality of the velocity of the prey and the predator. As it is known, uniform distribution is generally used in stochastic based optimization algorithms. However, in the MPA method, Brownian and Levy distributions are also used as well as uniform distribution. First, continuous time frequency responses of fractional order filters are generated. Then, fourth order discrete time filters are designed that can give similar responses with generated continues time filter frequency responses. Ten parameters were optimized for the design of fourth order discrete time filters numerator and denominator. The Marine Predators method’s results are compared with the results of the Fractional order Darwinian Particle Swarm Optimization (FODPSO) algorithm, from which discrete time filters are obtained for two fractional order continuous time filter models. In this way, it has been shown comparatively that the Marine Predators Algorithm can be used in real engineering problems and can do filter discretization better.

Food for everyone: differential feeding habits of cryptic bat species inferred from DNA metabarcoding

Ecological theory postulates that the niche of co-occurring species must differ along some ecological dimensions in order to allow their stable coexistence. Yet, many biological systems challenge this competitive exclusion principle. For instance, insectivorous bats from the Northern Hemisphere typically form local assemblages of multiple species sharing highly similar functional traits and pertaining to identical feeding guilds. Although their trophic niche can be accessed with unprecedented details using genetic identification of prey, the underlying mechanisms of resource partitioning remain vastly unexplored. Here, we studied the differential diet of three phenotypically and phylogenetically closely-related bat species of the genus Plecotus in an area of sympatry and throughout their entire breeding season (April-October) using DNA metabarcoding. Even at such a small geographic scale, we identified strong seasonal and spatial variation of their trophic niche at both intra- and inter-specific levels. Indeed, while the different bats fed on a distinct array of prey during spring, they showed higher niche overlap during summer and fall, when all three bat species switched their hunting behavior to feed on few temporarily abundant moths. Furthermore, by considering the ecological traits of prey species, we inferred from the menu of each bat species that feeding grounds and hunting techniques differed suggesting that niche partitioning was primarily habitat-driven. As predicted by their phylogenetic relationships, the two most-closely related bat species exhibited the most distinct foraging habitat preferences, while the third, more distantly-related species was more generalist. These results highlight the need of extensive samples to fully understand species coexistence.

Quantifying Southern Pacific Rattlesnake (Crotalus oreganus helleri) Hunting Behavior through Community Science

It is increasingly important to study animal behaviors as these are the first responses organisms mount against environmental changes. Rattlesnakes, in particular, are threatened by habitat loss and human activity, and require costly tracking by researchers to quantify the behaviors of wild individuals. Here, we show how photo-vouchered observations submitted by community members can be used to study cryptic predators like rattlesnakes. We utilized two platforms, iNaturalist and HerpMapper, to study the hunting behaviors of wild Southern Pacific Rattlesnakes. From 220 observation photos, we quantified the direction of the hunting coil (i.e., “handedness”), microhabitat use, timing of observations, and age of the snake. With these data, we looked at whether snakes exhibited an ontogenetic shift in behaviors. We found no age differences in coil direction. However, there was a difference in the microhabitats used by juveniles and adults while hunting. We also found that juveniles were most commonly observed during the spring, while adults were more consistently observed throughout the year. Overall, our study shows the potential of using community science to study the behaviors of cryptic predators.