Ecological and social drivers of neighbor recognition and the dear enemy effect in a poison frog

Navigating social relationships frequently rests on the ability to recognize familiar individuals using phenotypic characteristics. Across diverse taxa, animals vary in their capacities for social recognition, but the ecological and social sources of selection for recognition are often unclear. In a comparative study of two closely related species of poison frogs, we identified a species difference in social recognition of territory neighbors and investigated potential sources of selection underlying this difference. In response to acoustic playbacks, male golden rocket frogs (Anomaloglossus beebei) recognized the calls of neighbors and displayed a “dear enemy effect” by responding less aggressively to neighbors’ calls than strangers’ calls. In contrast, male Kai rocket frogs (Anomaloglossus kaiei) were equally aggressive to the calls of neighbors and strangers. This species difference in behavior is associated with key differences in reproductive ecology and characteristics of territories. Golden rocket frogs defend reproductive resources in the form of bromeliads, which is expected to create a threat asymmetry between neighbors and strangers favoring decreased aggression to neighbors. In contrast, Kai rocket frogs do not defend reproductive resources. Further, compared with Kai rocket frog territories, golden rocket frog territories occur at higher densities and are defended for longer periods of time, creating a more complex social environment with more opportunities for repeated but unnecessary aggression between neighbors, which should favor the ability to recognize and exhibit less aggression toward neighbors. These results suggest that differences in reproductive ecology can drive changes in social structure that select for social recognition.

Ecological and social drivers of neighbor recognition and the dear enemy effect in a poison frog

ABSTRACTNavigating social relationships frequently rests on the ability to recognize familiar individuals using phenotypic characteristics. Across diverse taxa, animals vary in their capacities for social recognition but the ecological and social sources of selection for recognition are often unclear. In a comparative study of two closely related species of poison frogs, we identified a species difference in social recognition of territory neighbors and investigated potential sources of selection underlying this difference. In response to acoustic playbacks, male golden rocket frogs (Anomaloglossus beebei) recognized the calls of neighbors and displayed a “dear enemy effect” by responding less aggressively to neighbors’ calls than strangers’ calls. In contrast, male Kai rocket frogs (Anomaloglossus kaiei) were equally aggressive to the calls of neighbors and strangers. This species difference in behavior was associated with key differences in reproductive ecology and characteristics of territories. Golden rocket frogs defended reproductive resources in the form of bromeliads, which is expected to create a threat asymmetry between neighbors and strangers favoring decreased aggression to neighbors. In contrast, Kai rocket frogs did not defend reproductive resources. Further, compared with Kai rocket frog territories, golden rocket frog territories occurred at higher densities and were defended for longer periods of time, creating a more complex social environment with more opportunities for repeated but unnecessary aggression between neighbors, which should favor the ability to recognize and exhibit less aggression towards neighbors. These results suggest that differences in reproductive ecology can drive changes in social structure that select for social recognition.

Recognizing Check Magnetic Code Based on Peak-Valley Location and Amplitude

Magnetic code is widely used in check, securities, tax invoice, etc. However, the traditional recognizing and reading method of magnetic code is mostly based on correlation coefficient and it takes significant time and cost. After analyzing the characteristics of magnetic code signals in E-13B standard, this paper has proposed a new algorithm based on the peak-valley location and amplitude (PVLA) to simplify the calculation and system design. Firstly, the magnetic code signal is separated into magnetic ink character signals by the thresholds of peak and valley. Secondly, the features of the peak-valley location (PVL) and peak-valley amplitude(PVA) of each magnetic ink character signal are extracted and normalized, then the nearest neighbor recognition algorithm based on the vectors of peak-valley location and amplitude is utilized to recognize the magnetic code. The recognition results and statistical parameters from a large number of experiments show that the new method has higher recognition rate and better robustness. In addition, the new algorithm only involves additions and subtractions, so it has a lower computation cost.

Recognizing Check Magnetic Code Based on Peak-Valley Code and Distance

The check is a popular form for the non-cash payment and accounts for more than 50% of the non-cash transactions. Magnetic ink character recognition system can recognize the check magnetic code automatically and get the information of the bank and account. In magnetic ink character recognition system, the recognizing algorithm is mostly based on correlation coefficient. The computational cost of this algorithm is very high. This paper has proposed a new algorithm based on the peak-valley code and peak-valley distance after analyzing the characteristics of magnetic code signals in E-13B standards to simplify the calculations and system design. Firstly, the magnetic code signal is normalized and separated into magnetic character signals by the thresholds of peak and valley. Secondly, the features of the peak-valley code and peak-valley distance of each magnetic character signal are extracted, then the recognition based on peak-valley code and the nearest neighbor recognition algorithm based on peak-valley distance are utilized to recognize the magnetic code. The recognition results and statistical parameters from a large number of experiments show that the new method has high recognition rate, good robustness and low computational cost.

Familiarity and mating behavior in the subterranean rodent Ctenomys talarum (tuco-tuco)

Biological odors that convey cues regarding individual identity are known to alter mating behavior in some rodents. Deposition of chemical signals by males on the substrate could give females information about their neighbors’ identity and allow familiarization with their odors. This study tested whether familiarization of females with conspecific male odors affects mating behavior in Ctenomys talarum Thomas, 1898, facilitating mating as a consequence of a decrease in aggressive behavior and an increase in sexual behavior. Tuco-tucos are solitary subterranean rodents that occupy and defend adjacent burrows. Both sexes usually scent-mark burrow openings, providing odor signals to neighbors during their aboveground patrolling and foraging activities. Hence, familiarity by odor cues may represent an important mechanism that mediates neighbor recognition and probably mate selection. In this study, familiarity was established by housing females with male odors for 8 days. In C. talarum, individual recognition by olfactory cues may reduce mating costs when pairing with neighbors, since females showed low aggression towards familiar males and copulations were not repeated in consecutive days. Females that were not exposed to male odors were more aggressive, but surprisingly these pairs copulated repeatedly.