By Laboratory of Behavioral Ecology and Evolution at Seoul National University February 5, 2024A collaborative research study presents the flush-pursue hypothesis to explain the evolutionary origins of wings and tails in birds, tracing back to feathered dinosaurs. The hypothesis, supported by robotic simulations and biological research studies, recommends that proto-wings and tail feathers were utilized to eliminate prey, boosting foraging effectiveness. This discovery adds a new dimension to our understanding of dinosaur habits and the evolutionary advancement of bird plumage. Credit: SciTechDaily.comDinosaurs might have used feathers on tails and forelimbs to flush and pursue their prey– a brand-new hypothesis integrates neurobiology.what, morphology and behavior are the origins of wings and tails in birds? This is among the crucial questions in the advancement of animals.It has long been accepted that their evolution began in feathered dinosaurs. Some of these dinosaurs had plumes on their tails and little wing-like feathers on their forelimbs (arms). These little wing-like structures called proto-wings are made up of special feathers called pennaceous feathers– the stiff plumes found in the wings and tails of birds. The ancient form of these plumes first emerged in dinosaurs throughout the Jurassic Period, and these dinosaurs, called Pennaraptorans, had proto-wings made of pennaceous feathers.However, it has actually been known that these proto-wings were too little for powered flight. Because we can not time-travel to observe their habits, what dinosaurs did and how they behaved stays unanswered.Various functions of proto-wings and tail feathers in the forefathers of birds have been considered considering that John Harold Ostrom proposed the first idea 50 years ago that proto-wings were used to tear down insect prey by small predatory dinosaurs residing on the ground and following their victim. How the small proto-wings and feathered tails helped the dinosaurian ancestors of birds in their lives has actually not been resolved.The Flush-Pursue HypothesisA brand-new clinical partnership involving a team of field-biologists and integrative ecologists (Piotr G. Jablonski, Sang-im Lee, Jinseok Park, Sang Yun Bang, and Jungmoon Ha), paleontologists (Yuong-Nam Lee and Minyoung Son), and roboticists (Hyungpil Moon and Jeongyeol Park), has proposed a brand-new idea: the flush-pursue hypothesis. The name of the hypothesis offers a hint to its content. Some birds employ a flush-pursue foraging technique, utilizing wings and/or tail displays to aesthetically eliminate hiding victim and pursue the flushed victim (e.g., Northern Mockingbird, © Linzys Vids). The hypothesis suggests that little dinosaurs with proto-wings use a comparable strategy.The hypothesis is rooted in years of in-depth field-ornithological research studies on a number of types of insectivorous birds performed by a co-author of the existing research study, Piotr Jablonski and partners, as well as by Ron Mumme and collaborators [The Painted redstart, the Slate-throated whitestart, the Spectacled Whitestart, and the Hooded warbler] Studies on these birds have revealed that showing contrasting plumage (often with black-and-white spots) on the wings and tails activates the escapes of their victim and hence increases bird foraging performance since the getting away prey is pursued and caught by the birds. Neurobiology behind this relationship was likewise studied. It has actually been proposed by Piotr Jablonski and Nicholas Strausfeld, a leading expert in arthropod nerve systems, that special nerve cells in bugs are triggered by simple homes of flush screens by insectivorous flush-pursuing birds.Piotr Jablonski with partners first discussed the flush-pursue hypothesis at the 2005 Gordon Research Conference on “Neuroethology: Behavior, Evolution and Neurobiology” chaired by N. Strausfeld. Because then, the idea was established and presented at 2018 International Ornithological Congress, and at the Society for Integrative Biology Annual Meeting 2023.” After performing extensive field studies on birds and diving into the assessment of nerve cells in their victim, I have unsuccessfully tried for years to persuade funding companies and skeptical grant reviewers in Poland, USA and Korea to support studies evaluating this hypothesis concerning early pennaraptoran dinosaurs,” comments field-ornithologist Piotr Jablonski.” Eventually, the funding provided by Seoul National University permitted us to initiate our collective research and complete it with some extra financing. After dealing with several refusals from the Editorial Boards of 11 journals, each rejecting approval for a basic peer-review procedure of the paper, we lastly found a journal that allowed our outcomes to be peer-reviewed, which led to its publication,” includes Piotr Jablonski.Figure 1. (A) Reconstructed Caudipteryx © Christophe Hendrickx. Used under the regards to the Creative Commons license (CC BY-SA 3.0). (B) Robopteryx, mimicing the morphology of Caudipteryx, positioned in front of a grasshopper in the field (marked by a red arrow). (C) Grasshopper tested in the experiments. Credit: Caudipteryx image (A) by © Christophe Hendrickx. Utilized under the terms of the Creative Commons license (CC BY-SA 3.0). Picture (B) by P.G. Jablonski, Photo (C) by Jinseok Park.Research Implications and findings” We have actually selected Caudipteryx as a representative of early Pennaraptoran dinosaurs,” describes paleontologist Yuong-Nam Lee, a specialist in dinosaur fossils and a co-author of the study. The robotics group led by Hyungpil Moon, a professional in robotics, has constructed a robot called Robopteryx, that resembles the morphology of Caudipteryx (Fig. 1A). At the same time, the biology team has actually carried out a detailed review of the variety of wing and tail screens utilized by existing flush-pursuing birds to trigger leaves in their victim visually. The scientists assembled links to clips showing this diversity amongst birds (see supplementary materials in their paper, and some other links to examples provided listed below). Geared up with 9 motors, Robopteryx was configured to mimic the movements of forelimbs and tail of ground-foraging flush-pursuing birds, such as the greater roadrunner ( © Kat Avila) or the rufous-tailed scrub robin ( © Nature Never Die), within the physiological constraints determined from paleontological literature by Minyoung Son, an expert in the anatomy of Cretaceous dinosaurs.This film shows three different methods which dinosaurs with proto-wings might have flushed their victim by visual display screens to consequently pursue them. The insect jumps/flies away in reaction to expanding Robotperyxs forelimbs with proto-wings. Second, the insect jumps/flies away in action to folding of forelimbs with protowings. Third, the insect leaves in response to upward movements of the tail.Jinseok Park (the first author of the paper and a field ornithologist concentrating on bird diet and foraging), with a team of field biologists, conducted tests with Robopteryx to observe behavioral reactions of wild insects (Fig. 1B, C), which come from the ancient order Orthoptera likely to co-occur with pennaraptoran dinosaurs. The outcomes revealed that grasshoppers got away more regularly when proto-wings existed on the forelimbs, compared to screens without proto-wings. Furthermore, insects got away more typically when the proto-wings had white spots, compared to when they were plain black. Grasshoppers left more frequently when tail feathers were present, particularly when the area of tail feathers was large.Robopteryx stuns insects to run away in response to visual stimulation from the folding and dispersing of forelimbs geared up with proto-wings, and in response to tail movements. The video reveals the robot movements decreased 12 times.Since the responses of basic neural circuits included in escapes in insect prey are vital for comprehending the evolution of flush-pursuing method in birds, the researchers chose to compare the reactions of nerve cells of grasshoppers to the hypothetical displays by the dinosaurs.” I produced computer system animations (examples in the extra materials of the paper) imitating the hypothetical display screens by Caudipteryx and provided them to grasshoppers in the laboratory,” explains Jinseok Park. “I used quickly offered affordable devices to tape actions of nerve cells,” Jinseok adds. The researchers discovered that the reactions of nerve cells, especially peak firing rates, were greater in response to the animations with proto-wings than those without.Based on the results, the researchers argue that dinosaurs prey would have been most likely to run away when proto‑wings made of plumes were present, particularly near completion of the forelimbs and with contrasting patterns, and when the tail feathers, specifically of a big area, were utilized throughout theoretical flush‑displays.” We propose that using plumage to flush victim might increase the frequency of chases getting away prey, hence amplifying the value of proto-wings and tails in navigating for successful pursuit. This could cause the development of bigger and stiffer feathers as these would make it possible for more successful pursuits and more pronounced visual flush-displays.” sums up Sang-im Lee, the integrative ecologist member of the research team, who earlier studied the role of bird alula in aerial maneuvers by flying birds.For more on this research, see Unveiling the Prehistoric Scare Tactics of Feathered Dinosaurs.Reference: “Escape behaviors in victim and the advancement of pennaceous plumage in dinosaurs” 25 January 2024, Scientific Reports.DOI: 10.1038/ s41598-023-50225-x.
Credit: SciTechDaily.comDinosaurs might have used feathers on forelimbs and tails to flush and pursue their prey– a brand-new hypothesis incorporates neurobiology.what, behavior and morphology are the origins of wings and tails in birds? The ancient type of these feathers initially emerged in dinosaurs during the Jurassic Period, and these dinosaurs, called Pennaraptorans, had actually proto-wings made of pennaceous feathers.However, it has actually been known that these proto-wings were too small for powered flight. Because we can not time-travel to observe their behavior, what dinosaurs did and how they behaved remains unanswered.Various functions of proto-wings and tail plumes in the forefathers of birds have actually been considered since John Harold Ostrom proposed the very first concept 50 years ago that proto-wings were utilized to knock down insect victim by small predatory dinosaurs living on the ground and following their prey. Grasshoppers escaped more regularly when tail feathers were present, particularly when the location of tail feathers was large.Robopteryx surprises insects to flee in reaction to visual stimulation from the folding and spreading of forelimbs equipped with proto-wings, and in response to tail motions. The scientists found that the reactions of neurons, particularly peak firing rates, were greater in action to the animations with proto-wings than those without.Based on the outcomes, the scientists argue that dinosaurs victim would have been more likely to run away when proto‑wings made of feathers were present, especially near the end of the forelimbs and with contrasting patterns, and when the tail plumes, particularly of a big location, were used during theoretical flush‑displays.