Birds of a feather may flock together, but that doesn't mean they share a genetic background. Though birds were first classified into groups primarily based on appearance, research forthcoming in The Auk: Ornithological Advances by Brett Benz of the American Museum of Natural History, Mark Robbins of the University of Kansas Biodiversity Institute, and Kevin Zimmer of the Los Angeles County Museum of Natural History demonstrates that this method isn't necessarily accurate: in a group of very similar-looking South American woodpecker species, genetic analysis has now shown one to be only a distant cousin of the others, in an intriguing case of visual mimicry. By copying the appearance of larger, socially dominant woodpecker species, it reduces the aggression and competitive interference that it receives from them and has more access to food resources as a result.
The most familiar type of mimicry typically involves warning or "aposematic" coloration, in which a harmless species apes the color patterns of a dangerous or unappealing one to avoid predators; a famous instance is the Viceroy butterfly, which shares the striking colors of the more noxious Monarch. By contrast, the Helmeted Woodpecker (Dryocopus galeatus) represents an example of a different and less well understood form of mimicry, known as interspecific social dominance mimicry or ISDM.
The shy and little-known species shares the red crest, black back, and barred underside of two larger woodpeckers Dryocopus lineatus and Campephilus robustus, all of which occupy the same habitat and share similar food preferences.
The Helmeted Woodpecker's similarity in appearance makes the larger, more dominant woodpecker species less likely to attack it, due to the costs of aggression between members of the same species. Though they had been previously classified in Dryocopus due to the remarkable similarities in their appearance, genetic analysis by Benz and his colleagues suggests that the Helmeted Woodpecker is actually not closely related to other Dryocopus woodpeckers at all and belongs in a different genus, Celeus. An independent group of researchers using the same data recently reported similar results in a paper published in the Journal of Ornithology.
"Co-author Mark Robbins and I had just finished a phylogenetic study examining species limits and vocalizations in Celeus woodpeckers when Mark, who was attending a meeting in Brazil, had the opportunity to observe a Helmeted Woodpecker at Intervales State Park," according to Benz.
"Upon hearing the bird vocalize, Mark was stunned that its call sounded nothing like Neotropical Dryocopus, and immediately knew we needed to examine its taxonomic status in the context of our recent Celeus study given that the Helmeted Woodpecker calls were most similar to several other Celeus species.
Upon returning from Brazil, Mark consulted with co-author Kevin Zimmer, who had independently arrived at the same conclusions about the Helmeted Woodpecker belonging with Celeus, based on his behavioral observations spanning 20 years of fieldwork in Brazil." As Benz puts it, "The Helmeted Woodpecker is basically a typical Celeus in Dryocopus clothing."
"After several decades working on the discovery of the avian Tree of Life, it is still amazing what we are discovering! Reconstructing the phylogeny of these woodpeckers has corrected a century-old classification mistake, but more interestingly, it has revealed an unexpected new example of avian mimicry," adds Richard Prum of Yale University, one of the originators of the ISDM hypothesis.
"It has only recently been appreciated that small species may benefit from deceptively mimicking larger species to protect themselves from aggressive attack. This is similar to how a 12-year-old kid walking home from school will look and act tough to try to prevent himself from being harassed by older, bigger kids."
Relatively little is known about the ecology and natural history of the Helmeted Woodpecker, which is found in Brazil, Paraguay, and Argentina, but it has experienced dramatic population declines and vanished from much of its former range due to deforestation. Hopefully, this new discovery about its evolutionary relationships and visual deception may increase interest in the species, as it provides an opportunity for scientists to further test predictions associated with ISDM. Ultimately, bringing the Helmeted Woodpecker's sneaky strategy into the light may be what saves it from oblivion.
"Phylogenetic relationships of the Helmeted Woodpecker (Dryocopus galeatus): A case of interspecific mimicry?" will be published on September 30, 2015, and will be available at http://www.
About the journal: The Auk: Ornithological Advances is a peer-reviewed, international journal of ornithology that began in 1884 as the official publication of the American Ornithologists' Union. In 2009, The Auk was honored as one of the 100 most influential journals of biology and medicine over the past 100 years.
Rebecca Heisman | EurekAlert!
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy