View source for Biology:Intraguild predation

{{short description|Killing and sometimes eating of potential competitors}}
[[File:Wolfkilledcoyote.jpg|300px|thumb|Rolf Peterson investigating the carcass of a coyote killed by a wolf in Yellowstone National Park, January 1996]]
'''Intraguild predation''', or '''IGP''', is the killing and sometimes eating of a potential competitor of a different species.<ref name="ECOLOGY AND EVOLUTION OF IGP">{{cite web|url=http://people.biology.ufl.edu/rdholt/holtpublications/019.PDF|title=''THE ECOLOGY AND EVOLUTION OF INTRAGUILD PREDATION: Potential Competitors That Eat Each Other''|author=Gary A. Polis|author2=Christopher A. Myers|publisher=Department of General Biology, Vanderbilt University|access-date=2014-02-18|url-status=dead|archive-url=https://web.archive.org/web/20140308021334/http://people.biology.ufl.edu/rdholt/holtpublications/019.pdf|archive-date=2014-03-08}}</ref><ref name="widespread interaction">{{cite web |url=http://www.bio.puc.cl/caseb/pdf/prog2/arim_&_marquet_2004.pdf |title=''Intraguild predation: a widespread interaction related to species biology'' |author=Matıas Arim |author2=Pablo A. Marquet |name-list-style=amp |publisher=Bio.puv.cl |access-date=2014-02-18 |archive-url=https://web.archive.org/web/20140113021826/http://www.bio.puc.cl/caseb/pdf/prog2/arim_%26_marquet_2004.pdf |archive-date=2014-01-13 |url-status=dead }}</ref><ref name="theory">{{cite web|url=http://people.biology.ufl.edu/rdholt/holtpublications/073.PDF|title=''A Theoretical Framework for Intraguild Predation''|author=Robert D. Holt|author2=Gary A. Polis|publisher=People.biology.ufl.edu|access-date=2014-02-18|url-status=dead|archive-url=https://web.archive.org/web/20140327031941/http://people.biology.ufl.edu/rdholt/holtpublications/073.PDF|archive-date=2014-03-27}}</ref>  This interaction represents a combination of [[Earth:Predation|predation]] and [[Biology:Competition|competition]], because both species rely on the same prey resources and also benefit from preying upon one another.  Intraguild predation is common in nature and can be asymmetrical, in which one species feeds upon the other, or symmetrical, in which both species prey upon each other.<ref name="ECOLOGY AND EVOLUTION OF IGP"/>  Because the dominant intraguild predator gains the dual benefits of feeding and eliminating a potential competitor, IGP interactions can have considerable effects on the structure of ecological communities.

==Types==
Intraguild predation can be classified as asymmetrical or symmetrical.  In asymmetrical interactions one species consistently preys upon the other, while in symmetrical interactions both species prey equally upon each other.<ref name="ECOLOGY AND EVOLUTION OF IGP"/>  Intraguild predation can also be age structured, in which case the vulnerability of a species to predation is dependent on age and size, so only juveniles or smaller individuals of one of the predators are fed upon by the other.<ref name="ECOLOGY AND EVOLUTION OF IGP"/>  A wide variety of predatory relationships are possible depending on the symmetry of the interaction and the importance of age structure.  IGP interactions can range from predators incidentally eating [[Earth:Parasitism|parasites]] attached to their prey to direct predation between two [[Biology:Apex predator|apex predator]]s.<ref name="ECOLOGY AND EVOLUTION OF IGP"/>

==Ecology of intraguild predation==
Intraguild predation is common in nature and widespread across communities and ecosystems.<ref name="widespread interaction"/>  Intraguild predators must share at least one prey species and usually occupy the same trophic [[Earth:Guild (ecology)|guild]], and the degree of IGP depends on factors such as the size, growth, and population density of the predators, as well as the population density and behavior of their shared prey.<ref name="ECOLOGY AND EVOLUTION OF IGP"/>  When creating theoretical models for intraguild predation, the competing species are classified as the "top predator" or the "intermediate predator," (the species more likely to be preyed upon).  In theory, intraguild predation is most stable if the top predator benefits strongly from killing off or feeding on the intermediate predator, and if the intermediate predator is a better competitor for the shared prey resource.<ref name="theory"/>

The ecological effects of intraguild predation include direct effects on the survival and distribution of the competing predators, as well as indirect effects on the abundance and distribution of prey species and other species within the community.  Because they are so common, IGP interactions are important in structuring communities.<ref name="widespread interaction"/>  Intraguild predation may actually benefit the shared prey species by lowering overall predation pressure, particularly if the intermediate predator consumes more of the shared prey.<ref name="dynamics">{{cite journal|title=Intraguild Predation: the dynamics of complex trophic interactions |author=Gary A. Polis |author2=Robert D. Holt |name-list-style=amp|doi=10.1016/0169-5347(92)90208-s |volume=7 |issue=5 |year=1992 |journal=Trends in Ecology & Evolution |pages=151–154|pmid=21235990 }}</ref>  Intraguild predation can also dampen the effects of trophic cascades by providing redundancy in predation: if one predator is removed from the ecosystem, the other is still consuming the same prey species.<ref name="trophic cascades1">{{cite journal|title=Intraguild Predation, Invertebrate Predators, and Trophic Cascades in Lake Food Webs |author=Deborah R.Hart|doi=10.1006/jtbi.2002.3053|volume=218|journal=Journal of Theoretical Biology|pages=111–128|year=2002|issue=1 |pmid=12297074 |bibcode=2002JThBi.218..111H }}</ref><ref name="trophic cascades2">{{cite journal|title=Predator diversity and the functioning of ecosystems: the role of intraguild predation in dampening trophic cascades |author=Deborah L. Finke |author2=Robert F. Denno |name-list-style=amp|doi=10.1111/j.1461-0248.2005.00832.x|volume=8|issue=12 |journal=Ecology Letters|pages=1299–1306|year=2005 |doi-access=free}}</ref> Asymmetrical IGP can be a particularly strong influence on habitat selection.  Often, intermediate predators will avoid otherwise optimal habitat because of the presence of the top predator.<ref name="habitat selection">{{cite journal|title=Habitat Selection by Predators and Prey in Communities with Asymmetrical Intraguild Predation |journal=Oikos |author=Michael R. Heithuas |jstor=3547171 | volume=92 |issue=3 |pages=542–554|year=2001 |doi=10.1034/j.1600-0706.2001.920315.x }}</ref> Behavioral changes in intermediate predator distribution due to increased risk of predation can influence community structure more than direct mortality caused by the top predators.<ref name="dugongs">{{cite journal|title=''Behaviorally Mediated Indirect Interactions in Marine Communities and Their Conservation Implications'' |author=Lawrence M. Dill |author2=Michael R. Heithaus |author3=Carl J. Walters|jstor=3107923 | volume=84|issue=5 |pages=1151–1157|doi=10.1890/0012-9658(2003)084[1151:bmiiim]2.0.co;2|journal=Ecology|year=2003 }}</ref>

==Examples==

===Terrestrial===
Intraguild predation is well documented in terrestrial [[Biology:Arthropod|arthropod]]s such as [[Biology:Insect|insect]]s and [[Biology:Arachnid|arachnid]]s.<ref name="lacewing"/><ref name="centipedes"/>  [[Biology:Hemiptera|Hemiptera]]n insects and larval [[Biology:Neuroptera|lacewings]] both prey upon [[Biology:Aphid|aphid]]s, but the competing predators can cause high enough mortality among the lacewings to effectively relieve predation upon the aphids.<ref name="lacewing">{{cite journal|title=''Influence of intraguild predation among generalist insect predators on the suppression of an herbivore population''|author= Jay A. Rosenheim|author2= Lawrence R. Wilhoit|author3= Christine A. Armer|name-list-style= amp|doi=10.1007/BF00317517|pmid= 28313662|bibcode=1993Oecol..96..439R|volume=96|issue= 3|year=1993|journal=Oecologia|pages=439–449|s2cid= 21465593}}</ref> Several species of centipede are considered to be intraguild predators.<ref name="centipedes">{{cite journal|author=Cari-Ann Hickerson|url=https://johncarroll.academia.edu/CariAnnHickerson/Papers/121273/Edge_effects_and_intraguild_predation_in_native_and_introduced_centipedes_evidence_from_the_field_and_from_laboratory_microcosms |title=''Edge effects and intraguild predation in native and introduced centipedes: evidence from the field and from laboratory microcosms''|publisher=Johncarroll.academia.edu |date=1970-01-01 |access-date=2014-02-18}}</ref>

Among the most dramatic examples of intraguild predation are those between large mammalian [[Biology:Carnivora|carnivores]].  Large [[Biology:Canidae|canines]] and [[Biology:Felidae|felines]] are the mammal groups most often involved in IGP, with larger species such as [[Biology:Lion|lion]]s and gray wolves preying upon smaller species such as [[Biology:Fox|fox]]es and [[Biology:Cheetah|cheetah]].<ref name="mammals">{{cite web |title=''Interspecific Killing among Mammalian Carnivores'' |author=F. Palomares |author2=T.M. Claro |name-list-style=amp |url=http://www.ebd.csic.es/carnivoros/publica/pdf/Palomares_Am_Nat_99.pdf |publisher=Ebd.csic.es |access-date=2014-02-18 |url-status=dead |archive-url=https://web.archive.org/web/20120321053046/http://www.ebd.csic.es/carnivoros/publica/pdf/Palomares_Am_Nat_99.pdf |archive-date=2012-03-21 }}</ref>  In North America, [[Biology:Coyote|coyote]]s function as intraguild predators of [[Biology:Gray fox|gray fox]]es and [[Biology:Bobcat|bobcat]]s, and may exert a strong influence over the population and distribution of gray foxes.<ref name="coyotes">{{cite journal|title=''Competition and intraguild predation among three sympatric carnivores'' |author=Jose M. Fedriani |author2=Todd K. Fuller |author3=Raymond M. Sauvajot |author4=Eric C. York |name-list-style=amp |doi=10.1007/s004420000448 |volume=125 |issue=2 |year=2000 |journal=Oecologia |pages=258–270 |pmid=24595837|hdl=10261/54628 |hdl-access=free |bibcode=2000Oecol.125..258F |s2cid=24289407 }}</ref>  However, in areas where wolves have been reintroduced, coyotes become an intermediate predator and experience increased mortality and a more restricted range.<ref name="wolves">{{cite web|title=''Coyote foraging ecology and vigilance in response to gray wolf reintroduction in Yellowstone National Park''|author=T. Adam Switalski|url=http://article.pubs.nrc-cnrc.gc.ca/ppv/RPViewDoc?_handler_=HandleInitialGet&journal=cjz&volume=81&calyLang=eng&articleFile=z03-080.pdf|publisher=Article.pubs.nrc-cnrc.gc.ca|access-date=2014-02-18|url-status=dead|archive-url=https://web.archive.org/web/20040814160329/http://article.pubs.nrc-cnrc.gc.ca/ppv/RPViewDoc?_handler_=HandleInitialGet|archive-date=2004-08-14}}</ref>

===Aquatic and marine===
Intraguild predation is also important in aquatic and marine ecosystems.  As top predators in most marine environments, [[Biology:Shark|shark]]s show strong IGP interactions, both between species of sharks and with other top predators like toothed whales.  In tropical areas where multiple species of sharks may have significantly overlapping diets, the risk of injury or predation can determine the local range and available prey resources for different species.<ref name="Hawaii">{{cite web|title=''Distribution and diet of four species of carcharhinid shark in the Hawaiian Islands: evidence for resource partitioning and competitive exclusion''|author=Yannis P. Papastamatiou|author2=Bradley M. Wetherbee|author3=Christopher G. Lowe|author4=Gerald L. Crow|name-list-style=amp|url=http://www.uri.edu/cels/bio/wetherbee/pubs_files/HawaiiFourSpecies.pdf|publisher=Uri.edu|access-date=2014-02-18|url-status=dead|archive-url=https://web.archive.org/web/20121005065446/http://www.uri.edu/cels/bio/wetherbee/pubs_files/HawaiiFourSpecies.pdf|archive-date=2012-10-05}}</ref>  Large pelagic species such as [[Biology:Blue shark|blue]] and [[Biology:Shortfin mako shark|mako]] sharks are rarely observed feeding in the same areas as [[Biology:Great white shark|great white shark]]s, and the presence of white sharks will prevent other species from scavenging on whale carcasses.<ref name="great white">{{cite web|title=''OBSERVATIONS ON LARGE WHITE SHARKS, CARCHARODON CARCHARIAS, OFF LONG ISLAND, NEW YORK'' |author=Harold L. Pratt Jr. |author2=John. G. Casey |author3=Robert B. Conklin |name-list-style=amp |url=http://fishbull.noaa.gov/80-1/pratt.pdf|publisher=Fishbull,noaa.gov|access-date=2014-02-18}}</ref>  Intraguild predation between sharks and toothed whales usually involves large sharks preying upon [[Biology:Dolphin|dolphin]]s and [[Biology:Porpoise|porpoise]]s while also competing with them for fish prey, but [[Biology:Orca|orca]]s reverse this trend by preying upon large sharks while competing for large fish and [[Biology:Pinniped|seal]] prey.<ref name="dolphins">{{cite journal|title=''Predator-prey and competitive interactions between sharks (order Selachii) and dolphins (suborder Odontoceti): a review'' |journal=Journal of Zoology|volume=253|pages=53–68|author=Michael R. Heithaus|url=http://journals.cambridge.org/action/displayFulltext?type=1&fid=63584&jid=ZOO&volumeId=253&issueId=01&aid=63583&bodyId=&membershipNumber=&societyETOCSession=|access-date=2014-02-18|doi=10.1017/S0952836901000061|year=2001|citeseerx=10.1.1.404.130}}</ref> Intraguild predation can occur in freshwater systems as well. For example, invertebrate predators such as insect larvae and predatory copepods and cladocerans can act as intraguild prey, with planktivorous fish the interguild predator and herbivorous zooplankton acting as the basal resource.<ref name="trophic cascades1"/>

==Importance to management and conservation==
The presence and intensity of intraguild predation is important to both management and conservation of species.<ref name="dugongs"/><ref name="wolves"/><ref name="fisheries"/>  Human influence on communities and ecosystems can affect the balance of these interactions, and the direct and indirect effects of IGP may have economic consequences.

[[Social:Fisheries management|Fisheries managers]] have only recently begun to understand the importance of intraguild predation on the availability of fish stocks as they attempt to move towards [[Earth:Ecosystem-based management|ecosystem-based management]].  IGP interactions between sharks and seals may prevent seals from feeding in areas where commercially important fish species are abundant, which may indirectly make more of these fish available to fishermen.<ref name="seals">{{cite journal|title=Do shark declines create fear-released systems?|author= Alejandro Frid|author2= Gregory G. Baker|author3= Lawrence M. Dill|name-list-style= amp |doi=10.1111/j.2007.0030-1299.16134.x|volume=117|issue= 2|journal=Oikos|pages=191–201|year= 2008|url= https://zenodo.org/record/889766}}</ref>  However, IGP may also negatively influence fisheries.  Intraguild predation by [[Biology:Spiny dogfish|spiny dogfish]] and various [[Biology:Skate (fish)|skate]] species on economically important fishes like [[Biology:Atlantic cod|cod]] and [[Biology:Haddock|haddock]] have been cited as a possible reason for the slow recovery of the [[Biology:Groundfish|groundfish]] fishery in the western North Atlantic.<ref name="fisheries">{{cite journal|title=Large-Scale Disturbance and the Structure of Marine Systems : Fishery Impacts on Georges Bank |journal=Ecological Applications |volume=8 |pages=S6–S22 |author=Michael J. Fogarty |author2=Steven A. Murawski | doi = 10.1890/1051-0761(1998)8[s6:ldatso]2.0.co;2 |year=1998 |doi-access=free }}</ref>

Intraguild predation is also an important consideration for restoring ecosystems.  Because the presence of top predators can so strongly affect the distribution and abundance of both intermediate predator and prey species, efforts to either restore or control predator populations can have significant and often unintended ecological consequences.  In Yellowstone National Park, the reintroduction of wolves caused them to become intraguild predators of coyotes, which had far-reaching effects on both the animal and plant communities in the park.<ref name="wolves"/>  Intraguild predation is an important ecological interaction, and conservation and management measures will need to take it into consideration.<ref name="dugongs"/>

==References==
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[[Category:Biological interactions]]
[[Category:Conservation biology]]
[[Category:Ecosystems]]

{{Sourceattribution|Intraguild predation}}