{"id":4587,"date":"2022-04-11T14:02:09","date_gmt":"2022-04-11T21:02:09","guid":{"rendered":"https:\/\/blogs.oregonstate.edu\/gemmlab\/?p=4587"},"modified":"2022-04-11T14:02:09","modified_gmt":"2022-04-11T21:02:09","slug":"what-drives-individual-specialization","status":"publish","type":"post","link":"https:\/\/blogs.oregonstate.edu\/gemmlab\/2022\/04\/11\/what-drives-individual-specialization\/","title":{"rendered":"What drives individual specialization?"},"content":{"rendered":"\n

Clara Bird<\/a>, PhD Student, OSU Department of Fisheries, Wildlife, and Conservation Sciences,\u00a0Geospatial Ecology of Marine Megafauna Lab<\/a><\/strong><\/p>\n\n\n\n

When I wrote my first blog<\/a> on individual specialization well over a year ago, I just skimmed the surface of the literature on this topic and only started to recognize the importance of studying individual specialization. The question, \u201cis there individual specialization in the PCFG of gray whales?\u201d is the focus of my first thesis chapter and the results will affect all my subsequent work. Therefore, the literature and concepts of individual specialization are a focus of my literature review and studies.<\/p>\n\n\n\n

In my previous blog I focused on common characteristics of individuals that are similarly specialized as an underlying driver of individual specialization. While these characteristics (often attributable to age, sex, or physical traits) are important to consider, I\u2019ve learned that the list of drivers of individual specialization is long and that many variables are dynamic. Of all the drivers I\u2019ve learned about, competition is among the most common.<\/p>\n\n\n\n

Competition is a major driver of individual specialization, and a common driver of competition is resource availability. When resource availability decreases, whether caused by increasing population density or changing environmental conditions, competition for that resource increases. As competition increases, individuals have a choice. They can choose to engage in competition, either by racing, fighting, or sharing\u00a0[1], which can be costly, or they can diffuse the competition by focusing on a different resource.\u00a0\u00a0This second approach would be considered\u00a0niche partitioning<\/a>\u00a0in the prey dimension. Niche partitioning is a way for individuals to share ecological space by using different resources. Essentially, individuals can share habitat without having to engage in direct competition by pursuing different prey types\u00a0[2].\u00a0<\/p>\n\n\n\n

This switch to different prey types can change the degree of individual specialization present in the population (Figure 1). But the direction of the change is not constant. If all individuals were pursuing the same prey type under low competition conditions but then switched to different alternate prey types under high competition, then individual specialization would increase (Figure 1a). This direction has been observed across a range of species including sharks\u00a0[3], otters\u00a0[4]\u2013[7], dolphins\u00a0[8], [9], stickleback fish\u00a0[10], [11], largemouth bass\u00a0[12], banded mongoose\u00a0[13], fur seals\u00a0[14], and baleen whales\u00a0[15].<\/p>\n\n\n\n

However, if individuals were pursuing different prey types under low competition conditions (maybe because of underlying differences such as age or sex) but then switched to the same alternate prey types under high competition, diet overlap would increase, and individual specialization would decrease (Figure 1b). Furthermore, an individual might not switch to an entirely new prey type but instead add prey items to its diet\u00a0[16]. This diet expansion under competition would also decrease individual specialization. Fewer studies have reported this direction but it\u2019s been found in the common bumblebee\u00a0[17]\u00a0and in several neotropical vertebrate species\u00a0[18], [19].<\/p>\n\n\n\n

\"\"<\/a>
Figure `1.<\/strong> Figure 3 from Ara\u00fajo et al. 2011\u00a0[20]. Illustration of how ecological mechanisms may affect the degree of individual specialization. Arrows linking resources to individual consumers indicate resource consumption (relative thickness indicates proportional contribution).\u00a0
Horizontal arrows indicate the sign (positive or negative) of the effect on the degree of individual specialization. (a) Consumers share the same preferred resource (dark gray tangle) but have different alternative resources (white and light gray triangles). As the preferred resource becomes scarce, consumers switch to different alternatives, increasing the degree of individual specialization. (b) Alternatively, consumers have distinct preferred resources, so that as resources become scarce, individuals converge to the alternative resource (dark gray triangle), reducing diet variation.<\/em><\/figcaption><\/figure><\/div>\n\n\n\n

Interestingly, its hypothesized that individual specialization driven by competition is one of the factors that facilitates the formation and existence of stable groups\u00a0[21]. For example, a study on resident female dolphins in Sarasota Bay, FL, USA found that females with high spatial overlap used distinct foraging specializations\u00a0[8](Figure 2). This study illustrates how partitioning prey enabled spatial and social coexistence. A study on banded mongooses reached a similar conclusion\u00a0[13]. They found that specialization was highest in the biggest groups (with the most competition) and not explained by sex, age, or other inherent differences. They hypothesized that specialization increasing with competition reduced conflict and allowed the groups to remain stable. This study also highlighted the role of learning to determine an individual\u2019s specialization.<\/p>\n\n\n\n

\"\"<\/a>
Figure 2. <\/strong>A bottlenose dolphin. <\/em>
Source: https:\/\/sarasotadolphin.org<\/em><\/figcaption><\/figure><\/div>\n\n\n\n

Learning drives the distribution of knowledge throughout a population, which can lead to either specialization or generalization. \u2018One-to-one\u2019 learning, where one individual learns from one demonstrator, tends to promote individual specialization\u00a0[21]. This form of transmission drives specialization because the individuals who learn the specialization tend to then carry on using, and eventually teaching, that specialization\u00a0[6]. A common example of \u2018one-to-one\u2019 learning is vertical transmission from parent to offspring. It has been shown to transmit specializations in dolphins\u00a0[22]\u00a0and otters\u00a0[6]. \u2018One-to-one\u2019 learning can occur outside of parent-offspring pairs; non-parent-offspring \u2018one-to-one\u2019 learning has been shown to drive specialization in banded mongooses\u00a0[13](Figure 3).<\/p>\n\n\n\n

However, other forms of social learning can promote more generalized foraging strategies. \u2018Many-to-one\u2019 or \u2018one-to-many\u2019 learning\u00a0\u00a0can reduce the presence of specialization in species\u00a0[13], [21]\u00a0as can the presence of conformity in a group\u00a0[23], [24].<\/p>\n\n\n\n

\"\"<\/a>
Figure 3.<\/strong> A group of banded mongooses.
Source: http:\/\/socialisresearch.org\/about-the-banded-mongoose-project\/<\/em><\/figcaption><\/figure><\/div>\n\n\n\n

The multiple drivers of specialization and their dynamic quality means that it is important to contextualize specialization. For example, a study on four species of neotropical frogs found varying degrees of specialization across multiple populations of each species [18]. The degree of specialization was dependent on a variety of drivers including predation and both intra- and inter-specific competition. Notably, the direction of the relationship between degree of specialization and each driver was species specific. This study highlights that one species may not always be more specialized than another, but that a populations\u2019 specialization is context dependent.<\/p>\n\n\n\n

Therefore, it is important to not only be\u00a0aware<\/a>\u00a0of the degree of specialization present in a population, but to also understand its dynamics and drivers. These relationships can then be used to understand how, and why, a population may react to competition from other species, predators, and changes in resource availability\u00a0[20].\u00a0\u00a0A population\u2019s specialization can also affect the specialization of other populations and community dynamics\u00a0[25], therefore, it\u2019s important to consider and study individual specialization on both the population and community level. I am excited to start using our incredible six-year dataset to start investigating these questions for PCFG gray whales, so stay tuned for results!<\/p>\n\n\n\n

Did you enjoy this blog? Want to learn more about marine life, research, and conservation? Subscribe to our blog and get a weekly alert when we make a new post! Just add your name into the subscribe box on the left panel.\u00a0\u00a0<\/em><\/p>\n\n\n\n

References<\/strong><\/h2>\n\n\n\n

[1]       M. Taborsky, M. A. Cant, and J. Komdeur, The Evolution of Social Behaviour<\/em>. Cambridge: Cambridge University Press, 2021. doi: 10.1017\/9780511894794.<\/p>\n\n\n\n

[2]       E. R. Pianka, \u201cNiche Overlap and Diffuse Competition,\u201d vol. 71, no. 5, pp. 2141\u20132145, 1974.<\/p>\n\n\n\n

[3]       P. Matich et al.<\/em>, \u201cEcological niche partitioning within a large predator guild in a nutrient-limited estuary,\u201d Limnol. Oceanogr.<\/em>, vol. 62, no. 3, pp. 934\u2013953, 2017, doi: https:\/\/doi.org\/10.1002\/lno.10477.<\/p>\n\n\n\n

[4]       S. D. Newsome et al.<\/em>, \u201cThe interaction of intraspecific competition and habitat on individual diet specialization: a near range-wide examination of sea otters,\u201d Oecologia<\/em>, vol. 178, no. 1, pp. 45\u201359, May 2015, doi: 10.1007\/s00442-015-3223-8.<\/p>\n\n\n\n

[5]       M. T. Tinker, G. Bentall, and J. A. Estes, \u201cFood limitation leads to behavioral diversification and dietary specialization in sea otters,\u201d Proc. Natl. Acad. Sci.<\/em>, vol. 105, no. 2, pp. 560\u2013565, Jan. 2008, doi: 10.1073\/pnas.0709263105.<\/p>\n\n\n\n

[6]       M. T. Tinker, M. Mangel, and J. A. Estes, \u201cLearning to be different: acquired skills, social learning, frequency dependence, and environmental variation can cause behaviourally mediated foraging specializations,\u201d Evol. Ecol. Res.<\/em>, vol. 11, pp. 841\u2013869, 2009.<\/p>\n\n\n\n

[7]       M. T. Tinker et al.<\/em>, \u201cStructure and mechanism of diet specialisation: testing models of individual variation in resource use with sea otters,\u201d Ecol. Lett.<\/em>, vol. 15, no. 5, pp. 475\u2013483, 2012, doi: 10.1111\/j.1461-0248.2012.01760.x.<\/p>\n\n\n\n

[8]       S. Rossman et al.<\/em>, \u201cForaging habits in a generalist predator: Sex and age influence habitat selection and resource use among bottlenose dolphins (Tursiops truncatus),\u201d Mar. Mammal Sci.<\/em>, vol. 31, no. 1, pp. 155\u2013168, 2015, doi: https:\/\/doi.org\/10.1111\/mms.12143.<\/p>\n\n\n\n

[9]       L. G. Torres, \u201cA kaleidoscope of mammal , bird and fish\u202f: habitat use patterns of top predators and their prey in Florida Bay,\u201d vol. 375, pp. 289\u2013304, 2009, doi: 10.3354\/meps07743.<\/p>\n\n\n\n

[10]     M. S. Ara\u00fajo et al.<\/em>, \u201cNetwork Analysis Reveals Contrasting Effects of Intraspecific Competition on Individual Vs. Population Diets,\u201d Ecology<\/em>, vol. 89, no. 7, pp. 1981\u20131993, 2008, doi: 10.1890\/07-0630.1.<\/p>\n\n\n\n

[11]     R. Svanb\u00e4ck and D. I. Bolnick, \u201cIntraspecific competition drives increased resource use diversity within a natural population,\u201d Proc. R. Soc. B Biol. Sci.<\/em>, vol. 274, no. 1611, pp. 839\u2013844, Mar. 2007, doi: 10.1098\/rspb.2006.0198.<\/p>\n\n\n\n

[12]     D. E. Schindler, J. R. Hodgson, and J. F. Kitchell, \u201cDensity-dependent changes in individual foraging specialization of largemouth bass,\u201d Oecologia<\/em>, vol. 110, no. 4, pp. 592\u2013600, May 1997, doi: 10.1007\/s004420050200.<\/p>\n\n\n\n

[13]     C. E. Sheppard et al.<\/em>, \u201cIntragroup competition predicts individual foraging specialisation in a group-living mammal,\u201d Ecol. Lett.<\/em>, vol. 21, no. 5, pp. 665\u2013673, 2018, doi: 10.1111\/ele.12933.<\/p>\n\n\n\n

[14]     L. Kernal\u00e9guen, J. P. Y. Arnould, C. Guinet, and Y. Cherel, \u201cDeterminants of individual foraging specialization in large marine vertebrates, the Antarctic and subantarctic fur seals,\u201d J. Anim. Ecol.<\/em>, vol. 84, no. 4, pp. 1081\u20131091, 2015, doi: 10.1111\/1365-2656.12347.<\/p>\n\n\n\n

[15]     E. M. Keen and K. M. Qualls, \u201cRespiratory behaviors in sympatric rorqual whales: the influence of prey depth and implications for temporal access to prey,\u201d J. Mammal.<\/em>, vol. 99, no. 1, pp. 27\u201340, Feb. 2018, doi: 10.1093\/jmammal\/gyx170.<\/p>\n\n\n\n

[16]     R. H. MacArthur and E. R. Pianka, \u201cOn Optimal Use of a Patchy Environment,\u201d Am. Nat.<\/em>, vol. 100, no. 916, pp. 603\u2013609, 1966, doi: 10.1086\/282454.<\/p>\n\n\n\n

[17]     C. Fontaine, C. L. Collin, and I. Dajoz, \u201cGeneralist foraging of pollinators: diet expansion at high density,\u201d J. Ecol.<\/em>, vol. 96, no. 5, pp. 1002\u20131010, 2008, doi: 10.1111\/j.1365-2745.2008.01405.x.<\/p>\n\n\n\n

[18]     R. Costa-Pereira, V. H. W. Rudolf, F. L. Souza, and M. S. Ara\u00fajo, \u201cDrivers of individual niche variation in coexisting species,\u201d J. Anim. Ecol.<\/em>, vol. 87, no. 5, pp. 1452\u20131464, 2018, doi: 10.1111\/1365-2656.12879.<\/p>\n\n\n\n

[19]     M. M. Pires, P. R. Guimar\u00e3es Jr, M. S. Ara\u00fajo, A. A. Giaretta, J. C. L. Costa, and S. F. dos Reis, \u201cThe nested assembly of individual-resource networks,\u201d J. Anim. Ecol.<\/em>, vol. 80, no. 4, pp. 896\u2013903, 2011, doi: 10.1111\/j.1365-2656.2011.01818.x.<\/p>\n\n\n\n

[20]     M. S. Ara\u00fajo, D. I. Bolnick, and C. A. Layman, \u201cThe ecological causes of individual specialisation,\u201dEcol. Lett.<\/em>, vol. 14, no. 9, pp. 948\u2013958, 2011, doi: https:\/\/doi.org\/10.1111\/j.1461-0248.2011.01662.x.<\/p>\n\n\n\n

[21]     C. E. Sheppard, R. Heaphy, M. A. Cant, and H. H. Marshall, \u201cIndividual foraging specialization in group-living species,\u201d Anim. Behav.<\/em>, vol. 182, pp. 285\u2013294, Dec. 2021, doi: 10.1016\/j.anbehav.2021.10.011.<\/p>\n\n\n\n

[22]     S. Wild, S. J. Allen, M. Kr\u00fctzen, S. L. King, L. Gerber, and W. J. E. Hoppitt, \u201cMulti-network-based diffusion analysis reveals vertical cultural transmission of sponge tool use within dolphin matrilines,\u201d Biol. Lett.<\/em>, vol. 15, no. 7, p. 20190227, Jul. 2019, doi: 10.1098\/rsbl.2019.0227.<\/p>\n\n\n\n

[23]     L. M. Aplin, D. R. Farine, J. Morand-Ferron, A. Cockburn, A. Thornton, and B. C. Sheldon, \u201cExperimentally induced innovations lead to persistent culture via conformity in wild birds,\u201d Nature<\/em>, vol. 518, no. 7540, pp. 538\u2013541, Feb. 2015, doi: 10.1038\/nature13998.<\/p>\n\n\n\n

[24]     E. Van de Waal, C. Borgeaud, and A. Whiten, \u201cPotent Social Learning and Conformity Shape a Wild Primate\u2019s Foraging Decisions,\u201d Science<\/em>, Apr. 2013, doi: 10.1126\/science.1232769.<\/p>\n\n\n\n

[25]     D. I. Bolnick et al.<\/em>, \u201cWhy intraspecific trait variation matters in community ecology,\u201d Trends Ecol. Evol.<\/em>, vol. 26, no. 4, pp. 183\u2013192, Apr. 2011, doi: 10.1016\/j.tree.2011.01.009.<\/p>\n","protected":false},"excerpt":{"rendered":"

Clara Bird, PhD Student, OSU Department of Fisheries, Wildlife, and Conservation Sciences,\u00a0Geospatial Ecology of Marine Megafauna Lab When I wrote my first blog on individual specialization well over a year ago, I just skimmed the surface of the literature on this topic and only started to recognize the importance of studying individual specialization. The question, \u201cis there … Continue reading What drives individual specialization?<\/span><\/a><\/p>\n","protected":false},"author":9938,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[188686,1310686],"tags":[1834,1310578,1310532,712908,677522,635445,1310685,634945,712886,1237804,39955,1310749],"class_list":["post-4587","post","type-post","status-publish","format-standard","hentry","category-current-projects","category-behavior-and-body-condition","tag-behavior","tag-behavioral-ecology","tag-clara-bird","tag-foraging-competition","tag-foraging-ecology","tag-gemm-lab","tag-gray-whale-individual-behavior-and-body-condition","tag-gray-whales","tag-individual-specialization","tag-individualization","tag-learning","tag-social-behavior"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/posts\/4587","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/users\/9938"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/comments?post=4587"}],"version-history":[{"count":6,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/posts\/4587\/revisions"}],"predecessor-version":[{"id":4597,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/posts\/4587\/revisions\/4597"}],"wp:attachment":[{"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/media?parent=4587"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/categories?post=4587"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.oregonstate.edu\/gemmlab\/wp-json\/wp\/v2\/tags?post=4587"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}