{"id":14576,"date":"2018-12-17T10:50:50","date_gmt":"2018-12-17T15:50:50","guid":{"rendered":"https:\/\/esa.org\/esablog\/?p=14576"},"modified":"2018-12-17T10:50:50","modified_gmt":"2018-12-17T15:50:50","slug":"hummingbird-vs-caterpillar","status":"publish","type":"post","link":"https:\/\/esa.org\/esablog\/2018\/12\/17\/hummingbird-vs-caterpillar\/","title":{"rendered":"The Ultimate Standoff: Hummingbird Vs. Caterpillar"},"content":{"rendered":"<h2><em>Researchers observe a defense mechanism for caterpillars can attract unwanted attention <\/em><\/h2>\n<div style=\"width: 1920px;\" class=\"wp-video\"><video class=\"wp-video-shortcode\" id=\"video-14576-1\" width=\"1920\" height=\"1080\" preload=\"metadata\" controls=\"controls\"><source type=\"video\/mp4\" src=\"https:\/\/esa.org\/esablog-preprod\/wp-content\/uploads\/sites\/90\/2018\/12\/MVI_0410-1920-1920.mp4?_=1\" \/><a href=\"https:\/\/esa.org\/esablog-preprod\/wp-content\/uploads\/sites\/90\/2018\/12\/MVI_0410-1920-1920.mp4\">https:\/\/esa.org\/esablog-preprod\/wp-content\/uploads\/sites\/90\/2018\/12\/MVI_0410-1920-1920.mp4<\/a><\/video><\/div>\n<h6><em>In a 26-minute standoff, a snake-mimicking caterpillar was unable to feed during attacks from a nest-defending hummingbird. (Video provided by James Marden)<\/em><\/h6>\n<p>When a caterpillar disguises itself as a snake\u00a0to ward off potential predators, it should probably expect to be treated like one.<\/p>\n<p>This is exactly what happened in Costa Rica earlier this year, when\u00a0<a href=\"https:\/\/mardenpix.smugmug.com\/Other\/Hummingbird-caterpillar-interaction\/n-BqjkqQ\/i-v8VfpGc\/A\">researchers\u00a0witnessed a hummingbird defending its nest<\/a>\u00a0from what it interpreted\u00a0to be a snake, but was actually a larva of the moth\u00a0<em>Oxytenis modestia<\/em>.\u00a0The encounter is described in a <a href=\"https:\/\/esajournals.onlinelibrary.wiley.com\/doi\/abs\/10.1002\/ecy.2582\">new paper<\/a> published in the Ecological Society of America\u2019s journal <em>Ecology<\/em>.<\/p>\n<p>These moths \u2014 sometimes called the dead-leaf moth or the Costa Rica leaf moth \u2014\u00a0<a href=\"https:\/\/www.gettyimages.co.uk\/detail\/photo\/dead-leaf-moth-group-camouflaged-in-leaf-high%20res-stock-photography\/112190314\">resemble flat dried leaves<\/a>\u00a0as adults. The caterpillars can inflate the top of their heads to expose a pair of eyespots. When disturbed, they raise their head up and move from side to side, increasing the snake-like appearance. In particular they resemble a green parrot snake, known to prey on nesting birds.<\/p>\n<div id=\"attachment_14593\" style=\"width: 381px\" class=\"wp-caption alignright\"><a href=\"https:\/\/esa.org\/esablog-preprod\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0490-2-1.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-14593\" class=\" wp-image-14593 img-fluid\" src=\"https:\/\/esa.org\/esablog-preprod\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0490-2-1-723x1024.jpg\" alt=\"\" width=\"371\" height=\"525\" srcset=\"https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0490-2-1-723x1024.jpg 723w, https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0490-2-1-212x300.jpg 212w, https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0490-2-1-768x1088.jpg 768w, https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0490-2-1-1084x1536.jpg 1084w, https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0490-2-1-1446x2048.jpg 1446w, https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0490-2-1-300x425.jpg 300w, https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0490-2-1-scaled.jpg 1807w\" sizes=\"auto, (max-width: 371px) 100vw, 371px\" \/><\/a><p id=\"caption-attachment-14593\" class=\"wp-caption-text\">The caterpillar had begun feeding during the night, but the comings and goings of a hummingbird disturbed it, causing it to expand and reveal its \u201ceyes\u201d and rear up into its snake-mimic posture. <em>Photo courtesy of James Marden.<\/em><\/p><\/div>\n<p>The\u00a0attacking\u00a0hummingbird\u2019s nest with eggs\u00a0was\u00a0about 10cm away from the caterpillar in a small tree.\u00a0When the\u00a0researchers\u00a0went to look for\u00a0an assumed snake, they instead found\u00a0the caterpillar feeding on a leaf immediately above the nest.<\/p>\n<p>\u201cHummingbirds have a few stereotypical styles of flying: visiting flowers, preying on swarms of tiny insects, chasing each other, and mating\/territorial display flights,\u201d says lead author James H.\u00a0Marden, professor with the Department of Biology at Pennsylvania State University. \u201cMobbing behavior directed against a threat to their nest is much less common but distinct and easy to recognize if you know their other flight behaviors\u2026 One can recognize this from a distance and only notice the source of their agitation upon close inspection.\u201d<\/p>\n<p>Caterpillars and adults of a variety of butterflies and moths have eye-like spots that deter potential\u00a0predators. Observations of how\u00a0these\u00a0eyespots affect animal interactions in natural settings are extremely rare.<\/p>\n<p>The interaction took place on a strip of secondary growth between the Pacific and primary rainforest on the\u00a0Osa\u00a0Peninsula, Costa Rica. The authors believe that the comings and goings of the female rufous-tailed hummingbird (<em>Amazilia\u00a0tzacatl<\/em>) around its nest may have disturbed the caterpillar, causing it to expose its eyespots, which in turn prompted the hummingbird to defend its nest\u00a0using what is referred to as \u2018mobbing behavior\u2019 by birds \u2014\u00a0darting flights\u00a0and pecking at a threat, commonly snakes.<\/p>\n<p>The caterpillar was unable to feed during the 26-minutes\u00a0of nearly continuous attacks.\u00a0Most of the\u00a0bird\u2019s\u00a0movements were cautious and exploratory, but included quick thrusts to peck or bite\u00a0the eyespots.<\/p>\n<div id=\"attachment_14594\" style=\"width: 848px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/esa.org\/esablog-preprod\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0502-1.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-14594\" class=\"size-large wp-image-14594 img-fluid\" src=\"https:\/\/esa.org\/esablog-preprod\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0502-1-1024x683.jpg\" alt=\"\" width=\"838\" height=\"559\" srcset=\"https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0502-1-1024x683.jpg 1024w, https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0502-1-300x200.jpg 300w, https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0502-1-768x512.jpg 768w, https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0502-1-1536x1024.jpg 1536w, https:\/\/esa.org\/esablog\/wp-content\/uploads\/sites\/90\/2018\/12\/IMG_0502-1-2048x1366.jpg 2048w\" sizes=\"auto, (max-width: 838px) 100vw, 838px\" \/><\/a><p id=\"caption-attachment-14594\" class=\"wp-caption-text\">A bite directly on the false eye. <em>Photo courtesy of James Marden.<\/em><\/p><\/div>\n<p>Marden\u00a0stated\u00a0that it was difficult for either the bird or caterpillar\u00a0to disengage from the standoff, with the hummingbird protecting its nest and the caterpillar just trying to finish its leafy meal. \u201cA\u00a0snake-like creature so near to its nest was too much of a distraction or threat to ignore for very long,\u201d he explained. \u201cThe caterpillar seemed more irreversibly committed.\u00a0When a camouflaged animal reveals itself as threatening, it is committed and cannot\u00a0easily go back to camouflage.\u00a0Hence, I think that it had no choice but continue looking like a snake until the threat had passed.\u201d<\/p>\n<p>Eventually the caterpillar gave up on eating and crawled away while still under attack, and the hummingbird resumed normal nesting behavior.<\/p>\n<p>When birds exhibit this mobbing behavior targeting\u00a0snake\u2019s eyes,\u00a0it\u00a0often\u00a0ends\u00a0with\u00a0snakes\u00a0being killed by\u00a0repeated bites and pecks\u00a0near the head and collar area.\u00a0As for creatures that mimic snakes to protect themselves\u00a0from being eaten, can they\u00a0in turn\u00a0protect themselves from this mimicry backfiring, such as in this encounter?\u00a0Because the hummingbird behavior was typical anti-snake behavior, it can be considered replicable.<\/p>\n<p>Marden\u00a0is fascinated by this interaction,\u00a0and he\u00a0believes future studies of this behavior can be conducted\u00a0using a tiny, caterpillar robot to experiment with eyespots.<\/p>\n<p>\u201cYou\u2019d want a cylindrical shape and green color, with the ability to rear up in the front and reveal an eyespot,\u201d he outlines.\u00a0It should be remote controlled,\u00a0light enough to attach to a leaf or stem, and wireless.\u00a0\u201cMany experiments have done this with clay or similar material, but those models lack the ability to combine eyespots with movement and behavior. That is what a robot could add.\u201d<\/p>\n<div id=\"attachment_27308\" style=\"width: 672px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/esa.org\/esa\/wp-content\/uploads\/2018\/12\/Untitled-1.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-27308\" class=\" wp-image-27308 img-fluid\" src=\"https:\/\/esa.org\/esa\/wp-content\/uploads\/2018\/12\/Untitled-1-1024x381.png\" alt=\"\" width=\"662\" height=\"247\"><\/a><p id=\"caption-attachment-27308\" class=\"wp-caption-text\">When disturbed, the caterpillar increases its internal pressure, causing the area behind the head to expand and expose a pair of eyespots. Expansion and exposure of the \u201ceyes\u201d is accompanied by rearing up and side to side movements, which closely mimic a small snake. <em>Photo courtesy of James Marden.<\/em><\/p><\/div>\n<p>With\u00a0such\u00a0a robot, researchers could vary the eye-like nature and contrast of spots on the head of the\u00a0robot\u00a0to test\u00a0various\u00a0responses of\u00a0nest-defending\u00a0birds.\u00a0A study like this\u00a0could definitively test the effects of eye-like versus other\u00a0mimicry\u00a0patterning\u00a0for provoking or repelling\u00a0defensive attacks.<\/p>\n<p>The day following the initial encounter, the researchers found the caterpillar feeding on a leaf on the same plant, as far away from the nest as possible. It had some marks by the edge of the right eyespot that may be beak marks \u2013 apparently the caterpillar learned its lesson.<\/p>\n<hr>\n<p>View more photos of this amazing encounter on the author\u2019s website:\u00a0<a href=\"https:\/\/mardenpix.smugmug.com\/Other\/Hummingbird-caterpillar-interaction\/n-BqjkqQ\/\">https:\/\/mardenpix.smugmug.com\/Other\/Hummingbird-caterpillar-interaction\/n-BqjkqQ\/<\/a><\/p>\n<hr>\n<p><strong><br>\nJournal Article<br>\n<\/strong>Marden, J.H., J.F.P. Carillo. 2018. \u201cAnti\u2010predator behavior by a nesting hummingbird in response to a caterpillar with eyespots.\u201d <em>Ecology<\/em>. DOI: 10.1002\/ecy.2582<\/p>\n<p><strong>Author contact<br>\n<\/strong>James H Marden\u00a0 \u00a0 \u00a0 \u00a0jhm10@psu.edu<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Researchers observe a defense mechanism for caterpillars can attract unwanted attention In a 26-minute standoff, a snake-mimicking caterpillar was unable to feed during attacks from a nest-defending hummingbird. (Video provided by James Marden) When a caterpillar disguises itself as a snake\u00a0to ward off potential predators, it should probably expect to be treated like one. This is exactly what happened in&#8230;<\/p>\n","protected":false},"author":20,"featured_media":14596,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[86,2],"tags":[1897],"class_list":["post-14576","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-homepage-featured","category-research","tag-hummingbird"],"_links":{"self":[{"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/posts\/14576","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/comments?post=14576"}],"version-history":[{"count":0,"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/posts\/14576\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/media\/14596"}],"wp:attachment":[{"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/media?parent=14576"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/categories?post=14576"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/esa.org\/esablog\/wp-json\/wp\/v2\/tags?post=14576"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}