{"id":7199,"date":"2018-10-04T16:56:22","date_gmt":"2018-10-04T23:56:22","guid":{"rendered":"https:\/\/www.vicnhs.bc.ca\/?p=7199"},"modified":"2018-10-05T14:31:56","modified_gmt":"2018-10-05T21:31:56","slug":"october-4-4","status":"publish","type":"post","link":"https:\/\/www.vicnhs.bc.ca\/?p=7199","title":{"rendered":"October 4"},"content":{"rendered":"
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2018 October 4<\/strong><\/p>\n

\u00a0<\/strong><\/p>\n

\u00a0\u00a0 <\/strong>Jeremy Tatum writes:\u00a0 Now that this site is not quite as busy as it was in mid-summer, here\u2019s a leisurely opportunity to think about tiger swallowtail identification.\u00a0 It should be easy:\u00a0 The background colour of the Western Tiger Swallowtail is yellow<\/span>.\u00a0 That of the Pale Tiger Swallowtail is white<\/span>.\u00a0\u00a0 Right?\u00a0\u00a0 My problem is that sometimes I can\u2019t be sure whether the colour I\u2019m seeing in yellow or white.\u00a0 Perhaps the yellow of a Western has become faded with time, or something like that.<\/p>\n

\u00a0 Here, then, are two additional clues:<\/p>\n

 <\/p>\n

\"\"<\/p>\n

<\/p>\n

Western Tiger Swallowtail<\/p>\n

 <\/p>\n

Western Tiger Swallowtail<\/strong><\/p>\n

    \n
  1. \u00a0\u00a0The yellow and black tiger stripes at the leading edge of the forewing are approximately equal in width.<\/li>\n
  2. \u00a0\u00a0The crescent-shaped spot at the base of the long hindwing tail<\/span> is yellow<\/span>.<\/li>\n<\/ol>\n

    \"\"<\/p>\n

    <\/p>\n

    Pale Tiger Swallowtail<\/p>\n

     <\/p>\n

    Pale Tiger Swallowtail<\/strong><\/p>\n

    \u00a0\u00a0 1.\u00a0 The black tiger stripes at the leading edge of the forewing are broader than the white stripes.<\/p>\n

    \u00a0\u00a0 2.\u00a0 The crescent-shaped spot at the base of the long hindwing tail<\/span> is mostly orange<\/span> (with maybe a little white at its tip).\u00a0 (Thanks to Mike Yip, who drew my attention to this feature.<\/p>\n

    \u00a0\u00a0 What brought this up is that I was recently perusing some past Invert Alerts, when I came across the following picture by Kirsten Mills, May 27, which I had identified and labelled as a Western Tiger Swallowtail.<\/p>\n

    \"\"<\/p>\n


    \nKirsten\u2019s photograph<\/p>\n

     <\/p>\n

    \u00a0\u00a0 Well, maybe the background colour looks slightly yellowish, but from the above criteria you can see clearly that I had misidentified it (apologies to Kirsten!), and\u00a0 it is in fact a Pale Tiger Swallowtail.\u00a0 I have now relabelled it as such.<\/p>\n

    \u00a0\u00a0 I do not know of any feature by which I can distinguish between the caterpillars<\/span> of the two species, other than foodplant, which is usually willow for the Western and alder for the Pale.<\/p>\n

    \u00a0 Do they ever hybridize?\u00a0 Are there some individuals that we cannot identify confidently, even if we try to use the above two features?\u00a0\u00a0 Let\u2019s keep a look-out next summer.<\/p>\n

    \u00a0\u00a0 Of course there are other species of tiger swallowtail, such as Canadian and Eastern Tiger Swallowtails, and at the moment I don\u2019t know how to identify them reliably.\u00a0 Presumably they don\u2019t occur on Vancouver Island \u2013 but who knows?\u00a0 Let\u2019s keep our eyes open!<\/p>\n

    \u00a0 Another complication:\u00a0 As with most other organisms, there have been name changes over the years.\u00a0 I am not sure why some recent authors have chosen to omit the word \u201cTiger\u201d from Pale Tiger Swallowtail, and call it just the Pale Swallowtail.\u00a0 Maybe because real tigers aren\u2019t white?\u00a0 \u00a0But the Pale one is obviously one of the tiger swallowtail group (subgenus Pterourus<\/em>); the omission of \u201cTiger\u201d somehow suggests that it should be set apart and doesn\u2019t belong to this group.\u00a0 That is why I usually prefer to retain the \u201cTiger\u201d.<\/p>\n

     <\/p>\n

     <\/p>\n

     <\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

    2018 October 4 \u00a0 \u00a0\u00a0 Jeremy Tatum writes:\u00a0 Now that this site is not quite as busy as it was in mid-summer, here\u2019s a leisurely opportunity to think about tiger swallowtail identification.\u00a0 It should be easy:\u00a0 The background colour of the Western Tiger Swallowtail is yellow.\u00a0 That of the Pale Tiger Swallowtail is white.\u00a0\u00a0 Right?\u00a0\u00a0 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"class_list":["post-7199","post","type-post","status-publish","format-standard","hentry","category-invertebrate-alert"],"_links":{"self":[{"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/posts\/7199","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7199"}],"version-history":[{"count":2,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/posts\/7199\/revisions"}],"predecessor-version":[{"id":7206,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/posts\/7199\/revisions\/7206"}],"wp:attachment":[{"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7199"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7199"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7199"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}