Fri, Apr 18, 2014 page3

• Abnormal weather blamed for dearth of butterflies, fireflies and some frogs

  MISSING IN ACTION? The beginning of April in Yunlin County’s Linnei Township is usually marked by the migration of tens of thousands of purple crow butterflies

  • By Huang Shu-li and Jake Chung / Staff reporter, with staff writer
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  Abnormal weather patterns and rapid shifts in temperatures may be behind the decreased sightings of purple crow butterflies — Euploea tulliolus — during their normal south-to-north migration to breed, the Taiwan Purple Crow Butterfly Ecological Preservation Association said.

  The association said there have also been fewer sightings of fireflies and the endangered Rhacophorus arvalis tree frogs, or in some cases, none.

  Association deputy director-general Chen Jui-hsiang (陳瑞祥) said Tomb Sweeping Day usually marks the start of the butterflies’ migration north, and they always pass through Linnei Township (林內), Yunlin County.

  

  A purple crow butterfly perches on a flower in Chiayi County in an undated photograph.

  Photo: Courtesy of the Chiayi Forest District Office

  Butterfly watchers spotted the purple crow butterflies as early as February last year, and when the sun was out and the temperatures high enough, hundreds of butterflies, even thousands, could be seen the following month, Chen said.

  “We only had a large sighting on March 26, with about 190 butterflies passing per minute,” Chen said.

  The number of purple crow butterflies that passed through Linnei this year was down 50 to 60 percent, Chen said.

  What makes it more puzzling is that watchers in the south said the butterflies were migrating as usual, but they were not going through Yunlin County.

  Association director-general Tseng Chen-nan (曾振南) said that the number of butterflies migrating north every year has been decreasing and researchers are trying to determine the reason.

  Weather patterns have been irregular this year, with the northeastern monsoon winds continuing until last month, which helped keep temperatures lower than normal, Tseng said.

  “We would normally be able to see many purple crow butterflies in Linnei’s Pingding Elementary School by now, but they are conspicuous by their absence this year,” Tseng said.

  Meanwhile, the cold spring may have delayed the appearance of fireflies and the tree frogs, the association said.

  Wu Teng-li (吳登立), a member of Ecological Protection and Restoration Association in Yunlin County, said that last year fireflies had been seen by the end of March.

  While conservation efforts have caused an explosion in the amount of fireflies seen in mountainous areas, people may have to wait until the end of this month to see them because of the weather.

  Lower-than-normal temperatures and a lack of rain has delayed the appearance of the frogs, Wu said.

  Their thunderous croaking could be heard by March last year, but so far this year there are very few around, Wu said.
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