Pa­per wasps men­ace monarch but­ter­flies

Waikato Times - - National News - Skara Bohny

If you haven’t seen many monarch but­ter­flies this year, it could be be­cause there’s a na­tional short­age this sum­mer.

Com­mer­cial but­ter­fly grow­ers Ian and Jill Knight re­leased about 100 monar­chs into the wild on Satur­day. The Knights’ farm, at Hope near Nel­son, has four tun­nel-houses, each filled with hun­dreds of monar­chs in var­i­ous stages of devel­op­ment; when the but­ter­flies are ma­ture, they are sold or re­leased into the wild.

Ian Knight said that this sum­mer there was a ‘‘huge short­age’’ of monar­chs, which he be­lieved was pri­mar­ily due to the asian pa­per wasp.

‘‘They’re the big­gest threat [to monar­chs] at ev­ery stage of life, from egg and cater­pil­lar to chrysalis and but­ter­fly.

‘‘Last year we had about 300 but­ter­flies in one tun­nel-house ready to re­lease, and the next day I went in, the floor was just lit­tered with dead but­ter­flies and there was one wasp that was in there, in a sting­ing frenzy.’’

Knight said he killed the wasp but the dam­age was mostly al­ready done: of the orig­i­nal 300 but­ter­flies, 150 died.

The Knights run a busi­ness, Oc­ca­sional Monarch, which sells monar­chs to be re­leased at spe­cial events like wed­dings, fu­ner­als, and un­veil­ings.

They send care­fully boxed-up but­ter­flies through the post in chilled con­tain­ers, ready to be re­leased af­ter warm­ing up again.

The but­ter­flies are com­pletely un­harmed by the process, as be­ing kept in cold, dark con­di­tions sim­ply sends them to sleep. The Knights have even kept but­ter­flies in the fridge over win­ter, feed­ing them ev­ery 10 days, to give them­selves a head-start for breed­ing when the weather warmed up again.

They said wild but­ter­flies of­ten came to the farm to lay eggs through the pro­tec­tive net­ting on to the swan plants in­side but this year the num­ber of wild monar­chs re­turn­ing was lower than pre­vi­ous years.

Jill Knight said they reg­u­larly checked the tun­nel-houses for wasp-in­vaders and the kill any pa­per wasp hives they find.

Un­like com­mon or ger­man wasps, pa­per wasps only take live prey and so do not re­spond to poi­son bait like Ve­spex. In­stead, pa­per wasp nests must be killed in­di­vid­u­ally with over-the­counter pes­ti­cides.

Pa­per wasps can be iden­ti­fied by the long, dan­gling back legs that hang be­low them when they fly. Ger­man and com­mon wasps tuck their legs up to fly.

Three species of pa­per wasp are es­tab­lished in New Zealand: the asian, aus­tralian and euro­pean. Jill said she and Ian were in it for the long haul to keep but­ter­flies safe in New Zealand.

LUZ ZUNIGA/STUFF

Left: Sophia Zhang re­leases monarch but­ter­flies at Wash­bourn Gar­dens in Rich­mond. Above: Ian Knight in the but­ter­flies’ pro­tected tun­nel-house.

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