Where do the but­ter­flies go?

Ontario Gardener Magazine - - CONTENTS - By Ta­nia Mof­fat

Many peo­ple have heard of the great monarch mi­gra­tion, where mil­lions of monar­chs make their yearly trek to Mex­ico for the win­ter, but do all but­ter­flies mi­grate?

Out of the ap­prox­i­mately 20,000 species of but­ter­flies around the world, 275 species re­side in Canada, and each has their own way of mak­ing it through our cold win­ters. With an av­er­age life­span of one month or less for most but­ter­flies, monar­chs and morn­ing cloaks are a cou­ple of species that are the ex­cep­tion. They can live up to nine months. But, a but­ter­flies life is fraught with dan­ger, be­tween preda­tors, dis­ease, and ac­ci­dents with ve­hi­cles, the life of a wild but­ter­fly isn’t easy.

Th­ese del­i­cate crea­tures are tougher than many give them credit for and have man­aged to adapt to win­ter sur­vival through var­i­ous meth­ods.


But­ter­flies all go through the same life cy­cle: egg, cater­pil­lar, pupa in a chrysalis and but­ter­fly, where they dif­fer is in their taste of host plants and their meth­ods of over­win­ter­ing. Species over­win­ter in dif­fer­ent stages of their life­cy­cle.

Many but­ter­flies are win­ter res­i­dents and spend the sea­son as cater­pil­lars, while oth­ers re­main as pu­pae and a rare few over­win­ter as eggs. A se­lect num­ber may spend the win­ter as adults hi­ber­nat­ing in notches in trees or other shel­tered lo­ca­tions. The monarch looka-like, the viceroy, spends the win­ter hi­ber­nat­ing as

a cater­pil­lar nes­tled in the fallen leaves of wil­low or po­plar trees. East­ern and black swal­low­tails hi­ber­nate as pupa within their chrysalis when the days be­come colder and emerge in the spring, adults do not sur­vive the cold. One of the few but­ter­flies that hi­ber­nates in its adult form is the mourn­ing cloak. Th­ese but­ter­flies will find crevices in trees to wait out the weather and are of­ten one of the first but­ter­flies we see in the spring.


In ad­di­tion to the monar­chs sev­eral other but­ter­flies, in­clud­ing the painted lady, Amer­i­can lady, and red ad­mi­ral, mi­grate to more southerly lo­ca­tions in­clud­ing the south­ern United States and Mex­ico. But­ter­flies mi­grate for many rea­sons in­clud­ing the loss of their food sources and the fact that they are cold-blooded in­sects that can­not with­stand the fall­ing tem­per­a­tures. Of­ten but­ter­fly mi­gra­tion is not no­ticed by peo­ple as many do not tend to fly in large groups. How­ever, mourn­ing cloaks, monar­chs and a few other species have been known to mi­grate in this man­ner, of­ten with thou­sands of but­ter­flies mak­ing the trek south to­gether.

Monar­chs are the most stud­ied and re­searched mi­gra­tory but­ter­fly. Their gor­geous colour, amaz­ing abil­ity to fly such a long dis­tance and re­cent de­clin­ing num­bers have brought this beauty into the public eye. Still, much is not known. How do they know where to fly? How do mil­lions find the same over­win­ter­ing sites, in many cases the same tree, when they aren’t the same but­ter­flies that were there the prior year? How are th­ese frag­ile crea­tures able to en­dure flights up to 2,500 miles away? Much is un­known, but re­search is on­go­ing in the pat­terns and lo­ca­tions of but­ter­fly mi­gra­tion.

A monarch but­ter­fly makes a pit stop on a milk­weed blos­som.

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