Study The Caterpillar

The monarch caterpillars.

       The  eggs  of  butterflies  are  interesting  microscopic  objects,  as  they  are usually  covered  with  a  hard  shell,  and  are  of  various  shapes  and  colors. The  majority  of  insects  pass  through  a  regular  series  of  changes.  The ''young''  on  escaping  from  the  egg  is  known  as  the  larva.  The ''larvae''  are  soft  creatures,  with  the  body  in  segments,  not  unlike  earthworms.  When  they  have  no  distinct  head  and  no  limbs  they  are  called maggots;  when  they  have  a  horny  head  and  no  limbs,  or  only  jointed  legs, they  are  known  as  grubs;  and  when  they  are  furnished  with  head,  joined legs,  and  pro-legs,  they  are  called  caterpillars.  After  the  final  moult  the larva  passes  into  the  ''pupa''  state,  and  is  sometimes  known  as  a  chrysalis. Before  taking  this  form  the  larva  usually  selects  some  shelter,  and  very  often also  makes  for  itself  a  protective  case  or   ''cocoon.''  After  a  period  of  quiet it  issues  from  the  shelter  as  the  ''imago‚''  or  adult  insect,  furnished  with wings.

Required for Observation In The Classroom: A  diagram,  illustrating  the  metamorphoses  of a  caterpillar,  will  be  necessary  while  giving  this  lesson;  but  the changes  should  be  studied  from  the  insects  themselves.
       The  eggs  and  the  young  caterpillars  of  the  common  cabbage-butterfly  may  be found  in  any  vegetable  garden,  on  the  leaves  of cabbages,  during  April  and  May,  and  again  about  two  months  later (the  second  brood).  The  caterpillars  may  be  fed  on  cabbage  leaves, and  observed  from  day  to  day. 
       If you cannot locate one of these in your garden at home there are companies that sell chrysalis for students to observe a butterfly transformation all over the web!

Method of Student Observation: 

• Exhibit  a  cluster  of  the  eggs,  and also  a  picture  of  the  egg  as  seen through  a  microscope.
• The  structure  of  a  caterpillar should  be  illustrated  by  diagram or video;  but  live  caterpillars  should  also  be  exhibited.
•  If  the  caterpillar  of  the  cabbage- butterfly  cannot  be  obtained,  any other  will  do,  for  all  are  similar  in their  general  characteristics,  except that  the  number  of  claspers  varies from  two  to  five  pairs.
• The  process  of  molting  should be  observed  if  possible.  The  approach of  molting-time  may  be  known  by the  temporary  fasting  of  the  insect.
  
• A  chrysalis  should  be  exhibited, and,  if  possible,  the  final  molting watched  at  intervals.
  

How to Grade Study Notes For Student Journals: Every student will need a journal to write in weekly for this online nature study series. Teacher will assign the weekly content in advance.

• Make sure the facts are: written in complete sentences, the first word of each sentence capitalized, and a period should be included at the end of each sentence.
• Spell check your vocabulary and write the words correctly.
• Dress up your journal entries with student clip art, drawings of your own in color or in black and white.
• Student may also include photographs of their own taking for extra credit.

Look for the following facts about caterpillars inside of student journals. Assign a point value to the quality of the content.

• Eggs - Laid  by  butterflies  on  the  proper food-plants.  Attached  by  a  gummy substance.
  
• Structure - Body  made  up  of several  segments,  the  number  usually given  as thirteen,  counting  the  head as  the  first.
  
• Head -  Covered  with  a  hard skin.  A  pair  of  jaws.  Twelve  very small  eyes.
  
• Limbs - Six  legs one  pair  on each  of  the  2nd,  3rd,  and  4th  segments.  In  addition to  these  legs, the  caterpillar  has  five  pairs  of  pro- legs,  each  one  provided  with  a circlet of  little  hooks.  The  pro-legs  are often  spoken  of  as  the  claspers.
  
• Moulting - A  caterpillar  casts its  skin  several  times  during  its growth.  The  old  skin splits,  and reveals  a  new  one  beneath.
  
• Final  Moult - This  occurs  when the  caterpillar  is  full  grown,  and  the insect  then appears  as  a  chrysalis. 
  

Video at Youtube for Students to Watch:

1. Watch a Monarch Caterpillar Change into A Chrysalis by The Jefferson Lab
2. What's inside a caterpillar ''cocoon? ''

Make Graphic Illustration of Caterpillar Metamorphosis: Draw from real-life observation or from a video or the photograph below.

       ''This caterpillar of the monarch butterfly-hanging head downward-is ready for the metamorphosis. It hatched from a minute egg in late summer and has grown for two weeks. It stopped eating and wandered restlessly about and has now chosen a secure spot on which it has spun a small thick carpet of silk. It walked over this until the hind feet with their many minute hooks were entangled in the silk, then letting go its hold with the other pairs of feet, it hung head downward, motionless. The skin now loosens, and after twenty-four hours splits over the head. At this stage the caterpillar becomes active: by muscular contraction it works the skin off upward into a small shriveled mass; then during the few seconds longer that it still remains attached to the skin, it reaches out its slender end (which also is supplied with hooks) and with great effort and force pushes it up into the silk carpet. the whole process has taken but three or four minutes by the watch. The creature now rests. Slowly the shape changes, the segments above contracting, the form rounding out; and behold an emerald-green chrysalis studded with gold spots! In this form the insect is wholly immovable-although wonderful changes are taking place within, absorption of structures useful to the caterpillar and perfecting of others necessary for the new life of the butterfly. In two weeks the pattern of the butterfly's brown and orange wings begins to show through, finally the chrysalis skin, in its turn, splits over the head, and the butterfly crawls out. Such is one of the simplest and best-known stories of insect metamorphosis.''

Arts/Crafts Projects:

• Make my caterpillar stick puppet... - 4th, 5th, and 6th Graders
• Craft a pom-pom caterpillar SWAPS for girl scouts here - 1rst -5th Grade
• Make a very hungry caterpillar... - kindergarten through 2nd grade

Extended Learning Content: 

• The Cocoon - Bible Lesson based upon the transformation of a caterpillar into a butterfly.
  
• Caterpillar On The Wall - illustrated poem

Free Student Clip Art: Clip art may be printed from a home computer, a classroom computer or from a computer at a library and/or a local printing service provider. This may be done from multiple locations as needed because our education blog is online and available to the general public.

Illustrations of Caterpillars, their eggs on a leaf, their chrysalis,
and anatomy like: head, legs and claspers.