Welcome to
Caterpillars Count!

Caterpillars Count!

Choose a Submission Method

General Tips for Conducting Surveys

Survey branches

  • The survey branch should typically have leaves at least 5 cm (2 inches) long on average.
  • Survey the same section of leaves every time you monitor your survey branches. An easy way to keep track of this is to survey the leaves closest to the survey tag.
  • The leaves you survey should be no more than 6 feet off of the ground, although the plant you survey may be much taller.
  • Count each individual leaflet within a compound leaf (e.g. hickory, buckeye, ash, etc.) as one leaf for the purposes of this project.
  • Note that we have a special protocol for surveying coniferous branches described here.


  • Make sure you are comfortable estimating lengths in millimeters.
  • Familiarize yourself with basic reference points, like the length of your pinky fingernail, length to first or second knuckle, etc.
  • Arthropod length is from the head to the abdomen - we don't count the length of legs, wings, or antennae.
  • Only report arthropods 2 mm long or longer. Don't spend time sweating the small stuff!
  • It's okay to call something 'UNIDENTIFIED'! Better to record it as unidentified than to not record it at all!
  • Taking photos of the arthropods you find is optional, but we strongly encourage photos of caterpillars!

...And when you do find a caterpillar, please note whether it is:

Noticeably hairy or spiny
In a leaf roll
Inside a silk tent

Tips for Visual Surveys

  • Be sure to check both the upper and lower sides of every leaf in your survey carefully.
  • Don't forget that the survey also includes the associated twigs and petioles, so scan those as well.
  • Many arthropods can be well camouflaged and can look just like the leaf or twig they are on - you will have to be vigilant!
  • When doing a survey, disturb the branch as little as possible. If you move it too much, arthropods may fall off or fly away from the leaves you are hoping to survey.

Tips for Beat Sheet Surveys

  • Hold the beat sheet directly under a branch that has ~20-100 leaves on it (special instructions for conifer branches are here.
  • Whack the branch strongly enough to knock off arthropods, but not so strongly that twigs and leaves are damaged.
  • A stick between 1/2 - 1" in diameter works best.
  • The branch should be whacked exactly 10 times.
  • Hold the beat sheet in one place during all 10 whacks.
  • Spend at least one minute looking at your beat sheet - bugs that are small, or pale, or look like debris may not be obvious at first glance, especially if you are in poor light.
  • Be aware that some insects may be knocked into your beat sheet very briefly but will then fly away. Try to identify and count any arthropods that might fly away first (e.g., flies, moths, beetles) before counting the more sedentary ones.
  • After recording all of the arthropods that have fallen onto the sheet, count the number of leaves (or linear branch length sampled for conifers) on the branch that were directly above your beat sheet when you were beating.