Saturday, September 23, 2023
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Diana’s Quiz – September 23, 2023

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Science & NatureWhat is That?What Is That … Green Caterpillar?

What Is That … Green Caterpillar?


While we are invigorated by the gradual greening of spring, we still find comfort in looking at pictures of the “greenness” from previous summers at our cottage.  We find the various shades and textures displayed by the larval stage of members of the butterfly and moth family of insects fascinating, in particular those with green caterpillars.  The life cycle of both butterflies and moths is similar, consisting of four stages: egg; larva (termed caterpillars); pupa (some butterfly pupae are termed chrysalis); and, adult.

The primary function of caterpillars is to eat and grow in preparation for the next stages of their life cycle.  These eating machines are much more difficult to spot than their winged adult stage since they are sedentary and their colouring often blends in with the leaves they are feeding on, a tactic termed crypsis. We find it especially rewarding when we spot, and manage to photograph, green-camouflaged butterfly and moth caterpillars.  We want to share some of this greenness as we patiently await the arrival of warmer weather so we can spend time at the cottage.

The Abbot’s sphinx moth larva starts off as a white caterpillar.  The mature larva is tan coloured with large green splotches on each segment, blending in with the grape vines and Virginia creeper on which it feeds.  It can grow to 7.5 centimeters in length.  It is a member of the hornworm moth family.

The Canadian tiger swallowtail butterfly caterpillar is brown and white when it hatches, resembling bird droppings.  The larva matures into a smooth green caterpillar with two eye spots on its enlarged thorax (front end).  The caterpillar feeds on leaves, usually high up in willow, poplar, basswood, and birch trees.  Larva can grow to 6 centimeters in length.  It belongs to the swallowtail butterfly family.

The crowned slug moth caterpillar has a flattened pale green body and sports numerous stinging spines that radiate out from the perimeter of its body and down its back.  It is recommended that you not handle them.  This caterpillar is small, growing to a length of 1.5 centimeters.  The caterpillars feed on oak as well as basswood, beech, elm, hickory, and maple.  One of our great nieces delighted us by pointing out and asking about this individual at the cottage one day – fortunately she did not touch it.  This species is a member of the slug moth family.

Young Io moth caterpillars are orange with grey spines, later developing a red and white stripe along their sides.  As they mature, the orange turns green and the spines become branched.  These spines can cause skin irritation so it is recommended that you not pick them up.  Mature larva can grow to 6.5 centimeters in length and feed on the leaves of maple, cherry, oak, poplar, and willow. They belong to the giant silkworm and royal moth family.

Many people are familiar with the yellow, white, and black striped caterpillar of the monarch butterfly which typically is found feeding on milkweed plants.  Less commonly observed is the green chrysalis or pupal stage from which the adult butterflies emerge.  The caterpillars can grow to 7.5 centimeters while the chrysalis is 5 centimeters in length.  Monarchs are members of the brushfoot butterfly family.

Promethea moth caterpillars start out sporting blue-green, yellow, and black bands.  Mature larvae are blue-green with rows of differently-coloured knobs, termed tubercles.   The caterpillars have two pairs of long orange-red tubercles on the two front segments, one pair of long yellow tubercles on the rear segment and short black tubercles on all the remaining body segments.  Mature caterpillars can grow to 8 centimeters in length, feeding on wild cherry, maple, apple, basswood and bitch.  These caterpillars are also members of the giant silkworm and royal moth family.

We are looking forward to seeing adult moths and butterflies at the cottage this summer flying about and feeding on the nectar of blossoms.  We will also be searching for their caterpillars in the plants they eat and where they hide while they try not to be eaten by birds and other predators.

We relied on two sources while preparing this article: David L. Wagner’s Caterpillars of Eastern North America; and, Amy Bartlett Wright’s Peterson First Guides – Caterpillars.




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