You might be annoyed by the insatiably eating caterpillar that just appeared on your cabbage, but what there probably is a cool and really fascinating insect that looks almost alien and moves in a special way!
With their grubs and ungrubby crawling movement, you may not want to know if caterpillars have legs.
Where they rank in their distribution and mobility is way different from insects and invertebrates.
In This Article: we’ll give you a definite answer to the question we have all contemplated “do caterpillars have legs?” and some other amazing features of caterpillar anatomy!
Caterpillars Are Leggier than You Think!
Lepidoptera larvae (moth and butterfly) all possess legs. Most will have at least three true legs (the genuine legs of insects) and five pairs of prolegs.
The true legs will allow movement of the caterpillar, however, the prolegs are not used for locomotion, they will maintain the caterpillar in position while coordinating the movement of their body segments.
Caterpillars will grasp branches, stems and other firm physical structures to hold onto while they voraciously consume the plant material.
Caterpillars also have anal claspers which work in a similar manner to the true and prolegs.
Caterpillars Vary in the Distribution of Legs along Their Bodies
Certain species of caterpillars, such as Geometer moth caterpillars, possess a only single pair of prolegs along with rear claspers.
These organs can be used to grasp a surface, then they fold its body to its secondary position in order to move. Therefore its body is dragged along in blocks, inch by inch.
Some other caterpillar species, for example, have more ventral prolegs, which are distributed evenly over the length of the 3rd, 4th, 5th and 6th segments.
Anatomy of a Caterpillar
Caterpillars can look very distinctive externally from each other, in size, and in features like smooth or hairy skin or spines.
However, in their anatomy they have similarities in the anatomy of a caterpillar from different species.
Caterpillar Body Structure
Like a worm or grub, caterpillars have a segmented body structure.
In fact, the immature stage of the butterfly is a larval stage seen in all insect species.
Caterpillars have:
- A head
- Three thoracic segments, each with a pair of true legs
- Ten abdominal segments with three to five pairs of prolegs
- Anal prolegs on the last abdominal segment
Caterpillars Also Have Body Projections That Are Different to Legs
These are referred to as setae: the hairlike projections on the skin of a caterpillar.
Although they are not always apparent, most caterpillars have a minimum of 3 pairs of primary setae on the body segments of their abdomen.
Setae can differ considerably in appearance by being long and flexible or short and stout and a caterpillar may have additional pairs of secondary setae.
Other Body Structures of a Caterpillar
Here are some other unique structures found in caterpillar anatomy.
Sutures: Caterpillars have several cranial sutures that resemble very deep grooves in the face of the caterpillar.
The primary sutures are:
- the adfrontal and epicranial sutures – which appear as facial grooves
- the vertical triangle – a triangle created by the epicranial suture meeting the edge of the head capsule of the caterpillar.
Spiracles: these are tiny openings that are used by the caterpillar to breathe. They are located on both the first thoracic segment of the caterpillar and on each abdominal segment.
Pinnaculum: this is the hardened area of skin where the setae emerge from, and it can vary in size, colour and prominence between species.
Prothoracic shield: this is a dark colour plate present on the first thoracic segment, in some species.
Prespiracular group: this is a group of setae that sit in front of the spiracle on the first thoracic segment. The number of setae in this grouping is useful in species identification.
Crochets: these are small hooked structures located at the end of a caterpillar’s prolegs, and can be arranged in a number of ways.
Recognising Caterpillar Legs and Other Anatomical Features Can Help You Identify and Eradicate Pest Species
You probably already know that for any good-sized vegetable garden, caterpillars are arguably the most significant pest.
Because caterpillars literally eat all day, they will chew on your plants no matter what stage of growth they are in, posing a threat to precious leaves, edible fruit or stems, etc.
Importantly, if you practice organic gardening, you have no intention of eliminating beneficial non-pest butterflies and moths that also call horti-culture their home.
Organic gardens need to be calculated and exacting in their approach to pest control. Pesticides may be somewhat effective, however, it is possible to create a list of the more troublesome and catastrophic sets of pests to manage.
Having a basic know-how of the anatomy and physical attributes of the common insect pest caterpillar will help you succeed in managing your garden.
Learning resources usually exist: Many agricultural extensions have guides and ticks to help you with identification of caterpillar pests to vegetable gardens.
Nature-friendly Methods of Keeping Caterpillars at Bay
Whether your plan is to be organic or not, you can expect a lot of caterpillar control tactics will be somewhat simple and effective in protecting the crops you have worked hard to grow.
These include:
- Identifying and removing the caterpillars from your plant. You can remove the offending caterpillars right off your plant, and put them in a bucket of water to kill them. Wear gloves to do this as some caterpillars can create allergic reactions and rashes.
- Bacillus Thuringiensi (BT) pesticides. This is the world’s most widely used biological pesticide. It is a bacteria that has several strains that are toxic to many insect pests. It works on cabbage worms and multiple caterpillar species that will perish if they eat plant material treated with BT.
- Natural predators of caterpillars. Ladybugs will eat the caterpillar eggs and parasitic wasps will hunt down and eat any caterpillars. Getting birds to come near your garden will also help control the caterpillar population, though they might take a bite out of your soft fruit. Backyard chickens and ducks will also easily take care of pest caterpillars for you.
- Neem oil. This essential oil is a very effective insecticide and will eliminate caterpillars on treated plants.
- Companion plants. Pungent herbs are effective at deterring caterpillars nearby our precious tomatoes or summer squash. Mentions herbs such as basil, thyme or mint to deter the hungry caterpillars in your garden!
Rounding Up
It can easily be overlooked that caterpillars don’t stay too long.
Caterpillars are just immature butterflies and moths that really enhance a spring or summer garden.
Some caterpillars are endangered, so by learning more about your chubby crawling guests in your garden, you can help to ensure you are not compromising the biodiversity in your garden whilst protecting your plants.