Daddy long legs, also known as harvestmen, are a group of arthropods that are closely related to spiders. They have oval-shaped bodies and extremely long, thin legs. Daddy long legs are widespread and can be found all over the world in a variety of habitats. But when it comes to their anatomy, how many body parts do daddy long legs actually have?
Quick answer
Daddy long legs have two main body parts – the cephalothorax and the abdomen. The cephalothorax consists of the head and thorax fused together, while the abdomen contains the digestive and reproductive organs. In addition to these two main segments, daddy long legs have eight legs attached to their cephalothorax for a total of 10 body parts.
Cephalothorax
The cephalothorax is the anterior body region of daddy long legs that is made up of the head and thorax fused together as one segment. It contains the eyes, mouthparts, legs, and digestive system of the daddy long leg.
Head
The head is the front portion of the cephalothorax. It contains the eyes and mouthparts of the daddy long legs. Daddy long legs have a pair of simple eyes on top of their head that enable them to detect light and movement. Underneath the eyes are the chelicerae and pedipalps – mouthparts that help direct food into the mouth. The chelicerae are a pair of small appendages that grasp and macerate food, while the pedipalps are sensory and feeding structures.
Thorax
The thorax is the rear portion of the cephalothorax where the legs are attached. Daddy long legs have eight walking legs extending from their thorax. Each leg has seven segments – the coxa, trochanter, femur, patella, tibia, metatarsus, and tarsus. The legs are extremely long and slender, which is how the daddy long legs got their name. The legs allow them to move quickly and grasp onto surfaces as they crawl around hunting for prey.
Abdomen
The abdomen is the posterior body region of daddy long legs. It is narrower than the cephalothorax and joined to it by a thin waist-like stalk. The abdomen contains the digestive system and reproductive organs.
Digestive system
Within the abdomen is the digestive system of the daddy long legs. They have a sucking stomach that allows them to digest food externally before ingesting it. The prey is crushed using the chelicerae and pedipalps. Digestive enzymes are secreted onto the food to pre-digest it into a liquid form. This liquid is then sucked back up through the mouth and into the intestinal tract for full digestion and nutrient absorption.
Reproductive system
The reproductive organs are also housed in the abdomen. Male daddy long legs have testes that produce sperm received by the female’s ovaries. Fertilization is internal and the female lays fertilized eggs. Young daddy long legs hatch from eggs and molt several times as they grow before reaching adulthood.
Legs
Daddy long legs have a total of eight legs – four pairs attached to their thorax segment. Each leg consists of seven parts moving from the body out:
Coxa
The coxa attaches the leg to the thorax. It allows some side-to-side movement at the base of the leg.
Trochanter
The trochanter is a short rigid segment after the coxa. It provides stability and attachment points for muscles.
Femur
The femur is the first long, slender segment of the leg. It contains muscles that enable the leg to extend and flex.
Patella
The patella is a short but movable segment with a bending joint.
Tibia
The tibia is the second lengthy, narrow leg segment after the femur.
Metatarsus
The metatarsus comes after the tibia. It is another long slender stalk of the leg.
Tarsus
The tarsus is the terminal segment of the leg that ends in a claw. This claw helps anchor the daddy long legs as they climb and latch onto surfaces.
Total Body Parts
In summary, daddy long legs have the following body parts:
- Cephalothorax:
- Head – Eyes, mouthparts
- Thorax – Legs (4 pairs)
- Abdomen:
- Digestive system
- Reproductive system
- 8 Legs:
- Coxa
- Trochanter
- Femur
- Patella
- Tibia
- Metatarsus
- Tarsus
So in total, daddy long legs have 2 main body segments, the cephalothorax and abdomen, along with 8 legs attached to the cephalothorax. This makes for a total of 10 body parts.
| Body Segment | Components |
|---|---|
| Cephalothorax | Head (eyes, mouthparts) Thorax |
| Abdomen | Digestive system Reproductive system |
| 8 Legs | Coxa Trochanter Femur Patella Tibia Metatarsus Tarsus |
| Total Body Parts | 10 |
Comparison to other arachnids
Daddy long legs have a similar body plan to other arachnids like spiders, scorpions, ticks, and mites. All arachnids have two main body segments – the cephalothorax and abdomen – along with four pairs of walking legs attached to the cephalothorax. However, other arachnids may have additional specialized appendages and mouthparts not found on daddy long legs.
- Spiders – 4 pairs of walking legs, plus 1-2 additional pairs of sensory pedipalps. Also have fangs and silk-producing spinnerets.
- Scorpions – 4 pairs of walking legs, plus enlarged pedipalps forming pincers. Also have a long tail with a venomous stinger on the end.
- Ticks – 4 pairs of legs. Mouthparts are adapted for blood-feeding.
- Mites – 4 pairs of legs. Tiny arachnids sometimes parasitic on plants, animals, and humans.
So while daddy long legs share the standard arachnid body pattern, they have adapted to their unique environmental niches by evolving extremely elongated legs for rapid movement as well as flexible mouthparts to slurp liquid from their prey.
Conclusion
Daddy long legs have a total of 10 body parts – a cephalothorax containing the head and fused thorax, an abdomen housing the digestive and reproductive systems, and 8 lengthy, spindly legs. These adaptations allow daddy long legs to hunt effectively across many habitats as they search for small prey to consume. Their specialized anatomy distinguishes them from spiders and other close arachnid relatives.
