How to Dissect a Grasshopper (“Bug Doc” Dave Shetlar)

Summary

In this video, Dave Shetlar, the 'Bug Doc' and urban landscape entomologist at The Ohio State University, demonstrates how to dissect a grasshopper. He explains the necessary tools, such as dissecting pans, fine scissors, and insect pins, as well as the steps to carefully remove the grasshopper's appendages and open its exoskeleton. Inside, he highlights key structures like the crop, proventriculus, gastric caeca, Malpighian tubules, and nerve cord, offering a fascinating look at the internal anatomy of a grasshopper. This educational demonstration provides insight into entomological dissection and the biology of insects.

Takeaways

• 😀 The narrator, Dave Shetlar, is an urban landscape entomologist at The Ohio State University, and his nickname is 'Bug Doc.'
• 😀 The main goal of the video is to guide viewers through the process of dissecting a grasshopper to explore its internal anatomy.
• 😀 If you can't find fresh grasshoppers, you can purchase preserved Lubber grasshoppers online for dissection.
• 😀 The tools required for the dissection include a dissecting pan, fine scissors, insect pins, and boiled distilled water.
• 😀 A dissecting pan can be made from a food cup with melted candle wax to stabilize the insect during dissection.
• 😀 The dissection process begins by removing the grasshopper's appendages (legs and wings) to expose the body for the incision.
• 😀 The first incision is made along the mid-dorsal line of the grasshopper, starting behind the last abdominal segment and cutting through the thorax.
• 😀 After the incision, the internal parts of the grasshopper are revealed, which initially appear as 'goo,' necessitating the use of boiled water to reveal the structures.
• 😀 Key internal structures observed during the dissection include the crop, proventriculus (gizzard), gastric caeca, Malpighian tubules, and the hindgut.
• 😀 The gastric caeca help with digestion, especially for plant material, by containing microbes that break down hard-to-digest food.
• 😀 The Malpighian tubules act as excretory organs similar to kidneys in humans, and they connect to the midgut and hindgut.
• 😀 The video concludes with a view of the nerve chord running down the mid-ventral line of the grasshopper, with segmental ganglia visible in each segment.
• 😀 Dave encourages viewers to not only observe the external anatomy of grasshoppers but also explore their internal anatomy for a deeper understanding.

Q & A

What is the main purpose of the video?

The main purpose of the video is to guide viewers through the process of dissecting a grasshopper and exploring its internal anatomy, led by Dave Shetlar, the urban landscape entomologist at The Ohio State University.

What are the main tools needed for dissecting a grasshopper?

The main tools required for the dissection are a dissecting pan, fine scissors, insect pins, and boiled distilled water. Additionally, a candle wax base is used to stabilize the grasshopper in the pan.

Why is boiled distilled water used during the dissection?

Boiled distilled water is used to prevent air bubbles from forming, which can obscure the internal structures and make it harder to observe the grasshopper's anatomy.

What is the significance of the crop in a grasshopper?

The crop is the part of the grasshopper's digestive system where food is initially stored before being processed further. It acts as a temporary storage space for ingested food.

What is the proventriculus, and what does it do?

The proventriculus is a grinding organ located in the grasshopper's digestive system. It functions similarly to a gizzard in birds, breaking down food mechanically to aid in digestion.

What are the gastric caeca and their function in the grasshopper?

The gastric caeca are lobe-like structures in the midgut of the grasshopper. They help break down tough plant material by hosting microbes that assist with the digestion process.

What role do the Malpighian tubules play in a grasshopper's anatomy?

The Malpighian tubules are excretory organs in the grasshopper, functioning similarly to kidneys in humans. They help filter waste and maintain the insect's internal balance by excreting waste products.

What is the nerve cord, and what does it do in a grasshopper?

The nerve cord is a long structure running along the grasshopper's ventral side. It is part of the insect's central nervous system and includes segmental ganglia, which are collections of nerve cells responsible for processing sensory information and controlling movement.

What steps are involved in the dissection process?

The dissection process involves removing the grasshopper's appendages (legs and wings), making a careful incision along the mid-dorsal line, and then submerging the body in water to expose internal structures like the crop, proventriculus, and Malpighian tubules.

Why is it important to remove the grasshopper's wings and legs during dissection?

Removing the wings and legs is crucial because they obstruct access to the internal body structures, making it difficult to perform a thorough dissection along the mid-dorsal line, which is necessary to examine the internal organs.