GRASSHOPPER DISSECTION    NAME____________

Purpose:
• observe the appearance of various organs found in a grasshopper
• Name the organs that make up systems of the grasshopper
• to differentiate between invertebrate anatomy
• To observe the external and internal characteristics of a  grasshopper
• to determine the sex of a grasshopper using external anatomy.

Materials:
 • safety goggles, gloves,  magnifying glass, a lab apron, plastic zip lock bag, preserved grasshopper,  pen, dissecting tray, paper towels, scissors, forceps, dissecting needle, and dissecting pins.

BACKGROUND: 
 The grasshopper belongs to the Class Insecta which is characterized by having three body regions (head, thorax and abdomen), one pair of antennae, and six legs.The body of the grasshopper is divided into: 
 Head  which as many sensory organs and the brain, 
Thorax - consisting of three segments to which the legs and wings are attached  Abdomen - composed of many segments that ends with the reproductive organs.  The body of the grasshopper is covered by a hard exoskeleton composed of chitin, a substance similar to your fingernails.
The thorax consists of three parts: 
Prothorax - the large anterior portion - bearing one pair of jointed walking legs 
Metathorax - the middle section - bearing the second pair of jointed walking legs and 1st  pair of wings  (protective)
Mesothorax - the posterior section - bearing the pair of jumping legs and 2nd pair of wings (flying)The anterior wings of the grasshopper are thickened, acting as shields for the larger pair of flight wings. The wings are derived from the cuticle and have thickened portions (called veins) which strengthen them. Stretch out the wings and examine the anterior protective wings and the flight wings.
The abdomen consists of 11 segments, the terminal ones being modified for reproduction. The male has a blunt terminal segment while the female has four conical prongs, the ovipositors, which are used in egg laying.Along the lower sides of the thorax and abdomen are 10 pairs of small openings, the spiracles. These connect to a system of elastic air tubes, or tracheae, that branch to all parts of the body and constitute the respiratory system of the grasshopper.

The head has one pair of slender, jointed antennae, two compound eyes, and three simple eyes. The mouth parts are specialized for cutting and chewing leaves. They consist of:             Labrum - the broad upper lip
Hypopharynx - the tongue
Mandibles - two heavy blackish jaws with teeth along the
 inner margin.  The mandibles move up and down.
 Maxillae - two smaller jaws that move side to side
 Labium - the lower lip
 Palp - maxillary and labial palps are sensory appendages
During feeding, food is held by the forelegs, labium, and labrum. Secretions from the salivary glands lubricates the food and it is chewed by the mandibles and maxillae.

ON YOUR GRASSHOPPER FIND AND IDENTIFY THE FOLLOWING  STRUCTURES

	1.
	2.
	3.
	4.
	5.
	6.
	7.
GRASSHOPPER MOUTH PARTS	8.

Procedure
1. Put on your lab apron, safety glasses, and plastic gloves.  Obtain a preserved grasshopper and place it in your dissection pan.    The terminal segment of males is blunt, whereas that of females is modified to lay eggs and is called an ovipositor. What is the sex of your grasshopper? _{______________________}

Position your grasshopper dorsal side upward, insert your scissor point into the anus and cut along the dorsal surface of the abdomen and thorax. Do Not cut into the head.   Pin the exoskeleton aside. Be sure to keep your scissors close to the body wall to avoid damage to the internal structures. 

    The digestive system fills most of the internal cavity of the grasshopper (except in mature females which may be filled with eggs). A muscular tube, the esophagus, conveys food from the pharynx into a large storage organ, the crop. Chewed food is stored in the crop. Next is the stomach to which are attached six double fingered-shaped digestive glands, the gastric caecae, which produce enzymes that are secreted into the stomach to aid in digestion. Because most of the digestive tract is lined with chitin (except the stomach and crop) digestion and absorption take place mainly in the stomach. The digestive tract continues as the intestine.  It leads to the short rectum which opens to the exterior via the anus.  The rectum removes excess water from any undigested food. 
    The hair-like tubules lying over the intestine are Malpighian tubules, the excretory organs.  These tubules remove urea and salts from the blood. 
    The sexes of the grasshopper are separate, and their reproductive organs are in the terminal abdominal segments.

FILL IN THE DATA TABLE BELOW 

LABEL THE GRASSHOPPER USING THE  WORDS ON THE ABOVE DATA TABLE   
 

FILL IN THE BLANKS ON THE FOLLOWING DATA TABLE

LABEL THE GRASSHOPPER USING TERMS THROUGH OUT THE LAB AND FROM THE DATA TABLE

ESSAY:  DRAW AND EXPLAIN COMPLETE AND INCOMPLETE METAMORPHOSIS

http://www.personal.psu.edu/faculty/w/x/wxm15/Online/Zoology%20Unit/Arthropoda/Insects/grasshopper_lab01.htm TAKE A LAB TEST

Grasshopper Dissection

Introduction: 

Insects are arthropods with jointed appendages, segmented bodies, and anexoskeleton composed of chitin. Insects are in the class Insecta, & are the largest and most diverse group of animals on earth. The genus Romalea is a large grasshopper common in the southeastern United States. Insects have three body regions (head, thorax, & abdomen), 3 pairs of legs attached to the thorax, a single pair of antenna attached to the head, mouthpartsadapted for chewing or sucking, and two pairs of wings. Some insects may have a single pair of wings or be wingless. Insect legs are often adapted for digging, crawling, jumping, or swimming. The insects are mostly terrestrial, they breathe air which enters small lateral openings on the body called spiracles and circulates in a system of ducts to all organs and tissues. Their chewing or sucking mouth parts are adapted  for  feeding on plant or animal materials.

Classification: 

Kingdom - Animalia
Phylum - Arthropoda
Class - Insecta
Order - Orthoptera

Objective: 

Identify & label the internal & external anatomy of a grasshopper.

Materials: 

Lab apron, gloves, eyeglasses, dissecting pan, dissecting kit with forceps & scalpel, t-pins, magnifying glass, preserved grasshopper, paper, pencil.

Procedure (External Anatomy): Examine the entire grasshopper and identify the major subdivisions and parts of the body.  

1. Obtain a preserved grasshopper & rinse off any preservative with water. Place grasshopper in the dissecting pan.

2. Observe that the body of the grasshopper is divided into 3 regions --- the head, the thorax, and abdomen. Label these on Figure 2.
3. Examine the head and locate the following parts: 
   HEAD
   Antennae (two, slender appendages)
   Compound eyes (2, large lateral)
   Ocelli (or simple eyes) - 3, small, between compound eyes
   Mouth parts - Labrum (upper lip), mandibles (jaws) below the labrum, maxillae located behind the mandibles to help cut & hold food, and the lower lip or labium

  

1. Labrum	4. Labium
2. Mandibles	5. Maxillary Palps
3. Labial Palps	6. Maxillae
7. compound eye	8. ocelli

 

4. Label the mouthparts, eyes, and antenna on Figure 1.
5. Using forceps, remove each of the appendages from the head, and attached them to table 1.
6. Examine the following appendages on the thorax (middle section of the grasshopper's body):

      THORAX
     Legs (first 2 pairs are for walking & the last pair are for jumping)
     Wings (forewings have a leathery appearance & protect the hind wings)

7. Using forceps, remove one of the walking legs and identify these parts --- the coxa connects the femur (the thickest part of the leg) to the grasshopper's body; a slender, spiny tibia connects the femur to thetarsal segments (lowest part of the leg). Label these on Figure 2.
8. Remove a jumping leg and attach the walking leg & jumping leg to Table 1.
9. Raise both pairs of wings and locate the first abdominal segment.
10. Locate the tympanic membrane or eardrum on the first abdominal segment. Label this on Figure 2.

11. Using a magnifying glass, locate the spiracles or tiny pores for respiration on each side of the abdominal segments.  Label these on Figure 2.
12. Determine if your grasshopper is a male or female by looking at the end of the abdomen. Females have a tapered abdomen that ends in a pointed egg laying tube called the ovipositor. Male have a more rounded abdomen that turns upward.

13. Label the ovipositor on Figure 2.

ABDOMEN
Spiracles (small openings on the side of somites or body segments)
Auditory Organs (two located laterally on the 1st body somite or segment)
Ovipositor (on female) 
 

Observations & Conclusion:

Figure 1 - Grasshopper Head (Label ALL parts.)

 

Figure 2 - External Grasshopper anatomy (Label ALL parts.)

Table 1 - External Appendages of the Grasshopper (Attach ALL parts.)

Antenna
Labrum
Mandible
Maxilla
Labium
Forewing
Hindwing
Walking Leg
Jumping Leg
Sex of Grasshopper

 

1. Which region of the insect's body is specialized for sensory functions? Explain your answer.

 

2. Which region of the insect's body is specialized for movement & explain why?

 

3. What is the purpose of compound eyes? of simple eyes?

4. List the grasshopper's mouthparts & their functions.

 

 

5. How are the ends of the legs adapted for holding onto plants?

 

6. How is the third pair of legs adapted for jumping?

 

7. Describe the differences between the two pairs of wings (appearance & function).

 

8. How does the tympanic membrane help a grasshopper?

9. What system do spiracles open into on a grasshopper?

10. Do all abdominal segments have spiracles? Are there any spiracles on the thoracic segments?

11. How did you determine the sex of your grasshopper?

 

12. Explain how grasshoppers dig holes to lay their eggs.