Reproductive System of Earthworm

The common earthworm, Lumbricus terrestris, is a cylindrical, segmented and tubular worm which plays an important part in maintaining the ecosystem. The reproductive system of earthworms is not very complicated given that all species are hermaphrodites.

That is, they each have a set of female and male organs. 

It would help if you remembered that earthworm reproduction is not always parthenogenetic, which is a form of asexual reproduction. As advanced students of biology, you must study further on sexual and sexual types of reproduction.

Let us proceed and find out more about how earthworms reproduce.

How do Earthworms Reproduce?

To answer that, we need first to identify the reproductive organs of an earthworm. Let us first analyse the male reproductive system.

Male Reproductive System 

The most important organs are listed below.

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• Testes & Testes Sac: Two pairs of testes are located at the 10th and 11th segments. These produce spermatogonia. The sac is white, with wide walls and is filled with fluid. The sac is bi-lobed, and the first sac at the 10th segment is larger than the second once since it houses the earthworm’s seminal vesicles as well.

• Seminal Vesicles: An earthworm has two pairs of seminal vesicles. Experts state that seminal vesicles of earthworms evolved nearly 1 million years ago and precedes parthenogenesis. The spermatogonia mature in these vesicles and develop into spermatozoa. These are mature sperms; producing them is the main function of testes in earthworms.

• Seminal Funnel: Earthworms have two pairs of seminal funnels. These are located at the 10th and 11th segments. These ciliated funnels play an essential role in passing on spermatozoa to the Vasa deferentia and onwards.

Female Reproductive System

The most important organs of the female reproductive system of earthworm are the following - 

• Ovaries: There is a single pair of ovaries attached to the 12th and 13th septa. Ova and multiple ovarian lobules rest within an earthworm ovary. Once the ova matures, it gradually moves towards the coelomic cavity. Before maturation, they rest in an ovary’s dorsal end.

• Oviducal Funnel: A saucer-shaped structure, an oviducal funnel is located in the 13th segment. The funnel plays an important role in collecting matured ova after an ovary of earthworm produces them. The funnel ends in a short and conical tube-like structure called an oviduct. Two of these oviducts meet at the 14th segment and then open out into the external genital pore.

• Spermatheca: Each earthworm has 4 pairs of spermatheca. They are flask-shaped and have a short diverticulum. This is the area where sperm is stored. The 4 pairs are located laterally at the 5th to 9th segments.

A task for you: Identify the various segments of these worms in your school’s laboratory. Try to locate the 12th and 13th septa. Some earthworms have naturally well-developed clitellums. That is why there is a ‘bulge’ on an earthworm. Clitellums are also found in leeches.

Earthworm Copulation

Now that you have an idea of the physical parts of the reproductive system of earthworms, we come to copulation. Earthworms are nocturnal creatures. Copulation generally occurs during night-time in the months of July to October, i.e. monsoon. 

Earthworms are simultaneous hermaphrodites, and hence reproduction involves both copulation and cross-fertilisation.  

Copulation is completed once spermatozoa from one worm is transferred to another. During mating seasons, two worms will attach ventrally to each other, allowing prostatic fluid and sperm exchange via an earthworm’s spermathecal pore. 

These are then stored within the respective spermatheca.

This process of copulation lasts for about an hour. The worms will then separate and eggs in cocoons will be laid after a few days.  Earthworms have no larval stage; a young worm emerges from these cocoons, fully formed. These young individuals have no clitellum.

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Known for their iteroparous nature, earthworms also never stop growing. Some species have been known to grow to as much as 14 inches long. These invertebrates can dig down up to 6.5 feet. 

Did you Know Your Average Earthworm is Nearly as big as Your Teacup?

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Quick Tips To Understand the Reproductive System Of Earthworm

Biology is a subject that some students find tough and some find it easy because it has more things to remember in this subject and there are practical things that are done in the lab. It is vast but it is an interesting subject. In order to ace in this chapter, students might follow the tips given below -

• Be attentive in class

Students might think they know the chapter on the Reproductive system of earthworms and might not be attentive to which they will be left behind with many doubts later or may not understand the chapter. So paying attention in classes always helps a student. It is the first step in understanding the chapter as a whole. 

• Read the chapter 

Students should keep in practice to always read or study the chapters after it is taught in the class. This will help the students to see whether they have understood the topic or not. It can be a lot to remember about the reproductive system of earthworms, such as the copulation, male and female reproductive system of earthworms. In order to memorise the details, students should read the chapter thoroughly. 

• Write down the doubts - 

After studying the topic of the reproductive system of earthworms, students might have some doubts about which they should write them down so that they can ask their teacher later. 

• Make notes 

Students should always make notes while the teacher teaches in class. They can make the notes in short but in a way that they can understand and will be easy to revise just by reading the notes. They can always make their own notes by referring to the book and notes. This will help the student to learn and remember in the process of making the notes for the Reproductive system of earthworms. 

• Practicals

Students should be attentive while the practicals are done in the lab, by watching the experiments they can get the knowledge of the topic. This has helped many students to remember the topic. 

• Study to understand

Do not simply read the powerpoints, notes, and books. Try to understand the topic while reading it so that even if it is vast with many points and terms to remember, it becomes easier during the exams. 

• Discuss with your friends 

Discussing with others about the reproductive system of earthworms and other points from the chapter makes the topic more interesting because this will be more interactive. Friends can also share knowledge which might be important.

• Try to test yourself

After completing the topic students should take a test for themselves which will make the student know which concepts are not clear and can be cleared with the teachers or tutors. Vedantu offers online tutoring for students and doubts clearing sessions by learned teachers who can help the students understand the chapter in-depth.  

• Solve the questions

After completing the chapter on the Reproductive system of earthworms, a student should try to solve the questions given at the back of the chapter. This will cover half of the chapter’s topic and will help the students to know the type of questions are present in the chapter. The solutions to the questions are available on Vedantu’s official website that can be downloaded in PDF formats. 

• Solve previous question papers

This step will help the students who will appear for the board exams. They should collect the previous year’s question papers and try to solve the answers by themselves. This will give them some idea about the pattern of the question paper and the questions which are important on the Reproductive system of earthworms. They are available on Vedantu’s official website that can be downloaded and that will surely help the students prepare for board exams. The materials available on Vedantu are updated and latest according to the latest board syllabus. 

• Practice diagram

In biology students need to keep practising drawing the diagram because some questions might come in which makes the diagram might be important. Since the chapter on the reproductive system of earthworms has no diagram, students should focus on learning the points and anatomy of the reproductive system of both male and female earthworms. It will surely help the students in preparing better for the exams.