Mantis Shrimp Luke Brubacher

Taxonamy

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Malocrustaca
  • Order: Stomatopoda
  • Family: Odontodactylidae
  • Genus: Odontodactylus
  • Species: O. scyllarus

The mantis shrimp is the only genus in its family. But there are two species within that gene. I was unable to find information as to why the mantis shrimp is the only genus in its family.

A phylogenetic tree for Odontodactylidae.

Evolution

Many believe that mantis shrimp have not evolved at all, although with closer consideration multiple changes are evident.

One of the most noticeable traits is the raptorial appendages (red arrow). The raptorial appendages in the modern mantis shrimp are much larger and highly specialized for predation.

These are photos taken of engraved mantis shrimp fossils.

In recent years it seems the mantis shrimp has had no need to adapt as they seem to be fully prepared for everything in their natural environment. With the best, most complex eyes containing 16 colour-receptive cones (humans only contain 3) they can see ultraviolet lights to help avoid predators and track down prey. As well as an appendage that strikes with a spring-like motion, with the ability to strike 50 times faster than the blink of an eye (the same speed as a .22 caliber bullet), the mantis shrimp seems to be prepared for anything.

It takes 0.033 meters per second to blink.

Now on the other hand, humans are creating multiple issues including the destruction of many coral reefs in which the the mantis shrimp inhabit. Humans are constantly polluting the water through oil spills, fertilizer runoff, and human waste that is dumped into the ocean. Along with the carelessness of boaters and fisherman, the uneducated scuba diving of tourists and the increasing amount of cyanide injections in order to stun fish to collect for domesticated aquariums, it seems coral reefs are dying off by the day. In the future mantis shrimp will have to adapt to live with more toxic water levels. As well as be able to survive in open ocean floors where there is less places to find cover from predators. Possibly meaning the mantis shrimp will have to evolve with less bright, variant colours in order to blend in with its new surrounding.

The mantis shrimp has a narrow habitat range. The mantis shrimp primarily lives off the coast of India, Africa and Australia.

Reproduction

Mantis shrimp reproduce sexually.

The mantis shrimp generally reproduce all year round, but have peak mating season during the warmer months of the year. Mantis shrimp have two sexes, male and female. I was unable to find the genetics of the sexes of mantis shrimp. Male mantis shrimp tend to be much more colourful than the female mantis shrimp, the males vibrant colours attract females in order to mate. This is beneficial because female mantis shrimp often chose the strongest, most colourful male. Meaning that the males that carry the best genetics pass them onto the next generation. The fertilization is external. The male releases sperm out of its external copulatory organ, which is then collected by the female. Once the sperm is collected, the female uses it to fertilize her eggs that she is holding inside. After the eggs are fertilized, the female brings them to a burrow for safe development. Mantis shrimp have a gestation period of 9 - 60 days, the average is 40 days. Mantis shrimp babies are hatched from an egg.

Male and female mantis shrimp mating during peak mating season.

Eggs

Varying pictures of female mantis shrimp carrying their batch of eggs.

I was unable to find the amount of offspring in which a mantis shrimp typically has. But as seen in the picture above is a female mantis shrimp carrying her eggs, which I would estimate to be well over 500. This is reasonable for this organism because mantis shrimp babies often die off or get eaten, very rarely does the full batch survive. Once the eggs hatch it only takes about 35 to 70 days for the mantis shrimp to reach sexual maturity.

Genetics

The mantis shrimp uses DNA for its chromosomal material. I was unable to find the the number of chromosomes the mantis shrimp has, but they are very closely related to the common shrimp which has 254 chromosomes. I was unable to find how the chromosomes in the mantis shrimp are arranged. There are no known genetic conditions that affect mantis shrimp. Although some genetic conditions can be found in the common shrimp. Such as cramped shrimp which is a condition in which the tail is drawn under the shrimp's body and becomes so rigid to the point it is unable to be moved.

Dihybrid Cross

*These are created alleles and may not be scientifically accurate

Mantis shrimp with blue tail have the dominant trait for colouration (T). Mantis shrimp with red tail have the recessive trait for colouration (t).

Mantis shrimp with with arched antennules have the dominant allele for shape (A). Mantis shrimp with straight antennules have the recessive trait for shape (a).

A male mantis shrimp homozygous for blue tail and heterozygous for arched antennules mates with a female mantis shrimp heterozygous for blue tail and homozygous for straight antennules.

The female is (Ttaa) with the possibility of Ta or ta

The male is (TTAa) with the possibility of TA or Ta

This shows that 100% of of the offspring will have a blue tail. Also, 50% of the offspring will have arched antennules and 50% will have straight antennules. The genotypes of the offspring can be described as a 1:1:1:1 ratio.

  • 1: homozygous blue tail, heterozygous arched antennules
  • 1: homozygous blue tail, homozygous straight antennules
  • 1: heterozygous blue tail, heterozygous arched antennules
  • 1: heterozygous blue tail, homozygous straight antennules

Digestive System

Mantis shrimp have a complex digestive system.

The cardiac stomach plays a very important role in the mantis shrimp's digestive system. The folded and muscular stomach is lined with rows of stiff bristles, teeth and filtering setae known as gastric mill. The cardiac stomach is large enough to hold remains of prey. It opens directly from the mouth without intervening with the esophagus. The mantis shrimp ingests food through its mouth, the food is then sent to the cardiac stomach where it is mashed and grinded. After that, the mashed up food goes to the pyloric stomach where it is absorbed by digestive glands which contain many enzymes that break down food and absorb nutrients. Then, the remainder of the food is sent through the intestine where more nutrients is absorbed. Finally, the waste is sent to the anus and disposed of.

The main food source for the mantis shrimp is clams, crabs and snails although certain mantis shrimp eat small fish because they primarily use a spearing technique to kill prey. These food sources provide essential proteins and omega-3 acids to help the mantis shrimp grow stronger as their strength is the main attribute used for defense.

Mantis shrimp food sources.

A limitation to this diet is the potential lack of prey. Due to the destruction of reefs, mantis shrimp are able to find less and less food each day. Mantis shrimp are burrowers so they are able to survive initial damage done to a reef, but their food sources mainly live in open water so they will die off. Without a constant food source a mantis shrimp will not be able to thrive. In order to overcome these limitations the mantis shrimp may have to adapt to eating microscopic crustaceans and plankton.

Capturing Prey

The method a mantis shrimp will use to obtain its food will depend on where exactly it lives. Mantis shrimp that live in an area of a reef with a high concentration of snails, crabs and clams will use a crushing or smashing method where they will use their club like appendages to smash through their prey's shell. Whereas mantis shrimp that live in an area with a high concentration of small fish will use a stabbing method in which they will spear their prey with their sharp claw. When using these methods the mantis shrimp will hide back in its burrow until its prey passes, then the mantis shrimp will strike from behind with speed and precision giving its prey no time to react. The mantis shrimp uses these techniques as they are most effective for catching prey.

Mantis shrimp using its long appendages to reach out and grab a small damsel fish.

Circulatory System

The mantis shrimp transports substances around its body via blood stream. The mantis shrimp has an open circulatory system. An open circulatory system is when blood is pumped into a hemocoel with the blood diffusing back to the circulatory system between cells. With a single chambered, elongated heart enclosed in a pericardial sinus located above the gut, the mantis shrimp pumps blood throughout its body with a unique method. This type of transportation system is beneficial for the mantis shrimp because it allows blood to be pumped throughout the body under the high water pressure in the deep reefs. This is ideal because the mantis shrimp needs to be fast and nimble in order to kill its prey, without proper circulation the mantis shrimp would be unable to survive.

Diagram displaying the mantis shrimps heart.

I was unable to find information about what types of blood cells are present in the mantis shrimp.

Little is known about the immune system of mantis shrimp. Although, basic concepts as to how the common shrimps immune system works have been discovered. The shrimps immune system essentially "scans" the body to identify substances that it considers as foreign. The shrimps immune system will then differentiate between "self" and "non-self", meaning it is deciding whether the substance is naturally present in its body or is a an infection, parasite, etc.

Mantis shrimp exiting its burrow.

THE END

References

Bair, D. (2013). Odontodactylus brevirostris. Retrieved January 17, 2017, from http://animaldiversity.org/accounts/Odontodactylus_brevirostris/

Creationists love mantis shrimp. (2009, November 9). Retrieved January 17, 2017, from https://arthropoda.wordpress.com/2009/11/24/creationists-love-manits-shrimp/

Cover, J. (2015). Peacock Mantis Shrimp. Retrieved January 17, 2017, from https://aqua.org/explore/animals/mantis-shrimp

5 Causes of Coral Reef Destruction. (2017, January 01). Retrieved January 17, 2017, from http://www.leisurepro.com/blog/ocean-news/5-main-coral-reef-destruction/

Nguyen, M. (n.d.). Habitat. Retrieved January 17, 2017, from http://projectmantisshrimp.weebly.com/habitat.html

Schwartzkopf, S. (n.d.). DIGESTIVE SYSTEM. Retrieved January 17, 2017, from http://mantisshrimpsjs.weebly.com/digestive-system.html

Johnson, S.K. Handbook of Shrimp Diseases. Retrieved January, 10, 2017, from http://nsgl.gso.uri.edu/tamu/tamuh95001.pdf

Schwartzkopf, S. (n.d.). CIRCULATORY SYSTEM. Retrieved January 17, 2017, from http://mantisshrimpsjs.weebly.com/circulatory-system.html

Diagram Photo References

Mantis Shrimp Evolutionary Diagram (2009, November 9). Retrieved December, 18, 2016, from https://arthropoda.wordpress.com/2009/11/24/creationists-love-manits-shrimp/

Schwartzkopf, S. (n.d.). Mantis Shrimp Digestive System. Retrieved January 17, 2017, from http://mantisshrimpsjs.weebly.com/digestive-system.html

Schwartzkopf, S. (n.d.). Mantis Shrimp Circulatory System. Retrieved January 17, 2017, from http://mantisshrimpsjs.weebly.com/digestive-system.html

Created By
Luke Brubacher
Appreciate

Credits:

Created with images by CybersamX - "Mantis Shrimp (25 cm) 1" • alicia3690 - "heart coral australia" • diongillard - "Coral 1" • Yohei Yamashita - "貝の酒蒸し" • Ed Bierman - "Snail with a Mission" • arhnue - "crab crustacean boxer crab" • Hardrockster - "fish feeding sea" • prilfish - "Mantis Shrimp - Odontodactylus scyllarus"

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