I need You to Survive!

Source

  Introduction: Fig wasps belong to the family Agaonid. These insects are closely involved with fig trees, Ficus.  Each species of fig wasps works closely with a specific type of fig tree. Figs trees are originally from the Mediterranean area, but they are grown all over the world [2], and there are multiple different varieties of figs as well. A fig tree has two types of fruit, caprifigs which are male and edible figs which are female [1]. The lifecycle of this relationship starts when a female wasp covered in pollen enters the ostiole, opening of an unripe fig, of a caprifig. While crawling through, the female usually loses her antennae and wings, so she will never escape. The female eventually reaches an area known as the syconium, which has both male and female flowers. There she lays her eggs and releases the pollen that she brought from her original fig and then she dies [3]. While the figs are ripening the male eggs hatch first and find the female eggs and fertilize them. Then the male eggs start chewing a hole in the fig to make an escape route for the females. Later the female wasps hatch and cover themselves in pollen. Once they have enough pollen they fly through the hole in search of another fig tree. And thus the cycle continues [4]. If a female wasp enters a female fig she eventually dies, but her death is not in vain because the pollen that she brings fertilizes the fruit, and creates the fruit people/animals eat[1].




Source

  Description of Relationship:  The relationship between figs and fig wasps has been occurring for the last 80 million years [1].  It is apparent that these two species coevolved over the years and have become dependent on each other in order to survive [2]. This relationship is also known as a mutualistic relationship because both the fig tree and fig wasp benefit from each other. These two species exist because the other helps with the process of reproduction. The biology of the female wasps is that they have wings and are able to fly [3]. The male wasps have no wings and are unable to fly [3].




Source

  Cost/Benefits Analysis:

The cost of this relationship is very minimal to the benefit. Fig trees main cost of this relationship is being dependent on the fig wasp. If the fig trees cannot get their flowers fertilized by the wasps they are unable to reproduce which is a major problem. The fig wasps main cost is sacrificing the mother wasp to the fig tree because she is unable to escape due to the loss of her antennae and wings. The benefit between this mutualistic relationship is that both species are able to reproduce through the help of the other species. Also the fig tree gives shelter to the fig wasps, and in return the fig wasps fertilize the flowers of the fig which are found within. The cost outweighs the benefit because through sacrificing the mother wasp she is able produce many more wasps that will carry on to the next generation.

Movies to Watch

References 

1)       http://animals.howstuffworks.com/insects/fig-wasp1.htm

2)      http://en.wikipedia.org/wiki/Common_fig

3)      http://en.wikipedia.org/wiki/Fig_wasp

4)      http://www.britannica.com/EBchecked/topic/206553/fig-wasp

Wolbachia: Enemy Becomes Friend

Introduction: A parasite whose "hand" seems to be in the pots of many is Wolbachia bacteria. Wolbachia is perhaps one of the most successful parasites [1]. Not only can it affect a wide array of hosts, but it does so effectively. This suggests that the parasite is highly compatible with its host. The Wolbachia is a genus, not a species. There are many different species of Wolbachia that correspond to different hosts although most of the species are closely related [2]. This post will focus on some of Wolbachia's most outstanding and noteworthy hosts. These hosts include but are not limited to Drosophila melanogaster, Asobara tabida, and Trichogramma wasps. Drosophila, more commonly known as the fruit fly, can be found near unripe or rotten fruit. The two latter hosts, both parasitic wasps, can be found in ferilte, infertile, or dead eggs of various host insect species. Wolbachia can be found all over the world. The bacteria affect a grand total of sixty percent of the arthropod population alone. Wolbachia are also capable of infecting spiders and filiarial nematodes. The fruit fly has a total lifespan of only thirty days at optimal temperatures. Trichogramma wasps live for about eight to ten days while A. tabida, can live for an average of fifteen days. Ecologically speaking, the importance of Wolbachia in regards to the hosts are simple: by understanding a highly prevalent parasite and its genetic effects upon hosts, it can hopefully be manipulated to serve ulterior purposes. Also, the prospect of horizontal transmission makes Wolbachia that much more evolutionarily fascinating in the eyes of science because it can cross a barrier that typically impedes transmission [2]. The main targets of Wolbachia research are Dengue fever and the ever-popular Malaria (both of which are vector-borne) [3]. It is hoped that by understanding the Wolbachia genome and its host interactions, the transmission of the disease can be stopped via Wolbachia infection. The main focus of Wolbachia research have been the aforementioned hosts; the idea of using Wolbachia to control or wipe out vector-borne diseases is relatively still in its infancy. However, I feel its necessary to understand the concept behind this new idea that is growing in its popularity.

Description of the Relationship:

In Drosophila, the Wolbachia relationship began as a parasitic one. As it causes in its other hosts, Wolbachia resulted in male feminization, sterility, cytoplasmic incompatibility, and parthenogenesis [1]. The specific foe turned friend is the Wolbachia pipentis. The parasite, known for it's sterilizing effects, actually reverses sterility in mutant females, increases female lifespan, and fecundity of the host [4, 5, 6, 7]. The means by which this relationship transformed is unknown. This relationship is mutualistic and highly common. The Wolbachia bacteria found in the reproductive systems of its hosts, are obligate symbionts. The entire genome of Wolbachia can sometimes be found in the genes of its hosts [8, 9]. The bacteria completely infects the ovaries of a fruit fly (left) in comparison to an uninfected ovary (right) [10].

[10]

In the both parasitic wasps, Asobara tabida and Trichogramma, both the host and its parasite have become obligate mutualists [11, 12]. In the case of A. tabida, the bacteria are necessary for the maturation of the female's oocytes [12]. For Trichogramma wasps, the bacteria are necessary for reproduction in an entirely different way. One of its parasitic effects, parthenogenesis, has become the main means of reproduction. There are extreme disparities in the male to female ratio (negligible amount of males) [11]. The Trichogramma wasp and A. tabida can be seen below [13, 14].

[13]

[14]

Cost/Benefit Analysis:

In each of the three relationships, Wolbachia is an obligate symbiont in a mutualistic relationship. The Wolbachia not only receives a habitat from its host but it also does not have to worry about the transmission of its genes. It's highly successful because it takes refuge in the reproductive systems of its hosts, is transmitted maternally (this explains the emphasis on female over male hosts) via egg cytoplasm [1, 2, 4, 5, 6, 7, 8, 9, 15]. The bacteria is a significant player in the A.tabida wasp and Drosophila; it is the opinion of the writer that the bacteria is highly evolved because A. tabida wasps parasitize the fruit fly. Not only does Wolbachia inhabit the host of the parasitic wasp, but of the parasite itself. The mutant female Drosophila owe any resulting progeny to the bacteria [6, 7]. Though the progeny will be infected, the Drosophila's fitness is increased from nil to existant. For non-mutant Drosophila, the bacteria still increase fitness [4]. As outlined in Combes' text, one of the motors of success is high fecundity [16]. With a greater number of progeny, there is a greater probability of gene transmission. Though Combes was discussing parasites, this host reaps this fitness-increasing trait from its host. In A. tabida, the bacteria, once again, rejuvenates the fitness of the female host. Upon being cured of the "infection" (Wolbachia), the female A. tabida's oocytes cannot mature (resulting in non-fertilization) [4, 11]. Her genes cannot be transmitted without the bacterial infection. In Trichogramma wasps, the bacteria is able to be transmitted intra- and interspecifically. This causes the male to female ratio to become extremely disproportional. The benefits of parthenogenesis are that it is simpler and less taxing than sexual reproduction. Less energy has to be devoted to the many facets of sexual selection (mate selection, sexually trandsmitted diseases/parasites, and less competition). However, the cost of the benefit (parthenogenesis) is a lack of genetic recombination that could increase genetic diversity. Also, sexual reproduction helps prevent harmful mutations via recombination. Both of these disadvantages (lack of sexual reproduction)are results of the sex ratio produced by parthenogenesis [11]. Wolbachia research could hopefully one day lead to the dissolution of certain parasitic infections. The aforementioned research on host relationships are the means to someday reaching that end.

References:

[1] http://news.nationalgeographic.com/news/2010/01/100126-sex-puppeteers-wasps-parasites-virgin-birth-sex-changes/

[2] http://mbe.oxfordjournals.org/content/16/12/1711.short

[3] http://www.youtube.com/watch?v=jiSOeOCe-zM

[4] http://www.brown.edu/Departments/EEB/rand/Fry.etal.04.pdf

[5] http://hydrodictyon.eeb.uconn.edu/people/fry/Evol2.pdf

[6] Combes, Claude. The Art of Being a Parasite. Chicago: The University of Chicago, 2005. 73-74.

[7] Starr, D., and T.W. Cline. 2002. A host-parasite interaction rescues Drosophila oogenesis defects. Nature. 418:76-79.

[8] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC368164/?tool=pubmed

[9] http://www.rochester.edu/news/show.php?id=2963

[10] http://www.wired.com/wiredscience/2007/08/the-great-bacte/

[11] http://edepot.wur.nl/121410

[12] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1765438/

[13] http://www.lucasbrouwers.nl/blog/2010/08/bacteria-force-wasps-to-leave-sex-behind/

[14] http://www.innovations-report.de/html/berichte/biowissenschaften_chemie/bericht-42700.html

[15] http://gbe.oxfordjournals.org/content/3/209.abstract wol genome diversity?

Fruit by the Foot

Introduction

Zenaida asiatica, more commonly known as the white winged dove, is a bird native to Southwestern USA, Mexico, Central America, and the Carribbean [1]. The dove is light gray in color and gets its name from a distinct bright white wing patch. These doves are migratory birds and can fly 15 miles for water and food [1]. They can feed on a variety of fruits, seeds, and grains but are highly dependent on the fruit and nectar of Carnegiea gigantea, also known as the Saguaro cactus. The Saguaro is a large cactus native to the Sonoran Desert in Arizona [3]. White flowering plants grow on the ends of cactus branches providing nectar and food for the dove while the dove pollinates the plant, thus resulting in a mutualistic relationship [4].

Relationship

Mutualism is an ecological interaction in which two species both benefit from eachother. There are many types of mutualisms, such as dispersive mutualism. These are interactions in which one partner recives food or nutrients in exchange for moving the seeds or pollen of its mutualistic partner [6]. Since Saguaro reproduction occurs in the hottest and driest months of the year, the fruit of the cactus provides nutrients and moisture for the dove to survive during these temperatures [4]. The flowers of the large Saguaro become fruit and a new source of food for the doves. The fruit is filled with tiny seeds that, once taken up by the dove, pass through its digestive system without harm [5]. These seeds may be dropped in the feces of the dove, creating a new Saguaro plant several feet or miles away from the parent plant.

Cost and Benefit Analysis

For the white winged dove, there seems to be no cost. The cactus is very beneficial and provides the dove with much needed food and shelter during hot summer months. The dove builds a nest inside the cactus for a moist place to live in the otherwise dry desert. It also feeds on the nectar of the flowering plant obtaining food and nutrients [4]. The Saguaro cactus also seems to have no cost. The dove is beneficial to the Saguaro because it carries the cactus seeds within the nectar in its body until its feces are dropped far away from the parent cactus, thus pollinating the plant.



[1] http://en.wikipedia.org/wiki/White-winged_Dove
[2] http://www.discoverseaz.com/Wildlife/White-wingedDove.html
[3] http://www.discoverseaz.com/Wildlife/Saguaro.html
[4] http://www.desertmuseum.org/pollination/doves.php
[5] http://www.nps.gov/sagu/naturescience/white-winged-dove.htm
[6] http://www.buzzle.com/articles/examples-of-mutualism.html

Three cheers for pom pom crabs

INTRODUCTION:
Lybia tesselata, commonly known as boxer or pom-pom crab, is a tiny, bright colored crab with striped legs and bold markings on its carapace [1]. They are best known for their behavior of using their pincers to hold sea anemones, which look like pom poms. These species are usually found in coral reefs anywhere in warm waters of the Indo-Pacific range and need rocky caves and crevices for hiding [2]. New species only emerge at night or in dim light when they feel secure. Boxer crabs are omnivores, they feed on detritus and small food particles that they pick off the substrate or that adhere to its anemone partner [1]. Sea anemones are marine organisms that belong to class Anthozoa. They are named after a wild terrestrial flower, anemone. A sea anemone is a polyp attached at the bottom of the surface and their body is topped by a ring of tentacles which are often colored. Most species thrust themselves into sand, live in furrows or attach themselves to other free-swimming organisms [3].

DESCRIPTION:
Boxer crabs and sea anemones have a mutualistic relationship in which the boxer crab carries a pair of anemones in its claws. These claws are small and delicate enough to only hold the anemones[5]. Both the organisms benefit from the relationship, providing each other with protection from predators and food. When approached by a predator, boxer crab waves the anemones in its claws at them as if it is boxing. The tiny anemones have strong stinging abilities and are so powerful that most predators back away [4]. The crab gets protection while the sea anemone obtains food particles that are dropped by the crab. Boxer crabs do not even put the anemones down to eat and typically sweep the anemones across the surface collecting food particles and debris in the anemones. The species later use their mouth to collect the food out of the anemone's tentacles. The remaining food particles that are not fetched by the crab are for the anemones to eat. During molting, the crabs place the anemones in a safe place, shed their exoskeleton and immediately pick the anemones while hiding in a safe place until a new protective exoskeleton grows [5].

COST/BENEFIT ANALYSIS:
Since the crab-anemone have a mutualistic relationship both of the organisms benefit from each other. As stated above, the sea anemone's tentacles provide the crab with protection from its predators. In return, the crab supplies the anemone with a constant food supply and helps the sea anemone catch more food by moving it from place to place. Moreover, the anemones are also used by the crabs to collect food particles and debris [4]. There are no costs for the sea anemone from taking part in this relationship. However, it is possible for the crab to accidentally sting itself resulting in the tentacles to eject a poisonous stinging threads that could paralyze the crab[6].

References:

1.http://en.microcosmaquariumexplorer.com/wiki/Pom_Pom_Crab
2.http://creationwiki.org/Boxer_crab
3.http://creationwiki.org/Sea_anemone
4.http://jrscience.wcp.muohio.edu/fieldcourses06/PapersMarineEcologyArticles/Symbiosisonthecoralreefsf.html
5.http://www.ehow.com/about_6164034_information-boxer-hermit-crab.html
6.http://animals.howstuffworks.com/marine-life/sea-anemone-info.htm

The Emperor and its Dancer

Introduction

Hexabranchus sanguineus, more commonly known as the Spanish dancer, is a carnivorous slug found mostly in the waters surrounding Hawaii. It is called a Spanish dancer because of how its bright colors and movement through the water resembles a Flamenco dancer [1]. Some species of the slug are toxic, obtaining their toxicity by ingesting other toxic organisms, like the Portuguese man-of-war and many are most active at night [2]. In the daytime, they are pink with white patches, and at night, they are pinkish red and blotchy. Its mutualistic partner, Periclimenes imperator, is an emperor shrimp found in all areas of the Pacific Ocean, from Hawaii to Indonesia [4]. These organisms look like mini-lobsters with a duck-bill like head [5]. They also have the pink-red with white spots coloration, similar to that of the Spanish dancer and other organisms it inhabits.

Description of Relationship

The relationship between Hexabranchus sanguineus and Periclimenes imperator has long been established as mutualistic [1]. Although both can survive without the other, there are advantages to a shared interaction. The relationship is established simply through encounter. If these organisms meet, and both do not mind creating a relationship with the other, then interaction is formed. The shrimp can be found within the gills of the slug [2] and cleaning off any kind of growth and even parasites. Usually the shrimp is not alone, cleaning and travelling with a partner. The slugs receive a thorough cleaning while the shrimp receive a great food supply. A unique characteristic of this relationship is that once it is established, it usually remains for the life of the organisms [3].

Cost/Benefit Analysis

The benefits have been discussed above; however, there are some possible risks to each organism as well. Sometimes, when predators of the shrimp try to attack, the slug gets damaged or killed in the process. This emphasizes the importance of the shrimp’s ability to blend in with the slug [5]. Also, because the slug has to carry around the shrimp, extra energy has to be expended. The costs for the shrimp are minimal as well. There could be a chance that the slug accidentally eats the shrimp or if the shrimp accidentally ingests part of a toxic slug. This, however, probably does not occur frequently since the shrimp stay by the gills of the slug.

References

[1]http://www.mauioceancenter.com/index.php?id=11&ss=0&page=marine&content=marine_detail&cat=2&CRid=62&limitstart=0

[2] http://www.mauinews.com/page/content.detail/id/513210/This-ocean-dancer-isn-t-sluggish.html?nav=16

[3] http://seaslugsofhawaii.com/species/Hexabranchus-aureomarginatus-a.html

[4] http://www.eol.org/pages/1024747

[5] http://www.seadb.net/en_Emperor-shrimp-Periclimenes-imperator_583.htm#

Remora: Not Quite a Drag

Introduction:

Remora are a group of fish that are members of the family Echineidae; there are eight known species, all belonging to one of four genera: Echineis, Phtheirichthys, Remora, and Remorina [4]. They are usually found in warm, southerly waters. Remora interact with a wide range of marine animals. They are known to attach themselves to fish (particularly sharks and rays) and whales, along with other large marine animals – and even the occasional snorkeler or scuba diver [2]. Remora possess a modified dorsal fin that runs from just above the snout of the fish to the nape of its neck. This fin has several transverse plates; it is used by the remora to attach itself to its host. Some remora cling to the host’s torso, but others are found on or near the host’s gills. The name “remora” is the Latin word for “delay”; they were believed to slow down ships and animals that they clung to because of the weight they add and the drag they produce.

http://www.kelongfishing.com/images/fishing_pic_7_bata_fish_or_remora.jpg

Description of the Relationship:

Unfortunately, very little is known about the origin of remora and the evolution of their unique trait and behavior. While other fish – such as the “cleaner fish” studied earlier in the semester – exist in a relationship that superficially resembles the one between a remora and its host, no other identical examples are known.

Depending on the type of remora and the host, the relationship can be either mutualistic or commensal. Most often the relationship is commensal – the remora attach themselves to a host and travel on it, gaining transport, protection from predators, and food. This relationship is commensal when the remora eats scraps left behind by the host or other debris it is exposed to in the host’s travels, but can become mutualistic if the remora is of a variety that eats dead skin and bacteria from the host’s body [1]. In either case the remora benefits from the relationship, while the host either is unharmed or actively benefits along with the remora; for this reason it is impossible to definitively categorize the remora/host relationship as either mutualistic or commensal.

http://www.britannica.com/EBchecked/topic/497706/remora

Cost/Benefit Analysis:

Whether the relationship is commensal or mutualistic, in nature there is little or no harm to the host. In commensal cases, it has an unexpected passenger that does not seek to harm it and that will, at worst, either slow it down by increasing drag on the host as it swims or perhaps cause some minor gill irritation. In mutualistic cases, the host benefits as the remora cleans its host of dead skin, bacteria, and ectoparasites.

Similarly, the remora always benefits from this relationship in a natural environment. Whether the relationship is commensal or mutualistic it gains food, shelter, and protection. Since the remora can detach itself from its host, and is capable of swimming freely, its well-being is not linked to that of the host [2]. Some scientists hypothesize that remora run the risk of being eaten by their hosts, but to date no evidence has been found supporting this idea.

This relationship has incurred some harm for both the remora and their hosts in cases where they live in a human-populated environment due to an unusual fishing practice of some aboriginal tribes. In some regions where remora are prevalent, fisherman use a live remora tied with a long cord in lieu of a fishing hook and rod – they wait until a game fish is spotted, release the remora, allow it to attach itself to the game fish, and then haul both back in with the rope. In some regions the un fortunate remora is eaten along with the game fish, but in other areas they are honored for their contribution to the tribe’s well-being [2]. Despite the man-made disadvantage, the relationship persists because it provides remora with ready food and the high-speed motion they need to keep their gills functioning [2].

http://www.fla-keys.com/news/news.cfm?sid=1514


Remora in Action: http://www.youtube.com/watch?v=9z3pqp12UEg

References:

[1] http://www.britannica.com/EBchecked/topic/497706/remora

[2] http://animaldiversity.ummz.umich.edu/site/accounts/information/Remora_remora.html

[3] http://www.gma.org/fogm/Echeneis_naucrates.htm

[4] http://en.wikipedia.org/wiki/Remora

Cordyceps: mind and body controller

Introduction:

The relationship between Cordyceps and its hosts is strictly parasitic since the Cordyceps end up killing their host. The host ranges from ants to moths to walking sticks. Cordyceps are endoparasitoids meaning they attack inside their hosts; ending up taking over the host brain and body[1]. This fungus spreads its seeds just like any other plant; however once the pollen infects its host is when it acts differently. The cordyceps, still unknown, but somehow travels through the host body until reaching the brain where it infects and takes over them. Infected ants are known to outcast infected ants and even taken as far away from the colony once known infected. The reason for this is the outcome of these infected hosts. They disorientate their host and forces them to attach to nearby limbs. There the fungus does its work by sprouting the fungus sprout out of the head where they later end with a cluster of capsules. When finished, the capsules burst to release more spores into the air to try to infect other host passing by.

Relationship:

The hosts of the Cordyceps ranges from different arthropods such as the Odonata, Blattaria, Hemiptera, Coleopter, Phasmida, Hymenoptera, and Lepidoptera, each depending on the species of the Cordyceps [2]. Even though the Cordyceps affects so many different insects, they are not considered harmful; they are more of nature’s pesticide for insects which get too numerous

Ecology:

Recently Cordyceps are used in Chinese medicine to help fatigue resistance, improve stress tolerance, enhance immune function and improve general health[3]. The specific species the Chinese use is the cordyceps sinensis species which is also known as the Chinese caterpillar.

The Cordyceps are very similar to species we learned in class such as the Dicrocoelium which infects the ant host into controlling the mind. They then force the ant to crawl up stalks and intentionally get eaten by the next host, live stalk. However instead of forcing the ant to crawl and get eaten, Cordyceps kill the ant and release spores from the body of the host.

Video:

References:

1.http://en.wikipedia.org/wiki/Cordyceps

2.http://neurophilosophy.wordpress.com/2006/11/20/brainwashed-by-a-parasite/

3.http://www.nutritionalreviews.org/cordyceps_sinensis.htm

4.http://www.freesciencelectures.com/video/cordyceps-fungus/