All for one and one for all: The intricate social structure of leaf-cutting ants

by: Raluca Ionescu and Laura Zeppetelli

Screen Shot 2016-04-10 at 8.56.15 PM.pngFigure 1

They are small, they seem fragile, and nevertheless, they are amongst the most remarkable and strong species on our planet! At any time of the day while walking through the Costa Rican forests, we could observe ants cutting leaves and transporting the pieces back to their nest, where they exercise their cunning gardening skills.

This article studies the ants that belong to genera of Atta from the attain tribe, regrouping about 210 species within. These particular ants, known as leaf cutters or fungi growing ants, are the perfect example of a mutualistic relationship between the ants and their fungi, since this species grow their own fungus and depend on it. To solve their problems, these ants are the champions of the collective and social work! These insects’ survival depends on the community and on the well-defined role occupied by every individual. They are among the species that reach the highest degree of social community in the animal Kingdom. It is indeed one for all, and all for one!

Castes

In order to manage these huge colonies that can lead up to more than 5 million individuals, Atta ants have learned to divide the work load into several social castes. They are a textbook example of polymorphic species: within them are many different body shapes and sizes specifically useful to a certain task for their group. Scientifics do not yet agree on an exact number of Atta cast, but they range around 5 to 12 different social groups within their species. (1) Usually, larger ants form the soldier group, whilst medium sized ones serve for foraging and other technicalities as the smaller group takes care of the nest and its fungi.

Screen Shot 2016-04-10 at 12.24.02 PM.pngFigure 2:  From the smallest to the biggest castes: the minims, mediae, majors and drones

Minims

The minims, often referred to as “garden ants” do most of their work underground. As their name suggests it, they are the smallest of all the castes and have a head width of less than 1 mm. They primarily take the role of fungi gardeners, groom other ants and act as nurses for the queen and larvae. In fact, the minims are responsible to a big degree of caste determination due the fact that they manipulate the pheromone concentrations and temperature that contribute to the “caste programming” of the future ants. (2) Minims are also charged with the task of cleaning cut sections of a leaf while they are being carried back to the nest by the mediae workers. Doing so will protect the mediae from a species of parasitic phorid fly which lays its eggs inside them. (3)

Minors

The minors are a bit larger than the minims and their head width varies from 1.8 to 2.2 mm. They are the first line of defense and constantly move around the territory surrounding the nest to attack any enemy which seems to be getting too close to the foraging lines. (1)

Mediae

The mediae, often referred to as “workers” are primarily foragers, but they also function as excavators. They are bigger than the minims and minors, but smaller than the majors. Their key tools are their mandibles which allow them not only to cut sections of leaves but also to bite any intruders. While they feed on the fungus like other castes, a part of their diet also consists of plant sap which they ingest while physically cutting out sections of various plants. (4)

Majors

The majors, very often called “soldiers”, are only produced when the colony includes at least around 10 000 workers (5) and their most distinguishable characteristic is their size. Their total body length can go up to 16 mm with head widths of 7 mm. The soldiers primarily defend the colony from other insects and vertebrate predators using their massive jaws. Also with the help of those mandibles, they move the objects that are too heavy for the smaller castes.

Males

The males of these colonies do comparatively less work than the females, yet they are crucial to the survival of the species. They are considered drone ants since only them and the queens have wings. Indeed, their sole purpose is the transfer of genetic information from one nest to another during the reproduction period. That period is the only time when they are produced since they do no other work in the colony. Surprisingly, they are mostly haploid individuals: they all carry the exact genetic information as they have a unique set of chromosomes. They die shortly after reproducing during their nuptial flight. (6)

Queen

A new queen must always have wings because without them she would not be able to move around so easily and accomplish all the tasks required of her to establish a new colony. After leaving the original nest during nuptial flight, she mates with about 3 to 8 male drones and carries a small piece of the old fungus. (6) She will then take this piece underground and spit it up, remove her wings and begin her gardening. She will tend on the crucial fungi by feeding it with her fecal matter until the first wave of worker ants is born and can carry on the leaf foraging task. As the fungus gets bigger, the colony does the same: it produces millions of ants that get bigger and more various in body types in order to increase and diversify the work done. Even though the queen does not do much of that work after starting her colony, she lives long enough and is crucial since she remains the only fertile ant and the pillar of her social network.

Screen Shot 2016-04-10 at 8.53.29 PM.pngFigure 3: The nursing minim ants on top of the much larger queen ant

References

  1. Wilson, Edward O. “Caste and Division of Labor in Leaf-Cutter Ants (Hymenoptera: Formicidae: Atta).” Behavioral Ecology and Sociobiology. 7, 1980: 157-165.
  2. Suen G, Teiling C, Li L, Holt C, Abouheif E, Bornberg-Bauer E, et al. (2011) The Genome Sequence of the Leaf-Cutter Ant Atta cephalotesReveals Insights into Its Obligate Symbiotic Lifestyle. PLoS Genet 7(2): e1002007. doi:10.1371/journal.pgen.1002007
  3. Vieira-Neto, E. H. M.; F. M. Mundim; H. L. Vasconcelos (2006). “Hitchhiking behaviour in leafcutter ants: An experimental evaluation of three hypotheses”. Insectes Sociaux 53: 326–332. doi:1007/s00040-006-0876-7.
  4. Littledyke, M.; J. M. Cherrett (1976). “Direct ingestion of plant sap from cut leaves by leafcutting ants Atta cephalotes (L.) and Acromyrmex octospinosus“. Bulletin of Entomological Research 66: 205–217. doi:1017/s0007485300006647.
  5. Hölldobler, Bert, and Edward O. Wilson. Journey to the Ants: A Story of Scientific Exploration. Cambridge, MA: Belknap of Harvard UP, 1994. Print.
  6. Wirth, H. Herz, R.J. Ryel, W. Beyschlag and B. Holldobler.  In Herbivory of Leaf-Cutting Ants. New York: Springer-Verlag Berlin Heidelberg. 2003.
  7. Fendt, Lindsay. “The Secret Lives of Leaf-cutting Ants.” The Tico Times. N.p., 03 Apr. 2015. Web. 07 Apr. 2016.

Figure 1: Courtesy of Wikipedia Commons

Figure 2: http://dx.doi.org/10.1371/journal.pgen.1002007.g001

Figure 3: http://ecolibrary.org/page/DP177

Toxic Species in Costa Rica

by: Lucas Thow, Gabrielle di Gironimo, Annie Quadros and Lily Ragsdale

The forests of Costa Rica are home to a wide range of amazing creatures. Large or small, cleverly camouflaged or vividly coloured, their presence is what makes Costa Rica one of the most biodiverse regions in the world. Despite their beauty, many of the species can be lethal if not properly handled, or in some cases, completely avoided. A common defense many species have developed throughout their evolution is the use of toxins, dangerous to both predators and humans alike. Toxins are found in species of all types, however they may vary in chemical composition, potency and method of transfer from species to species. Below are four species common to the Costa Rican forests, each with it’s own form of toxic defense.

Strawberry poison dart frog

The Strawberry poison dart frog (Oophaga pumilio) is a common species of poisonous frog found throughout Central America. It’s habitat ranges from eastern Nicaragua, through Costa Rica, and into north-eastern Panama. This species is often found dwelling on rainforest floors, under low growing vegetation (Penner 2011). The species is considered to be of Least Concern status on the IUCN Red List, meaning the threat of it’s extinction is extremely low (IUCN 2015).

Poison-dart-frog-map-distri.jpg                                         Figure 1: strawberry poison dart frog habitat region.

Strawberry poison dart frogs can easily be identified by their bright and vivid coloration. The entire body of the frog is a bright red-orange colour, save for it’s feet, and often times entire hind legs, which are a metallic gray-blue speckled with black. The frog is often referred to as the “blue-jeans” poison dart frog due to the colour of it’s hind legs. Relatively small in size, the Strawberry poison dart frog ranges from 17-24mm in length (Sandmeier 2001). The aposematic coloration of the frog is used as a warning mechanism to alert predators of it’s poisonous nature (Summer et. al. 2001). The coloration within the species is incredibly diverse, which is said to be due to sexual selection over time, however other research suggests their vivid coloration could have developed in correlation with their toxicity (Summer et. al. 2001). Despite their small size, their presence rarely goes unnoticed due to the characteristic “chirp” noise they often emit (Penner 2011).

medium.jpgFigure 2: strawberry poison dart frog common morph.

The term “poison dart frog” is derived from the frog’s toxin being used for coating the tips of indigenous tribes’ blow-darts. The toxins were generally extracted via one of two methods: the first was to simply rub the tip of the dart on the frog’s moist back, and the second is to heat the frog up to a temperature at which it would sweat and secrete the toxins, which would then be collected.

Poison_dart_frog-1.pngFigure 3: poison retrieval from poison dart frog.

The Strawberry poison dart frog is considered to be the most toxic in the Oophaga genus, but not the most poisonous among frog species. When agitated, the poison dart frog secretes a liquid containing alkaloids, a nitrogen based organic compound that causes blocking of the Na+ channels of the affected species’ nervous system, resulting in paralysis (Elder 2006). Certain similar dart frog species, such as the Golden dart frog (Phyllobates terribilis) are toxic enough to kill a 150lb. human with only 136 micrograms of it’s secretion (Elder 2006). Interestingly, the frogs themselves do not produce the toxins which they carry; these toxins are acquired through the small insects which they prey on, who have built up small toxin levels through the plants that they consume (Penner 2011).

Golden Orb weaver spider

The golden orb weaver spider is a unique, highly fascinating, venomous species of spider that can be found in many of the warmer regions of the world, from Southeast Asia to Australia, to the Americas all the way up to the United States (Weems 2004). Its name arises from the golden coloration of its silk, while it body colour ranges from silver to dark plum to orange, with brown, yellow-stripped legs (Australian Museum 2015).

The golden orb weaver spins one of the strongest and toughest webs in the world, and unlike most other spider species, their intricate webs are much like permanent homes, often lasting for multiple years (Ria Tan 2001). They use their webs, which are strung between trees in forests, to catch a variety of medium to large flying insects, such as wasps, moths, flies and butterflies (Weems 2004). Though they do not feed on them, their webs have even been known to entangle small birds! Birds also happen to be the main predator of this spider species. The male golden orb weaver, whose size is approximately 5mm, is significantly smaller than his female counterpart, who is usually 2-4 cm in length. Males have been known to take advantage of this difference in size by living on the female’s web, feeding off her catches without her even noticing. The male is even able to inseminate the female without her realizing, often while she is distracted by eating (Ria Tan 2001). Once fertilized, the female will dig a hole and bury her egg pouch underground. The golden orb weaver has a potent venom, which it injects into its prey through its chelicerae, or jaws, in order to paralyze it (Australian Museum 2015). Though the venom is a neurotoxin, it is not considered lethal to humans, and results only in redness, mild pain around the area of the bite, and a blister, which usually subsides after one full day.

12946937_1268914126456124_1.jpgFigure 4: golden orb weaver spider

Fer-de-Lance snake

The Bothrops asper, or Fer-de-Lance, is a venomous snake native to tropical Central America (Fer-de-lance), favouring moist and wet environments over drier climates (Streiter), however, that is not to say they are not present in dry tropical regions as well. In Costa Rica, this species is most common in lowlands of both the Pacific and Caribbean coasts up to an elevation of 1300-m (Streiter).

Species of the Bothrops genus are recognizable by their noticeably broad, flat heads; the Fer-de-Lance are actually named so for their lance heads (Encyclopedia Britannica). They are also pit vipers, so they have heat sensitive moveable fangs that are positioned between each large eye and nostril (Brown 2011); these are used to accurately attack and target their warm-blooded prey (Encyclopedia Britannica). Their eyes are also recognizable by their large, vertical pupils (Streiter). Bothrops aspers also exhibit dimorphism; the females are noticeably larger than the males from birth, as well as have more ventral and subcaudals scales (Brown 2011). Both males and females have distinct coloration patterns consisting of pale cream-coloured diamond shaped patterned bands on their back and sides that complement their dark brown/grey scales (Streiter). They are usually 4-7 feet long, with the females being noticeably larger than males, both as juveniles and as infants, and can reach up to ten times the size of a male Fer-de-Lance (Brown 2011). Juvenile females also have brown-tail tips while juvenile males have yellow ones, which they completely shed after maturation (Brown 2011).

venomous_vs_non-venomous.jpgFigure 5: pit-viper vs. nonvenomous snake

12966757_10154154147504759_.jpgFigure 6: fer de lance snake

The Fer-de-Lance is considered the most dangerous snake in the Central America and is responsible for a majority of snake-induced deaths in humans (Strieter). Given their choice of diet, which ranges from small reptiles, invertebrates and arthropods as juveniles and slightly larger mammals as adults (Streiter), one could assume their natural defenses evolved to attack their prey more successfully, although this information has yet to be confirmed.

Manchineel tree

The Manchineel (Hippomane mancinella) is thought by many to be the worlds most dangerous tree. It is indigenous to Central America and the Caribbean (Sparman et. al. 2009). In central America the locals call it “Manzanita de la muerte” which means little apple of death (McLendon 2014). This name originates from the small apple shaped fruits produced by the tree. When ingested the fruits are reported to have a pleasantly sweet flavor. However, moments after ingestion tingling in the throat is felt, which quickly progresses into a burning sensation. Ingestion of the fruit ultimately leads to blistering of the mouth and throat and respiratory symptoms (Sparman et. al. 2009). The trees poison is not restricted to its fruit. Almost every part of the Manchineel including leaves, bark and sap are toxic. If skin comes in contact with Manchineel sap, bullous dermatitis and acute keratoconjunctivitis can occur (Sparman et. al. 2009). After brief exposure to the sap painful blisters can develop. The reason the Manchineel evolved such extreme toxic defenses is not yet confirmed. However, it is hypothesized that it may have something to do with how the tree reproduces. The Manchineel is located in costal areas and mangroves and uses the wind to disperse its seeds. Therefore, it is not necessary for animals to ingest the Manchineel fruits in order to spread seeds. Most animals are affected by the Manchineel’s potent toxins. However, certain species, like the iguana, are resistant.

12980864_1047206948688004_3.jpgFigure 7: Manchineel tree’s poisonous apple

Fig 8 ToxicCE.jpgFigure 8: Manchineel tree

Costa Rica’s great biodiversity and subsequent high levels of competition and predation have lead to incredible biological adaptations. Many organisms have evolved to use toxins. Some, like the Poison Dart Frog and Manchineel tree, secret poison as a defense mechanism. Others, such as the Golden Orb Weaver spider and Fer-de-Lance, use poison for predation. There is a huge diversity in the toxins found in organisms. Some poisons are lethal, with the intention to kill the predator or prey. Others result in unpleasant reactions like blisters, meant to deter predators. Just as some organisms have evolved to use toxins to their advantage, others have developed immunity to these toxins.

References

Brown, Kelly. “Bothrops asper.” Animal Diversity Web. University of Michigan Museum of Zoology, 2011. Web. 01 Apr. 2016. http://animaldiversity.org/accounts/Bothrops_asper/

Elder, Jill. “Toxic Effects of Native Poison Dart Frogs (Dendrobatidae) in Costa Rica.” 2006 Costa   Rica Ecology Pre-Course Presentation Topic Reports. University of Miami of  Ohio, 18 May  2006. Web. 02 Apr. 2016. http://jrscience.wcp.miamioh.edu/fieldcourses06/PapersCostaRicaArticles/Toxiceffectsofnativepoiso.html

“Fer-de-lance.” Encyclopedia Britannica. Encyclopedia Britannica, n.d. Web. 02 Apr. 2016. http://www.britannica.com/animal/fer-de-lance-snake-genus

“Golden Orb Weaving Spider.” Australian Museum. Australian Museum, n.d. Web. 01 Apr.       2016. http://australianmuseum.net.au/golden-orb-weaving-spiders

“Golden Orb Web Spider.” Mangrove and Wetland Wildlife at Sungei Buloh Nature Park. Ria       Tan, 2011. Web. 01 Apr. 2016. http://www.naturia.per.sg/buloh/

IUCN “The IUCN Red List of Threatened Species. Version 2015-4”. iucnredlist.org.        Downloaded on 04 Apr. 2016. http://www.iucnredlist.org/details/55196/0

McLendon, Russell. “Why manchineel might be Earth’s most dangerous tree” Mother Nature Network. Mother Nature Network, 23 Oct. 2014. Web. 01 Apr. 2016. http://www.mnn.com/family/protection-safety/blogs/why-manchineel-might-be-earths-most-dangerous-tree

Penner, Austin. “Oophaga pumilio.” Animal Diversity Web. University of Michigan Museum of   Zoology, 2011. Web. 02 Apr. 2016. http://animaldiversity.org/accounts/Oophaga_pumilio/

“Pit viper.” Encyclopedia Britannica. Encyclopedia Britannica, n.d. Web. 02 Apr. 2016. http://www.britannica.com/animal/pit-viper

Sandmeier, Fran. “Oophaga pumilio: Strawberry Poison Frog”. Amphibiweb. UC Berkeley, 21   Mar. 2001. Web. 05 Apr. 2016. http://amphibiaweb.org/cgi/amphib_query?where-genus=Oophaga&where-species=pumilio

Sparman, John and L. Willis. “Manchineel poisoning bradyarrhythmia. A possible association.”   West Indian Medical Journal, Vol. 58 no. 1 (2009). carribean.scielo.org. Web. 03 Apr.2016. http://caribbean.scielo.org/scielo.php?script=sci_arttext&pid=S0043-31442009000100012

Streiter, Amy. “Fer-de-Lance.” Anywhere Costa Rica. Anywhere Costa Rica, n.d. Web. 02 Apr. 2016. http://www.anywherecostarica.com/flora-fauna/reptile/fer-de-lance

Summers, Kyle, and Mark E. Clough. “The Evolution of Coloration and Toxicity in the Poison     Frog Family (Dendrobatidae).” Proceedings of the National Academy of Sciences of the   United States of America. The National Academy of Sciences, 15 May 2001. Web. 05 Apr. 2016. http://www.pnas.org/content/98/11/6227.abstract

Weems, H.V. and G.B. Edwards. “Golden silk spider.” Featured Creatures: Entomology and       Nematology. University of Florida Institute of Food and Agricultural Studies, Aug. 2001.         Web. 01 Apr. 2016. http://entomology.ifas.ufl.edu/creatures/misc/golden_silk_spider.htm

Figures:

Figure 1: http://www.facts-about.info/poison-dart-frog/

Figure 2: http://animaldiversity.org/accounts/Oophaga_pumilio/

Figure 3: https://dixonapbio-taxonomywiki 2015.wikispaces.com/Poison+dart+frog+(chordate-+amphibian)

Figure 4: Lily Ragsdale, 2016.

Figure 5: http://asawright.org/venemous-snakes-of-trinidad-tobago/

Figure 6: http://ambergriscaye.com/photogallery/101229.html

Figure 7: http://www.planetdeadly.com/nature/most-poisonous-plants

Figure 8: http://fortlauderdaleforester.blogspot.ca/2013/01/tree-thursday_17.html

The Strangler Fig: The Ultimate Tree Hugger

by: Nicole Kitner, Ella Martin, Mikayla Salmon-Beitel, Carole-Anne Williams

In the depths of the Costa Rican rainforest, one can find many species of animals, insects, and plants. The interactions of these organisms vary, from the symbiotic relationship between hummingbirds and bromeliads, to the incredibly organized nest of leaf cutter ants, where they tend to their mutualistic relationship with fungi. Out of all the incredible wonders you may find on your journey through the rainforest, there is one species that seems to, quite literally, overtake the rest. The strangler fig trees are unlike most other trees in their environment. Their adaptations to utilize another tree’s resources, their unique relationship with wasps, and interactions with their ecosystem, make them an exceptionally fascinating species that have important impacts on their environment.

The strangler fig tree has certain adaptations to better suit its typical tropical rainforest environment. They are semi-deciduous, and only lose their foliage for short periods of time, usually during the dry season. They have a high drought tolerance, which is an adaptation that proves to be very important, particularly during the summer months when humidity and access to water is decreased (Brown). This tolerance enables survival, despite the less-than-optimal conditions during this period. The strangler fig’s foliage is entire, alternate, dark green, and somewhat leathery, and its leaf’s shape is elliptical to oblong, with cordate, acute, or obtuse bases, and a pointed apex (Brown). The pointed apex of the leaf is optimal in the tropical rainforest, allowing for easy runoff of water. Although the tree has no visible flowers, they are actually hidden within the hollow receptacle, which is called the fig. The pollination of these flowers is dependent on fig wasps, which have a symbiotic relationship with the tree (Prasertong).

The fig-fig wasp relationship is one of the key examples of coevolution and mutualistic symbiosis: each species of fig has evolved alongside a unique species of wasp that is small enough to crawl inside the fig through a tiny opening called the ostiole to lay its eggs inside, although they often may lose their wings or antennae in the process. In exchange, the wasp brings pollen into the fig, which is actually a cluster of seeds and flowers called an inflorescence (not a fruit), fertilizing the ovaries (Kline). Due to competition for a limited number of oviposition sites, the queen may visit three or four different figs to increase reproductive chances, but because she lost her wings they must be within close proximity to each other (Suleman, Nazia, et al.). Once her mission is complete, the queen then dies and is digested by the fig, providing it with nutrients. Once her eggs hatch, the males and females first mate with each other, then the females collect pollen to continue the process, while the males carve a path out of the fig to allow the females’ escape. The males are wingless and will spend their entire life within the fig (Kline).

Although it seems simple, several factors can arise to complicate this relationship. One is the possibility of uncooperative symbionts. In this case, one of the organisms (generally the wasp), fails to uphold its end of the deal (pollinating the fig), and becomes parasitic. If such a situation arises, the host fig tree can provide sanctions that limit the reproductive success of the cheating wasps. However, the tree is only able to target the entire fruit that are not performing, as opposed to individual wasps. Thus, pollen-free wasps are persistent in fig trees, albeit at low levels, as long as there are others within the same fig that can do their job for them (Jandér, et al.).

Another complication is specialized parasitic wasps that can lay their eggs within the fig from the outside using a long ovipositor, and that do not pollinate the fig in return. This leads to increased competition for oviposition sites, and possibly a lack of sites for the wasps that are pollinating. Something that reduces this effect is the presence of some ant species, which live on the fig tree and are able to move rapidly to catch flying insects, and actually patrol the fig to prey on the parasitic wasps. They have been shown to significantly reduce the wasps’ negative effect on the mutualism, and allow this relationship to continue (Schatz, Bertrand, et al.).

Strangler figs also participate in another form of symbiosis. This is their most notable, as well as arguably most interesting adaptation: it has the ability to steal another tree’s access to sunlight and nutrients by essentially killing the host tree. The strangler fig can grow from seeds, but in tropical rainforests, it has adapted to start as an epiphyte on another tree instead.

Picture1.jpg

At the epiphytic stage, the fig tree’s relationship with its host is seemingly innocent. Birds eat the fig’s fruit and drop its seeds between the leaf bases or in the nooks between branches of the host tree – usually palm and oak trees (Brown). The seedling grows there, finding nutrients in decaying leaves and soil, and growing towards the sunlight. This relationship is referred to as commensalism: the fig tree is benefitting from the host’s resources, while the host remains unaffected (Sack). As the epiphyte grows and sends its roots down along the trunk of the host, their relationship begins to change. When two root tendrils touch, they fuse together in a process called anastomose, eventually forming a massive woody mesh that completely encircles the trunk of the host. As the host continues to grow, the roots’ grip gets tighter, crushing its bark and constricting vital phloem and cambial layers (Armstrong). If the grip is tight enough, the host may no longer be able to transport nutrients throughout its system, dying of strangulation. Though the fig is not directly feeding on its host’s resources, it can be argued that their relationship at this point is parasitic, as the fig is harming the host tree in the hopes of eliminating competition for rain and sunlight (Sack). In most cases though, the host is sooner affected by the shading effects of the fully grown fig tree than by strangulation. This is especially true when the host is a palm tree, as palms lack an outer cambial and phloem layer (Armstrong).

The ficus family of trees, vines and shrubs are absolutely vital to many tropical ecosystems. One study recorded a total of 990 bird and 284 mammal species who eat figs as a part of their diet at one point during the year (Shanahan, Mike et al). These numbers include frugivores such as bats, monkeys, hornbills, toucans and parrots in addition to some invertebrates, that have been known to eat figs and aid in seed dispersal like the dung beetle, ants and, of course, fig wasps (Shanahan, Mike et al). Some of these animals rely completely on figs; they are called specialists (hornbills, some parrots and some toucans) and they would die out if figs disappeared. The majority of the animals that fall into the category of fig-eaters only do so at certain periods of the year when the main fruits of their diet are unavailable, or in times of food shortage. Despite the fact that figs are only eaten for a short period of time, in these cases they are vital: without them, these animals could starve (Kinnaird, M. ). In the food shortage of 1971 when only 50% of fruit trees in Barro Colorado Panama were producing fruit, the rates of starvation were better than they would have been due to fig trees in the area. In this case figs were a fallback food source for many species (Leigh, Egbert Giles).

Picture2.jpg

Ficus tree shading out its cabbage palm host in Fort Lauderdale, Florida        

There are several reasons why figs sustain so many animals in tropical rainforests. A big part is due to their fruiting patterns: most have very short periods between fruiting episodes, so there is fruit practically all year round. Also, they produce in the hundreds of thousands of figs that ripen at the same time, which increases the incentive of animals to feed there (Shanahan, Mike et al). The fruit itself comes in different colours and scents which caters to the variety of animals foraging for food. For example, the figs that ripen to be a deep red colour are easily spotted by birds whereas cauliflorous figs, that remain green but smell sweet, are scented at night by bats (Shanahan, Mike et al).

Picture3.jpgPicture4.jpg

Figs are also very easy for animals to eat. They do not have any protective coat ( no thorns or hard outer layer to dissuade hungry animals) and they are very nutritious. Although they do not contain high levels of carbohydrates or lipids like other fruits, they are much higher in protein, calcium and magnesium. Fig fruits contain 3.2 times more calcium than other tropical fruits, which is important for strong eggshells and increasing bone density (Kinnaird, M.). The protein often comes from the fig wasps inside the fruits, dead male wasps or eggs. Also, the sheer amount of available fruit per tree reduces competition between animals because there is more than enough for all (Shanahan, Mike et al). All in all, it is undeniable to say that if the ficus family disappears, many other animals would disappear with them.

The strangler fig is a unique species of tree that holds an important role in its tropical rainforest ecosystem. Over time, it has evolved a slew of adaptations that make it competitive to the many other species in its surroundings. Not only is the strangler fig physically well adapted to its environment, but it has also developed both mutualistic and parasitic relationships with other species in order to ensure its survival. Its fruit also serve as the main food source for many species of mammals and aves. The strangler fig is a perfect example of the complex adaptations necessary for survival in the tropical rainforest ecosystem. Due to its warm climate and fertile land, the tropical rainforest is a very productive environment, where plant species evolve twice as quickly as those in Antarctica (“Hotspots for Evolution”)! Because of this speedy rate of change, plant species have needed to develop complex interrelationships with other species in order to maintain a competitive advantage. Though strangulation may seem like a violent means by our standards, it is not in fact one of the most intense adaptations. The Acacia tree, for example, is covered with spikes housing colonies of poisonous ants that will not hesitate to attack the unsuspecting passerby. So unless you are Tarzan, we suggest being very careful when entering the rainforest jungle, as you never know what sneaky adaptation evolution will surprise you with next!

References:

Armstrong, Wayne P., “Stranglers and Banyans: Amazing Figs Of The Tropical Rain Forest.” Wayne’s Word. Palomar College, 1999. Web. 3 April 2016.

Brown, Stephen H. “Ficus Aurea.” (2011): n. pag. University of Florida IFAS Extension. University of Florida, 2011. Web. 2 Apr. 2016.

Brown, Stephen H. “The Prop and Buttress Roots of Banyan/Ficus Trees.” (2012): n. pag. University of Florida IFAS Extension. University of Florida. Web. 2 Apr. 2016.

Charlotte Jandér, K., et al. “Precision Of Host Sanctions In The Fig Tree-Fig Wasp Mutualism: Consequences For Uncooperative Symbionts.” Ecology Letters 15.12 (2012): 1362-1369. Academic Search Premier. Web. 15 Mar. 2016.

“Fig Wasps.” Figs Traditional Herbal Medicines for Modern Times The Genus Ficus (2010): n. pag. Web. 2 Apr. 2016.

“Hotspots for Evolution.” Understanding Evolution. University of California Museum of Paleontology, 2016. Web. 5 April 2016.

Kinnaird, M. The Ecology and Conservation of Asian Hornbills: Farmers of the Forest. Chicago: U of Chicago, 2008. Google Books. Web. 3 Apr. 2016

Kline, Katie. “The Story of the Fig and Its Wasp”. Ecological Society of America. ESA, 20 May 2011. Web. 15 Mar. 2016.

Laman, Timothy G (1995). “The ecology of strangler fig seedling establishment.” Selbyana, v. 16 issue 2, p. 223.

Leigh, Egbert Giles. Tropical Forest Ecology: A View from Barro Colorado Island. New York: Oxford UP, 1999. Google Books. Web. 3 Apr. 2016.

Prasertong, Anjali. “Strange Symbiosis: The Fig and the Wasp.” The Kitchn. N.p., 14 Sept. 2010. Web. 02 Apr. 2016.

Sack, Leo. “Growth and Ecology of Strangler Figs.” Tropical Ecosystems: Coral Reefs, Rainforests & A Potpourri of Weather, Earth Science & Other Good Things. Miami University, May 7 2014. Web. 3 April 2016.

Schatz, Bertrand, et al. “Complex Interactions On Fig Trees: Ants Capturing Parasitic Wasps As Possible Indirect Mutualists Of The Fig–Fig Wasp Interaction.” Oikos 113.2 (2006): 344-352. Academic Search Premier. Web. 15 Mar. 2016.

Shanahan, Mike, Samson So, Stephen G. Gompton, and Richard Gorlett. “Fig-eating by Vertebrate Frugivores: A Global Review.” Biological Reviews 76.4 (2001): 529-72. Web. 3 Apr. 2016.

Suleman, Nazia, et al. “Putting Your Eggs In Several Baskets: Oviposition In A Wasp That Walks Between Several Figs.” Entomologia Experimentalis Et Applicata 149.1 (2013): 85-93. Academic Search Premier. Web. 15 Mar. 2016.

Picture 1:  Ella Martin, 2016

Picture 2: Brown, Stephen H. “Ficus Aurea.” (2011): n. pag. University of Florida IFAS Extension. University of Florida, 2011. Web. 2 Apr. 2016.

Picture 3: Mulvihill, Robert. “Let’s Talk About Birds: Hornbills.” Post-Gazzette. Pittsburgh Post-Gazette, 13 Nov. 2013. Web. 08 Apr. 2016.(Link: http://www.post-gazette.com/news/science/2013/11/13/Let-s-Talk-About-Birds-Rhinoceros-hornbill/stories/201311130019)

Picture 4: Wilson, Dede. “Comparing Fresh Fig Varieties.” Bakepedia. Bakepedia, 24 Aug. 2013. Web. 08 Apr. 2016. (Link: http://www.bakepedia.com/tipsandtricks/comparing-fresh-fig-varieties/)

 

 

 

 

 

 

 

 

 

 

 

Baird’s Tapir in Costa Rica: In Danger of Extinction

By Jessica Di Bartolomeo, Michelle Rijski and James Theodore

IMG_20160112_091210Figure 1: Mural of Baird’s Tapir at Rio Celeste, Bijagua.

Baird’s Tapir are the largest mammals in Central America. They were declared in danger of extinction by the International Union for Conservation of Nature and Natural Resources (IUCN) in 2002. As one of the countries home to Baird’s Tapir populations, Costa Rica must use effective conservation strategies to ensure extinction does not occur.

Overview

Many threats such as deforestation have a great impact on Baird’s Tapir’s populations. Smaller factors such as poaching, cattle farming and agriculture also play a role in the decline. Due to their low and slow reproductive rate, they cannot rapidly regenerate the lives of their population. To prevent further loss, strategies must be put in place in order to protect the Baird’s Tapir’s population. Limiting deforestation, enforcing rules against hunting, reducing cattle farming and agricultural farms where Baird Tapirs are found are all possibilities to help their population regenerate.

General Information

Physical description and classification

Tapirus Bairdii, commonly referred to as Baird’s Tapir, belongs to the family Tapiridae and is one of four remaining Tapir species, all of which are threatened or endangered (Brooks, Bodmer and Matola; Terwilliger 1978). It is the least subjected member of its family to research (Terwilliger 1978). Baird’s Tapir is the largest native mammal in Central America (Tobler 2002; Foerster and Vaughan 2002), with an average weight of 150-320 Kg, a length of 180 – 250 cm, and a height of 73-120 cm. Juveniles possess a red-brown coloration with light coloured stripes and spots for camouflage. As they mature, their thick bristly fur becomes a fully dark brown or grey. Tapirs have a long snout, stocky bodies and strong legs adapted for moving quickly in dense vegetation (EDGE 2010). A distinguishing characteristic is their long snout, called a proboscis which extends past their chin and resembles a shortened elephant trunk. It is used to forage through vegetation, picking up eatable plants and bringing them to their mouths (EDGE 2010).

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Figure 2: Tapirus bairdii. Tapirs.org

Habitat, distribution and population

Baird’s Tapir is found from southeastern Mexico through to northwestern Columbia and the Andes of Ecuador (Tobler 2002), ranging from sea level to 3600 meters in altitude, and has been wiped out completely in El Salvador (Cuaron, Matola and Rubio-Tolgler 1997).

It is very difficult to directly observe Tapirs due to their small numbers, preference for dense vegetation and their brown hide that enables them to blend in with their surroundings (Fragoso 1987). When studying Tapirs, researchers often use indirect methods such as tracing tracks and feces. This has shown the Tapir’s habitat preference to be dense forests with bodies of water, such as tropical sub-deciduous forests and cloud forests, as opposed to pine forests and grasslands, which are drier and more exposed. Foerster and Vaughan’s study (2002) indicated a preference for secondary forest, likely because these habitats consist of a dense understory, therefore provides the Tapir with a multitude plants at accessible heights for consumption. Secondary forests would also have fewer forest fires and minimal human disturbance (Naranjo 2009). Studies conducted in Mexico and Costa Rica found that undisturbed areas had twice as many Tapirs. They tend to keep away from hiking trails as well as villages, such as Villa Mills in Costa Rica, where they have been hunted in the past. (Naranjo 2006). These studies also showed that no Tapirs are found near agricultural lands, whose formation by deforestation destroys the Tapirs’ habitat.

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Figure 3: Map of Tapir Habitat. Ultimate Ungulate

Diet

Tapirs eat the stems, leaves, and fruits from over 100 species of plants, from various families including Poacae, Fagaceae, Solanaceae, and Rubiaceae. Studies have reported that they “forage in a zig zag pattern” (Terwilliger 1978; Cuaron, Matola and Rubio-Tolgler 1997). Although Tapirs have been found to prefer certain plant species, their broad diet allows them to live in a variety of habitats and at a wide range of elevations (Naranjo 2006). Tapirs are considered to be seed predators, because many seeds they consume are either destroyed through chewing and digestion or dispersed through expulsion. Tapirs also play an important role in seed dispersion by either spitting out the seeds from fruit they eat, or by defecating them. Baird’s Tapir is important for the maintenance of swamp ecosystems in Costa Rica and Nicaragua because of their effective ability to disperse seeds. In fact, Tapirs can disperse hundreds to thousands of seeds at a time, which have been found sprouting from their feces, often many kilometres away from the parent plants. Furthermore, Tapirs tend to defecate in streams, often further promoting plant growth (Brooks, Bodmer and Matola).

Mating

Tapirs have a 13-month gestation period and produce a single offspring, called a calf, which remains with its mother for the first two years of its life, until it reaches sexual maturity. For the first 10 days or so the calf remains hidden while its mother retrieves food; it then starts following its mother around. Females can have babies until they are approximately 10 years of age, and at most one baby every 14 months. Their low rate of reproduction is a contributing factor in population decline (Brooks, Bodmer and Matola).

Photo_2016-04-06_5_38_47_PMFigure 4: Tapir calf. Prague zoo

Behaviour

Tapirs are very shy and generally solitary but have been found to come together to feed and drink, where they communicate through vocalizations, whistles, and nose touching (Brooks, Bodmer and Matola; Terwilliger 2002). To locate one another, they usually use their sense of smell, or call out with a high-pitched whistle (Brooks, Bodmer and Matola). Although Tapirs are neither distinctly nocturnal nor diurnal, they tend to be most active at night (EDGE 2010). One study found that Tapirs were active 20.2% of the time during the day and 80.4% at night (IUCN 2002). It has been suggested that the Tapir’s behaviour is an adaptation to avoid the heat, as the large mammal would not be efficient at eliminating heat to return to its homeostatic temperature. Furthermore the Baird’s Tapir’s nocturnal activity would allow them to steer clear from humans (Foerster and Vaughan 2002). Tapirs are also highly sensitive to and fearful of noise, resulting in an avoidance of areas with greater human activity (Terwilliger 1978).

Threats

The International Union for Conservation of Nature and Natural Resources (IUCN) categorizes Baird’s Tapir as endangered because of its significant decrease in numbers (IUCN 2002). Its declining population is primarily due to habitat destruction but hunting contributes to the loss (Cuaron, Matola and Rubio-Tolgler 1997; Foerster and Vaughan 2002). Estimates have shown there to be less than 5,500 Baird’s Tapirs left in the wild, with the majority in Mexico (over 1500), Guatemala, Costa Rica and Panama (each with less than 1000) (IUCN 2002). Because of deforestation and habitat fragmentation, Tapirs now mostly live in protected areas and regions not easily accessible to humans. It is not certain whether these areas are adequately large enough to sustain Tapir populations long term (Naranjo 2009). Tapirs’ low reproductive rates make them especially vulnerable to extinction (Cuaron, Matola and Rubio-Tolgler 1997). Decreases in population size slowly recover; therefore, changes in their environment can cause great damage to the species’ survival.

Main threat: Effect of Deforestation

Central America today is home to 70% less forested regions than 40 years ago. Since Baird’s Tapir lives in these forests, much of its habitat has been lost. As forests become more fragmented, the general trend for Tapir populations is to decline. Tapir habitat, including rivers and areas with dense vegetation, are increasingly being transformed into land suitable for logging, farming and agriculture. The remaining forest fragments thus contain a smaller, isolated Tapir population. Many of these forest fragments in Mexico have shown a sharp rise in other species like collared peccaries and white-tailed deer, which Tapirs must compete with for food (Naranjo 2009).

Other threats: Effects of Cattle Farms and Agriculture

Cattle farms are potential source of disease which can harm Perissodactyla populations such as Tapirus Bairdii. The fences put in place for these farms also inhibit Tapirs’ movement (Cuaron, Matola and Rubio-Tolgler 1997). Furthermore, pesticide and fertilizer runoff pollute drinking water, and soil erosion on hills and steep slopes can be deadly (Naranjo 2009). Tapirs must also compete for food with free ranging farm animals like cattle and horses.

Photo_2016-04-06_4_24_07_PMFigure 5: Baird’s Tapir in Water. Los Angeles Zoo.

Conservation

Baird’s Tapir in Costa Rica are likely found in the following areas: Arenal, Cordillera Volcanica Central, La Amistad, Corcovado, Osa, Guanacaste-Santa Rosa, and Llanuras de Tortuguero (Cuaron, Matola and Rubio-Tolgler 1997; Tobler 2002). More research is needed to map out Tapir presence throughout Costa Rica in order to determine with more precision the locations where they have survived and where they have been eliminated (Cuaron, Matola and Rubio-Tolgler 1997). Current studies are also needed for more accurate quantifications of Tapir population in Costa Rica. The most recent study to quantify the number of Baird’s Tapir in Costa Rica, which estimated the population reached no more than 1000, took place in 1990 (Vaughan 1990).

Preservation

A main goal for protection of Baird’s Tapir is habitat preservation, which includes reducing forest fragmentation. Since Tapirs’ habitat usually approaches water sources, the quality of these bodies is vital to conserve as well. Monitoring and reduction of harmful chemicals in agriculture should be an important part of conservation efforts (Foerster and Vaughan 2002).

Hunting

In 1992, the Costa Rican government passed a conservation law which protects Baird’s Tapir and other species from hunting. Current data is needed to verify the upholding of hunting-prohibition laws.

Because of their naturally low density and low birth rate, it is not believed possible for Tapirs to be hunted sustainably. Communities that hunt Tapirs for meat must switch to species with higher densities and birth rates, such as white-tailed deer, peccaries, and armadillos (Naranjo 2009).

In Mexico, Tapir populations are continuing to become isolated from each other, despite an increase in protected regions. This is likely because laws concerning unsustainable practices such as overhunting and crop burning are not properly imposed. Policy-makers are inconsistent in the laws they implement to protect endangered areas and frequently grant subsidies for conventional farming and cattle grazing. Conventional farming should also be discouraged and replaced by sustainable cattle ranches, organic agriculture and agroforestry (Naranjo 2009).

Environmental Education

If rural communities were to get involved in conservation efforts, the Tapir’s status could significantly improve. Jobs like ecotourism, Tapir observation, and feces and track counting should be introduced into these communities. Additionally, communities could host captive breeding areas for Tapirs, which would attract tourists and promote conservation awareness. Environmental education should be encouraged by governments to be taught in schools from elementary through to the end of high school and beyond. Schools and other institution should offer wildlife management courses to rural residents as well as students in larger cities (Naranjo 2009).

References

  1. Brooks, D. M., Bodmer, R. E. and Matola, S. Tapirs. [Online]. HTTPS://portals.iucn.org [2016, Jan 29]
  2. Cuaron, Alfredo D., Sharon Matola and Heidi Rubio-Tolgler (1997).Status and Action Plan of Baird’s Tapir (Tapirus bairdii) [16pp]. IUCN Tapirs Status Survey and Conservation Action Plan. [Online]. Available: https://portals.iucn.org/library/efiles/documents/1997-053.pdf [2016, Feb. 4].
  3. EDGE (12 November 2010). Baird’s Tapir. [12 pp.] [Online]. Available: http://www.edgeofexistence.org/mammals/species_info.php?id=34 [2016, Jan. 29]
  4. Foerster, Charles R and Vaughan, Christopher (2002, September). Home Range, Habitat Use, and Activity of Baird’s Tapir in Costa Rica. [14pp] Biotropica [Online serial], 34(3). Available: http://www.jstor.org/stable/4132941 [2016, Feb. 11].
  5. Fragoso, Jose Manuel V. (1987). The Habitat Preferences and Social Structure of Tapirs [101pp]. Master’s Thesis; University of Toronto. Available: http://web.stanford.edu/group/fragoso/docs/Fragoso%20JMV%201987%20MS%20thesis%202.pdf [2016, Jan. 30].
  6. IUCN (2002). Tapirus bairdii. [Online]. Available: http://www.iucnredlist.org/details/21471/0 [2016, Feb. 3].
  7. Los Angeles Zoo. Tapir, Baird’s. Los Angeles Zoo and Botanical Gardens. [Online]. Available: http://www.lazoo.org/animals/mammals/tapir-bairds/ [2016, April 6].
  8. Naranjo, Eduardo J. (2009, May 25). Ecology and Conservation of Baird’s Tapir in Mexico [19pp]. Tropical Conservation Science [Online serial], 2(2). Available: http://tropicalconservationscience.mongabay.com/content/v2/09-05-25_140-158_naranjo.pdf [2016, Jan. 30].
  9. Naranjo, E.J., M.W. Tobler and I Lira-Torres. (2006). Habitat Preference, Feeding Habits and Conservation of Baird’s Tapir in Neotropical Montane Oak Forests. In Ecology and conservation of neotropical montane oak forest. [Online]. Available: https://www.researchgate.net/publication/225961764_Habitat_Preference_Feeding_Habits_and_Conservation_of_Baird’s_Tapir_in_Neotropical_Montane_Oak_Forests [2016, Jan. 30].
  10. Tobler, Mathias W. (2002, September). Habitat Use and Diet of Baird’s Tapir (Tapirus bairdii) in a Montane Cloud Forest of the Cordillera de Talamanca, Costa Rica. [7pp] Biotropica [Online serial], 34(3). Available: http://www.jstor.org/stable/4132948. [2016, Feb. 11].
  11. Prague Zoo. Prague Zoo Celebrates Newest Tapir Calf. [Online]. Available: http://www.zooborns.com/zooborns/2015/05/prague-zoo-celebrates-newest-tapir-calf.html [2016, April 5].
  12. Tapirs.org. The World’s Tapirs–The Baird’s Tapir (Tapirus bairdii). Tapir Specialist Group. [Online]. Available: http://www.tapirs.org/tapirs/bairds.html [2016, April 5].
  13. Terwilliger, Valery J. (September 1978). Natural History of Baird’s Tapir on Barro Colorado Island, Panama Canal Zone. [9pp] Biotropica [Online serial], 10(3). Available: http://www.jstor.org/stable/2387906 [2016, Feb. 11].
  14. Ultimate Ungulate. Baird’s tapir, Central American tapir. An Ultimate Ungulate Fact Sheet. [Online]. Available: http://www.ultimateungulate.com/Perissodactyla/Tapirus_bairdii.html [2016, April 5].

Figures:

Figure 1: J. Di Bartolomeo, 2016.

Figure 2: http://www.tapirs.org/tapirs/bairds.html

Figure 3: http://www.ultimateungulate.com/Perissodactyla/Tapirus_bairdii.html

Figure 4: http://www.zooborns.com/zooborns/2015/05/prague-zoo-celebrates-newest-tapir-calf.html

Figure 5:http://www.lazoo.org/animals/mammals/tapir-bairds/

Shedding a Light on Bioluminescence

by Julia Cohen, Michelle Gervais, Alexandra Moisan.

Bioluminescence is an emission of light caused by an oxidation reaction that occurs in living organisms. Many diverse microbes and marine animals are able to produce their own light, predominantly those concentrated in the ocean. This light production can be used as a means of communication among a species. The compounds involved in the chemical reaction are luciferin and either luciferase or photoprotein (1). Luciferin produces the light and the luciferase or photoprotein acts as the catalyzing protein of the oxidation reaction (6). The light given off is referred to as cold light as it is 100% light energy. This means that none of it’s energy is transformed into heat (5).

Adaptations

Feeding

Many deep sea fish will use bioluminescence as a lure in order to attract prey. Anglerfish, for example, grow a long appendage that hangs in front of them is used to bait smaller fish into swimming within striking distance. Other fish also use bioluminescence to attract their prey; the cookie cutter shark’s entire body is lit up except for a small patch on it’s stomach that resembles the shadow of a smaller fish. This small shadow-like patch lures in larger predatory fish, who upon attempting to attack what they believe to be a smaller fish, are met with the cookiecutter shark that preys on them (2).


Attraction

Many marine animals use bioluminescence to attract mates. Ostracods, or crustaceans that can be found in the western Caribbean sea, use a complex combination of lights to attract their mates. There are over a dozen different species of Ostracods living within similar habitats. In all of these crustacean species only the males produce bioluminescent light and yet their mating displays are all very different (4).

A non aquatic example of bioluminescent attraction occurs in fireflies. These insects use their bioluminescence to attract a mate and, similarly to the crustaceans each species has its own distinct lighting pattern. The differing patterns allow the female to be drawn to a male of their own species (5).

Protection

Bioluminescence is used by some animals to scare off predators or to distract them long enough to escape. Swima Bombiviridis, also known as the green bomb worm, releases a flash of bright green bioluminescent light when threatened. The same tactic is used by certain squid that produce bioluminescent liquid instead of ink. They release this liquid to distract predators while they escape (2).

Evolution

It is estimated that bioluminescence has evolved at least 40 times independently, but most likely 50 times among extant organisms. Non Symbiotic luminous organisms possess the gene for either luciferase or photoprotein, which are the compounds required to produce bioluminescence. It is believed that for bacterial symbionts, the trait may have evolved only once, but each marine animal lineage that uses those microbes has had to develop specialized organs to host the light and maintain the bacterial culture (10). A type of luciferin known as coelenterazine occurs in many marine bioluminescent groups. It previously had antioxidant properties that helped defend aquatic species from oxidative stress. Oxidative stress is a chemical imbalance that occurs in a body and is cause by free radicals. At some point there was a shift from its antioxidative function to the light emitting function that exists today. This is most likely due to the fact that the need for antioxidative defence mechanisms decreased when marine animals began inhabiting deeper waters. In these waters, the animals were less exposed to oxidative stress because there is less light and oxygen available. Within the organisms, there was a reduction in metabolic activity as they increased their depth in the sea. As a result, through evolution, these organisms developed mechanisms to create the bioluminescence produced by coelenterazine that can be seen today (9).

Dinoflagellates of Costa Rica

Screen Shot 2016-04-10 at 10.24.30 AM.png

In Costa Rica we observed bioluminescent dinoflagellates, which are a type of plankton. Ninety percent of all dinoflagellates are marine plankton. Dinoflagellates are approximately 0.04 mm in size, making them invisible to the naked eye, and are present in large agglomerations in the epipelagic zone of the ocean which is located up at the surface (7). Dinoflagellates are motile, they move by means of two flagella, a protein and microtubule strands which propel it through the water. They have an internal skeleton made of cellulose like plates (8).

Dinoflagellate Bioluminescence Chemistry

These tiny marine organism produce light through a luciferin-luciferase reaction. The luciferase found in dinoflagellates is related to the green chemical chlorophyll found in plants (1). Although the chemistry of the dinoflagellates luminescence is not completely understood, it is most likely caused by a drop in pH due to an influx of protons within its cell. It is an extremely fast cellular process and the dinoflagellate can produce a flash of light lasting up to 100 ms. However, once all its luciferin has been oxidized, it must wait until the following day for its chemicals to recharge to be able to flash again. (8) The cell alternates between photosynthesis and luminescence on a 24 hour cycle.

Ecological Roles and Relationships

Dinoflagellates use their luminescence for many different ecological functions. These protists can be autotrophic or heterotrophic. Photosynthetic dinoflagellates are important primary producers in coastal waters; some are symbiotic living in their hosting coral cells. Seen as they are small photosynthetic organisms, they are at the bottom of the food chain. Because of this, many aquatic creatures prey on them. Therefore, they primarily use their bioluminescence as a defence mechanism. By emitting light when stimulated by movement they can scare away smaller predators. They also act as a signal to larger predators. When they light up they draw the larger predators in, signaling the presence of a smaller predator they can prey on. This indirectly protects the dinoflagellates, creating a mutualistic relationship with the larger coastal predators (7).

References

  1. “Bioluminescence.” National Geographic Education. National Geographic, 13 June 2013. Web. 25 Mar. 2016. <http://education.nationalgeographic.org/encyclopedia/bioluminescence/&gt;.
  1. ”Adaptations for Bioluminescence – Bioluminescence.” Adaptations for Bioluminescence. Smithsonian National Museum of Natural History, n.d. Web. 25 Mar. 2016. <http://www.biology-online.org/articles/bioluminescence/adaptations-bioluminescence.html&gt;.
  1. ”Dinoflagellate Bioluminescence.” Latz Laboratory. Scripps Institute of Oceanography, 09 June 2014. Web. 25 Mar. 2016. <https://scripps.ucsd.edu/labs/mlatz/bioluminescence/dinoflagellates-and-red-tides/dinoflagellate-bioluminescence/&gt;.
  1. Rivers, Trevor J., and James G. Morin. “Complex Sexual Courtship Displays by Luminescent Male Marine Ostracods | Journal of Experimental Biology.” Complex Sexual Courtship Displays by Luminescent Male Marine Ostracods | Journal of Experimental Biology. Journal of Experimental Biology, n.d. Web. 27 Mar. 2016. <http://jeb.biologists.org/content/211/14/2252.long&gt;.
  1. United States. National Park Service. “Synchronous Fireflies.” National Parks Service. U.S. Department of the Interior, n.d. Web. 27 Mar. 2016. <https://www.nps.gov/grsm/learn/nature/fireflies.htm&gt;.
  1. Nealson, K. H., and John W. Hastings. “Bacterial bioluminescence: its control and ecological significance.” Microbiological reviews 43.4 (1979): 496.
  1. Wilson, Thérèse. Bioluminescence. Harvard University Press, 2013.
  1. ”Dinoflagellate Bioluminescence.” Latz Laboratory. Scripps Institution of Oceanography. UC San Diego, 09 June 2014. Web. 05 Apr. 2016.
  1. Others, J.-F. Rees. “THE ORIGINS OF MARINE BIOLUMINESCENCE: TURNING OXYGEN DEFENCE MECHANISMS INTO DEEP-SEA COMMUNICATION TOOLS.” The Journal of Experimental Biology 201, 1211–1221 (1998): 1211. Web. 5 Apr. 2016.
  1. Haddock, Steven H.D, Mark A. Moline, and James F. Case. “Bioluminescence in the Sea.” Marine Science 2 (2009): 443-49. Web. 5 Apr. 2016.

Picture 1: http://inhabitat.com/5-bioluminescent-species-that-light-up-the-world/

Picture 2: http://knowledgebase.lookseek.com/Angler-Fish-teleost-order-Lophiiformes.html

Picture 3: http://beneficialbugs.org/bugs/Firefly/boreal_firefly.htm

Picture 4: http://matadornetwork.com/trips/15-places-to-see-bioluminescence-pics/

Picture 5: http://visualsunlimited.photoshelter.com/image/I0000duZGSLe8aoU