How was the flamingo tongue snail named?

By Sandy Van Dijk

The flamingo tongue snail… how does a snail receive such an odd name? Was the researcher who discovered the snail an expert on flamingo tongues? Or did he or she perhaps find the snail on the tongue of a flamingo? To find out the answer, you will have to learn a bit about the snail first.

The flamingo tongue snail (Cyphoma gibbosum) is a member of Phylum Mollusca, which also includes organisms like octopus, squid, clams, oysters, scallops, slugs and others. They are found within Class Gastropoda, containing slugs and snails, and Subclass Prosobranchia which means the gills are in front of the heart. Flamingo tongue snails are part of the Family Ovulidae, also known as cowries, which have smooth, shiny shells with a long aperture (Nahabedian et al. 2007).

Flamingo tongue snails grow up to one inch in length, have a shell that is generally covered by a yellow to orange mantle with a pattern of many odd-shaped, black-edged spots. When the snail is disturbed or stressed, it will withdraw its mantle to reveal the white-to-cream coloured shell underneath (Brockman 2009).

A flamingo tongue snail showing off the brightly coloured mantle that covers its shell. Photo by Laszlo Ilyes. Used under Creative Commons Attribution-Share Alike 2.0 Generic License.

Flamingo tongue snails are marine, living from North Carolina to Brazil in the Atlantic and Caribbean on shallow reefs (Brockman, 2009). Unfortunately, this rules out the theory that the flamingo tongue snail was found on the tongue of a flamingo. The snail lives on gorgonian corals, also known as sea fans and sea whips, individually or in pairs. Interestingly, the snails feed on the gorgonian corals on which they live, but the corals are allelochemically rich (Whalen et al. 2010). In other words, the corals contain chemicals that deter predators from eating them. Most organisms are unable to feed on gorgonian corals because of the toxic chemicals present. So you may be wondering, how does the flamingo tongue snail feed on a toxic sea fan or sea whip? The snails contain enzymes also known as Glutathione S-transferases (don’t worry, we’ll shorten that up to GSTs because I can barely pronounce that!) which are detoxification enzymes. The GSTs either biotransform allelochemicals into non-toxic chemicals which the snail is able to cope with, or the GSTs sequester the allelochemicals within the snail’s body (Whalen et al. 2010). This feeding habit of eating toxic organisms is beneficial for flamingo tongue snails for a couple of reasons. First of all, not many organisms contain GSTs that can detoxify allelochemicals, so there is a lack of competition to eat sea fans and sea whips. Another benefit is that flamingo tongue snails now contain allelochemicals which make them distasteful to organisms which prey on them. Therefore, flamingo tongue snails only have a few predators, including hogfish, pufferfish and Caribbean spiny lobsters. Many organisms have bright and striking colouration to warn predators that they don’t taste good. The common belief is that the striking black-edged spots on the pinkish mantle of the flamingo tongue snail is warning colouration, scientifically known as aposematic colouration (Gerhart, 1986).

Flamingo tongue snails on a sea fan. Photo by Paul Asman and Jill Lenoble. Used under Creative Commons Attribution-Share Alike 2.0 Generic License.

When breeding occurs, the snails form large aggregations. The snails are dioecious, so each individual is either male or female. The females deposit eggs onto the gorgonian coral which hatch into nocturnal, plankton eating larvae, less than 5 mm long (Nahabedian et al. 2007). Because the larvae feed on plankton, they do not take in allelochemicals that cause them to be unpalatable to other organisms. This is believed to be the reason why the larvae are nocturnal, so they can avoid other organisms that may prey on them.

Flamingo tongue snails used to be very abundant across their range. Recently, their numbers have been declining as a result of scuba divers collecting them to sell for jewelry products (Nahabedian et al. 2007). Many don’t realize that the mantle is part of the living snail and when the snail dies, the mantle decomposes leaving only the cream-coloured shell exposed. So I encourage readers that go diving in any aquatic ecosystem to leave with only pictures and memories.

Let’s get back to the mystery behind the name of the flamingo tongue snail! The truth is, I am unaware as to how this yellow-orange snail with the black-edged spots got its name. After much research, I could not find any reference or reason behind the name. Personally, I believe the researcher who discovered the snail named it as a result of an overly exuberant imagination!

References

Brockman D. 2009. The flamingo tongue snail: a dangerous beauty. Coral Magazine. Accessed online February 19, 2015 at http://www.coralmagazine-us.com/

Gerhart DJ. 1986. Gregariousness in the gorgonian-eating gastropod Cyphoma gibbosum: tests of several possible causes. Marine Ecology Progress Series 31: 255-263.

Nahabedian S, Wood JB, Parr M. 2007. Marine invertebrates of Bermuda: flamingo tongue snail (Cyphoma gibbosum). Bermuda Institute of Ocean Sciences. Accessed online February 19, 2015 at http://www.thecephalopodpage.org/MarineInvertebrateZoology/

Whalen KE, Lane AL, Kubanek J, Hahn ME. 2010. Biochemical warfare on the reef: the role of glutathione transferases in consumer tolerance of dietary prostaglandins. PLoS ONE 5(1): e8537.

The Hunting Techniques of the Net-Casting or Ogre Faced Spider (Araneae: Deinopidae)

By Fiona Raymond

The order Araneae encompasses all spiders; the net-casting or ogre faced spider is an arthropod classified in the order Araneae, the superfamily Deinopoidea and the family Deinopidae (Griswold et. al 1998). Ogre faced spiders, found in mainly tropical regions, were so named for their prominent eyes which give them a humanoid appearance, while some of these spiders have net casting abilities. Their net casting ability is a unique hunting technique specific to this group. This ability gives this spider another common name, which is the net-casting spider. Spiders have adapted to hunt insects for their primary source of food, and these are spiders that hunt by pursuit by using intricate webs woven from silk produced in structures known as spinnerets located near the posterior end of the abdomen (Chickering 2014). Although most spiders hunt passively by allowing insects to entangle themselves in the webs that have been spun, the net-casting spider spins a web between its legs and actively hunts both aerial and terrestrial insects.

A male web-casting spider Deinopis subrufa. Photo by Jurgen Otto. Used under the Creative Commons Attribution-NonCommercial-NoDerivs 2.0 Generic license.

The silk used to make a spider’s web is made up of a scleroprotein; this protein produces a web that is not only both fine and lightweight, but also elastic and strong (Chickering 2014).  The web of a net-casting spider is woven differently than that of a normal spider. It is created with a large supporting scaffold that the spider hangs from and a small web that is expanded between the four front legs; this is the web that it uses to capture its prey. The spinnerets along with the cribellum are both structures that aid the net-casting spider in creating these webs (Peters 1992). The capture web is spun with specific capture threads, and while not in use this web hangs loosely between the spider’s legs, although while in use it can be expanded greatly in order to capture large prey.

The web of a net-casting spider is very complex and therefore is constructed and primed for attack with an equally complex process. Initially the spider spins its capture web with its head up in respect to the webs position, but once it is complete it turns head down. The dragline is the line that allows the spider to hang from the supporting scaffolding while holding its capture web between its four front legs. When the spider turns its head down it attaches the dragline to its own midline which allows it to control its fall when capturing prey on the ground (Coddington and Sobrevila 1987). The spider is now holding the capture web in its four front legs while hanging from the dragline. The spider then cuts a segment of the dragline from where it is attached at the midline, which initially allows it to fall forward; the spiders allows the dragline to slip through its hind legs in a controlled descent until it makes contact with the surface beneath it with its two front legs (Coddington and Sobrevila 1987). The spider does this to orient itself above the ground and estimate its distance so that when it is hunting it knows how fast to release the dragline (Coddington and Sobrevila 1987) It then reels itself back up with its hind  legs while still holding the net in its first two pairs of legs. Before it performs a strike it can be seen in its prey-ready position: the net is held parallel or perpendicular to the ground and the spider is suspended about 1.5 – 3cm in the air (Getty and Coyle 1996). Once this has been done the spider is prepared to attack.

The net-casting spider hunts during the day; at night it avoids predators and constructs its elaborate net system.  The attack of the net-casting spider can be classified into two general types: forward strike and backward strike. The forward strike is used to capture prey walking on the ground beneath the spider. First the spider expands its capture web by spreading out its legs; then the fourth legs allow the dragline to slip rapidly through its legs and as it descends it pivots and rotates until it contacts the ground hopefully with dinner now ensnared in the web (Coddington and Sobrevila 1982). The forward strike utilizes gravity as its source of power. The backward strike is used to capture aerial prey that may be flying near the spider. To carry out this attack the spider retains its grip on the dragline with its fourth legs while rotating its body backwards; it then bends its first and second legs (the legs that hold the capture web) out and back towards the insect. It can be caught on either the inside or outside of the web (Coddington and Sobrevila 1982). Unlike the forward strike the backward strike does not move up or down. Both attacks prove useful in the net-casting spider’s arsenal.

The net-casting or ogre faced spider hunts in a very unique way compared to other spiders. It utilizes attacks that allow it to actively hunt for aerial and terrestrial prey. An elaborate web system and setup process is required in order to enable this process. This spider has a highly sophisticated attack system, so be thankful you’re not a fly.

References

Chickering, A.M. (2014). Araneae. AcessScience. McGraw-Hill Education. Retrieved from http://www.accessscience.com/content/araeneae/046200.

Coddington, J. & Sobreliva, C. (1987). Web manipulation and two stereotyped attack behaviors in the ogre-faced spider Deinopis spinosis Marx (Araneae Deinopidae). Journal of Arachnology, 15(2), 213-225.

Getty, R.M. & Coyle, F.A. (1996). Observations on prey capture and anti-predator behaviours of ogre-faced spiders (Deinopis) in Southern Costa Rica (Araneae Deinopidae). Journal of Arachnology, 24(2), 93-100.

Griswold, C.E., Coddington, J.A., Hormiga, G. & Schaff, N. (1998). Phylogeny of the orb-web building spiders (Araeneae, Orbiculariae: Deinopoidea, Araneaoidea). Zoological Journal of the Linnean Society, 123,1-99. DOI: 10.1111/J.1096-3642.1998.TB01290.X.

Peters, H.M. (1992). On the spinning apparatus and the structure of the capture threads of Deinopis subrufus (Araneae, Deinopidae). Zoomorphology,112, 27-37. DOI: 10.10007/BF01632992.

The mimic octopus: a master of disguise

By Camille Martens

The mimic octopus, Thaumoctopus mimicus, is the first known cephalopod species to not only perform mimicry of a poisonous species, but also the only animal to quickly interchange morphs of many different species, specialized for any given threat (Norman et al. 2001). Also known as the long arm octopus, the mimic was only recently discovered in 1998 in the waters off Sulawesi, Indonesia (Norman et al. 2001). This octopus’ habitat consists of shallow open, sandy plains with minimal reef and coral cover, leaving the cephalopod highly exposed and vulnerable to predation (Norman et al. 2001; Hanlon et al. 2008).

Its odd foraging behaviour is what first caught the eye of biologists, also the first of its kind to emerge during the daylight in spite of the presence of large predators (Norman et al. 2001). It was first found swimming with all its tentacles trailing behind, head flattened, and eyes positioned, creating the shape of what is now interpreted as the impersonation of the poisonous sole (Baker 2010). The mimic would then approach burrows and tunnels, reaching its long arms underground for food (Norman et al. 2001). The shape shifting is not the only amazing feat by the mimic; it also imitates behaviour specific to the sole, rippling its ‘body’ in short quick bursts over the sandy floor (Norman et al. 2001; Hanlon et al. 2008).

Thaumoctopus mimicus portraying the first discovered impersonation, the poisonous sole, swimming with all its tentacles trailing behind its head in a teardrop shape. Photo by Klaus Steifel. Licensed under the Creative Commons Attribution-NonCommercial 2.0 Generic license.

Biologists can only guess what the camouflage is alluding to by investigating common species in the area, but it is said that the mimic has 13 species up its long sleeve (Hanlon et al. 2008). By swimming with its tentacles splayed out, it seems as though it is trying to mimic the spines on the fins of the poisonous lionfish; with six tentacles in a tunnel and two splayed out lengthwise it looks to be a venomous banded sea-snake, both species common in the Indonesia waters that are its territory (Norman et al. 2001). While swimming high in the water it looks as though it may be a jellyfish, and while lying sessile on the ocean floor with its arms floating, it looks as if it’s an anemone -two possible interpretations that are still up for debate (Norman et al. 2001; Hanlon et al. 2008). Thaumoctopus mimicus is incredibly intelligent and will morph into certain species dependent on which predators are passing by as it forages; for example, in the presence of damselfishes, the mimic has been observed impersonating a sea snake, its known rival (Norman et al. 2001).

Mimic octopus spreading its tentacles in what is interpreted as impersonating a poisonous lionfish. Photo by Steve Childs. Licensed under the Creative Commons Attribution 2.0 Generic license.

Thaumoctopus mimicus is unusual in many ways, and crypsis (changing colour to camouflage themselves into the background of reefs) is no exception; a common trait to cephalopods, but this octopus also changes to dark colours and bold patterns in an instant, what some scientists think may even attract other species (Baker 2010).

It is still unknown whether T. mimicus is itself a poisonous species; making the difference whether it is Batesian or Mullerian mimicry that this species performs (Baker 2010; Norman et al., 2001). Also undetermined is whether this trait of advanced polymorphism is learned or an innate knowledge they are born with (Baker 2010). This master of camouflage is one of a kind, and there is certainly reason behind its impersonations that we have only just begun to understand. A fairly recently discovered species, much more research is needed on the mimic octopus and its bizarre behaviour, but finding the subjects might prove harder than expected.

References

Baker, B. 2010. Unusual adaptations: evolution of the mimic octopus. BioScience. 11: 962.

Hanlon, R. T., Conroy, L., and Forsythe, J. W. 2008. Mimicry and foraging behaviour of two tropical sand-flat octopus species off North Sulawesi, Indonesia. Biological Journal of the Linnean Society. 93: 23-28.

Norman, M. D., Finn, J., and Tregenza, T. 2001. Dynamic mimicry in an Indo-Malayan octopus. Proceedings of the Royal Society B: Biological Sciences. 286: 1755-1758.

Salps, The Goo of Stealth and Survival!

By Michael Yue

Imagine walking along the warm sandy bleach from the coast of Washington – with every step, your feet sink into the sand, feeling the cool tingly grains between your toes. However, you step into something slimy. You immediately move away from the source – anticipating the sharp agonizing stings of a sea jelly. But seconds later, with yours eyes closed with fear; there was nothing – no pain at all. What was it? As you look closer, there laid a glop of goo; the strange organism was small, cylindrical, and transparent. The gelatinous form resembled a sea jelly, but clearly it lacked tentacles and stinging cells. What is this strange organism? It is a salp! What in the world are salps?

Colonial salps displayed in an aggregate chain. Photo by Lars Lougmann. Used under the Creative Commons Attribution-Share Alike 2.0 Generic license.

Salps are barrel-shaped, planktonic tunicates from the family, Salpidae. These gelatinous and translucent organisms are common in equatorial, temperate, and/or cold seas, living near the surface1. They move through the water by contraction of their bodies, creating vortices for jet propulsion2. For obtaining nutrients, they capture tiny plankton from suspension feeding3. Remarkably, salps are quite small as individuals vary from only micrometers to centimeters in dimension! These transparent creatures are able to make beautiful salp chains within the sea during the colonial phase of their life cycle, however. Salps are sometimes mistaken as sea jellies by people, which may be due to the similar appearance to a sea jelly because of their simple and transparent body form4.

Interestingly, salps are structurally more closely related to vertebrates, than they are to sea jellies4.Salps are very important for evolutionary inferences of early vertebrates. Salps appear to have a form ancestral to vertebrates. Because of this, they are used by scientist as an evolution model for primitive vertebrates. Scientists speculate that their primitive nervous system gave rise to the central nervous systems of an ancestral vertebrate4.

Even though salps may appear rather simple (or even like a glop of goo), these remarkable invertebrates can display mesmerizing complexity, e.g., vast salp chains, bioluminescence and optical deception.

A circular ring cluster of pelagic salps at Aorangaia, Poor Knights Islands, New Zealand. Photo by Peter Southwood. Used under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Salps have a fascinating life cycle. Like a lone warrior, a salp starts off a solitary life. In their solitary phase they are often referred to as oozoids5. After feeding and surviving well in pelagic waters, an oozoid utilizes its energy for asexual reproduction. The salp produces blastozooids, forming a chain of salps.  A single oozoid can produce an army of efficient suspension feeders. Interestingly, salps start off as a female which then matures into a male. Because of this, young chains of blastozooids are fertilized by older chains during mating season 6. If successful, an attached viviparous oozoid embryo will develop in the fertilized female6. Thus, it renews the cycle of alteration between solitary and colonial phase5.

Surprisingly, when salps form vast aggregate chains, communication is not distorted. Try to imagine yourself as a professor, who attempts to communicate to hundreds of students during a lecture – clearly, there will be some degree of confusion between classmates. For salps, they use a bioluminescent cascade signal2. The first oozoid of the chain is the messenger. When the salp is going to communicate, it creates bioluminescence (which produces light) 2. Adjacent blastozooids capture the light signal with a specialized cell called a photoreceptor. This energy is then transformed to the next bastozooid. The process is repeated until the very last blastozooid receives the message. This elegant systematic way of communication prevents confusion and aids in cooperation2.

So, at the moment, we know that an oozoid can remarkably produce an army of blastozooids and communicate efficiently by light signals. However, what if I tell you that they are also masters of disguise, the stealth of the pelagic seas? Due to their small, gelatinous and clear body form, it is difficult for predators to see them7 – salps appear invisible like a ghost or a ninja. In addition, maybe they are even experts in physics? Since salps stay near to the surface, light polarizes8. This effect causes salps to appear cloaked within the background of the sea.

So, next time when you walk along a sandy beach, there might be glop of goo. However, if that glop of goo is a salp, don’t become deceived by the appearance because they are like a sea jelly in disguise, a master of survival, and a stealthy ninja in the sea!

Citations

1 Hereu, C. M., & Suarez-Morales, E. (2012). Checklist of the salps (Tunicata, Thaliacea) from the Western Caribbean Sea with a key for their identification and comments on other North Atlantic salps. Zootaxa, 3210, 50-60.

2 Mackie, G. O., & Bone, Q. (1977). Locomotion and propagated skin impulses in salps (Tunicata: Thaliacea). The Biological Bulletin, 153(1), 180-197.

3 Alldredge, A. L., & Madin, L. P. (1982). Pelagic tunicates: unique herbivores in the marine plankton. Bioscience, 32(8), 655-663.

4 Yount, J.L. (1954). The taxonomy of the Salpidae (Tunicata) of the Central Pacific Ocean. Pacific Science, 8(3), 276-330.

5 Deibel, D., & Lowen, B. (2012). A review of the life cycles and life-history adaptations of pelagic tunicates to environmental conditions. ICES Journal of Marine Science, 69(3), 358-369.

6 Lucas, C. H., & Dawson, M. N. (2014). What Are Jellyfishes and Thaliaceans and Why Do They Bloom? In Jellyfish blooms (ed. by K.A. Pitt and C.H. Lucas ), pp. 9–44. Springer, Dordrecht.

7 Hongli, L., Long, Z., Zhidong, T., & Yaolin, J. (2014). Dynamic Behaviors of Holling Type II Predator-Prey System with Mutual Interference and Impulses. Discrete Dynamics in Nature & Society, 2014, 1-13.

8 Sönke, J. (2011). Polarization sensitivity as a contrast enhancer in pelagic predators: lessons from in situ polarization imaging of transparent zooplankton. Philosophical Transactions of the Royal Society B: Biological Sciences, 366(1565), 655-670.

Are You Smarter than a Cuttlefish?

By Jamie Yoshida

Cephalopods are considered to be the most advanced of the molluscs in terms of speed, intelligence and sensory ability. Out of all the cephalopods, focus will be shifted to one species in particular, the cuttlefish. These marine critters belong to the family Sepiida, which belong to the phylum Mollusca. They are closely related to other members of the phylum Mollusca, which include octopuses and squid (Dees. 1961). Cuttlefish inhabit shallow temperate ocean waters and are found along the coasts of Africa, Asia, Australia, the Mediterranean and Western Europe (Dees. 1961). Although these creatures may appear similar to their close relatives, cuttlefish have a distinguishing and unique feature that is exclusive to their species. The cuttlebone is composed of aragonite and includes several other features; is highly porous and serves as an internal shell, which provides buoyancy (Allmon. 2008). Diets consist of shrimp, fish, crabs, small molluscs, worms and other cuttlefish (Zumholz. 2006). Predators include sharks, fish, seals, dolphins and larger cuttlefish (Costa et al. 2005).

Out of all the invertebrates, cuttlefish have been shown to have the largest brain-to-body size ratios (Wells. 1962). Although brain size is not always correlated with intelligence, cuttlefish have been shown to have a capacity for learning (Alves et al. 2007).  As defined by Kamil (1987) intelligence is “encompassing those processes by which animals obtain information about their environment, retain it, and use that information to make decisions during their behavioural activities” (p. 273). This learning capacity or in other words, animal cognition is often what is referred to when studying animal intelligence. Cuttlefish have managed to demonstrate their level of intelligence by exhibiting various forms of learning; including visual, cognitive and associative methods (Alves et al. 2007).  They have also illustrated advanced navigational and communication abilities, learning capacity and mating techniques.

An example of social interactions between cuttlefish. Photo by David Iliff. Used under the Creative Commons Attribution 2.5 Generic license.

 

Camouflage between interspecific species is nothing new within the animal kingdom. Despite being colour blind, cuttlefish and other cephalopods have demonstrated the ability to communicate using various colour patterns that are dependent on environmental textures (Mathger et al. 2008). Cuttlefish have highly advanced visual and sensory organs, which allow for the regulation and expression of visual features, including textures, spots and lines (Kelman et al. 2008). With a total of 40 chromatic components, chromatic behaviour can be used to coordinate and produce a particular pattern colouration to suit a particular situation, ranging from courtship rituals to camouflage from predators ((Kelman et al. 2008). This behaviour is neurally controlled as opposed to hormonal (Wardill et al. 2012). Visual strategies utilized by this species have shared similarities to human object recognition (Kelman et al. 2008).

A juvenile cuttlefish demonstrating its camouflage ability to blend in with the environment to avoid predation. Photo by Raul654. Used under the Creative Commons Attribution-ShareAlike 3.0 Unported license.

 

Cuttlefish have managed to evolve and develop an alternative mating strategy that often gives smaller males the upper hand. Sexual mimicry utilized by cuttlefish is a demonstration that size isn’t always an advantage. Due to a much higher male to female ratio, there is high mating competition (Hanlon et al. 2005). Smaller males, under normal circumstances would be at a mating disadvantage against larger males. This dimorphic difference has lead to the development of the ability to “impersonate” the appearance of a female in an attempt to deceive other cuttlefish guarding potential mates (Hanlon et al. 2005). Males hide their sexually dimorphic fourth arm and imitate moulted skin patterns (Norman et al. 1999). These crafty creatures even go as far as shaping their arms to mimic the same posture as egg laying females!  Females more often choose those cuttlefish that exhibit this visually deceiving mating technique.

There is evidence suggesting that cuttlefish have demonstrated the use of spatial skills. They are able to understand their environment to maximize hunting efficiency and return safely to their den. Several experiments have been conducted in order to find out exactly how much spatial knowledge cuttlefish possess. An experiment conducted by Alves et al. (2007) was set up which involved training cuttlefish to solve a spatial task with distal cues within a T-maze. The final results yielded all cuttlefish successfully reaching the learning criteria within 3-10 trials. Performance increased throughout the trails, with the number of correct choices made also increased (Alves et al. 2007). This is a strong indication that cuttlefish do possess some understanding of spatial skills and their surrounding environment.

References

Alves, C., Chichery, R., Boal, J. G., & Dickel, L. (2007). Orientation in the cuttlefish Sepia officinalis: response versus place learning. Animal cognition, 10(1), 29-36.

Catalani, J. A. (2008). Cephalopod intelligence. American Paleontologist, 16(3), 35.

Costa, P. R., Rosa, R., Duarte-Silva, A., Brotas, V., & Sampayo, M. A. M. (2005). Accumulation, transformation and tissue distribution of domoic acid, the amnesic shellfish poisoning toxin, in the common cuttlefish, Sepia officinalis. Aquatic toxicology, 74(1), 82-91.

Dees, L. T. (1961). Cephalopods: Cuttlefish, Octopuses, Squids. US Department of the Interior, Fish and Wildlife Service, Bureau of Commercial Fisheries.

Hanlon, R. T., Naud, M. J., Shaw, P. W., & Havenhand, J. N. (2005). Behavioural ecology: transient sexual mimicry leads to fertilization. Nature, 433(7023), 212-212.

Kamil, A. C. (1994). A synthetic approach to the study of animal intelligence. Behavioural Mechanisms in Evolutionary Ecology (ed. LA Real), 11-45.

Kelman, E. J., Osorio, D., & Baddeley, R. J. (2008). A review of cuttlefish camouflage and object recognition and evidence for depth perception. Journal of Experimental Biology, 211(11), 1757-1763.

Norman, M. D., Finn, J., & Tregenza, T. (1999). Female impersonation as an alternative reproductive strategy in giant cuttlefish. Proceedings of the Royal Society of London. Series B: Biological Sciences, 266(1426), 1347-1349.

Wardill, T. J., Gonzalez-Bellido, P. T., Crook, R. J., & Hanlon, R. T. (2012). Neural control of tuneable skin iridescence in squid. Proceedings of the Royal Society B: Biological Sciences, 279(1745), 4243-4252.

Wells, M. J. (1962). Brain and behaviour in cephalopods. Stanford University Press.

Zumholz, K., Hansteen, T. H., Klügel, A., & Piatkowski, U. (2006). Food effects on statolith composition of the common cuttlefish (Sepia officinalis). Marine Biology, 150(2), 237-244.

Phylum Tardigrada: From the Ocean Floor to Earth’s Orbit

By Nick Wingfield

Tardigrade, moss piglet, waterbear, all synonyms for one of the most extreme microbial animals that you never knew existed. With an average size of only 0.5 millimeters(3) (barely larger than these periods), a person might ask “How can these guys be interesting or extreme?” Well, by the end of this entry you won’t just be interested in tardigrades, you’ll want to be one.

As a phylum, Tardigrada are most closely related to Onycophorans and Arthropods (3). Their appearance resembles something like an earth worm crossed with a shar pei, with a little bit of grizzly bear thrown in. They are cylindrical and bulky, with their bodies split into five sections; a defined head and four body sections (6). On the head you will find a simple eyespot, as well as a sucking pharynx and basic mouth parts (6). Due to their microscopic size, tardigrades usually feed on bacteria(6). There is however, one big mean eating machine known as Milnesium tardigradum, that is carnivorous and grows up to 1.2 millimeters long who is known for eating smaller invertebrates and other tardigrades (2).  Each body section contains a pair of short, stubby, clumsy looking legs equipped with some form of claws that can vary in structure between species(6). The rear pair of legs, however, are not like the others. They are attached backwards. These legs are generally used for grasping, and allows for tardigrades to contort and climb all around their environment(6).

Water bear (tardigrade), Hypsibius dujardini, scanning electron micrograph by Bob Goldstein and Vicky Madden, http://tardigrades.bio.unc.edu/. Used under the Creative Commons Attribution-ShareAlike 3.0 Unported license.

Unlike their insect cousins, tardigrades show much less diversity with approximately 1000 species discovered so far, possessing only 10 discernable physical characters (2,3). They are however found in much more diverse habitats. They are prevalent in Antarctica, found on mountain tops, barnacles, riverbanks, and even present on the ocean floor(2,3,6,7,8). They live amongst lichens, mosses, barks, various sediments, basically anywhere with food (6,7).

The ability of a tardigrade to undergo cryptobiosis is the reason for this huge habitat tolerance (7, 8). Basically, this means a tardigrade can shut down its body and stop the aging process until favorable conditions arise. This can be induced by freezing, osmotic changes, anoxia (lack of oxygen), or most famously, anhydrobiosis (almost total dehydration) (4). Through these techniques tardigrades can survive exposure to the vacuum of space, boiling ethanol, CO2,H2S, huge doses of radiation, and nearly a decade in -80 degrees Celsius (7). While it appears that the upper range of survival in cryptobiosis is a decade, there have been observations suggesting near rehydration from pieces of wood kept in a museum after as much as 100 years! (4)

The dominant speciesat utilizing cryptobiosis is again M. tardigradum. While the exact mechanism is not known, this species has adapted some cellular skill that allows it to survive the most extreme environmental stresses (8). When sent into low orbit, this species was the only one to survive vacuum and complete exposure to all levels of solar radiation, as well as their eggs still bearing young when exposed to space vacuum conditions (5).

Even more incredible than space survival is a tardigrade’s inert radiation tolerance. These little guys are tougher than the incredible hulk. A lethal dose of gamma radiation to a human is in the 7.5-10 Gy (j/kg) range, while a fly can live up to around 1400 Gy (J/kg), but astoundingly the average tardigrade can survive exposures of up to 6000 Gy(1). In a recent study however, it was seen that our friend M.tardigradum’s eggs (that’s right, unborn animals) can survive exposures of up to 500 Gy, by apparently adjusting the very mechanisms of mitosis(1). So, even if you still don’t want to become a tardigrade, I definitely wouldn’t mess with them; they’ll outlast you everytime.

References

(1) Beltran-Pardo E, Jonsson KI, Wojcik A, Haghdoost S, Harms-Ringdahl M, Bermudez-Cruz RM, and Villegas JEB. 2013. Effects of Ionizing Radiation on Embryos of the Tardigrade Milnesium cf. tardigradum at Different Stages of Development. PLoS ONE 8(9): e72098.doi:10.1371/journal.pone.0072098

(2) Blaxter M, Elsworth B, and Daub J. 2004. DNA taxonomy of a neglected animal phylum: an unexpected diversity of tardigrades. Proc Biol Sci.. 271:S189-S192

(3) Campbell LI,  Rota-Stabelli O, Edgecombe GD, Marchioro T, Longhorn SJ, Telford MJ, Phillippe H, Rebecchi L. Peterson KJ, and Pisani D. MicroRNAs and phylogenomics resolve the relationships of Tardigrada and suggest that velvet worms are the sister group of Arthropoda. PNAS 108(38):15920-15924.

(4) Jonsson KI, and Bertolani R. 2001. Facts and fiction about long-term survival in tardigrades. Journal of Zoology, London. 255:121-123

(5) Jonsson KI, Rabbow E, Schill, RO, Harms-Ringdahl M, and Rettberg P. 2008. Tardigrades survive exposure to space in low Earth orbit. Current Biology. 18(17):R729-R731

(6) Kinchin, I. M. 1994. The Biology of Tardigrades. London and Chapel Hill, N.C.: Portland Press.

(7) Sands CJ, McInnes SJ, Marley NJ, Goodall-Copestake WP, Convey P, and Linse K. 2008.Phylum Tradigrada: an “individual” approach. Cladistics 24:861-871.

(8) Wang C, Grohme MA, Mali B, Schill RO, and Frohme M. 2014 Towards Decrypting Cryptobiosis—Analyzing Anhydrobiosis in the Tardigrade Milnesium tardigradum Using Transcriptome Sequencing. PLoS ONE 9(3): e92663. doi:10.1371/journal.pone.0092663

Pseudomyrmex ferruginea: The ideal tenant

By Brooke Wiebe

Pseudomyrmex ferruginea, commonly known as the acacia ant, is classified under the phylum Arthropoda and class Insecta (Pechenik, 2010). and is found in Central America (Janzen, 1966). They are called acacia ants because they are usually found living in acacia trees under a mutualistic relationship (Janzen, 1966). A Mutualistic relationship is when both participants benefit from interacting with each other (Pechenik, 2010). In this case the acacia provides the ants with food and shelter (Janzen, 1966), while the ants protect the acacia from herbivores (Martins, 2010). Due to the coevolution of these two species, it is unlikely that either would survive without the other (Janzen, 1966).

For shelter the ants occupy and hollow out the thorns scattered along the acacia’s branches. These areas are used to protect larvae and queen, and to store food (Janzen, 1966). One-fourth to three-fourths of the thorns are used just by the larvae (Janzen, 1969). The thorns are what protect the ants from predators and poor weather conditions since most of the ones used are water proof and have thick walls that can be difficult for predators to crack (Janzen, 1969). The acacia also provides nectar though foliar nectaries called Beltian bodies, which are found on modified leaves (Janzen, 1966). Although the ants will eat small insects, plant nectar and honeydew from scale insects, about 99% of the ants’ diet is supplied by the acacia (Janzen, 1966).

Acacia ants (Pseudomyrmex ferruginea). Photo by Ryan Somma. Used under the Creative Commons Attribution-ShareAlike 2.0 Generic license.

In exchange for shelter and food, the ants are assigned the task of protecting the acacia tree from herbivores. For a new colony it takes 7 to 9 months for the population to become large enough to protect the acacia completely (Janzen, 1966). Groups of senior workers will patrol the acacia 24 hours a day and attack most foreign species that approach the tree (Janzen, 1966). When an insect invades the ants will become excited and will produce an odor that will accelerate their speed, allowing them to charge (and usually miss) the invader (Janzen, 1966). Normally a group of workers will attack a single invader by biting them, but they do not seem to cooperate when taking down an intruder (Janzen, 1966). Also even though insects are a part of their diet, they rarely eat the intruders and usually just let the insect fall from the tree (Janzen, 1966).

They are also effective at clearing any foreign plants that get within a certain radius of the tree (Janzen, 1966). Not only will they completely clear the base of the tree (distance from the trunk depends on the size of the colony), but they will destroy any plant that touches the acacia from above (Janzen, 1966). Again it is possible for the acacia ants to eat the products from some of these plants, but the workers behaviour shows that this action is more about protecting the tree than collecting food (Janzen, 1966). In fact, they will even eradicate other acacia saplings instead of moving into them if they haven’t produced thorns or nectaries yet (Janzen, 1966).

As for mammals, the acacia ants do not appear to be as effective, since they are unable to strike down the larger creatures. They do have stingers which they use to attack mammals (Janzen, 1966). The stings are painful enough to deter animals from eating the trees (Madden & Young, 1992).

With both species relying so much on each other, it isn’t unreasonable to assume they would struggle without each other. In fact, there have been no reports of acacia ants creating colonies outside of acacia trees (Martins, 2010), since queens won’t settle unless she finds an acacia sapling that supports her need for thorns and nectar (Janzen, 1966). Also studies have shown that unoccupied acacia saplings are preyed upon more heavily than occupied saplings (Janzen, 1966). It really is amazing how much these species rely on each other to survive, and how the extinction of one could bring the other one down with it.

References:

Janzen, D. H. (1966). Coevolution of mutualism between ants and acacias in Central America. Evolution, 20, 249-275.

Janzen, D. H. (1969). Birds and the ant x acacia interaction in Central America, with notes on birds and other Myrmecophytes. The Condor, 71, 240-256.

Madden, D., & Young T. P. (1992) Symbiotic ants as an alternative defense against giraffe herbivory in spinescent Acacia drepanolobium. Oecologia, 91, 235-238.

Martins, D. J. (2010). Not all ants are equal: obligate acacia ants provide different levels of protection against mega-herbivores. African Journal of Ecology, 48, 1115-1122.

Pechenik, J. A. (2010). Biology of the Invertebrates (6th ed.). New York, NY: McGraw-Hill.

Acyrthosiphon pisum: The little Pea Aphid that could

By Grant Usick

At first glance the pea aphid looks like your average insect. Little, green, and something your mother curses in the garden. Recent sequencing of its genome (The International Aphid Genomics Consortium 2010) has revealed a very different tale involving the co-evolution of two completely unrelated organisms.

Carotenoids are naturally occurring pigments produced in photosynthesizing plants, algae, bacteria and… aphids? These pigments are responsible for the varying coloration found in organisms on Earth. The most common being the orange carrot that owes its bright color to the carotenoid carotene. For pea aphids, carotenoids display green, a darker red/orange, or a yellowish/white color when environmental conditions aren’t as favorable as carotenoid synthesis is a taxing process.

Pea aphids extracting sap from the stem and leaves of garden peas. Photo by Shipher Wu. Used under the Creative Commons Attribution 2.5 Generic license.

Pea aphids set themselves apart from the rest of the insects and all other animals, except the two-spotted spider mite, in their ability to produce carotenoids on their own (Altincicek et al. 2012). All the credit cannot be given to the pea aphid alone though. It and all other modern aphids can thank an ancient common ancestor who lived alongside a fungus and received the necessary genes for the synthesis of carotenoids through a process known as horizontal gene transfer. This is defined as the transfer of genes from one individual to another by means other than reproduction, such as conjunction. Conjunction is where genes are transferred between two bacteria cell membranes uncoupled by cell division rather than vertical gene transfer, from mother to daughter cell. Phylogenetic analysis done by Moran and Jarvik (2010) supports this with many similarities between the structure of genes found in modern fungus and the bacterial symbionts of aphids.

Sequencing of the pea aphid’s genome has revealed insight into its many interesting biological features, such as how one genotype can produce winged and non-winged individuals by either sexual or asexual reproduction. The ability to capture energy from the sun was an unexpected addition to that list. The carotenoids form a thin layer underneath the skin of the back of the insect, positioning it perfectly to capture sunlight. True photosynthesis is not achieved, as the fixation of carbon dioxide to produce organic molecules does not occur. It is thought of as a more primitive form of photosynthesis. Research done by Jean Valmalette et al. (2012) found significantly higher levels of ATP (energy currency in organisms) in green colored aphids compared to orange. Pigments were extracted and absorbance tests revealed a striking difference between the level of absorbance of orange and green pigments, showing much higher levels of absorbance in green colored aphids.

Pea aphid on alfalfa. Photo by Jpeccoud. Used under the Creative Commons Attribution 3.0 Unported license.

This is a peculiar finding that seems to raise a lot more questions than it answers, like why would an insect with a diet rich in carbohydrates waste its energy on expensive carotenoids to capture the more energy from the sun? One theory suggests that the energy captured acts as a store to be later utilized while traveling to a new host plant. There are many questions that remain unanswered, and the little pea aphid continues to surprise.

References:

Altincicek, B., Kovacs, J.L., Gerarda, N.M., (2012). Horizontally transferred fungal carotenoid genes in the two-spotted spider mite Tetranychus urticaeBiol Lett. 2: 253-257.

Moran, N.A.., Jarvik, T., (2010). Lateral transfer of genes from fungi underlies carotenoid production in aphids. Science. 328: 624-627.

The International Aphid Genomics Consortium, (2010). Genome sequence of the pea aphid Acyrthosiphon pisumPLoS Biol(2): e1000313. Doi:10.1371/journal.pbio.1000313

Valmalette, J.C., Dombrovsky, A., Brat, P., Mertz, C., Capovilla, M., Robichon, A., (2012). Light-induced electron transfer and ATP synthesis in carotene synthesizing insect. Scientific Reports. 2 Article number: 579. doi:10.1038/srep00579

Glaucus atlanticus: the mini ninja of the ocean

By Vanessa Uschenko

Glaucus atlanticus, commonly known as the blue sea slug, is a marine gastropod of the nudibranchia clade and is one of only two species found in the Glaucus genus (Rudman 1998).  Found in the temperate and tropical waters of the Pacific, Indian and Atlantic oceans, the blue sea slug can grow up to 3 cm in length (Kumar et al 2012).

Despite its size, the blue sea slug has a reputation for being a voracious predator, consuming some of the most dangerous ocean dwellers. This small invertebrate preys upon many hydrozoa species, preferring the Portuguese Man-o-War (Physalia physalis) when available but has also been documented to prey upon by-the-wind-sailor (Velella velella),and the blue button jelly (Porpita porpita) (Bieri 1966). During conditions with limited food, the blue sea slug will also resort to cannibalism (Scocchi and Wood 2011). Contrary to its size, the blue sea slug is always full of surprises. Its mouth is comprised of a strong jaw made of chitin, holding together many sharp teeth-like structures that the invertebrate uses to latch on and tear off chunks of prey (Savilov 1956). The blue sea slug is not only unaffected by the poisonous sting from its prey, but has developed a unique way of utilizing the venom for its own benefit. Upon swallowing the nematocysts (stinging cells), the blue sea slug is then able to store the poison in their 84 tentacle-like structures called cerata (Natural History Museum 2011). This stored venom is then used as a defense mechanism against potential predators including birds and predatory fish.

A blue sea slug (also called sea swallow, blue glaucus, blue dragon, blue ocean slug, lizard nudibranch), Glaucus atlanticus. Photo by Sylke Rohrlach. Used under the Creative Commons Attribution-ShareAlike 2.0 Generic license.

Another mechanism the blue sea slug uses to avoid predation is camouflage. The blue sea slug uses its bright blue underside  to avoid detection from below, and its grey topside to avoid detection from above (Scocchi and Wood 2011). The blue sea slug has another unique adaptation to life in the ocean. This small nudibranch lives a pelagic upside down life, both floating and swimming (seldom) at the surface using a small air bubble, which they swallow and store inside their stomachs, allowing them to float along the surface, driven by wind and ocean currents, or by using their cerata that slowly allow them to swim closer to both prey and potential mates (Kumar et al 2012). Due to their wandering lifestyle, it is not uncommon for this species to wash up on shore, often in large numbers commonly referred to as “blue fleets”, posing danger to individuals utilizing the beaches (Rudman 1998). As these “blue fleets” wash up many blue sea slugs, the danger of people being stung increases, either by swimming in the waters, or interactions with the species on land.

This species is anything but ordinary. Little is known regarding its reproduction, but it has been documented sexual interactions between this species lasts between 43-59 minutes, and that males have small spines along the penis, a feature common in many animalian species (Alejandrino  et al 2013). It has also been documented that individuals of this species are hermaphroditic and lay large amounts of eggs on either the carcasses of prey they have previously killed or in free floating masses when carcasses are not readily available (Savilov 1968). The unique adaptations of this small pelagic nudibranch are a surprise to many: the ability to harness their prey’s defenses, superb camouflage and their voracious appetite make the blue sea slug a mini ninja of the ocean.

References

Alejandrino, A., Churchill C.K.C., Foighil, D.O., Valdes, A. 2013. Paralled changes in genital morphology delineate cryptic diversification of planktonic nudibranchs. Proceedings of the Royal Society. 280(1765):1-5

Bieri, R. 1966. Feeding Preferences and Rates of the Snail, Ianthina prolongata, The Barnacle, Lepas anserifera, The Nudibranchs, Glaucus atlanticus and Fiona pinnata, and the food web in the marine Neuston. Publications of the Seto Marine Biological Laboratory. 14(2): 161-170.

Kumar, G.C., Srinivasulu, B., Srinivasulu, C. 2012. First record of the blue sea slug (Glaucus atlanticus) from Andhra Pradesh-India. Taprobanica. 04(01):52-53 Accessed March 26, 2015

Natural History Museum. 2011. Taxonomy. London. Retrieved from: http://www.nhm.ac.uk/nature-online/species-of-the-day/collections/our-collections/glaucus-atlanticus/taxonomy/index.html Accessed: March 23, 2015

Rudman, W.B .1998. Glaucus atlanticus Forster, 1777. Sea Slug Forum. Australian Museum, Sydney. Retrieved from: http://www.seaslugforum.net/factsheet/glauatla Accessed: March 23, 2015

Beware the Red! The Red Tide!

By Brian Tse

When you think of the colour red, thoughts of love and passion are often evoked. However, in the world of marine microorganisms, the colour red, can have potentially more deadly connotations. As a person from Vancouver, BC, I am used to being near the ocean and enjoying delicious seafood and wonderful ocean breezes. However, a phenomenon that can occur in the coastal waters off BC known as Red Tide has heightened my fears of eating the delicacy that is fresh shellfish from our waters.

Red Tide effect at Thermaikos Bay, Greece. Photo by Anthony Sigalas. Used under the Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic license.

Red tide occurs in waters when there are giant eruptions of growth of certain marine microorganisms. Known in the scientific world as harmful algal blooms or HABs, the species responsible for these events are dinoflagellates, taxonomically classified as a Phylum of protozoans, usually in the genera Alexandrium, Gymnodinium, or Karenia (Mudie et al., 2002). A clarification of what dinoflagellates are for those not savvy with the biological jargon: they are tiny prokaryotic, and sometimes photosynthetic, organisms that have two flagella protruding from them (Lackey, 2014). Photosynthetic dinoflagellates of the genus Symbiodinium, also called zooxanthellae, form symbiotic relations with corals and other multicellular organisms (Pechenik, 2010). Some genera also have bioluminescent properties (Pechenik, 2010) and look quite beautiful if seen at night producing a bright blue glow.

Breaking waves at La Jolla, California, creating bioluminescense from dinoflagellates. Photo by Kevin Baird. Used under the Creative Commons Attribution-NonCommercial-NoDerivs 2.0 Generic license.

Back to the HABs. Bi-valve shellfish such as clams or mussels, feed by letting water pass through them and essentially filter the water by catching any tiny microorganisms that unfortunately get caught inside it. When there are large amounts of dinoflagellates in the water, the shellfish can’t help to pick up one or two along the way. However, the dinoflagellates produce a toxin that gets picked up by the shellfish as it doesn’t get filtered (Setala et al., 2014). Under normal conditions, the amount of toxin is negligible, but when HABs occur, the amount of toxins collected by a shellfish is high enough that eating said shellfish, is potentially fatal. While the shellfish are not harmed for just accumulating these toxins, other marine species such as fish and crustaceans are killed. (Pechenik, 2010).

The toxins produced by the various dinoflagellates are neurotoxins, which can cause paralysis at varying severity. The condition for people who suffer paralysis after consuming toxic shellfish is aptly named “Paralytic Shellfish Poisoning” (Setala et al., 2014). The different genera of dinoflagellates produce different types of neurotoxins such as brevetoxin from Karenia (Pierce and Henry, 2008) or saxitoxin from Alexandrium (Setala et al., 2014). What makes things worse is that cooking infected shellfish does not get rid of the toxins and some shellfish can store toxins within their body for years afterwards (Pierce and Henry, 2008). Less severe cases can result in symptoms of vomiting, nausea, and diarrhea (Pechenik, 2010).

Now that you’ve learned about paralytic shellfish poisoning and HABs and all the dangers that surround them, aren’t you just craving for a fresh oyster at the local seafood bar? While the threat of toxins and deadly shellfish do loom, especially for those who live in coastal cities, it is thankful that many countries like Canada and the United States have good laws on commercial farming as well as food inspectors which alleviates a lot of the risk from eating shellfish. Personally, I won’t be stopping anytime soon, but if you’re out by ocean with some friends, and find some shellfish in a pool of beautiful red water, and proceed to eat it, don’t say I didn’t warn you.

Works Cited

Lackey, James B. (2014). Dinoflagellida. In AccessScience. McGraw-Hill Education. Retrieved from http://www.accessscience.com/content/dinoflagellida/196600

Mudie, P.J., Rochon, A., and Levac, E. (2002). Palynological records of red tide-producing species in Canada: Past trends and implications for the future. Palaeogeography, Palaeoclimatology, Palaeoecology, 180, 159-186.

Pechenik, J.A. (2010). Biology of the Invertebrates. New York: McGraw-Hill.

Pierce, R. H., and Henry M.S. (2008). Harmful algal toxins of the Florida red tide (Karenia brevis): Natural chemical stressors in south Florida coastal ecosystems. Ecotoxicology, 17(7), 623-631.

Setala, O., Lehtinen, S., Kremp, A., Hakanen, P., Kankaanpaa, H., Erler, K., and Suikkanen, S. (2014). Bioaccumulation of PSTs produced by Alexandrium ostenfeldii in the northern Baltic Sea. Hydrobiologia, 726, 143-154.