Hmm well I’m still standing after a week’s worth of bad hotels and bat surveys, not to mention long (and cold?!) bat surveys. Here I usually put a link to last week’s animal, but this time I’m going to skip that, and head straight to the next inn on my list of accommodation. Hope you guys enjoy this issue.

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Issue #80 – Fat Innkeeper Worm

Kingdom – Animalia

Phylum – Echiura

Class – Echiuroidea

Order – Echiurida

Family – Urechidae

Genus – Urechis

Species – unicinctus

Related Species – The Fat Innkeeper Worm, also known as the Penis Worm, is one of the Marine Spoon Worms (1)

Range – The Fat Innkeeper Worm is found in tidal mudflats and shallow seas off the Californian Coastline

Plenty of room in the Inn

The Fat Innkeeper Worm, is a small flesh coloured spoon worm, which looks like a 20cm long tube left on the seabed with a slight swelling on one end. While many other marine worms have hard segmented bodies, or are toxic upon consumption, the Innkeeper Worm defends itself by digging a burrow in the mud in the shape of a U, with the deepest point being over a meter under the surface of the seabed. These burrows can be easily identified at low tide, by a small cone of displaced mud and sand around the entry hole (2).

When its burrow has been excavated, the Fat Innkeeper Worm places a web of mucus around one of the holes. Sitting at the bottom of the U, the worm pumps water up through the hole and past the web where any organic particles get stuck. As respiration gets harder due to the hole being blocked with organic detritus, the worm consumes the web and its contents, before spinning a replacement structure. This laid back method of hunting attracts a number of other animals including scale worms, pea crabs, clams and gobies, all of whom steal food from the web, and hide in the worm’s burrow from predators (3).

Due to the actions of the worm, and its many loggers, the burrow quickly fills up with biological waste and debris from the tunnel walls. As the level of waste rises, the Innkeeper pulsates its rear, and blows all the detritus out of the second hole (the one without the food web) to clear its burrow. The worm uses a similar tactic when it comes to breeding, pumping out eggs or sperm (depending on its gender) into the water current. After fertilisation young Innkeeper worms float in the plankton for a few months, before falling to the ocean floor and digging burrows of their own.

Ecology 101 – Guide to Environmental Mechanics - #9 Symbiosis in the Natural World

Symbiosis comes from the two Greek words; Syn (together) and biosis (alive or living), and despite common belief, includes a wide range of behaviours and partnerships found in the natural world. The most common interaction linked with symbiosis is mutualism (where both parties benefit from living together) but also contains commensalism (where one party benefit from the relationship whilst the other is unaffected) and even parasitism (where one party actively damages the other party). In this instance we will be concentrating on commensalism and mutualism, since parasitism has already been covered in an earlier issue.

Commensalism (formed from the French word commensalis which translates to ‘sharing a table’) consists of one group of animals or plants benefiting from the actions of another, but not harming or repaying their host. The interaction of the Fat Innkeeper Worm and its loggers is a commensal relationship.

That said not all commensal relationships are so intentional, most probably came about as an accident, something that can be seen in the nests of Eastern Screech Owls (Otus asio). Like all owls, the Screech Owl is a skilled predator that takes many prey items, including the Texas Blind Snake (Leptoypholus dulcis) a harmless burrowing species which comes to the surface at night. Being rather defenceless, these snakes are often picked up by the owl and taken back to the nest and fed to the chicks. While this sounds grim, the slippery snakes often get luck, evading the waiting becks of the owlets and escaping into the nest. Once here, the Blind Snake happily feeds off insects attracted to the waste in the owl nest, effectively keeping the place clean. Once the chicks have fledged, the snake slithers down the tree and quickly returns to its burrow. Without meaning too, the Screech Owl has managed to reduce chick mortality by almost 30% thanks to the Blind Snake’s actions. Despite the benefits all further interactions and benefits come about from chance, and likely won’t evolve past this stage.

The difference between commensalism and mutualism is rather thin, but ultimately comes down to whether both parties benefit. If the relationship is intentional is insignificant, this kind of interaction is seen between the Dotted Humming Frog (Chiasmocleis ventrimaculata) and the Columbian Lesserblack Tarantula (Xenesthis immanis) (4). Despite the tropical surroundings it find itself in, the frog runs the risk of dehydrating and often takes refuge in the tarantula’s burrows, often at the same time and within close proximity of its owner. At first glance the relationship looks very one sided, the tarantula is a ferocious predator, even eating small snakes, so a tiny frog wouldn’t stand a chance if the spider decided to turn on it. Thankfully, for the frog, chemical cues in its skin picked up by the tarantula state that the frog is toxic, and therefore inedible. Its survival guaranteed, the frog stays inside the burrow and feeds off insects that wander in, especially ants which would often try and eat the tarantula’s eggs and spiderlings. While such instance rely on the frog being too toxic to eat, both species benefit from the relationship, and the frog intentionally moves into the burrow suggesting a mutualistic relationship.

While the relations between owls and blind snakes, and tarantulas and frogs may be relatively new, there is one species of animal that specialises in forming partnerships with other animals and plants. Humanity (Homo sapiens sapiens) more than any other animal, seeks partnerships with such a wide range of species, be it for protection (dogs), labour (horses, donkeys, cattle), food products (chickens, honey bees), materials (sheep, llamas) or even hunting (dolphins). This list only shows a tiny number of our animal partners, and unlike most examples of positive symbiosis humanity actively chooses which species it partners with from the offset, rather than relying on blind luck.

The reason for such behaviour comes from our relationship with, what is likely, our first animal partner; the Greater Honeyguide (Indicator indicator) (5). It’s well known that primates, including humans have a sweet tooth, and that there are confirmed behaviours of many species risking the stings of bees, to get at honey. Yet despite our obvious prowess at getting said honey, bee hives are often well hidden, and are not always in places that hunter check. The honeyguide however, has the opposite problem, it’s well versed at finding bee hives, but lacks any way to easily breach the hive and eat the wax and honeycomb it craves. It is probable that the relationship between man and honeyguide came about from early humans following the bird to bee hives, quickly learning the flight pattern of its guide. At this point it appears humanity is in charge, but this view quickly changes once you take in the tales the Boran and San people tell of the bird and its vengeful streak.

According to folklore, a honeyguide who isn’t left a reward of bee larvae, honeycomb or bee wax will decide to punish its partner. Using the same flight signals and sounds it uses to guide its partners to honey, the bird will instead lure those who wronged it into the path of a dangerous animal or area of hostile ground. While such tales are considered just that, there is always an element of truth in such folklore, and it is possible that honeyguides actively trained their partners to always leave something for their services. Certainly such partnerships relying on both sides being rewarded, such as humanity’s early interactions with the ancestors of our modern domestic animals, are very similar to our relationship with the honeyguide. It is highly likely that our current partnerships would have taken a lot longer, or may not even have happened without the early training the first humans received from our relationship with the honeyguide.

References

1. www.arkive.org

2. http://www.elkhornslough.org/sloughlife/inverts/fatinnkeeperworm.htm

3. Walls, Jerry G. (1982). Encyclopedia of Marine Invertebrates. TFH Publications. pp. 262–267

4. http://scienceblogs.com/tetrapodzoology/2009/07/03/tiny-frogs-and-giant-spiders/

5. Isack, H. A. and H.-U. Reyer (1989). "Honeyguides and honey gatherers: interspecific communication in a symbiotic relationship". Science 243 (4896): 1343–1346.

Picture References

1. http://nathistoc.bio.uci.edu/Echiurids/P1120690b.jpg

2. http://3.bp.blogspot.com/-vMUx8jfJ-o4/USkLPIYAXhI/AAAAAAAAH4k/-HKkfoB_XnA/s1600/fat_innkeeper_worm.jpg

3. http://www.newtonsapple.org.uk/wp-content/uploads/2014/07/texas-blindsnake.jpg

4. http://i.crackedcdn.com/phpimages/article/9/9/0/295990_v1.jpg

5. http://ibc.lynxeds.com/files/pictures/3-Greater-Honeyguide.jpg

Well that’s defiantly something to think about, what with the kind old Innkeeper Worm sharing his burrow with no fuss, not to mention all those animal partnerships. Next week we have a rubbery issue, but until then remember to critic, comment and discuss future species to cover as well as checking out past issues in Impurest’s Bestiary.

Many Thanks

Impurest Cheese