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I'm a big fan of the various species of the so called "ant plants"; plants which have developed symbiotic relationships with ants. In some species (such as the Myrmecodias and Hydnophytums) the plants produce highly modified stems which naturally develop hollow internal chambers which provide living spaces for ant colonies. The ants in turn benefit the plants by protecting their host from insect pests and providing nutrients derived from decomposing detritus from the ant colony. In addition to the previous examples there are a few members of the greater milkweed family which produce modified leaves which also provide sheltered sites for ants to establish their colonies. Some species, such as Dischidia pectinoides and D. major produce modified pouch-like leaves which serve as nesting sites. Other species produce large leaves which provide shallow, dome-like enclosures between the leaf and the substrate which can serve as a living site for ant colonies.
Hoya imbricata is one particularly attractive example of this last type of plant. It is an epiphytic plant with long, thin climbing stems which cling to tree trunks and branches, and bear very large succulent, plate-like leaves (reputedly measuring from about 2 inches, to nearly 10 inches in diameter in some varieties), which clasp the vertical surfaces upon which they grow. These leaves typically grow rather close together, slightly overlapping one another like roofing shingles or fish scales (the specific epithet "imbricata" alludes to this similarity to roofing tiles). Ants colonize the spaces beneath these leaves, often using adjacent leaves to serve as "nurseries", food storage and other specialized rooms or chambers for the ant colony. The spaces beneath the overlapping leaves may also serve as a protected highway, by which ants can travel from the ground to the upper branches of forest trees. This Hoya produces roots all along the length of the stems - those which are located just beneath the leaves will absorb nutrients from the detritus from the ant colony - providing the plant with a significant portion of its fertilization. The plant may also absorb a significant percentage of the carbon dioxide exhaled by the ants - providing the plant with vital carbon necessary in the production of sugars, proteins, and lipids.
Mature plants can grow many yards in length, and will branch and re-branch to produce intricate networks giving its host tree the appearance of being covered with shingles, or giant fish scales.
There are a number of varieties of this species in the wild, but the specific traits which distinguish the different varieties are not entirely clear to me - nor have I been able to find a listing of all of the recognized varieties in my research. Some varieties have closely spaced leaves which overlap, blanketing the trunks upon which they grow, while at least one variety is said to have long internodes with more widely spaced (non-overlapping) leaves. Most have comparatively small leaves (2 to 5 inches in diameter), while at least one variety produces leaves to about 10 inches across. In some, the leaves are of a uniform green coloration, but in others, the leaves are a dark green and are attractively marbled in pale greenish/grey tones. The leaf undersides of all varieties bear magenta to purplish pigments - which in many other plant species, is usually an adaptation to lower light levels - the purplish undersides to the leaf act as an accessory pigment to chlorophyll, which enables the plant to make use of additional wavelengths of light.
The flowers are produced in loose dangling umbels, which in my plant, measured to about 2 inches across. Larger, more mature plants will probably produce larger umbels with more flowers than this. The flowers are quite attractive, bearing "furry" greenish/cream colored petals. Other portions of the flower are of the same coloration, but are glossy and polished looking, earning them the common name for the genus, "Wax Flowers". While the flowers of other Hoya species can be highly fragrant, to my nose, the scent of this species is extremely faint: it is slightly sweet, with a trace of a musty under-tone. My plant has only flowered once: I am uncertain what combination of cooler temperatures, reduced light intensity, shorter daylight hours and less humid conditions may have helped initiate the formation of flower buds, but my plant flowered in November, about 2 months after I brought it indoors for the winter.
Hoya imbricata is not the easiest plant to maintain under typical household conditions. In my 19 months of growing this plant, I have struggled to discover which conditions best suits it: in summer, my plant usually produces a modest flush of growth, but it remains dormant through much of the other 9 months. It responds well to the increased light levels and higher temperatures of summer, especially when I move it into my unheated greenhouse in late spring. This species requires warm temperatures, bright but diffuse light, and quite humid conditions. Without high humidity, my plant languishes in a sort of persistent dormancy, and in winter, it has the tendency to loose moisture from its leaves and abort roots and young stems until humid conditions are restored. It is only when humidity exceeds about 60% that my plant even begins to show signs of growth: at levels closer to 90%, it seems to produce its most rapid growth. I am presently growing cuttings in a sealed 2 liter soda bottle with a soil-less mixture of peat moss and vermiculite watered with a weak solution of Miracle Gro fertilizer. This terrarium is kept just below two 40-watt fluorescent lights (the bulbs actually resting on the surface of the bottle). Because of the proximity of the lights, the temperature inside of the terrarium can rise to as much as 95 degrees Fahrenheit by day. At night (when the lights are off), temperatures typically fall to about 72 degrees. Conditions are very moist, so the sides of the container are perpetually drenched in condensation. This combination of warmth and moisture would rot practically any other plant, but my plant seems to thrive under these conditions, quickly responding with renewed, vigorous growth. After just a few weeks, one small cutting has produced 4 new stems, and the beginnings of at least 2 new leaves. Following this initial success, I started another cutting (a single leaf with several branching stems) under similar conditions. This cutting had been dormant for nearly one year - but within one week of this treatment, I observed the initiation of new growth at two nodes - probably the beginnings of two new vines; about a week later, it is producing the beginnings of new roots. Larger plants can be grown in a sort of mini greenhouse - I am growing my "main" plant horizontally in a long plastic storage container (the type designed for under-the-bed storage) with a pane of glass placed over the top to provide a more or less sealed environment (to ensure high humidity levels). I place fluorescent tubes on top of this (with the tubes resting just a few inches above the plant), and maintain light for approximately 14 hours a day. Even though I grow my plants on the basement floor (the coolest location in the house), temperatures inside of this container will rise to approximately 80 degrees by day, and cools to about 68 degrees at night (conditions which are probably a bit cooler than optimum). It would probably be best to place a 1 inch layer of very moist blend of Vermiculite/Perlite on the bottom of the container to provide adequate humidity, but any moisture retentive medium (such as peat-moss, or sterilized potting soil) will do.
In spite of the purple/magenta pigments on the underside of its leaves, (which is usually an adaptation to low light levels), Hoya imbricata seems to thrive when provided with bright but indirect light. When grown outdoors, bright dapple shade is probably best, but indoors, plants should be maintained just a few inches beneath fluorescent lights. Extended exposure to direct sunlight will tend to bleach and scorch its leaves.
Hoya imbricata requires a good support and a more or less solid surface upon which to grow in order to assure typical growth, otherwise the leaves of unsupported vines tend to roll in upon themselves (imagine a paper plate rolled into a cylinder). Cork-bark slabs, osmunda fiber slabs and posts, even long sections of logs and thick tree branches are good supports. For my own plant, I take two sections of black plastic mesh "gutter guards", and sew these along their sides and bottom to produce a long "sock". I fill this with an orchid potting mix consisting mostly of chipped coconut husk and cork bark. This mix retains moisture much better than cork-bark slabs, and may provide more humid conditions under the leaves than cork slab would alone. This support is rigid enough for the leaves to "clasp" normally, although I have found that it is best to wire new growth against it to assure good contact with the growing medium, at least until roots become established enough to hold the new leaves in place.
As with all Hoyas, this species requires warm temperatures to thrive: 80 to 90 degrees seems to be best, although it will tolerate higher temperatures than this: Extended periods of cooler temperatures (68 to 52 degrees) will tend to send plants into dormancy, and freezing temperatures will practically kill it instantly. While I have not tested its ultimate tolerances to cold, it will likely die if exposed to temperature in the 40's for any more than a few days, so if you do move your plants outdoors in summer, be prepared to bring it back indoors at the first predictions of cool weather.
It seems that only a few conservatories, and dedicated hobbyists grow Hoya imbricata here in the United States. Exceedingly few nurseries stock any of the varieties of this species, so it may sometimes be easier to acquire cuttings from other growers than it is to find in trade. My plant (Hoya imbricata var. basirotunda), for example, was originally acquired as cuttings generously provided by Myron Kimnach. The scarcity of this species in the trade is unfortunate, as this is an exceptionally interesting, and (in my humble opinion) one of the most attractive Hoya species that I know of. Perhaps its reputation as an "ant plant" works against it. While plants which are grown outdoors in the tropics and subtropics may sometimes become colonized by ants, it has been my experience that plants grown in more temperate climates do not attract ants, and can be grown without the presence of ants without ill effects. In nature such symbiotic relationships tend to be fairly specific, and usually involve a relatively few ant species; most ant species from northern latitudes would not colonize this plant. Grown indoors, particularly when grown in a more or less sealed environment, the chances of ants colonizing this species are virtually nil.
The specialized growing needs of Hoya imbricata will probably forever relegate this plant to dedicated growers only, particularly those from non-tropical climates. But for those growers who are not daunted by the challenges of providing year-round warm temperatures, high humidity and bright light, this species may very well be the plant for you. Its distinctive growth habit, attractive foliage (particularly those varieties with attractively marbled leaves), attractive "furry" flowers, and its fascinating adaptations to live symbiotically with ants will make it a standout in any collection. And it is unquestionably the most attractive "ant plant" which I have ever grown.
"Therapy"
Original Painting by Cara Buchalter of Octavine Illustration
Painted in gouache on Plywerk, a hand-crafted substrate wood board handmade in Portland, Oregon.
*The Inspiration*
My friend Dani is an art therapist. When looking at my work she always analyzes me, rather than my art. She pointedly asks, "What were you thinking when you drew this?" Or, "How does this image make you feel." I simply chuckle at her, smile and ignore telling her to stop shrinking my brain.
Her comment on this piece includes the psycho-babble that I love her for: "This is really a significant piece. I love the tension between the green and the diagonal red and wine colors. This piece must have come from deep in your subconscious..."
To be honest, I have no idea where my inspiration is derived from. Most of the time, I find a model--a photograph, magazine clipping or even a poem and start from there; my creativity a force unto itself.
For more information please visit my blog:
www.octavineillustration.blogspot.com
©2008 Cara Buchalter. Please don't take and use the images without permission, thanks.
The beginnings of the giraffe sculpture. 44" tall. Styrofoam cut to shape and glued together.
#kimlarsonart
Substrate: Quercus robur.
Eesti punase nimestiku liik, äärmiselt ohustatud (CR). LK II.
Rakvere, Lääne-Virumaa.
Seda seent ootasin täpselt 3 aastat. 2015 oli vana viljakeha, 2016 ja 2017 ei olnud üldse.
The fungus I was waiting to appear for three years.
24" substrate with 12" mirror I have covered in a mosaic of glass tile, stained glass, glass gems and tempered glass.
Suggestions for the collection, examination and
photography of rock dwelling Patella species.
Ian F. Smith, April 2020
Casual photographs of the shell exterior of Patella species are unreliable evidence for differentiation and are likely to be declined as records by verifiers on iRecord, especially when they would alter the established distribution patterns. In north-west Europe, if a lateral view shows that a shell has a height 50%, or more, of its length, it can usually be accepted as Patella vulgata (but it often has a lower shell). Otherwise, the interior of a fresh shell may suffice but, often, a view of the foot and peripheral pallial tentacles is needed. This requires removal, without damage, of a live limpet from the substrate.
Collecting equipment
Dining knife with a strong, broadly rounded tip (sharp point risks damage).
Plastic box, lined with polythene, part-filled with seawater.
Collecting method
Please be sparing in how many you take, especially if limpets are not locally common.
Carefully approach a limpet in a pool or on damp rock; its shell will probably not be applied with full force to the substrate. Sudden movement or shadow may cause it to clamp down. When close enough, quickly force the knife, angled into the rock under the shell and foot. A horizontal thrust risks lethal damage. If the rock is soft, try to push the knife tip into its surface. Complete the removal by striking the handle of the knife with your free hand, as if hitting a chisel. If your first thrust fails to go under the limpet, abandon the effort as it will have clamped down and be impossible to move without damage. Try another one.
Place the removed limpet, sole down, in the lined box in water sufficiently deep to cover the shell; there should be air left in the box. Leave the box undisturbed for the limpet to settle and grip the polythene before transporting it. Upturned limpets are likely to die, so check as soon as home is reached that it is still upright. If collecting more than one, place each in a separate box as if one dies it will foul the water and kill its companions. If processing is delayed, keep in a refrigerator at about 7°C.
If you decide to examine/photograph the limpet on the beach you can dispense with the box. If replacing a limpet, it should be at the spot where found.
Examination equipment.
1. Container about 4 cm deep with base painted with black bituminous paint (or clear base on top of black polythene).
2. Piece of glass that will fit inside container.
3. Four identical flat supports about 15 mm thick (e.g. dissection blocks).
4. Sea water.
5. Spirit-levelled work surface. e.g. an aquarium stand with top of toughened glass such as door off old audio system cabinet. On the shore do your best to level the container.
Examination method.
Take the polythene with limpet out of its box and slide the limpet off it onto the glass.
Place the glass on the supports in the container with seawater deep enough to just cover the glass.
When limpet has gripped the glass, turn glass over and replace on supports. If the limpet moves to the edge you can usually slide it to the centre without it detaching.
The expanded foot will now be visible. When the limpet has settled down it will likely extend its head and you may see the mouth open, and the radula make feeding strokes. Eventually, the mantle will expand to the shell’s rim, and the peripheral pallial tentacles will extend and be visible against the black base of the container.
Compare what you see with images in the accounts at flic.kr/s/aHskokisge and flic.kr/s/aHskqnXPqt ; both contain comparative images of P. vulgata. Magnification and good lighting will help.
Photography
If the shell height is 50%, or more, of the shell length, an untilted side-image showing its profile is usually sufficient evidence for P. vulgata in north-west Europe. Otherwise, a clear photograph of the vacant shell interior may be enough. If foot and pallial tentacles are used for positive identification, a clear record photograph is needed for acceptance as personal judgement about what is opaque white or translucent is subjective, especially until the different species have been experienced. (From this cause I initially made mistaken records which had to be removed from NBN maps.)
Cameras vary widely in what they can do. A digital SLR with manual focus, rack and pinion tripod and two side flashes, as in the image above, is ideal but expensive. A separate sheet is available for Nikon 300s which may be of use with other DSLRs. This article is to guide you to general principles that I hope you will find useful with automatic compact cameras, mobile phone cameras etc, as well as DSLRs.
If about to buy a compact camera, one that is put to very good use by many is the Olympus Tough TG series shop.olympus.eu/en_GB/cameras/tough/tg-6 . It can withstand being dropped and can even be used submerged in a pool. It can be used by divers to moderate depths, but may have a short life if used without a camera housing. It has a 12 megapixel image sensor. Cameras with fewer pixels will take poorer images, those with more should do better.
Camera Handbook It is essential to read the handbook to learn how to use different features on your camera. Keep a note of what you find useful. Use the camera for general photography before attempting close ups.
Focusing
For zoomed-in close ups the depth of field of focus is tiny. If the subject and lens surface are not parallel, one part may be in focus and the rest blurred.
1) Avoid tilting the camera or the subject/base of container (unless both tilted at same angle) if possible. The most reliable method is with camera facing vertically down mounted on a rack and pinion tripod with both work surface and back of camera levelled horizontal with a spirit level.
2) Avoid the slightest movement of the camera as the automatic focus is unlikely to adjust quickly enough to minor movement. Use tripod as in 1; otherwise use whatever is available to steady the camera with lens surface parallel to subject/container base. One impromptu shore technique used by A. Rowat when photographing with an Olympus TG, is to hold it in two hands and project his little fingers to rest against the substrate. If the telescopic legs are withdrawn to their minimum, a tripod is very stable and can be stood on a table with the subject raised for closer focusing on a rigid box on the table.
3) Zoom in (closeness possible varies with camera) to fill as much of the frame as is possible with the subject so the automatic focus adjusts to the subject rather than a larger expanse of background.
4) Keep the subject as close as possible to the background which is likely to be what it focuses on when it is not possible to fill the frame with the subject. Holding the subject in one hand and the camera in the other while standing on the shore is likely to give a focused image of the shore and a blurred image of the subject and hand, added to by unavoidable small movement.
5) Use flash, as with it the lens aperture will close to the minimum for the bright light it provides. Small apertures give sharper images than large ones. Images taken in weak light will cause the aperture to open wide and the result is likely to be blurred, or very dark if it doesn’t open.
Glare and reflection
In the open, a horizontal water surface reflects the sky, including clouds. This hinders what can be seen in the water and gives photos a milky appearance. Ask a companion to block the sky by holding a black umbrella, or similar, high above the container or pool containing the subject.
Indoors, a flash located on the top of a camera pointing vertically down emits light at 90° to the water surface, and the light reflects directly back on the same track into the lens causing glare. If the camera can be operated with flash units off the camera, two should be placed, one at either side, at c. 45° tilt to the surface. Flash units can be free standing or mounted on a lens bracket protruding right and left. The light then is reflected away at 45° in the opposite direction, not into the camera. If a single side flash is used, one side will be brilliant and the other in black shadow. To avoid this if only one is available, put a reflector of crumpled aluminium foil close to the subject on the side away from the flash. But many cameras only have the option of single top-mounted flash. In this case, deviate slightly from focusing item ‘1’ (above) by tilting the camera and flash up a little. Experiment to find the minimum tilt that will get rid of reflection; you may find that when zoomed in very close that the small distance between lens and flash is sufficient for the reflection to miss the lens, even when the camera is untilted.
Damp/wet shells have a curved surface that reflects at an infinite number of different angles. However you position the camera or light source, some light will enter the lens and cause glare. To avoid this, either dry the shell or submerge it completely and photograph it as above. If part protrudes from the water, the curved meniscus at point of emergence will cause glare.
Exposure
The automatic exposure of a camera sets itself according to brightness of what it senses in the frame. If a small dark subject is surrounded by a large white background the aperture reduces to avoid what it senses, mainly the white background, from being too bright. This results in a correctly exposed background and an underexposed dull dark image of the subject. To avoid this, try photographing with a black smooth background, such as a base painted with black bituminous paint or a clear base resting on black polythene. Avoid textured surfaces as they catch and reflect light. Different camera models vary, so you may need to experiment.
Editing
An editing suite can vastly improve images. Photoshop is the best known, but is expensive and complicated to use. A simpler, cheaper one may be easier to master.
There may already be some editing facilities on your pc; it is worth having a look. I use PhotoStudio 6, but it is no longer available for official sale. Features I find most useful are crop, rotate, auto enhance, sharpen, brightness, saturation, contrast, fill, clone, brush, text, and stitch. Practice is required to get the best from editing.
A pale individual, blending nicely with the Carrizo Plains substrate. Elkhorn Plain, Carrizo Plains National Monument, San Luis Obispo County, CA.
Substrate: Watercolour paper 180gsm
Light sensitive anthotype dye: Paprika in water
Application: immersion + brush
Opaque layer: Eukalyptus leaves.
Exposure time: 2days intermittent sunlight.
Titled: Paris Blues
Ice Resin Substrate & Canvas
Made for the Ice Resin Creative Team Technique Tuesdays.
From Jack & Cat Curio.
For more info:
Editor's note: great story we posted today about how a NASA light technology, originally developed for plant growth experiments in space, is being used to reduce the side effects of various medical treatments, including those for cancer, wounds, etc. You can read more about the technology here: www.nasa.gov/topics/nasalife/features/heals.html. I love success stories like this!
Glowing red light from High Emissivity Aluminiferous Luminescent Substrate, or HEALS technology -- previously used to grow plants for space experiments -- also has been proven to aid in the healing of human wounds, burns, diabetic skin ulcers and oral mucositis – a common and extremely painful side effect of chemotherapy and radiation treatment. NASA has partnered with Quantum Devices Inc. (QDI), of Barneveld Wis., to develop the WARP 75 light delivery system device for wound healing. A two-year clinical trial using the WARP 75 device on cancer patients undergoing bone marrow or stem cell transplants, concluded that there was a 96-percent chance that the improvement in pain relief of those in the high-risk patient group was the result of the HEALS treatment. The clinical trial was funded by NASA's Innovative Partnerships Program at the Marshall Space Flight Center in Huntsville, Ala. The NASA program works with industry and commercial partners to spinoff space technology and adapt it for new, innovative applications.
Image credit: NASA/MSFC/David Higginbotham
View more images:
www.nasa.gov/topics/nasalife/features/heals_photos.html
Watch a video of HEALS in action:
www.nasa.gov/multimedia/videogallery/index.html?media_id=...
This ATC is an illustration board substrate with embossed metal from a Coke can covering it. I kept it simple with just a star embellishment because I wanted to show the texture and color of the metal (color added with alcohol inks). Hooray for recycling!
And no, the idea was not mine. Someone posted a link on one of my Yahoo art groups that showed an ATC with some pop-can metal that had been run through a Cuttlebug. I loved the idea SO much, that I asked for (and got!) a Cuttlebug for my birthday (which is 2 days from now).
You can expect more of these to come. LOL
going to live with careysniche. :)
Vacant shells in water. Colour variation from reddish-brown to purple brown depends partly on lighting and colour of substrate and whether shell is vacant or occupied, and in water or air.
1: whorls distinctly convex, but in profile shell is a depressed dome.
2 : debris lodged in suture.
Shell length 2.3 mm. North Yorkshire, September 2014. (leg. Jan Light.)
Illustrated pdf of this account available at
www.researchgate.net/profile/Ian_Smith19/contributions
Otina ovata (Brown, 1827)
Full SPECIES DESCRIPTION BELOW
Sets of OTHER SPECIES at: www.flickr.com/photos/56388191@N08/collections/.
Synonyms: Helix otis Turton, 1819; Otina otis (Turton, 1819); Gallericulum ovatum Brown, 1827.
Vernacular: Little ear-shell.
GLOSSARY BELOW
Shell Description
Usually up to 2.5mm long, maximum 3mm. Thin, semi-translucent. Very large body-whorl and single tiny bulbous spire-whorl forming lateral, inwardly-twisted apex; resembles tiny limpet or Haliotis shell 1Oo flic.kr/p/qfV1Vb . Whorls distinctly convex, but in profile shell is a depressed dome 2Oo flic.kr/p/qi2ddH . Aperture ear-shape, very extensive but does not expose interior of spire. Interior glossy. Inner and outer lips together form uninterrupted rim. Outer (palatal) lip smoothly-curved and thin; paler band within rim is area outside of foot-muscle attachment. Inner (columellar & parietal) lip forms almost transparent whitish shelf; no umbilicus 3Oo flic.kr/p/q1Dh3A . Exterior of shell superficially smooth, but magnification reveals sculpture of distinct growth lines and fine, regularly-spaced, parallel spiral striae forming lattice of oblongs 1Oo flic.kr/p/qfV1Vb ; growth lines sometimes emphasized by debris lodged against them 4Oo flic.kr/p/q1MiYR . Colour various shades of brown 2Oo flic.kr/p/qi2ddH , often darkened to dark chestnut-brown or purple-brown by closely adhering periostracum; groups of white specimens sometimes found (Killeen & Light, 1990), and newly hatched young are transparent showing yellow yolk in viscera. No operculum.
Body Description
Flesh white, slightly translucent. Head has large oral veil of two oral lappets and no protruding snout 5Oo flic.kr/p/qi8MYs . Mouth a ventral slit between lappets 9Oo flic.kr/p/q1CBfJ . Internal black sclerotized jaw near mouth shows as grey mark near junction of head and veil. Other blackish internal organs show grey through translucent head and body 6Oo flic.kr/p/q1CBwf . Strong short wide radula covers entire free surface of odontophore; up to 100 lateral teeth plus marginal teeth per row. Rudimentary cephalic tentacles consist of mound bearing large black eye 7Oo flic.kr/p/q1Dgzb . Mantle white; thin and transparent over mantle cavity; reflected as white rim at edge of shell-aperture 7Oo flic.kr/p/q1Dgzb . Mantle cavity has no special respiratory capillaries (usually present in less primitive pulmonates). Pneumostome near posterior of right mantle_rim 8Oo flic.kr/p/q1Dgum . Anus adjacent and anterior to pneumostome. Female and male genital openings on right side under posterior of oral lappet; penis a simple introverted tube. Foot white; sole oval, divided transversely at a third of way from anterior edge 9Oo flic.kr/p/q1CBfJ .
Internal anatomy
Image 10Oo flic.kr/p/qi2cfF shows features visible in specimen extracted from shell; includes jaw, transparent mantle skirt over mantle cavity containing no ctenidium or special respiratory capillaries, horseshoe-shaped loop of intestine, digestive gland surrounding intestine, stomach, ovotestis and very small kidney.
Key identification features
·Otina ovata
·Minute (2mm long) limpet-form shell with tiny spire.
·Lives near HW mark in humid chasms and caves, and in crevices.
Similar species
Several species of small limpet in NW Europe might have juveniles around 2mm with small spire, but none lives at HW mark.
Habits and ecology
In humid shaded positions on clean rock from splash zone of MHWN down to EHWN, including moist walls of caves 11Oo flic.kr/p/pmrqyZ , north facing walls of chasms and outer parts of not-heavily-silted crevices on north faces of reefs of slate, shale, chalk etc. Favours fissured rock, but not unstable rapidly-eroding outcrops. Unlikely to occur where turbid water deposits film of mud over rock surfaces.
Obligatory hygrophile, unable to survive constant immersion of entire 12-hour tidal cycle so not below EHWN, but needs air humidity near 100%, becoming shrivelled and inert after twelve hours at 90%. Negatively geotactic when submerged, promptly moving up to escape total immersion when possible 6Oo flic.kr/p/q1CBwf . If exposed to non-humid air, moves promptly to humid shelter if possible, or clamps down onto substrate if none accessible.
Often associated in crevices with Melarhaphe neritoides, Littorina saxatilis, Cingula trifasciata, Auriculinella bidentata, Lasaea adansoni, Spirorbis borealis (tube worm), and Chthamalus spp. (barnacles). On open surfaces, active during periods of wave-splash, and at other times may venture out in very humid weather, especially if can shelter in dead barnacle shell, tuft of Lichina pygmaea or byssus of small Mytilus edulis. Positively thigmotactic, so often found in packed groups of about ten that conserve moisture.
Respiration is with atmospheric air admitted to the mantle cavity through a pneumostome 8Oo flic.kr/p/q1Dgum , but, unlike most pulmonates, O. ovata lacks special respiratory capillaries in the mantle cavity 10Oo flic.kr/p/qi2cfF . Broad lateral tracts of foot-surface 5Oo flic.kr/p/qi8MYs may have accessory respiratory function as blood comes here to body-surface under very thin epithelium through which respiratory interchange might easily be possible (Morton, 1955); probably sufficient respiration for slow-moving animal with small volume.
Feeds by scraping wave-lodged diatoms and filamentous algae from rock surface with radula while jaw grips on substrate. Food particles compacted at mouth with copious mucus from suprapedal gland on upper surface of anterior lobe of foot. Stomach with rotating protostyle of mucus and faeces, similar to that of bivalves, is most primitive yet described in a pulmonate (Morton, 1955) 10Oo flic.kr/p/qi2cfF . Faecal string never compressed into pellets, much more loosely compacted than in prosobranchs 9Oo flic.kr/p/q1CBfJ ; unlike them, has no ctenidium to be fouled and anus does not discharge into pallial cavity. Small kidney in front of looped intestine opens into pallial cavity with no water current to carry discharges out of cavity 10Oo flic.kr/p/qi2cfF ; probably assisted by accessory excretion from amoebocytes in broad lateral tracts of foot (Morton, 1955).
Travels by advancing anterior third of foot, fixing it to substrate and then bringing up the rest of the foot. Foot moved by muscles and disposition of blood in pedal sinus.
Breeding: protandrous hermaphrodite with no clear cut separation of male and female phases, each animal produces sperm in September – December, followed by an egg-producing phase December - June. Copulation with simple penis occurs before late March. Spawns in late May/ early June. Loose clusters of 20-30 eggs in tough, yellow/straw-coloured mucal secretion, 4-5mm across, loosely attached to substrate in humid conditions where adults live. Operculum, but no velum, present in embryos. Young hatch as crawlers with transparent shell revealing viscera yellow with egg-yolk in apical bulb. Uncertain if annual life cycle, but presence of all sizes simultaneously suggests biennial or longer.
Search technique “if properly searched for it would doubtless be found in every suitable locality” (Jeffreys, 1869).
Take a torch and large hand lens to help detect the tiny white glistening blobs of flesh, or, in late May and early June, the larger (4 or 5mm across) yellowish egg masses. Choose a humid misty day, if possible, as O. ovata is then more likely to emerge from cover, and visit as soon after high tide as access is possible; wellingtons or waders may help early access to caves with entrances still awash. Seek, in fissured rock, a cave or chasm that is narrow, so likely to retain humid air and exclude direct sun 11Oo flic.kr/p/pmrqyZ . Search wet and damp rock faces around high water mark; sometimes different coloured algal films indicate differences of moisture. Shaded, north-facing faces of fissured reefs may have some within crevices, but splitting them open is destructive of the habitat and should be done very sparingly, if at all. If you take specimens for study, transport them in a wet air-tight box that preserves 100% humidity. At home keep box in a fridge between 6°C and 10°C. Examination and photography can be of animal in seawater to save from dehydration, but it will become inactive and drown if kept submerged for more than a few hours.
Also, see 12Oo flic.kr/p/q1CALh & 13Oo flic.kr/p/qicbXR .
Distribution and status
Sparse scattered records, but can be locally common. Probably overlooked because of its small size and specialized habitat requiring targeted searching, and unfamiliarity of recorders with it as often omitted from id guides of both terrestrial and marine molluscs. Known distribution: Britain, Ireland, Normandy and Brittany. Isolated records of beached dead shells from N.W. Spain, S. Portugal and Sardinia. GBIF map www.gbif.org/species/5189862 . NBN UK map species.nbnatlas.org/species/NBNSYS0000041447 has records on S. and W. coasts of Britain from Isle of Wight to Mull, but there were 19th Century east-coast finds in Northumberland and Yorkshire (Forbes & Hanley, 1853), and Jan Light found live specimens in N. Yorkshire in September 2014.
Acknowledgements
I am indebted to Dr Jan Light for providing specimens and sharing her expertise at the visit by the Conchological Society of G.B. & Ireland to N. Yorkshire in September 2014. I gratefully acknowledge Dr C.M. Cunha and Dr G. Rosenberg for help with sources and their interpretation.
Links and references
Eales, N.B. 1967. The Littoral fauna of the British Isles 4th ed. Cambridge, Cambridge University Press.
Forbes, E. & Hanley S. 1849-53. A history of the British mollusca and their shells. vol. 3 (1853) London, van Voorst. (As Otina otis; Free pdf at archive.org/details/historyofbritish03forb Use slide at base of page to select pp.320-323.)
Hayward, P.J. & Ryland, J.S. 1995. Handbook of the marine fauna of north-west Europe. Oxford, Oxford University Press.
Jeffreys, J.G. 1862-69. British conchology. vol. 5 (1869). London, van Voorst. (As Otina otis; Free pdf at archive.org/stream/britishconcholog05jeffr#page/108/mode/2up . Use slide at base of page to select pp.109-111.)
Killeen, I. & Light, J.M. 1990. Observations on Otina ovata (Brown): a little known pulmonate. J. Conch., Lond 33: 317 – 318.
McMillan, N.F. 1968. British shells. London, Warne.
Marshall, J.C. 1913. Additions to British conchology. Part 7. J. Conch., Lond. 14: 65-77. 12Oo flic.kr/p/q1CALh
Melville, J.C. 1918. Otina otis Turton at St Mary’s, Scilly. J. Conch., Lond. 15: 261. 13Oo flic.kr/p/qicbXR
Morton, J.E. 1954. The crevice faunas of the upper intertidal zone at Wembury. J. Mar. biol. Ass. U.K. 33: 187 – 224. plymsea.ac.uk/view/year/1954.html#group_M
Morton, J.E. 1955. The functional morphology of Otina otis, a primitive marine pulmonate. J. Mar. biol. Ass. U.K. 34: 113 – 150.
(Free pdf at core.kmi.open.ac.uk/download/pdf/6185241.pdf . pp144 - 145 missing from pdf). Also plymsea.ac.uk/view/year/1955.html#group_M
Sosso, M. & Dell’Angelo, B. 2010. Prima segnalazione di Otina ovata (Brown, 1827) (Systellomatophora: Otinidae) in Mediterraneo Boll. Malacol. 46: 1-3.
Current taxonomy: World Register of Marine Species (WoRMS) www.marinespecies.org/aphia.php?p=taxdetails&id=140661
Glossary
amoebocytes – mobile cells (moving by pseudopodia like amoeba) in invertebrate bodies that variously digest food, dispose of waste, fight infection etc.
aperture – mouth of gastropod shell; outlet for head and foot.
apical - at the apex.
cephalic – (adj.) of or on the head.
columella - solid or hollow axial “little column” around which gastropod shell spirals; hidden inside shell, except on final whorl next to lower part of inner lip of aperture where hollow ones may end in an umbilicus or siphonal canal.
columellar – (adj.) of or near central axis of spiral gastropod.
columellar lip - lower (abapical) part of inner lip of aperture.
coll. – in the collection of (named person or institution) (cf. legit).
ctenidium – comb-like molluscan gill; usually an axis with a row of filaments either side.
epithelium – tissue forming outer layer of body surface, “skin”.
EHWN – extreme high water neap tide (the weakest high tides of the year i.e. those that rise the least, usually near June and December solstices)
geotactic – (adj.) of species that moves towards pull of gravity (positively geotactic) or away from it (negatively geotactic). (Synonyms: gravitaxic, ? geotaxic.)
hygrophile – species that prefers moist conditions; often at water’s edge, but not permanently submerged. obligatory hygrophile – unable to survive out of moist conditions.
introverted – turned in on itself.
legit – (abbreviation; leg. or lgt.) collected/ found by (compare with coll.)
mantle – sheet of tissue that secretes the shell and forms a cavity for the gill in most marine molluscs (but not in adult nudibranchs), part or all of dorsal body surface when shell absent or internal.
MLWN – mean low water neap tide level (mean level reached by weakest low tides for a few days every fortnight. i.e. those that fall the least).
MHWN – mean high water neap tide level (mean level reached by weakest high tides for a few days every fortnight. i.e. those that rise the least).
odontophore – firm, approximately ellipsoid, structure of cartilage supporting radula. Protruded like a tongue to operate radula.
operculum – plate of horny conchiolin, rarely calcareous, used to close shell aperture.
oral lappets – flaps of flesh by mouth.
oral veil – flat anterior extension of head (may consist of lappets).
ovotestis – hermaphrodite organ serving as both ovary and testis.
palatal lip - outer lip of gastropod aperture.
pallial – (adj.) of the mantle.
parietal lip – (=parietal wall) part of inner lip of gastropod aperture, adapical of columellar lip.
pedal – (adj.) of the foot.
periostracum – thin horny layer of proteinaceous material often coating shells.
plankton – animals and plants that drift in pelagic zone (main body of water).
pneumostome - breathing pore in mantle of pulmonate molluscs.
protandrous hermaphrodite – each individual starts mature life as a functioning male, later changing to female function.
pulmonate – (adj.) of terrestrial and freshwater, air-breathing, slugs and snails.
radula – ribbon of chitinous teeth extruded on a tongue-like structure (odontophore) to rasp food.
rec. – recorded by (person who submitted record, may be different from leg. and coll. persons/institution).
sensu lato – (abbreviation s.l.) in the wide sense.
sensu stricto – (abbreviation s.s.) in the strict sense, excluding species that have been confused with it.
stria – very narrow spiral groove or ridge (plural: striae)
taxis – directional locomotary response to external stimuli such as light, gravity, temperature or chemicals.
thigmotactic – (adj.) of animal that moves towards (positively thigmotactic) or away (negatively thigmotactic) from physical contact with others.
umbilicus – cavity up axis of some gastropods, open as a hole or chink on base of shell, often sealed over.
velum – bilobed flap on veliger larva, with beating cilia for swimming.
A supermacro of a circuit board when glaring golden sunlight emanating across the etched copper pathways amongst all of the green substrate.
AWESOME when viewed in LIGHTBOX!!!!!
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The ballast & substrate had been completely removed from near the mid-way point nearly to the northern portal dropping the floor by about 18 inches which had flooded. Even though it was mid Summer the cold water was a shock to the system, only having my trainers on but needs must. The view is looking north with bridge 488 beyond, the lowest on the line.