Turning the compost pile the other day, I uncovered the usual fossorial critters - those that have a subterranean lifestyle, adapted to digging or burrowing. There were your earthworms, millipedes, beetles and sowbugs, but then something different caught my eye. At first I thought it was a worm, but the absence of a segmented body had me take a closer look. Sure enough, that dark brown, shiny slitherer was none other than the Hawaiian Blind Snake, a.k.a. flower pot snake, Ramphotyphlops braminus. This snake is said to be the most widespread of terrestrial snakes, probably owing to the fact that it likes to burrow into the pots and containers of plants and agricultural products, which are then shipped around the world in the plant trade. It's believed that is how it was introduced to Hawaii, likely in the 1930's, in a shipment from the Phillipines. Once they have landed in a new location that has favorable conditions, they | have a leg up (so to speak) on establishing themselves, as they are parthenogenetic: the females can produce offspring asexually, without fertilization from a male. This is rare among snakes, and all of these snakes are believed to be female. They are harmless and nearly blind - the rudimentary eyes are light sensitive. To me, they are welcomed visitors to my compost pile, as they feed on the eggs, larvae and pupae of ants and termites as well as small invertebrates. Dirty deeds, done dirt cheap. |
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They say all good things take time, and that is certainly the case for these slow-growing native treasures: the hapu'u, or Hawaiian tree ferns. The four Cibotium species endemic to Hawaii can grow anywhere from ten to thirty-five feet tall, and yet grow mere inches per year. A "tree fern" is the term given to a group of ferns whose fronds are lifted above the ground by means of a trunk-like mass of roots. They reproduce as do other ferns by spores, found on the underside of the frond, and so require semi-wet to wet habitats. The beautiful spirals, soon to unfurl into the large and lacy fronds, are a sight to behold. Hapu'u pulu (Cibotium glaucum) is the most common of the four, its softening effect and tolerance of lower elevations making it a favorite in landscape design. It can reach heights of twenty feet or so, and the individual fronds get as large as nine feet. A bluish-green to gray coloring on the undersides of the fronds is characteristic, and the reason behind the species name, glaucum. Unfurled fronds and stalks are covered in a soft golden yellow to brown hair, or "fur" called pulu (in Taiwan, they have a related species that they refer to as "golden dog hair"). In early times, the soft pulu was used both as a dressing for wounds, and for embalming. In the mid 1800's to 1880s, it was greatly over-harvested and exported as pillow and mattress stuffing. Later still, it was harvested again, this time for its core, which was used to produce cooking and laundry starch. Fortunately, many are now aware that the tree ferns are an integral part of our forests and important to our watersheds. If we try, we're gonna get by with a little help from our fronds.
These fish know how to sell. I think of them as the neon signs of the reef, dancing and weaving their brilliant yellow and purple blue bodies in advertisement: "free cleaning, it'll just take a minute." Yup, these are the reef's tiny but efficient cleaner wrasses, procuring their food from the "skin" of other reef denizens without having to go out and search for it. They set up shop on prominent corals on the reef, and the fish queue up. Goatfish, parrotfish, moorish idols, even morays will drive on up to their station and give a little posture signal that they are ready to be serviced. Then, in moves the wrasse, plucking off an ectoparasite here, a bit of mucous or scales there (ectoparasites live on the outside of a host, as opposed to endoparasites which are internal). No wonder they earned the species name phthirophagus, which translates to "louse-eater." This reverse fast food drive-up is beneficial to both, the Hawaiian Cleaner Wrasse getting nourishment and the host fish getting a free grooming and "delousing," so to speak. It is referred to as mutualism, a biological win-win situation. They'll even venture inside a moray eel's mouth for a little session of teeth cleaning, though it would be easy enough for the moray to make a meal of it. Seems that the moray and other host fish have figured out they are better served in the long run by a living, hard-working cleaner wrasse. At night these little fish, just around four inches in length, close up shop. Most small wrasses will snuggle into the sand for nighttime protection, but the cleaner wrasse sleeps in a cocoon of mucous (a behavior seen in one of their clients, the parrotfish), content with their excellent job security. Hawaiian Cleaner Wrasse from Bertil Holmqvist on Vimeo. A flash of red from the treetop, and then the familiar whoo-ett, whoo-ett, whoo-ett, tuer tuer tuer. That followed by a series of persistent and loud metallic chirps, and you know you're being paid a visit by the Northern Cardinal, Cardinalis cardinalis. What is the "northern" cardinal doing in the tropics? Well, the northern part refers to the fact that this species has the northernmost range of the cardinals. Introduced to the islands in the late 1920's by the Hui Manu Society, they are now well established. The brilliant red of the male has made this species a real favorite, with seven states claiming it as their state bird. You'll often see him up in the top branches, calling out, though they often feed on the ground. The female is lovely too, all dusky brown with wings, tail, and crest splashed with red. During courtship, the male will feed the female, beak to beak, and bring twigs and other materials to her for nest construction. It is unusual for female songbirds to sing, but this one does, especially during courtship and often from the nest, which she builds in low shrubs, tangles, and trees. Many report that the pair remains monogamous and mate for life.
How I love the diversity of creatures on this earth, and here is one that is in the running for most bizarre design: the Scalloped Hammerhead, Sphyrna lewini. If the hammer wasn't enough, they have the scalloping on the front edge to make it extra special. The other species of hammerhead in Hawaiian waters is the Smooth Hammerhead, but this one is more common. The adults live off-shore, coming into the shallow bays, including Kane'ohe, Hilo, and Waimea bays, to pup and breed, usually in the late spring and early summer. It would seem that the turbid and protected waters of the bays help to keep the pups safer from predation. They are born live after a nine month gestation, and may have anywhere from fifteen to thirty siblings. The pups' hammers are soft so birthing is easier, then become less flexible over time. After hanging out in the "nurseries" for three or four months, the pups eventually leave and join the adults in deeper waters. Some estimates have anywhere from 8000 to 10,000 pups passing through Kanehoe Bay in a year.
Today's post is intended to give voice to the native tree snails of Oahu, genus Achatinella. I hope you become as enamored as I am with these "jewels of the forest." Once abundant throughout Oahu, this genus of forty-one species of endemic, nocturnal snails has suffered from a "perfect storm" of events that has caused the loss of at least half to extinction, with the rest endangered or critically endangered. Those that remain cling to life on isolated ridges in the Ko‘olau and Wai‘anae ranges. They are small wonders indeed; all species are just around two centimeters long, with beautiful coloration and patterning that varies from species to species. As their name suggests, they are arboreal, but do little damage to the native trees that they prefer. Instead, they dine on a fungus that grows on the leaves, which may actually help the trees to photosynthesize. Achatinella young develop in eggs inside the mother, then are born live. They live for as many as ten years, but their reproductive capacity is low. For example, Achatinella mustelinadoes only produces four to seven offspring a year, and this occurring only after sexual maturity is reached, between ages three to five. As you can imagine, their slow growth rate and fecundity would make them a vulnerable species. Recovery would be extra tough after any event that would reduce their numbers. And there have been several. For years they were over-collected for their beautiful shells. Add to that the loss of much of their native habitat to farming and other human activities. If that isn't enough, we opened the door to one of their most dreaded predators: the carnivorous rosy wolf snail. Introduced in 1955 to combat the Giant African snail, the rosy wolf snail decided that the smaller, native snails tasted a lot better. Rats have also taken their toll on the population. But instead of throwing their hands up in the air, some have come to the snail's rescue, including The Hawaiian Tree Snail Conservation Lab, whose main goal is to care for rare Hawaiian tree snails and breed them in captivity. Nine species of Achatinella are under their loving care. Also fighting the good fight is the U.S. Fish and Wildlife Service and the Oahu Army Natural Resources Program (OANRP), who are involved with the effort to build snail refuges with elaborate "exclosure" systems to keep predators out. I, for one, am grateful for their efforts to save these jewels, and for the important lesson that sometimes, big things come in small packages.
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