Spiny lobsters are capable of communicating and sounding warning calls by means of stridulation - the rubbing together of two body parts to make a rasping noise. Unlike crickets that stridulate by rubbing their wings together, these sea bugs (as crustaceans are sometimes called) produce sounds by moving their antennae. This results in a soft tissue called the plectrum to stick, then glide, stick, then glide - cello players know what I mean - over a file near the eyes, creating a sound something like running your finger down a comb. An advantage of this is that they can make these noises even when they are in the vulnerable time after moulting.
Spiny lobsters are capable of communicating and sounding warning calls by means of stridulation - the rubbing together of two body parts to make a rasping noise. Unlike crickets that stridulate by rubbing their wings together, these sea bugs (as crustaceans are sometimes called) produce sounds by moving their antennae. This results in a soft tissue called the plectrum to stick, then glide, stick, then glide - cello players know what I mean - over a file near the eyes, creating a sound something like running your finger down a comb. An advantage of this is that they can make these noises even when they are in the vulnerable time after moulting.
Once threatened from overharvesting, pressure on ula poni was relaxed a bit in 2000 when a commercial lobster fishery in the NWHI was closed, and the area was designated a protected marine sanctuary under the Hawaiian Islands Coral Reef Ecosystem Reserve. Here in the MHI, ula cannot be taken May through August, females are off limits year round, and males must have a carapace length of three and one quarter inches. Spearing is prohibited. Check http://dlnr.hawaii.gov/dar/fishing/fishing-regulations/marine-invertebrates/ for updates. Consider that it takes a good eight years for the lobsters to reach maturity. And further consider that overharvesting by humans means less for young monk seals.
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While visiting Kaho'olawe last October, I came across this beauty eking out an existence in the parched landscape. It's the endemic Hawaiian poppy, pua kala, which translates as thorny flower, and indeed, these delicate blooms are expertly defended by prickly bluish-green leaves, stems, and seed capsules. This deterrent, combined with a bright yellow sap of bitter alkaloids, keeps even ever-munching cattle from grazing on it. The only native poppy, Argemone glauca has exquisite bright white petals surrounded by a deep yellow center of stamens and a purple stigma. It can be found on the dry leeward slopes of all the MHI, upward to around 1700 feet. Its preference for full sun and dry conditions makes it a great choice for xeriscape gardens. The yellow poppy you are more likely to come across is the non-native Mexican poppy, Argemone mexicana, which is naturalized in the islands.
Let's do the twist. Place a pili grass seed in water, and it's long and twined awn will begin contortions that will amaze. In it's natural environment, this response enables the barbed end of the seed to be screwed into the soil, and have earned the grass its botanical name, Heteropogon contortus, and its Hawaiian name, "pili" which means to cling or stick. It's a beautiful tussock grass, forming large clumps with a two to five foot spread. Pili grass loves the sun and can do well in dry, coastal environments. Its pleasant scent, color, and durability made it the choice grass for thatching, and is likely why Hawaii is famous for its "little grass shacks." On Kaho'olawe, pili plays a big role in restoration efforts, growing well despite low rainfall and poor soils. Bales of pili are are scattered about the Mars-like terrain, catching wind-blown sediments and serving as a growing medium for natives such as aʻaliʻi.
They're innocent looking enough. Just some marine snails in conical hats, clamped to the rocks in the intertidal zone, and doing their part for the ecosystem by keeping the fuzzy algae in check. But the saying, He ia make ka opihi - the opihi is the fish of death, serves as a reminder that picking 'opihi for their tasty flesh is a risky business. While their shape and strong muscular foot allows them to hold fast through pounding surf, the tidal surge can be downright frightening for the 'opihi harvester. There are three species of 'opihi here: the blackfoot, 'opihi makaiauli; the yellowfoot, 'opihi alinalina; and the kneecap 'opihi, or koele. The blackfoot inhabits areas closest to shore, the kneecap likes it a bit deeper, and the yellowfoot prefers it where the surf is roughest. Despite the difficulties for the collector, 'opihi numbers have declined significantly due mainly to overharvesting. A gallon of 'opihi can go for as much as $200. Presently, the 'Opihi Partnership, spearheaded by the Nature Conservancy, is working to gather baseline data about 'opihi populations near Maui and Kaho'olawe. Others are attempting to raise 'opihi using aquaculture techniques to relieve pressure on this humble limpet. On a side note, genetic studies have been underway by researchers at the Hawaii Institute of Marine Biology. They have determined that each island has it's own unique populations of 'opihi. 'Opihi are similar to other marine snails in that they have gills, a mouth tube, a head with tentacles, and a strong muscular foot. They are known to create shallow depressions in the rock which becomes their "base camp." After venturing out for feeding, they return to the snugly-fitting base camp for extra gripping power. Though they do not permanently attach themselves like barnacles do, they are the "super gluers" of the snails and may be near impossible to pry off once a failed attempt to pluck them has been made. Their low profile also helps them to remain steadfast through wave action and the ribbing of the shell allows water to drain off easily. Traditionally, 'opihi were also used as scrapers for taro, and for jewelry.
If you're looking for attractive and native ground-huggers, Nanea and Pa'u o Hi'iaka have got you covered. Don't let their delicate flowers fool you; they are hardy, as their coastal to low-elevation habitat demands, tolerating wind, drought, heat, and salt spray. Nanea (Vigna marina) is also known by the common name beach pea, and can spread a good five to fifteen feet while getting no taller than a foot. Keep your pruning shears handy, as it is a fast grower; a good clipping will also encourage denser growth. On the plus side, Nanea provides erosion control and is able to fix nitrogen from the air surrounding the roots, so no extra fertilizer need be applied. Neighboring plants will benefit from the nitrogen as well. The leaves are trifoliate, comprised of three leaflets with a pointed tip. In earlier times, they were pounded with the stems and midribs to make a poultice used to treat wounds. The fruit is, of course, a legume which turns brown upon ripening, and then opens and twists to release its seeds. Around the world are other Vigna species, which are closely related, and are well-known crop plants: adzuki beans, mung beans, and Chinese long beans, among others. Pa'u o Hi'iaka known botanically as Jacquemontia ovalifolia sandwicensis, is another excellent groundcover and suitable for erosion control. It can be grown easily from stem cuttings, and may naturally root at the leaf nodes.The stems can twine along the ground for a good ten feet or so. As its bell-shaped flowers suggest, it is in the Convolvulaceae, or Morning glory family of plants. The leaves are thick and fleshy, and arise from stems covered in hairs, adaptations to dry environments. Pa'u o Hik'iaka was one of the plants I saw hacking out a living on the arid landscape of Kaho'olawe. It is told that the Hawaiian name for the plant came about when Pele took her sister Hi'iaka to the beach. Out went Pele to surf (or fish, as some may tell), leaving her sister. Pele got caught up in her pursuits, while her sister fell asleep under the hot Hawaiian sun. The gods, concerned about Hi'iaka, had the twining and vining plant form a thick mat over her, protecting her from sunburn. Thus the name, pa'u o Hi'iaka, which may translate as skirt of Hi'iaka.
Long-beaked and sleek, Hawaii's spinner dolphins thrill the lucky onlooker with their aerial acrobatics. Leaping out of the water, they twirl away, making two to five or so spins before loudly splashing back down. Spinning is often repeated several times in a row. And the acrobatic repertoire doesn't end there. They tail slap, do nose-outs, and leap head over tail too. (see video below) But they are the only dolphins known to go for a "spin." What's that all about? Well no one knows for sure, though it's possible that it may be a way to to rid themselves of parasites; or for communicating with the pod; or as a courtship; or maybe it's just for the fun of it.
One thing that researchers have discovered is the daily pattern of the dolphins around the islands. NOAA Fisheries Service reports that they are night hunters, foraging cooperatively to capture squid, shrimp, and fish. According the Polynesian Voyaging Society Website, the spinner dolphins sometimes accompany "a voyaging canoe, riding on the wave at the bow. At night, when they stir up phosphorescent organisms as they swim, they look like glowing torpedoes." Come morning, they swim along the shallow bays for what researchers have termed "rest." During this time, vocalizations and acrobatics taper off and the dolphins swim closing together in a behavior called milling. Dolphins don't sleep the way we do, but what they can do is shut down one hemisphere of their brain at a time. This allows them to remain watchful enough to respond to threats such as tiger sharks. Come the late afternoon, they get ready to resume their evening hunt. Adult spinner females may have several mates and give birth about once every three years, after about a ten to eleven month pregnancy. The Wild Dolphin Organization reports that the calves are born fluke first, and may display fetal folds, or evidence of wrinkling while in the mother's womb. They form strong bonds with mother, and become very active, often seen "playing" with others as they practice, often humorously, their aerial skills. This morning brought me to the North Shore, and a fabulous walk to Ka'ena Point from the Mokule‘ia side. The westernmost tip of Oahu, Ka'ena Point has been known as the leaping off place for souls ready to be reunited with their loved ones. It's also a great place to get reunited with Hawaii's native plants, in one of the few protected coastal dune ecosystems we have. Today's post features a few of these plants that are living happily together in this sacred area, and as a side note, all of them are also growing on Kaho'olawe! 'Ohai, Sesbania tomentosa: Happy day to see this endangered, endemic plant thriving here. In this environment, its form is a sprawling shrub. One look at 'ohai and you can see it is in the pea family. The leaves are light grey-green that add such a beautiful color and texture contrast to the shinier and brighter green of the naupaka it was snuggled up against. The pop of red-orange of the flowers is icing on the cake. Pohuehue, Seaside Morning Glory, Ipomoea pes-caprae subsp. brasiliensis: The ultimate Hawaiian sunbather, this indigenous plant thrives in full sun on hot and sandy dunes. Its vining nature actually helps to control erosion, and its beautiful bell-shaped flower lasts but one day. The species name, pes-caprae, translates to goat foot, referencing the shape of the leaves. `Ilima papa, Sida falax: As with its fellow plants at Ka'ena Point, ilima papa is sun, drought, and wind tolerant. The light green leaves are thick and downy to preserve water, and they are as soft as can be! The beautiful yellow to orange flowers are delicate, and most striking when strung into a lei. In the 1920's, ilima was made the official flower of Oahu. Naupaka kahakai, Scaevola sericea: A real winner in the xeric plant category, this naupaka is hardy to the max, with thick and shiny leaves that help it to survive with little water. They have tiny whitish "half-flowers" that are followed by white, marble-like fruits. This indigenous species is the only one of the native naupakas to bear the white fruit; others have a purple fruit. Naio, Myoporum sandwicense: Along the beach, the endemic naio takes on a shrubby form, and is easily identified by its lance-like and fleshy leaves. The whitish to pinkish flowers are nestled close to the branches, bloom throughout the year, and may have a fragrance similar to that of sandalwood. In fact, this plant is also known as false sandalwood, as it was attempted to be passed off for the real thing when supplies of sandalwood dwindled. Today's post celebrates the wiliwili, Erythrina sandwicensis, or Hawaiian coral tree, an endemic tree so rich in history and with so many interesting twists (yes, wili means twist), I was inspired to share what I have learned about it. First, it's the only member of its genus to be native here. It is also one of the few native trees that is deciduous, losing its leaves when in bloom, often in the late spring and summer, though reports on this vary. Yet another unusual feature is it's spiky trunk, which become less pronounced as the tree matures. You'll find it on the leeward slopes, from sea level to about 2000 feet, as it prefers dry habitat. Leaflets are wider then they are long, and come in groups of three. The seed pods usually hold one to three stunning orange to red seeds (color variation is possible) which are used in lei making. Wiliwili means to twist and twist, referring to the way the pod winds opens to expose the seeds. Flowers are clustered, curved and come in a variety of colors including greenish-white, yellowish, salmon, and orange, and are pollinated by birds. The tree itself averages about thirty feet in height. Because the wood of the wiliwili has a low density, it was used to make everything from fishing net floats, to surfboards, to outrigger booms. And it's a tough old tree: drought tolerant, wind tolerant, and one of the few natives to survive on Kaho'olawe. Its nitrogen-fixing abilities also make it easier for other plants to get started on lava flows and eroded areas. Ah, but it has its challenges. Enter the beasts: the Erythrina gall wasps. They were first detected in July of 2005, and quickly spread throughout the islands, wrecking havoc on the wiliwili and other tropical coral bean trees. Curled up leaves and bulbous stems and petioles signaled the presence of the wasp, as the eggs of the wasp laid within the plant's tissues began to swell with their growing larvae. Some feared 100% mortality of the native wiliwili, as foliage loss and an inability to transpire meant the quick deterioration of the trees. Seeds were collected and banked, while specialists worked to control infestations. By 2008, the Hawaii Department of Agriculture employed the parasitic services of a second wasp brought all the way in from Africa, Eurytoma erythrinae. Let the battle begin. 5000 of these teeny tiny wasps (a few millimeters in length) were released, and quickly laid their eggs. Where? Right inside the gall created by the gall wasp. When their larvae hatched, they dined on the larvae of the gall wasp. I know... not a pretty visual, but war is hell. While the verdict is still out on the fate of these keystone trees of Hawaii's dryland forests, it seems that there is good progress being made. If there is a tree out there that can get up after a punch like that, it's the wiliwili.
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