Wow... the beauty in the natural world! Looking like a piece of art, Porpita porpita (also known as Porpita pacifica), or the Blue Buttons are real stunners, literally. They belong to the phylum Cnidaria, which are known for their stinging cells used to capture prey. Blue buttons don't deliver a real wallop, but they could cause some discomfort if handled. Passively floating along on the sea's surface, they eat planktonic copepods, a group of small crustaceans, and other drifting larvae. They are not true jellyfish, but a colony of animals, each performing a function such as reproduction, feeding, or defense. The central float is made of chitin, and just about an inch in diameter. This rather flat disc is filled with gas and keeps the Blue Button afloat. Two predators of this beauty are just as striking: the sea slug Glaucus atlanticus, and the violet shells, planktonic sea snails in the genus Janthina.
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People are really sounding off about these little guys, the coqui frogs, and the big ko-KEE noise they make. Comparisons of the frog's call with jet planes, chainsaws, and lawnmowers are not uncommon. Coqui frogs, Eleutherodactylus coqui, much beloved in their native Puerto Rico, were accidentally introduced to Hawaii in 1988, probably through the plant trade. Since then, there numbers have exploded, particularly on the Big Island. And it's not just the noise that concerns a number people (though there are those who do love this frog). According to the College of Tropical Agriculture and Human Resources at the University of Hawaii, there is the issue of their appetite for insects and spiders, some of which are native, as well as the concern that they compete with native birds for these food resources. And with their establishment, they could power the establishment of the brown tree snake if we were to find it accidentally released here. There are several reasons that the coqui infestations happened so quickly. First, they are habitat generalists, at home in urban areas as well as forests, and from sea level to close to 3900 feet in elevation. Unlike many frogs, coqui don't require water to lay their eggs, because there is no tadpole stage. Instead, the female lays her eggs in leaf litter, an abandoned bird nest, or inside a rolled up leaf, and it's the male's job to guard the eggs and keep them moist. In a little over two weeks, out come the little froglets. With up to seventy-five eggs per clutch, and several clutches per year, you can get quite a few coquis. Not only that, but they have few predators here, and so their populations can get big rather quickly. By the way, it's the male coquis that are making all the ruckus, the females and juvies, not so much. They "Ko-KEE" both to defend their territory as well as attract mates, and tend to be most vocal when it is raining, and at night, when they are active. Coqui frogs are not large: a few inches or so, with the female larger than the male. They have little spatula-like toe pads that help them to grip on to trees and other moist surfaces. Color can vary quite a bit, and may include mottled individuals. A thin light stripe running from the head down the middle of the back may or may not be present. Coqui have been found Oahu, but have been fairly well controlled. 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.
Scuttling along in tide pools throughout Hawaii are some familiar critters that really deserve a second look. They are hermit crabs, probably one of the creatures most responsible for getting children interested in the natural world. Today's post features a few from the genus Calcinus that inhabit tide pools and shallow reefs, though other hermit crabs live in deeper waters. With a closer look, you'll notice that the rainbow of colors on their eyes, legs, and claws that help to identify them. What you don't see, of course, is the soft and vulnerable abdomen that is modified to fit into the protection of a discarded shell, with back legs specially designed to grip and hook. As hermit crabs grow, they need to find a suitably sized new home. Empty shells are a valuable resource to hermit crabs, and a prospective home is thoroughly explored to see if the fit is right. The crabs try it on for size, and take up residency if everything is snug. If, for whatever reason, they begin to outgrow a shell but are unable to find a new one that fits well, they are more vulnerable to predation from any number of enemies, including crabs, reef fish, and octopi. They themselves are omnivores, and are happy munching on the abundant algae in the tide pools, as well as whatever tidbits float by, including debris. So next time you visit a tide pool, take a closer look at these colorful little guys, but leave any empty shells you may see. Housing is in short supply.
By NASA/George Varros [Public domain], via Wikimedia Commons So, it's August, that time of year when the Earth's orbit takes us through the debris field of meteoroids left behind by comet Swift-Tuttle. And what do we get? Quite a show, in the form of the Perseid meteor showers. Swift-Tuttle orbits the sun in a eccentric (elongated) path, and as it moves into the inner solar system, the warmth of the sun causes bits and pieces of it to break off, leaving a trail that traces its orbit. As we pass through, the comet rubble hits our atmosphere at tremendous speeds, heating up from the friction, and often disintegrating about sixty miles above the earth's surface. If any of the rubble were to land on Earth intact, that would be called a meteorite, though comet stuff isn't as hardy as asteroids bits, which make up the majority of meteorites. By Philippe Tremblay (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons Though experts note that it is difficult to pinpoint just when peak activity will occur, it's expected to be best on the nights of August 11-12 and 12-13, no matter where you are. It is also suggested after midnight and later is when you you'll get a good show, with the pre-dawn hours your best bet. Though you don't need to know where the constellation Persues is to see the meteor shower, the name Perseid is given to this event, because the meteors appear to come from this constellation. So grab a blanket, a hammock or lawn chair, and sit back and enjoy the show.
Hihiwai, Neretina granosa, is an endemic snail that inhabits cool, clean freshwater streams. And though snails have a slow reputation, these guys are quite the travelers. They lay capsules of eggs during the summer months, which hatch and get washed downstream into the ocean. They'll spend a good part of the year at sea before recruiting back up the stream, pulling themselves along single-file with their strong, muscular foot. They have a distinctive shell: about an inch and a half in length, with a dark top dotted in red, and an orangish operculum (the lid-like structure the snail uses to close the opening of the shell when it is retracted inside). The texture and shape of the shell may vary a bit, depending on what part of the stream they inhabit; those at the lower elevations tend to have rougher shells than those further upstream. They're algae grazers, but do most of their feeding at night when they are less likely to be gobbled up by 'auku'u (night heron) and other waders. Because their life cycle requires clear, well oxygenated waters and unimpeded access from the streams to the ocean, they are now uncommon on Oahu, which has had most of it streams modified.
Some of the stunners of the butterfly world, the Swallowtails have only one representative in Hawaii: the Asian Swallowtail, a.k.a. Chinese Yellow Swallowtail, Papilio xuthus. They're a good-sized butterfly, with a wingspan that can get as big as 10 cm. or so, about 4 inches. They were first recorded in Hawaii in the early 1970's, and do not occur on the mainland, though they are widespread throughout Asia and the Pacific Islands. You can tell the males from the females by the coloration: males are blacker all over, and have just a reduced amount of blue scales near the tail, where you also find the yellow eyespot. The females have much more blue along the margins, and have an orange eyespot. Like many butterflies in the Papilio genus, the hindwings have an extension, or "tail," hence the name swallowtail. Host plants (used for laying eggs and feeding the caterpillar) for the Asian Swallowtail are citrus plants in the family Rutaceae, and include orange, lemon, lime, grapefruit, and tangelo. Often eggs are laid singly, which will hatch into a blackish-white caterpillar with spikes. The early instars of the larval stage look like bird droppings, and as such, are fairly well camouflaged. As the caterpillar molts and gets too large to pass themselves off bird waste, they change color to a beautiful green which blends in with the leaves of the citrus. They have prominent eyespots, and an orange osmaterium, a tentacle-like forked structure which can be inflated when they are threatened, emitting a smelly secretion. After about two weeks, they pupate, attaching themselves with the head side up. And then, let the remarkable transformation begin.
The endangered Hawaiian stilt, or Ae'o (Himantopus mexicanus knudseni) is a beautiful sight to behold in Hawaii's wetlands and marshes with it's dark upper body offset by white underneath and up through the neck and near the bill. It has red eyes, with a variable white dot above. The legs are pink, and, um yeah, they're pretty long. It shares it genus Himantopus with four other species that look quite similar. According to the Cornell Lab of Ornithology, birds of this genus "have the second-longest legs in proportion to their bodies of any bird, exceeded only by flamingos." Ae'o are well adapted to their environs: the long legs help them to gracefully and slowly navigate the shifting surface of the wetlands, and the legs can bend backward to bring the body nearer to the ground. The slender bill is suitable for probing the muddy waters for aquatic invertebrates, or for having a go at small fish. A long and flexible neck helps with the hunting techniques as well.
They are quiet while hunting, but can emit a sharp call in flight, or when defending their nests, which are often shallow depressions dug in the ground. Three or four eggs are typically laid, and both male and female will share in the incubating and brooding of their young. Ae'o are known to be fierce defenders of their nests, and will dive bomb intruders, or feign a broken wing to divert the intruder's attention from the nest (I haven't seen the Ae'o do this, but I have seen killdeer put on the broken wing act, and it is pretty convincing). Young stay with their parents for several months. Places to see Ae'o here on Oahu include Hamakua Marsh and at Kahuku Point on the James Campbell National Wildlife Refuge.
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