Oh, they're big. And if their size doesn't get your attention, their beautiful webs will. The female Argiope appensa, referred to here as the Hawaiian or yellow garden spider (though not native), can get close to three inches in length, though the males are commonly less than an inch, and mostly brown in color. Look for the pentagon-shaped abdomen and darker cephalothorax, eight eyes, and banded legs. They are known to be master web-casters, spinning orb webs made of sticky capture silk. Like other members of their genus, these spiders also weave in a zig-zag stabilimentum, a decorative pattern of non-capture silk, though the function of this pattern is a matter of debate. It may be a way of luring in prey, due to the UV reflectiveness of the silk; others believe it to be a defense mechanism, warning birds and others critters not to crash into their web. Either way, it is striking, and another key to identification, though it may not always be present. While all spiders have some venom used to stun their prey, these garden spiders have so little as to be considered non-venomous. So instead of getting that broom and knocking down this amazing feat of engineering, admire the craftsmanship and let them catch the cockroaches.
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.
I wish I could end the tale of the Jackson's chameleon there, but the story is just getting started. As populations of these chameleons were getting established, there was little to no research on their ecological impact. In 2009, a study was published, entitled: A reptilian smoking gun: first record of invasive Jackson’s chameleon (Chamaeleo jacksonii) predation on native Hawaiian species. In this report, the authors documented predation of native tree snails by Jackon's chameleons. Further research is needed, but let it be yet another cautionary tale about how exotic species can disrupt the delicate balance of island ecosystems.
Though you may not realize it, tucked away in the nooks and crannies of Hawaii's reefs are more than forty species of moray eels. If you're lucky, you'll see the snout of one as it guards its den, oftentimes with its mouth agape. This promotes water circulation over its gills, which are but a small hole on the side. These sly and shy bony fish are some of the reef's top predators, slithering out of their hiding places to hunt at night, though some species, such as the snowflake moray, will venture out during the day. Without pelvic and pectoral fins, locomotion is achieved by a serpentine undulation of their bodies. Some morays eat fish, octopi and the like, others prefer crustaceans, and their anatomies are adapted for this variation in diet. The fish-eating morays have a longer snout and backward curving teeth; the crustacean-eaters have a blunter snout and nubbier teeth better suited for crunching and munching.
While eels have a fearsome reputation, they are not generally aggressive unless you disturb them in their den, and if bitten by a fish-eating moray, the wound can be serious due to the curve of the teeth. If you do any spearfishing, though, you may encounter one of the larger and more common eels, the Yellowmargin moray, Gymnothorax flavimarginatus. The Waikiki Aquarium's fact sheet on this eel, known as the puhi-paka, or fierce eel, reports that they show a particular interest in injured fish, and have been known to investigate the goings-on of spearfishermen.
Cabbage on a stick, cabbage on a baseball bat: those are terms of endearment for the lovely and unusual endemic plants of the genus Brighamia. Though they may be found in tropical gardens and in nurseries, they are critically endangered in the wild here in Hawaii. There are two species: Brighamia insignis, called ‘ōlulu or ālula, with yellow flowers and coming from Kaua'i and Ni'ihau; and Brighamia rockii, pua ‘ala, with white flowers and hailing from Moloka'i. With the thick stem and sturdy leaves you'd be right in thinking they're succulents, and if you're growing them in your garden, they're not difficult as long as their feet aren't wet (and watch out for the slugs and snails, too!) They are usually three to ten foot high, rarely branching in cultivation, but can get as tall as sixteen feet.
Found naturally on steep cliffs and rocky outcroppings, their design allowed them to hang on during the blustery trade winds, but even these guys couldn't withstand the intense winds of hurricanes 'Iwa and 'Iniki, when many of the plants in Kaua'i were lost. Other issues including feral goats and the suspected loss of its natural pollinator have been devastating for Brighamia insignis. The National Tropical Botanical Garden reports that there is only one plant believed to exist in the wild in Kaua'i, and none have been reported from Ni'ihau since 1947. Many plants are being cultivated at Limahuli and McBryde Gardens, and may be outplanted in the future. I appreciate how they have really stepped up to the plate for this great plant.
Over the past few months, I have watched as more and more of these little hangy-things have grown in number on one of my plant containers in the backyard. They're different from the hangy-things in the laundry room, which are smoother and thinner, and probably belong to a case-bearing moth. No, these are spikier and more grassy. So a trip to the library and a bit of searching, and I think I have cracked the case, pun intended (thanks to Jamieson & Denny's Hawaii's Butterflies and Moths)!
It's the home of the caterpillar of the bagworm moth, Brachycyttarus griseus in the family Psychidae. First reported in Oahu in 1984, the species is well established in South East Asia. The male moth is about one and a half centimeters in length, not so big, and the female is wingless. She's got it in the bag....living her entire life there, never to leave. The male impregnates her while she's in her protective casing and then she releases her eggs to the ground. Upon hatching, the little caterpillars eat grass, such as Paspalurn conjugaturn and Zoysia pungens, and immediately get to work constructing their casings. They drag them behind as they feed, and enlarge them with bit of grass and webbing as they go. Once they are about one centimeter in length, the larvae climb up to a spot, say, on a plant pot, the eave of a roof, or a garden shed, and attach themselves to pupate. Only the males will leave the casing, when they go in search of a mate. They are said to be pretty harmless, though I did find a website that said they were pests of basil and lemongrass. So, now the caterpillar is out of the bag.
This eye-popping, brilliant red belongs to the Scarlet Skimmer, a.k.a. Crimson Darter, Crocothemis servilia. Found in East and South East Asia, it has also has taken up residence in Florida, Cuba, and Hawaii. They frequent habitats with still waters and grassy fields, and are commonly seen around disturbed areas such as ditches and golf ponds. Reaching lengths up to one and a half inches or more, they are one of the larger red dragonflies. While many dragonflies are known for their frenetic flight, these guys are perchers; sitting tall on marsh vegetation, ready to ambush their prey or chase off any intruders to their territory. Their striking color makes them easy to spot; even the eyes of the male are red, and a dark line running along the abdomen helps distinguish this from other species. The females and younger males are yellowish in color. Males undergo "nupital coloration," a change in their body color which signals sexual maturity. Recently, scientists discovered that the color change is redox dependent. Epidermal pigments in young males and even females turned from yellow to bright red when injected with a reductive agent. So I guess it's fair to say that those bright red males.... have a certain chemistry.
For more info on the chemistry of nupital coloration: see Redox alters yellow dragonflies into red Ryo Futahashia,1, Ryoji Kuritab, Hiroaki Manoc, and Takema Fukatsua
welcomes you to visit with the all the wonderful flora and fauna that we share this lovely aina with.