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.
6 Comments
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
The monarch butterfly, Danaus plexippus, is a familiar backyard visitor and easy to recognize with its bold orange and black patterning. They arrived in the Hawaii islands around 1850, not long after the introduction of the host plants Asclepias curassavica, also known as the tropical milkweed, and later, Calotropis gigantea, the crown flower. Whether they came here on their own, or with the aid of humans is not known. They are capable of great migrations and have crossed the Atlantic, though they never became established in Great Britain, probably due to the absence of their host plants. Host plants are the plants that different butterfly species lay their eggs on and which their larvae eat. They also need nectar plants, which attract and feed the adult butterflies. Monarchs are present in the Pacific islands wherever their host plant exists; however, those in Hawaii don't appear to migrate. Monarchs are poisonous to many potential predators due to the Cardiac glycosides they have from eating the milkweed plants. These substances are strong heart stimulators, and can be fatal to birds. However, the two bulbul species here, the red-vented and the red-whiskered bulbul apparently do eat monarchs. It has also been noted that certain mice are able to eat monarchs. Other predators of adults include wasps. Spiders and ants may attack the eggs, which is the first of the four stages in the complete metamorphosis that the monarch undergoes. The female lays the eggs on the undersides of the milkweed leaves, and they hatch in three to five days. The larvae, or caterpillars, wriggle out and start feeding on the host plant. They will grow and molt four times, before they attach themselves to a secure spot and molt for a final time. The skin then hardens, and the beautiful green chrysalis forms, protecting it while it undergoes the most amazing transformation of them all. In less than two weeks, the chrysalis becomes clear, and soon after, the adult monarch emerges. The adults lives only for several weeks, feeding on nectar with their straw-like tongue, the proboscis. Life for this beauty is truly short but sweet. They're beautiful, they don't sting, and they eat mosquitoes - what more could you want in an insect? This is Hawaii's endemic pinao, the Giant Hawaiian Dragonfly, Anax strenuus. Found at higher elevations, this skilled hunter often scouts his way around ponds, marshes, and other aquatic habitats in search of insects, zipping around at impressive speeds and with great maneuverability. They can hover, move forward, backward, up, down, and execute sharp turns with the greatest of ease. This is due in part to the wings of the dragonfly; they can move their fore-wings and hind-wings independently, unlike bees and butterflies that flap their wings in unison. Eggs are laid in or near the water by the female, who uses her abdomen like a needle to cut into plant tissue to deposit her eggs. Such behavior of this and related dragonflies earned them the name "darners." The eggs hatch into larvae known as nymphs, or naiads, and live aquatic, carnivorous lives. How to Tell Damsels From Dragons
If you're not sure of the difference between dragonflies and damselflies, here are a few easy tips to get you started. The first thing to do is notice their flight. If they are energetic flyers, it's probably a dragonfly. Damselflies tend to perch more often and are weaker fliers. Next, observe their wing position when they are at rest. Dragonflies hold their wings out to the side like an airplane, while damselflies will hold their wings vertically, pressed together above their thorax and pointing up and back. You'll also observe that the wings or the damselfly are smaller than the dragonfly's, and are similar in shape. The dragonfly's fore and hind-wings are shape differently. The eyes offer another helpful clue: dragonfly eyes often meet in the middle; the damselfly's eyes are set apart father to the sides of the head. No matter which, both members of the Odonata Order are a delight to watch and deserve our kokua: many are endangered due to loss or degradation of habitat, and the nymphs are often preyed upon by invasive fish, frogs, and invertebrates. The butterfly garden at Foster Botanical is a great place to decompress. Try sitting among some of Hawaii's seventeen species of butterflies, as see if you don't agree. That's where I became acquainted with the Gulf Fritillary, Agraulis vanillae. It's about two and a half to three inches in length, and a beautiful deep orange. The undersides of the wings sport silvery white spots, making it a stunner from top to bottom. One tip for correct identification is the three white dots encircled in black on the forewing. Its name comes from its migration over the Gulf of Mexico. The range is as far north as Northern California and south through Central and parts of South America. At night, this butterfly may roost in loose groups, usually no more than six feet or so off the ground. The caterpillar of Agraulis vanillae has a passion for the passion vine (Passifloraceae), which is the host plant for this species. The caterpillars emerge from small yellow eggs and are black and orange with lots of dark spikes. The bright colors and spikes are a defense mechanism, advertising to would-be predators that they should stay away. The spikes are actually soft, and do not sting. This is true for most butterfly caterpillars, it is some of the moth caterpillars that can inflict a nasty sting. The larval (caterpillar) stage of this butterfly lasts for about two weeks, during which time there are several molts. Entomologists refer to the developmental stage between molts as an instar. This is followed up by the pupal stage, when the caterpillar forms a chrysalis that looks very much like a withered leaf. In about two more weeks the stunning butterfly emerges and pumps hemolymph through its wing veins. Hemolymph is to insects as blood is to mammals and birds - a fluid that contains nutrients such as proteins and sugars. Instead of hemoglobin, insect "blood" contains hemocyanin, which turns bluish-green when oxygenated (that's why bugs don't bleed "red blood" when squashed). Once the wings are fully expanded, the metamorphosis is complete, and the world is graced by one more beautiful pulelehua. When you first see this bee, you might think black bumblebee, but nope, it's not even in the same genus. This is none other than the sonoran carpenter bee, Xylocopa sonorina. The name comes from the Greek for wood cutter, and there you have it: they nest and rear their offspring in wood structures, or old logs, like the ones in my backyard do. They don't actually eat the wood, but make a fair amount of sawdust in the process of excavating their tunnels. Some of this sawdust is used to enclose the eggs which they have laid on a pollen ball in the back of the tunnel. The larvae hatch and spend some time maturing before venturing out on their own. They are said to be solitary bees, though the ones that live in my backyard share the same log. I have seen females as well as males snuggled into separate tunnels on the same log. In the picture I took below, you might be able to see the the female and male in the tunnels on opposite sides of each other. The females are black and have stingers; the males are golden and are stingerless. They seem to love the purple flowers in my yard, especially the lilikoi, of which they are important pollinators. The sonoran carpenter is said to be shy, not likely to sting, though I myself was stung when I was moving around some cut logs and discovered them. The initial pain was searingly hot, but quickly subsided and seemed less painful than other bee stings I have had. But no offense taken - I quite like them and the way they lumber happily around the yard in search of nectar. Say hello to Orcus chalybeus (Halmus chalybeus), and yes, it is a ladybug... except ladybugs aren't really bugs, they're beetles. This gem of a beetle's common name is the Steelblue lady beetle. Who needs spots when you have a color like that? This beetle came to Hawaii from its native Australia, and like some of the other Coccinellidae, it is valuable for its predation of pests such as mites, aphids and scale insects. I have seen them come to the rescue of my hibiscus plants. That's a big job for a little beetle - these guys are just a few (3-4) millimeters in length. That's about half the width of your pinky nail. Just what makes a beetle different from a bug? Well for starters, beetles have two pairs of wings (as do all winged insects), but the outer wings are hardened, protecting the more fragile flying wings that are tucked underneath. Secondly, the mouth of beetles is different from those of bugs. Beetles are chewers while true bugs prefer to pierce and suck. Yup. So remember not to bug the beetle.
|
welcomes you to visit with the all the wonderful flora and fauna that we share this lovely aina with. Categories
All
Archives
October 2014
|