Saturday, January 3, 2015

Jumping Bugs

Most land insects get around by walking and many by flying. Active flying is usually long-distance and more or less direction controlled and it depends on specialized extremities, with aerodynamic structures and powerful, aerobic muscles that need suitable operating temperatures to function (parachuting spiders are a different story).
Many arthropods have an efficient, simpler way of locomotion: they jump or hop. Jumping is often less directional than flying and may be used as a startling, sudden way to escape from danger, even in insects that are able to fly. But flightless arthropods like spiders may also jump in attacks with great precision. To jump, arthropods may employ their specialized hind-legs, usually elongate and muscular, but there are many other structures that are also used – don’t forget click beetles and spring tails ….. So let’s see where this new theme will get us (this was another week's topic for our Facebook group) – and, by the way,  I hope you had a pleasant jump into the New Year 2015!

Lepidocyrtus sp., Slender Springtail
 Springtails (Collembola) are no longer considered insects. But they are Hexapoda (have 6 legs) and (probably) closer to insects than Arachnids which our group does include, and they certainly are 'jumping bugs'.
I had never photographed any, so yesterday I grabbed one of our hedgehog cacti that died last year and shook it over a white basin. sure enough, hundreds of 'slender springtails' fell out. They are too small for my camera but I'm showing a shot anyway.
M...ost species of springtails have an abdominal, tail-like appendage, the furcula, that is folded beneath the body to be used for jumping when the animal is threatened. It is held under tension by a small structure called the retinaculum and when released, snaps against the substrate, flinging the springtail into the air. All of this takes place in as little as 18 milliseconds.

Systena sp. Rock Disk Park, Marana, Pima co, AZ November
Within the beetle family of the Chrysomelidae (Leaf Beetles) is a tribe called Alticini (Flea Beetles). The hind-femur of most beetles in this group is enlarged to accommodate big muscles and they can get away with considerable leaps. Some are metallic, some are striped some have spots, but they are all leaf eaters and rather small.

Acanthoscelidius utahensis, Photo by Won Gun Kim
 There are not many families of beetles that can jump in the traditional sense, using their legs: D.G. Furth and K. Suzuki. 1992. The independent evolution of the metafemoral spring in Coleoptera. Systematic Entomology 17, 341 -349: “The metafemoral spring jumping organ was known previously only from all Alticinae (Chrysomelidae), one genus of Bruchidae, and two species of Rhynchaeninae (Curculionidae).” ""In the Bruchidae the metafemoral spring has been found in one genus Eubaptus. ... The extent to which the metafemoral spring was discovered in the Ceutorhynchinae was unexpected, particularly because only three genera Hypocoeliodes, Aulentes and Acanthoscelidius have been observed to jump." Thank you to Henry Hespenheide for finding the quotation and to Won Gun Kim for the permission to use his weevil photo!

Platycotis vittata (Oak Treehopper)
Molino Basin, Catalina Mts, April
 One of my favorite hoppers. They often occur in big groups, and that must look really spectacular. But I have only found single ones in my beating sheet. Maybe most of them are not easily knocked off their branches. They are wide-spread: much of US and Canada / Mex. to Brazil

Antianthe expansa, Keeled Tree Hopper
on Datura, Sabino Canyon, Pima Co, AZ
 Treehoppers (Membracidae) in the order Hemiptera differ from related families in having a large pronotum that extends back over the abdomen and (often) covers the head; many species appear humpbacked or thorn-like; others have spines, horns or keels
Members of the genus Antianthe are subsocial, you'll find maternal egg guarding and ant-attended nymphal aggregations. They, like all hemiptera, are hemimetabolic. This means that they are undergoing an incomplete metamorphosis without a pupal state. Instead they develop over several instars of nymphs. Adults on the left, nymphs on the right.

Scolopsella reticulata, Alphina glauca, Poblicia fuliginosa,
Rhabdocephala brunnea, Acanalonia sp., Poblicia fuliginosa nymph
Very typical jumpers are in several families of the order Hemiptera. My collage shows actually members of a superfamily, Fulgoroidae, the Planthoppers. They can look quite bizarre, especially in the tropics, like the alligator look-a-like, the Lantern Bug. Some of our Arizona ones (my picture) also have moderately fancy head gear and some nymphs can produce fluffy waxy tails ... they are all able to hop, they have piercing sucking mouthparts
and are vegetarians (although the story of the biting Lantern Bug will not die....) I like them very much because they are the life-long specialty of my octogenarian close friend Lois O'Brien who just sent me the most hilarious year-end letter about her ongoing research.

Cat Flea
One of the most well known and athletic jumpers, a circus star, but usually very much despised is the flea.
Siphonaptera (Fleas) » Pulicidae are wingless insects with sucking mouth parts and strong jumping legs.
Living with 5 dogs and 2 cats In Arizona, we had one infestation in 12 years. It meant disinfecting all carpets and dog beds repeatedly and washing 8 animals every second day with flea shampoo. We got rid of that pest and afterwards I have only once seen a single flea - strangely on a white surface, not even on an animal. We were expecting the worst again, but no further signs. Arizona's dry climate and sandy soils are not the 'best' conditions for fleas it seems. Constant vigilance and cleaning also keeps any larvae from growing up because they rely on the excrement of adult fleas for food.

Alaus zunianus (Zuni Click Beetle)
Upper Madera Cny, 8/8/2013
 Click Beetles (Elateridae) have no specialized extremities that allow them to jump. Instead, the joint at the union of the prothorax and mesothorax is much more flexible than in most beetles, allowing up-and-down movement of the head/prothorax against the rest of the body. On the underside of that junction, a prosternal spine fits barely into a groove on the mesosternum. Whenever the beetle lies on its back (it often lands like that when threatened and playing dead), it begins to press the thorn against the grove (which has a restricting rim at its entrance), building up potential energy like a coiled spring. When the thorn eventually snaps into the grove, the two jointed body parts perform a sudden movement (click) that catapults the beetle off the ground (hopefully landing right side up) or out of and attackers grasp. If you see one of the large species like this 2 in long Alaus perform the trick, you will agree that this can qualify as jumping.

Bristletail from Peppersauce Canyon, Catalinas, Pima County, Arizona, USA
July 14, 2011
 Microcoryphia (Bristletails)
are 'wingless (insects); body cylindrical, brownish or yellowish with darker mottling or irregular pattern; thorax arched dorsally; tip of abdomen with 1 long medial filament and 2 shorter lateral cerci; long thread-like antennae with many segments; eyes large and meet in middle; mandibles articulate at one point only; short lateral styli (rudimentary appendages) on abdominal segments 2-9; able to jump up to 10 cm by snapping abdomen against ground' quote from

Salticus palpalis, the Metallic Clown Jumper, Tucson Mountain Park, February
When arthropods are cute enough for the general public to care, they actually have memorable common names! Meet
Salticus palpalis, the Metallic Clown Jumper
Jumping spiders have typically 3 pairs of eyes. The anterior median eyes (the pair of eyes in the center front) are comparatively very large and give these spiders excellent color vision and a high degree of resolution. The shape of the retinae indicates that these eyes function like tele lenses. Obviously they also provide binocular vision, meaning that the spider can judge distances accurately - a must for a jumping predator. The spiders behave like they are more intelligent than other bugs. I think this impression is partly based on the fact that humans and salticids both are very much vision-oriented and thus seem to understand each others reactions quite well.

Cydia latiferreana (Filbertworm Moth)
You are probably surprised to find a moth under this heading. And our Arizona species Cydia latiferreana (Filbertworm Moth) is really no jumper in any way I know of.
Its mexican genus-mate is Cydia deshaisiana, the Jumping Bean Moth. The adult moth of that species does not jump either. But the caterpillar does, sort of: It develops in the bean shaped fruit of a shrub (Sebastiania). When the ripened fruit falls to the ground, it may land in an exposed locatio...n where it gets much too hot for the caterpillar inside. So the caterpillar begins to spasm and buck inside the 'bean'. Since the caterpillar has attached itself firmly to the inside of the bean with silken threads, it is able to move the whole fruit, to make it actually jump. So the bean may eventually end up in a micro climate more suited to the needs of the inhabitant. Or not. But what is there to lose if the stimulus for action is sudden overheating?

1 comment:

  1. What the hell kind of hat is that Oak Treehopper wearing? Beautiful though. Magnificent post Margarethe and happy new year to you. x