Coco plums

Coco plums, originally uploaded by allspice1.

It's a hedge, it's a tree, it's a delicious edible fruit! It's a Coco Plum! Next to Palm and Pine it is also probably one of the most over-used obligatory plant-name/business-monikers in the tropics. Seriously, there's a resort in Belize, there's a Beach and Tennis Club in Key West, and an appliance store in Vermont (?) that all get higher google ranking than the wikipedia article about the plant.

But it shouldn't be so. It's a very nice plant, Chrysoblanus icaco. All over south Florida, every well-groomed native planting and every scrubby wetland ecosystem is bursting with this attractive, round-leaved native plant.

It has two varieties- an upland and a coastal type. In the picture above you can see the fruit of the upland type. This coco plum can become a bushy tree up to 10 feet tall, bearing dusky purple fruits and dark red growth tips. The coastal type, on the other hand, grows shorter, maybe three feet tall, its new growth blushing only slightly, and its fruits a soft white to pinkish-purple as below.



As my parents and I strolled through a coco plum corridor in Apoxee Park, I squeezed the soft white and pink fruits, wondering how they would taste, but uncertain if their attractive, smooth skin hid poison beneath. My grandmother came to visit us for Thanksgiving and encouraged me to taste the upland variety on another hike. The dark purple fruits turned out to be mostly seed, with a thin layer of white bread-like pulp, dry but sweet. It retreated from my bite, mashed into a shiny white mold of my front teeth. The dark eggplant skin was thick and a little rubbery. I found myself disappointed that I couldn't find more juice in them.

Powering the Cell: Mitochondria

Yay cell biology!

Leviticus

Spur-throated Grasshopper, originally uploaded by OakleyOriginals.

Leviticus 11 is a chapter of Hebrew law dealing with what is and is not permissible to eat as meat. God prohibits eating of pigs, shellfish, birds of prey, lizards, etc. These animals do not fit the cleanness requirements of God's law, and so Israel is not to consume them. Insects are on the list too (vs. 20):

"All flying insects that walk on all fours are to be detestable to you."

Putting aside for a moment the anatomical inaccuracy of saying that insects "walk on all fours" (who really says "walks on all sixes" anyway?), the message is clear: don't eat bugs. But then there's an exception (vs. 21-23):

"There are, however, some winged creatures that walk on all fours that you may eat: those that have jointed legs for hopping on the ground. Of these you may eat any kind of locust, katydid, cricket or grasshopper. But all other winged creatures that have four legs you are to detest."

The Orthoptera are on the menu! The order Orthoptera includes grasshoppers, locusts, crickets, and katydids. Leviticus gives us the easiest sight ID characteristic for this order: jumping legs. If you want to be fancy you can call them "saltatorial" legs. Check out this handsome fellow in the photo above. Nice saltatorial legs, eh?

So, why are Orthopterans invited to dinner, but nobody else from Insecta? This is a difficult question. Some say that they are hygienic, less likely to carry parasites than other insects. They are good, meaty insects too, nutritious. Some say that they aren't as close to the ground because they hop, and so they are cleaner. Others say that they are clean because they are exclusively herbivorous. Others remember that locusts are a major agricultural pest problem in the near east, and in some years the locust swarms would blot out the sun and consume every fruit, leaf, and stick in their path, leaving only the locusts themselves to be consumed by the devastated farmers.

Personally, I like thinking of the Orthoptera as the skilled musicians of the insect world. A vast majority of the Orthoptera chirp, sing, drum, or rattle to call their mates. Few other insects make such pleasing music. Perhaps the singers are invited to dinner to remind the Israelites about their role as praisers of God, commanded to make a joyful noise to him who gives life to all the creatures that swarm on the ground.

Hippoboscidae

Jelenja uš, originally uploaded by natalija2006.

I went for a hike along the Allegheny Front Trail this Sunday and I got lost. Not really badly lost, just frustrated lost. The-directions-say-ignore-trail-so-I-ignore-trail-here-right? lost. As I was bushwhacking my way back to the trail from one of my unfortunate detours, I felt a slight pinch at my neck. My hand found a little critter sucking on my delicious blood- a deer ked.

Deer keds belong to the family Hippoboscidae, a very special family of parasitic flies. They have stout dark hairs on their bodies and long legs that curl themselves around your finger. Their wings are fine and diaphanous. What is most shocking about Hippoboscids is just how flat they are. I tried to squish the little blood-thief that I found on my neck, but he just wouldn't squish. I couldn't make him any flatter than he already was.

Deer keds typically spend their early life flying around looking for a nice, juicy host deer to suck on. Once they find one, they use their prehensile feet to nestle themselves into the deer's fur. Their wings aren't necessary anymore, so they break them off and settle down. You can see one wing gone in the picture of the Hippoboscid above - perhaps he fell off while he was still trying to get comfortable on his chosen deer. Deer keds find love on their deer host, and little deer keds are birthed shortly thereafter.

The female deer ked does not lay eggs like most insects. Instead she nurtures a single larva at a time in her abdomen, waiting until it is nearly full-grown before she releases it. Deer ked reproduction is not unlike our own in this respect. They have an organ that can only be described as a "uterus," and glands that can only be described as "milk" glands, with which they feed the larva until it is big enough to pupate. The mother deer ked then releases the larva and it drops to the ground where it immediately begins the transformation into an adult by pupating. No activity is apparent during the pupal stage. The little brown capsule of the puparium, however, hides profound changes. In the puparium, the deer ked goes from a legless, eyeless, featureless white bag of goo to a hairy, strong flier with excellent eyesight and a vampiric drive. Eventually the adult deer ked emerges from its protective puparium and flies off to find its own nice, juicy deer.

The life cycle of the deer ked reminds me a lot of our own. We are cared for by our mothers for years, then released to the world that sometimes expects us to immediately begin functioning as an adult. But all of us need a period of pupation. Time to change, to grow, to transition from the old way of life to the new way. In some way, every period of our life is probably a time to pupate and prepare for the next phase.

Reflex bleeding

Today I spent most of the day at a friend's wedding. It was a rare sunny, warm October day, and the beetles were swarming. Harmonia axyridis, to be exact: ladybugs from Asia, hit-men imported to take care of aphids and scale insects plaguing many crops here in the US. Unfortunately, these efficient aphid-killers proved to be real goons-- indiscriminately killing their own ladybird-kind and other beneficial insects. In addition, H. axyridis likes to overwinter in our houses, amassing in hoards under eaves and in crevices. They also bite. They're not nice bugs.

One of the other delightful tricks of H. axyridis (and other ladybeetles) is something called reflex bleeding. When something scary happens to the ladybeetle, such as when a lovely girl in white sits upon a little Harmonia beetle hidden in the folds of her voluminous dress, the squeezed beetle panics. The beetle tears open specialized weak spots in its cuticle, allowing its yellow-orange hemolymph (blood) to bubble out in a little droplet. This defensive secretion, in addition to making an unsightly orange stain on a white dress, will release a bitter chemical and a noxious odor.

Sometimes I too bleed uncontrollably. A little thing can set me off and before I know it I'm pouring out bitter chemicals and a noxious odor. It can't be helped. Is the burst of ugly emotions that I experience --like the ladybeetle's reflex bleeding-- meant to protect me from being eaten by an even uglier fate?

Photo by Flickr user Ombrosoparacloucycle, licensed for re-use under a Creative Commons license.

Roach reflexes

I've told you about the spectacle that is the Great Insect Fair Cockroach Races. Roaches are impressive runners. Apparently the fastest roach ever recorded sprinted at an amazing 3.4 miles per hour, which, when you're only 2 inches long, is lickety-split.

Perhaps you have had the surreal experience of being sure that you have stamped on an offending cockroach, only to find that he has Houdini'd his way out from under your shoe and is now across the room and disappearing under your fridge. How is it- you ask yourself- that roach-kind has invented teleportation?

Roaches, it turns out, have mastered the art of escape not with magic, but with fast reflexes.

Cockroaches are characterized by the presence of two appendages called cerci (SIR-see, singular cercus) on their last abdominal segment (read: butt). In many species, the cerci are covered with delicate sensory hairs for chemoreception or mechanoreception and act kind of like antennae for the rear end of the insect. The cerci of cockroaches are exceptionally sensitive. They are sensitive enough to pick up the tiny air currents created by your foot sweeping toward them threateningly. The sensitive cerci send a signal up the ventral nerve chord directly to the nerve center of the thorax controlling the roach's legs. Only three neurons stand between the cerci and the legs. Accordingly, the roach can react in less than 70 milliseconds. A blink of an eye is 300-400 milliseconds.

It is grace, is it not, that God gives cockroaches this kind of speed? They are universally hated and feared, constantly persecuted by stomping feet or chemical warfare. But at least the cockroach has been given the reflexes to escape from impending doom with near-clairvoyant speed.

Jet-propulsion

In a previous post I talked about how totally awesome and totally impossible it would be to be born with rocket-thrusters. As personally disappointing as this is, I take joy in the fact that many other animals are blessed with magnificently bizarre methods of locomotion.

Dragonfly larvae, for example. They are rather ugly brown critters that swim around in shallow ponds, catching small invertebrates and fish with an extensible bear-trap jaw, biding their time until they can emerge as adult dragonflies and take up their rightful place among the high-speed insect jewels in the sky.

Dragonfly larvae do not have paddle-like appendages for swimming under the water. They are not helpless, however, against predators. God, in his wisdom, has given them jet-propulsion. When chased, a dragonfly larva will suck water into its anus like a turkey-baster and then blast it out, propelling itself through the water with surprising speed. Yes, dragonfly larvae are equipped with their very own rectal rocket-thrusters.

If that wasn't awesome enough for you, the gills of dragonfly larvae are also housed within the rectum. Picture, for a moment, what a different life it would be to use your rectum for both jet-propulsion and breathing.

And now you know why I feel my heart rise into my throat when I study insects. There is something ludicrous everywhere you look.