Enemies and Allies
As human beings, we all have certain fundamental needs .. things that we HAVE to have in order to survive. This shouldn't be a surprise to anyone, and I'm sure that most of us know what at least a few of these things are without having to think about it very hard. We can manage without water for about three days, they tell us, food for up to a month, and shelter .. well, that depends on the situation. In extremes of weather, lack of adequate shelter can be life threatening in a matter of hours, or even minutes, but one thing is certain - we will need shelter at some point. There are other needs as well, but I think that we should come back to those at a later date - for now, lets just contemplate those first three. While it may be obvious that we all need water, food, and shelter, have you stopped to think that every living thing on Earth also needs these three things?
All over the world, right now, there are over one billion metric tons of insects .. they account for half the weight of all animal life on the planet, and they are all very busy trying to satisfy their basic needs. "Pests" have plagued agriculture ever since its invention, and even today, with all of the chemical arsenal at our disposal, we are not winning the fight. We are outnumbered, out massed, and if we are being perfectly honest with ourselves .. we are barely managing a 'holding action' on most fronts, and loosing on others. It is time to take a step back, reassess our strategy, take a lesson from Sun Tzu and know our enemies .. and perhaps recruit a few allies as well.
If you were with us last week, most of the pictures above should be familiar already. The aphids in the first picture are attracted to the sweetness of the allium flower - any plant that is a heavy feeder, and those that 'fix' nitrogen are primary targets for aphids, but if you should see them going after plants that don't fall into this category, it is a good indication that you are providing too much nitrogen. The ladybug larva in the second picture is busy acquiring its food, too .. and if it manages to get through its pupa state intact, will become a ferocious predator of the almost defenseless aphids .. I say almost, because though they lack any direct defense themselves, they have a powerful ally in certain species of ants, who will defend them from predators like the ladybug. In the third picture, we see the noble ants have banded together in common cause, and vanquished their common enemy .. the farm is saved, huzzah!
So lets turn our attention to the ant. Their food in this case is up in the foliage, close to the tender tips of the plants, but that isn't where they live - they live down in the soil, and have to make a commute from their nests to the high ground in order to provide protection to the aphids, and food for themselves. Students of military tactics may be familiar with the advantages to controlling the high ground, but a true tactician knows that in order to control high ground, it isn't always advantageous to occupy it .. controlling access to the point of interest is often preferable - a force that takes the high ground, but then finds themselves cut off from their lines of supply is in serious trouble. The aphids have their ally, fine. Lets find an ally for the ladybugs, too.
There are over 6,000 species of lizard in the world, and I could not even begin to tell you about all of them. I'm not even certain which one that is in the first picture above, but one thing is certain: Garden lizards like to eat ants, among other things. Dominating the space on the ground, a garden lizard can make the trip from nest to food a hazardous one for the ants, but having an abundance of food is not enough to entice lizards to take up residence in your garden .. there are a lot of predators that find lizards to be quite tasty, and they will need some habitat if they are going to consider signing on with your army. First and foremost, lizards are cold blooded - they need an open space that gets sunlight to keep their body temperature up. A large flat rock that can absorb and release heat throughout the day is ideal .. and even better if it is close to shelter. Rock overhangs, a broken vase turned on its side, or a small pile of stones with plenty of nooks and crannies make for a good place for lizards to go when they feel threatened. Rock walls do a good job at both functions.
While the common image that the word 'lizard' conjures is of a four legged reptile, some lizards, notably skinks, have short limbs, or none at all. The second picture above shows a legless lizard known as a 'slow worm' - there are many varieties, but all of them like to burrow in the ground, and they are often found in conjunction with ants. Guess what they like to eat? In addition to the usual lizard habitat, skinks and slow worms appreciate moist, shaded areas, like herbaceous plants that come all the way down to the groundcover layer, preferably with a good padding of moist, dead leaves for them to snuggle under. You can tell the difference between a slow worm and a snake by looking at its head: As lizards, slow worms have eyelids and ear holes, and snakes do not. Slow worms are not venomous, and aren't likely to bite you .. they would rather be out during the dark hours, looking for a nice tasty slug to nibble on.
The little insect in the picture above may look like some kind of bee or wasp, but don't be fooled - she is just wearing a disguise in the hopes of scaring off potential predators. This is one example of the nearly 6,000 species of Syrphid fly, also known as 'hoverflies' that can be found all over the world, usually lapping up nectar from flowers like the one shown here. The adult hoverflies live on nectar, but they don't have long tongues like some butterflies, so they have to have open flowers, like echinacea or dandelions to feed from. They are particularly fond of bright colored flowers, as well. Now while the adults are beneficial as pollinators, the larva are another potential ally - some like to consume dead vegetation and other remains, while others go after aphids and thrips .. those insects that like to suck the juices from your plants. They don't posses stingers, and don't bite .. but if one is hovering about you, don't be annoyed - just change to some color of clothing that isn't so bright, and avoid floral scents, and they will stop mistaking you for a flower.
While I'm thinking of insects that like to eat dead vegetation, lets have a look at these three characters above. In the first picture, we have a woodlouse .. call them roly-polies, pill bugs, sow bugs, or even armadillo bugs, these little critters live all over the world, and aren't actually insects at all: they are crustaceans, and are more closely related to shrimp than anything else on land. I've even heard that in some parts of the world, people eat them .. but I'm not that hungry or adventurous. They have no sting, no bite, and are completely harmless. They serve as a food source for many of the predators that you want to attract, so having them around is a good thing.
Number two in this trio of scallywags is the cricket. There are a great number of species of this insect, most of them located in the tropics. The chirping sound that they make is made by the males only, in an attempt to attract a mate - but they aren't singing love songs - the sound is made by rubbing the legs together. Funny, but when my legs rub together, no one finds it attractive. As omnivores, crickets eat .. a little bit of everything. While not consuming enough other insect eggs or larva to be considered a predator, they don't present much of a threat to established plants, either - although they have been known to eat the tender young shoots of emerging seedlings, so if you find them in your seed starting space, encourage them to move along. Crickets are yet another prey species for many predators, and have also made it on to the human menu in some places.
The final miscreant in the panel above is a boxelder bug. Considered a 'nuisance' pest owing to their tendency to stage home invasions when the weather turns cool, boxelder bugs are otherwise mostly innocuous. They feed on the juices in the leaves and seeds of boxelder and maple trees, but rarely seem to inflict sufficient damage to warrant extermination ,, and that's a good thing, too, since there are very few predators that relish eating a boxelder bug. they have the ability to secrete foul smelling or tasting chemicals in defense, much like stink bugs, and leave nasty stains on clothing, floors, and other surfaces when squished. If they have invaded your home, treat them like a harlequin ladybird beetle: sweep them up, vacuum them up, and send them on their way. My best guess as to their purpose? Maybe to keep certain trees that drop far too many seeds from being overly prolific.
Keeping with the theme of insects that use offensive odors as a defense mechanism, here are a couple more: The eggs shown at the top of this set of three pictures belong to a squash bug, but also resemble the eggs of a stink bug somewhat .. colors may vary, but the clusters of round eggs on the undersides (usually) of your plant's leaves are the first indicator that a problem might be brewing. There are a number of parasitic wasps and flies that can help eliminate some of these pests by depositing their own eggs in and upon either the eggs of the pest, or on the pest itself. At the time of this writing, I do not have a good example of these predators to show, but will add them when I can catch them.
The second picture is of a stink bug, fully mature. Stink bugs earn their living by feeding on un-ripened fruit of many kinds .. as such they can really hurt your yields, but there is yet hope! Remember the very second picture in this presentation? Yep .. the larva of the ladybug and ladybeetle don't give a fig about the noxious smell that stinkbugs use to deter predators, and they love gobbling down young stinkbugs before they can do too much damage to your figs. So long as you can resist over feeding your fruit bearing plants, aphids and their ant bodyguards wont be attracted to the same plants that the stinkbugs are, and your myrmidon ladybug larva will be able to devour those baby stinkers unopposed.
Picture number three shows a side profile of an insect that resembles a stinkbug in shape, and that also utilizes a foul tasting chemical deterrent to predation, but this nasty nasty is a squash bug, and its feeding pattern is somewhat different. Squash bugs appear when the weather gets hot, and commence to mining the leaves of cucurbits for their juices. They will poke scores, hundreds, thousands of tiny holes in the broad leaves, leaving a speckled pattern on them. Eventually, the leaves will begin to wilt, then die. In many cases, this feeding occurs close to the end of the plant's life cycle, and the squash bug is simply doing its job - helping to clear away one plant, to make room for something else - but when there is a bumper crop of squash bugs, they might bring down your vines before their time. Fortunately, there is a predator that can help you. Unfortunately, many of them are killed by humans who mistake them for pests.
Both of the pictures above present a glimpse of a terrifying insect predator - the assassin beetle. The lovely couple on top are an example of a variety commonly called 'wheel bugs', owing to that hump on the thorax, which, if I could have found a good side profile to demonstrate, bears a passing resemblance to a wheel sticking out of the insect's back. Perhaps I will be fortunate enough to capture a good picture sometime this summer, we shall see. The bottom picture shows us this mighty guardian of the garden's main weapon: a long, sharp, hollow spear, hinged in three places called a 'rostrum' which it uses to first inject its prey with a venom laced with digestive enzymes, and then to suck out the liquified innards of any passing squash bug that gets too close.
Although assassin beetles don't attack humans, they are not afraid to wield their weapons in self defense, and a bite from an assassin can be painful - but not deadly. There IS a cousin of the assassin beetle that lives in tropical climates, particularly in South America that goes by the name of the 'kissing beetle' It is so called on account of its habit of creeping up on sleeping persons, and piercing the lips with its rostrum to drink a bit of blood. Unfortunately, the kissing beetle is a transmitter of a heart-affecting disease called 'Chagas', for which there is currently no cure. It can be fatal .. in about thirty years or so. Aside from the kissing beetle, no other assassins carry Chagas, so invite them into the garden freely. How? by propagating plants bright colored flowers, which they love to parade about upon. Squash flowers, for example.
Here in picture one, we have an example of a longhorn beetle .. just one of over 26,000 species that are known. It is the larva of the longhorn beetle that pose the greatest threat - the beetles lay their eggs on green vegetation, and a boring grub hatches out from it. In some species, those grubs can spend up to 3 years burrowing under the bark of trees, even making their way down into the heartwood, and sometimes killing a tree outright. Longhorns use chemical means to deter predators, ranging from a foul musk, in the case of the beetle in the top picture, up to and including an irritant that can cause contact dermatitis - and it for this reason that some people label them as 'blister beetles', but that name properly belongs to an insect of an entirely different family.
The family Meloidae is the home of the proper blister beetles, and has about 7,500 known members. Many of these bugs have bright colors announcing their toxicity to the world, but some, like the example in picture two above, have a more low-key sense of fashion. A long abdomen, tapering at the thorax, and tapering at the end are good indicators that the insect that you are looking at might be a blister beetle. The toxin that they secrete causes contact dermatitis, and is sufficiently potent that animals accidently consuming them in hay or fodder can be killed. The number necessary to reach a lethal dose varies from one species to another, but can be as low as five beetles, or as many as thirty. Aside from risks posed to grazing animals, blister beetles can wreck havoc on vegetable crops, and seem to have a special love for members of the nightshade family .. all of that being said, they do posses one redeeming quality: Their larva are predators. More on that in a moment.
The insect in photo number three above requires no introduction: it is known the world over as a plague organism, and is almost universally despised. There are over 11,000 different species of grasshopper, and although they will all eat just about any kind of vegetation if they are hungry enough, they all have their unique preferences. the common preference to all grasshoppers is a love of tender annual vegetation .. and they have been working hard for the past 250 million years to clear it away, to make room for perennials. The adults lay their eggs in the soil, and this is where the blister beetles come in: Blister beetle larva feed on grasshopper eggs. The interaction is so close between these two insects, that one can actually track their cycles. First, an overabundance of tempting fodder for the grasshopper occurs: too many annual plants in one place. Grasshoppers move in to do their job, laying eggs. In the following season, local grasshopper populations experience an increase, and even more eggs are laid - but this available food resource attracts the Meloidae beetles, who lay their eggs to feed on the grasshopper's eggs. In the next season, an overabundance of blister beetles lay even more eggs .. but with fewer grasshopper eggs to feed on, most of the larva fail to reach adulthood, and the numbers of both grasshoppers and blister beetles declines. The entire cycle takes about five years, and the key to breaking it is to stop the grasshopper, either by depriving them of their preferred diet, or by encouraging their predators.