Scientific Beekeeping

Apis mellifera
Honey bee (Apis mellifera), Courtesy of Charles Sharp at Wikimedia Commons

When I first moved to the country in the late nineties, one of the first things I wanted to do (after establishing several vegetable gardens to indulge my tomato obsession) was to become a beekeeper.

So I took a six week course sponsored by West Virginia University, read the full documentation available from the University of Maryland and Penn State as well as back issues of beekeeping magazines, and checked with some hobby beekeepers in the area.

Unfortunately, at that time, honeybees were being devastated by an invasive species … the Varroa mite (Varroa destructor), and the amount of effort needed to keep colonies free from them discouraged me, and the message I was getting from experienced hobby beekeepers was one of “be prepared”, and “I’m, regretfully, giving it up because of the effort involved.”

Basically … too much work … not something I was willing to commit to.

But I never lost my fascination with them (and other bees and wasps, for that matter.)

Then in 2006, I started hearing about Colony Collapse Disorder, or CCD, and it was while researching it, that I found the site of Randy Oliver, a biologist who also made his living beekeeping.

The site is Scientific Beekeeping.

From his About tab.

I started keeping bees as a hobbyist around 1966, and then went on to get university degrees in biological sciences, specializing in entomology. In 1980 I began to build a migratory beekeeping operation in California, and currently run about 1000 hives with my two sons, from which we make our livings.

In 1993, the varroa mite arrived in California, and after it wiped out my operation for the second time in 1999, I decided to “hit the books” and use my scientific background to learn to fight back.

The site is not a beginner’s “how to”, but a way to share what he has learned with others:

What I try to do in my articles and blogs is to scour scientific papers for practical beekeeping applications, and to sort through the advice, opinion, and conjecture found in the bee magazines and on the Web, taking no positions other than to provide accurate information to Joe Beekeeper.

(If you’ve been following my blog posts here, then you’ll probably recognize the pattern of places that rise quickly in my judgment, as ones I like)

The site has become my “go to” source for all things related to honeybees, and I recommend it to others who want to stay abreast of the subject.

Scientific Beekeeping

Ask an Entomologist

Aedes_aegypti_CDC-Gathany
Aedes aegypti mosquito. The image is in the public domain from Wikipedia Commons

No, I’m not one.  But the folks who run the Ask an Entomologist site are.  You can ask them anything about bugs, and some of their best posts result from questions that come from kids.

Don’t think of it as a place for identification, although they’ll do their best to answer, or direct you to a good place where that can happen; think of it as a way to prompt them to explain some aspect about the science of Entomology that may not be well understood by the general public.

From their About Section

If you’re interested in how insects are related to one another, how they work on the inside, how they behave, current events in the news, or anything else … you’ve come to the right place.

And here’s how they addressed the identification part in a recent post, introducing the science of Taxonomy:

Please don’t take this the wrong way. We *want* to help you, we’re just not qualified. Insects make up 58% of the biodiversity on the planet, with beetles alone consisting of over 350,000 species. People who study scarab beetles may not even have the expertise to help you identify your sap beetle. Joe and I are just two people, and two people just can’t know all the bugs. That’s why we refer you to places where many people with various areas of expertise are present.

And they’re not afraid to tackle controversial issues, with explanations and links to the science to explain how something works.  This one, for example, which addresses the Sterile Insect Technique (SIT) using the new process of genetic engineering to create the sterile insects.

People have asked Nancy and me a lot of questions about the sterile GMO mosquitoes the British company Oxitec is planning to release in Florida. We get these questions on a Facebook page we administrate as well as through this blog. People are really curious about what’s going on with these mosquitoes, and we’re really excited to talk about them!

Since I used to be responsible for a mosquito management program targeting the mosquitoes that spread West Nile Virus, as well as provide general public pesticide education, that post provided a great deal of clarity on the whole topic.  In particular, the part about Rachel Carson and a quote from her seminal work, Silent Spring, which endorsed SIT as a way to reduce dependence on pesticides; a way to selectively manage a pest in a local area at the species level.  That means zero impact on non-target species.  What an exciting possibility!

Two other places I follow to learn more general things about bugs and insects are Gwen “Bug Girl” Pearson, and the Facebook Page Relax, I’m an Entomologist.

For a more specific understanding of pests in and around the home, there’s Insects in the City and everything you need or want to know about ticks, and how to protect yourself from them, Tick Encounter Resource Center.

Digging these wasps!

After writing about the unusually bad scourge of Japanese Beetles earlier in the month, I thought I’d continue on down the “garden bugs” path. The Japanese Beetles have died down, but now we have oodles of these pretty black and yellow-spotted waspy things around. They’re everywhere, and in large numbers. I planted some buckwheat over our potato garden bed, and it is covered up with them. The point of the buckwheat was as a primo late-season nectar source for our honeybee hives as they prepare for winter. Blooming for the last week or two, I kept checking it expecting to see happy bees, feasting away. Nada. Just the wasps.

Intriguing. A brief googling revealed the wasp to be Scolia dubia, one of the “digger wasps.” They rarely sting, and better yet -their larvae are parasites of Japanese Beetles! All that swooping around over our so-called lawn is apparently the mating dance, then the female digs into the soil to find the grubs. After stinging the grub, she lays an egg…and you see where this is going. Cozy winter grub cocoon for the pupating larvae!

Blue Wing Digging Wasp on buckwheat.
Blue Wing Digging Wasp on buckwheat.

Back to the bed of gourmet buckwheat. I’m thrilled to see all those wasps feeding on the nectar. Eat, dig, and be merry, ladies! But what about the honeybees – seemingly ignoring this glorious patch of buckwheat planted just for them? I don’t need any more picky eaters…aren’t our two dinner-snubbing dogs enough? So I asked Dr. Richard Fell, legendary Apiculture faculty here at Virginia Tech, about this mystery. “Honeybees only work buckwheat in the morning” sayeth Rick. Went out this morning and observed that buckwheat is indeed the breakfast of champions. The entire patch was literally humming with multiple species, including loads of honeybees. I’d only been checking in the evening.

Addendum:
So my post apparently isn’t breaking news. Just came across this as I checked my Scolia spelling. Sounds like they had beetles galore in Maryland as well this summer.
If you’re not familiar with Dr. Michael Raupp, Entomologist and Extension Specialist at University of Maryland, he’s awesome, and his “Bug of the Week” blog is a must. His September 1 post reviews the digger wasp/japanese beetle relationship as well, with more factoids and a lovely video featuring writhing grubs. http://bugoftheweek.com/blog/2014/9/1/white-grubs-beware-the-blue-winged-digger-wasp-iscolia-dubiai-has-arrived

Beetlemania

File this under “if it’s not one thing, it’s another.”
Which may be, upon further reflection, the most profoundly absurd statement ever when it comes to gardening. It’s nature! Of course there’s always something!
Here in the Blue Ridge mountains of Virginia, we’ve had insect pests come and go, with each summer featuring something different.

Two years ago? Chewing up everything in the vegetable garden plus lots of perennials… Blister beetles!

Last year we had record rainfall, which brought out the gnats in gnumbers we’d never seen before. While not plant pests, they managed to take a lot of the fun out of gardening, hell-bent on clogging every facial orifice and nibbling on exposed flesh. Then the stinkbugs came. And stayed all winter long, keeping us company in the house.

This season goes down as the summer of Popillia japonica, the Japanese Beetle. Holy cow. I’m no entomologist (let’s ask Dr. Jeff!) so I can’t speak to how we got to this lowly place. But in any gathering of two or more local gardeners, The Beetle Issue will come up immediately.

Orgy in my beans! (NSFW)
Orgy in my beans! (NSFW)

There’s a ton of literature out there on life cycle, control, etc. They are a noted pest of turf, as the larvae munch away at the roots before emerging in early summer. I am not personally familiar with that aspect, as we don’t really have turf at our house; it’s a mix of white clover, orchard grass, broadleaf weeds, and some kind of fescue that that still make a decent green substance when mowed to 3.25″ (and viewed from a distance). If I come across grubs while pulling weeds or planting, I’ll call over a couple of hens to take care of business. Biological controls such as spores of bacterial Milky Disease and insect parasitic nematodes have been only marginally successful.

For adult control, the debate continue regarding the efficacy (and wisdom) of traps baited with floral or pheromone lures. “Hey there, neighbor! Mind if your Japanese Beetles come over to my place?” Most of the pesticides recommended in the literature are broad spectrum (pyrethroids, carbaryl, etc.) so, heck no on that count. Hand-picking them into a cup or bucket of soapy water to die a bubbly, fragrant death is an option for a small garden (and extremely patient gardener). Note chickens also enjoy the crunchy outer coating and creamy center; spiny, thrashing legs and all.

Back to our regional plight – they attacked the usual suspects – favoring anything in the Rosaceae family including brambles,apple, etc. Any kind of Hibiscus now looks like a lace doily. Veggies were indiscriminately perforated – the beans were especially hard-hit. All that beetle poop is especially unappetizing on chard. A big surprise was the Japanese or Fall-blooming Anemone. They took mine down to the stem. I am currently enjoying flowers on a stick.

There's an "Anemone" pun here somewhere..
There’s an “Anemone” pun here somewhere..

Both the Anemone and I will live, of course. But here’s the thing. One of the mantras that got us all through one of the coldest winters on record was “At least the bugs won’t be as bad this summer!” Ha, ha! If it’s not one thing, it’s another! Aargh.


Go here to download a PDF of the exceedingly-informative 20-page USDA APHIS Homeowner’s Guide to Managing Japanese Beetles

Does fertilization increase insect herbivores?

Always fun when you find a research paper that confirms what you’ve suspected all along.  I ran across a paper last week in the Annals of Applied Biology entitled  ‘Fertilisers and insect herbivores: a meta-analysis’ (Butler et al. 2012. Ann Appl Biol 161:  223–233).  I’m interested in the topic because in recent years a dogma has emerged that if you fertilize a landscape tree it will be immediately devoured by insects.   In this study the authors conducted a meta-analysis (basically a compilation of studies on a given topic and then combining and analyzing the aggregated results) and looked at dozens of studies of the response of insect herbivores to fertilization to answer the question, does fertilization increase insect damage?  The answer was absolutely no surprise to me: It depends.

 

What does it depend on? First, what type of insect.  Secondly, what kind of fertilizer. For example, fertilizing with nitrogen greatly increases populations of sucking insects.  This makes sense when you stop to think that aphids and other sucking insects have to consume a lot of phloem sap –which is essentially sugar water – in order to get sufficient nutrients.  Nitrogen fertilization did not significantly increase populations of chewing insects, however.  This could be related to off-setting effects of improved nutritional quality of leaves versus increased presence of defense compounds or leaf toughness.  For  other fertilizer elements Butler et al. found that phosphorus decreased insect populations in 2/3rd of the studies (14 out of 21) and that potassium decreased insects in 7 out of 10 cases. As with nitrogen only, complete fertilizers (NPK) tended to increase insect populations, especially for sucking insects.

 

I should hasten to point out some limitations of the study as it relates to tree fertilization.  First, of course, is the British spelling of fertilizer. Second, the study mainly dealt with fertilization in agronomic crops, not trees.  Lastly, the authors only included studies on insect adults.  In many cases insect larvae, not adults, are the most damaging life stage, especially for insects that affect trees.  Nevertheless, the study highlights the difficulty of making generalizations when discussing host stress and insect interactions.  In addition to type of insect and type of fertilizer, we could have added nutritional status of the plant before fertilization to the ‘It depends’ list.  My rule of thumb is that trees shouldn’t be fertilized unless a problems is noted by visible symptoms, a soil test, and/or a foliar test – and preferably by more than one of these.

 

Bottom line: Before you buy into the notion that fertilizing a tree is going to increase insect problems make sure you know what type of pest you’re dealing with, what type of fertilizer and the current nutrient status of the tree.

Aphids Marching

Was out enjoying the last of the SW Virginia fall color from our deck, the day before we got our dose of Sandy…the wind was picking up and the barometer and temperature were dropping

Twenty-four hours later, we had an inch of snow and 40 mph winds. No more fall color.
Looked down at the railing and the ENTIRE length of it – 45′ – had aphids streaming back and forth.  They were absolutely pouring off a Clematis terniflora vine (the same species that attracted all the blister beetles this summer – what a prize) that had clambered up over the deck. It was like two lanes of traffic, going in each direction, and at a (relatively) high rate of speed.  I’ve never seen aphids move so fast. But to where??



I believe it’s time to re-stain the deck.

We also had the interesting phenomenon of congregating swarms of lady beetles (the Asian species – Harmonia axyridis) a couple of weeks ago. The south side of the house and my Jeep were covered.  At least there’s an upside to that infestation – I’ve noticed lots of larvae around.

As you know, lady beetle larvae are very effective predators of aphids, and were out in full force amongst the aphids…I counted 30. But they couldn’t make a dent in the thousands of aphids streaming along the rail. Upon closer inspection, they were actually trying to avoid the aphids.  They had obviously had their fill and could barely move. I swear they looked nauseous.

“No thanks, we’re full.”
So – any thoughts on why the aphids were so active?

So that’s why they’re called blister beetles…

I’ve had several discussions with gardening folks in the region on one of our more annoying pests, the blister beetles.  Big appetite, eats lots of things we value, and darned hard to get rid of.  Someone invariable says “yep, they bite, too” and “be careful – you’ll get blistered.” However, I’ve yet to hear any first-hand experience with the personal-injury aspect of blister beetles.

I’ve suffered from the heartbreak of blister beetles for two summers in a row.  They’ve eaten ALL the foliage from the fall-blooming Anemone (leaving flowers on a steeck), badly damaged our chard and lettuce, and have turned their attention to the sweet-autumn clematis (Clematis terniflora).


Perp: Epicauta funebris (Margined Blister Beetle) – chock full of Cantharidin, a caustic terpenoid.

With nothing left but a mountain of bare stems, skeletonized leaves, and the occasional flower, the clematis was not adding to the general aesthetics of our home garden (unlike the 7′ tall poke weeds -whoops).  I began gingerly pulling the bazillion vines off the fence, but then thought of you (yes, you).  So what if one bit me or did whatever it does to cause a blister?   I could then speak authoritatively instead of “I heard…”

I went at the vines with gusto, gray and black beetles a-flying.  Sure enough, I mushed one against my arm in gathering up the vines toss in the cart.

Ouch.  First, a burning sensation.  Success! Then I watched with fascination as a bunch of welts popped out, at which point I ran and got my camera. The discomfort persisted through a couple of hours and a glass of wine. But by bedtime, my blisters were gone. No scars remain.


Oooh, lovely!

So there you have it. Yet another example of the things Garden Professors do – so you don’t have to!

A little about bugs

I’m not much of an entomologist.  (Okay, I’ve never had a single bug-related class.)  But I do appreciate insects in all of their bewildering shapes and behaviors.  And after this weekend I’ve become a little more entomologically educated.

I spent the weekend in Prescott, Arizona at the annual MG conference.  Besides meeting lots of great Master Gardeners (and Extension educators) in that state, I also met Dr. Whitney Cranshaw from Colorado State University.  He gave a keynote talk called “Gardening for Insects – or not!”  This was a seminar that presented positive and negative aspects of gardening for butterflies, honeybees, and other favorite insects.

Here are just a few of the nifty things Whitney had us consider:

  • Not all butterflies are nectar feeders; some prefer rotting fruit or dung.  Hmmm.  I might have to limit my varieties.
  • The caterpillars of some striking butterflies might need you to share some garden greens.  Larvae of black swallowtail butterflies eat parsley, fennel, and dill, for example.  Accepting damage on these plants will ensure a healthy population of adults for your viewing pleasure.
  • It’s best to accept some degree of pest insect presence, like aphids, to provide food for beneficial insects.  Insecticides are not part of a successful garden for insects.
  • The first bumblebees of the season are always small; they’re produced by overwintering queens whose resources are limited.  These new workers help gather more food, so that those produced later are larger.

Whitney has a fantastic collection of photos of insects, up close and personal.  Some of these are also in his book Garden Insects of North America (Princeton Press). It’s over 600 pages of full-color photos and engaging text.  Instead of being organized by family, it’s organized by feeding habit, so you can quickly look up and identify whatever weird bug you’ve found snacking on your snapdragons. There are sections on how to manage pest insects, and a chapter dedicated to beneficial bugs. 

 

Amazingly, this book is only $29.95.  I bought one.   

Finally, I have to recognize Dr. Cranshaw as one of an unusual breed of faculty.  He is passionate about educating adult audiences like Master Gardeners, and indeed his book is dedicated to entomology educators and the nationwide Extension system.  What a great resource for gardeners everywhere!

Getting Stung Can Be Fun!

Today I was reading a review of Amy Stewart’s new book Wicked Bugs and noticed the glee with which the reviewer noted that stings of various insects have been rated on a four point scale.  Having read Amy’s book I can wholeheartedly recommend it, but in terms of the stings I thought, what the heck?  Let’s see if I can impart some glee to our readers by taking a look at the pain that stings cause (I think it’s kind of like highbrow slap-stick).  So here is a brief review of sting science over the years.

First of all, scientists have known for some time that the pain of an insect (or spider) sting is not necessarily correlated with the amount of damage which the sting causes, so scales that have been used to assess the pain of insect stings do not necessarily correlate with the amount of damage done by the sting.  The stinging critter is not actually trying to kill the person which it stings (though stings may certainly kill smaller critters), rather, it’s trying to keep them away from itself and its family.

The first person in modern history to actually go to some trouble to figure out how badly a sting could hurt you was William Baerg who, from what I can tell, was dared by a colleague to get himself bitten by a black widow around 1923.  He did so, but since the bite didn’t hurt too badly he had the spider bite him again the next day.  After this second bite he recorded his reactions – including difficulty in breathing and talking.  Apparently a masochist, Baerg continued to allow himself to be stung by scorpions, centipedes, and tarantulas — supposedly in the name of science.  And here I’ve gotta say that, as a scientist, you need to set some limits.  Actually the stings must not have affected Baerg too badly – he lived from 1885 to 1980.

Following in the footsteps of Dr Baerg, another scientist, Justin Schmidt, has been sting by a tremendous variety of venomous insects (I’ve heard that it’s over 100 different species) and has actually developed a scale to sort out which hurts the worst.  The scale runs from 1-4 with a 4 being “debilitating” and 1 being a “spark”.  Apparently he never gets stung on purpose – but dang, you can’t be trying too hard to avoid the stings if you’ve got that many species on your “been there done that” list.

Dr. Schmidt published his first paper on the painfulness of stings in the early 1980s.  His work was soon followed by a paper published by Christopher Starr.  The name of this paper was “A simple pain scale for field comparison of Hymenopteran stings”.  This paper includes a list of insects and the level of pain which they cause with their sting – basically following Schmidt’s work – but Starr makes sure that he has at least two data points before he lists the pain which the insect causes.  He also makes a point of noting when the insect was induced to sting instead of having the sting just happen.  According to his chart he was stung by 34 (if I counted right) different insects, and of those stings only 6 were induced.  Obviously this guy didn’t take his work as seriously as Baerg or Schmidt!

Most of the stings that we’re accustomed to – bees and wasps – are around a 2.  There are a few at a level of 4 – probably the most notable is the bullet ant.

Starr ends the conclusion section of the article by listing 6 important rules for grading stings – I found them fascinating – so here they are:

  1. Reports should only be made by adult observers in good health.
  2. Disregard all stings accompanied by allergic reactions.
  3. Reports should not come from observers who are rarely stung.  This is to avoid mixing pain and novelty.
  4. Reports should be based only on events in which a very small number of stings are received at once.
  5. A ranking should never be based on just one sting.  Although individual social wasps probably sting rarely (I suspect that most never do), so that significant day-to-day variation in venom volume is unlikely, uncompleted or grazing stings are uncommon.  It is not known to what extent the regular use of the stinger by solitary wasps causes variation in venom delivery.
  6. Reports on stings received through free attack by the insect (volunteer stings) are preferable to those deliberately induced by holding her between the fingers or against the skin (induced stings).  We are not always so fortunate, though, to be attacked by those species of special interest……[deleted for brevity]

Insects and Fertilization

Linda got a few comments and questions on her post a couple of weeks ago on fertilization and insect resistance.  This is an issue I’ve been peripherally involved with over the years so I wanted to share a few thoughts.  First, the relationship between plant nutrition and insect resistance is extremely complex.  We often have difficulty predicting how a plant is going to respond to fertilization, let alone predict how an insect is going to respond to how the plant responded.  I haven’t kept up but Koricheva (2002) reported over a dozen different theories have been proposed to explain insect response to plant nutrition.  One of the factors that makes it difficult to generalize about plant/insect interactions is that various insects feed on different plant parts in different ways; some are leaf feeders, some suck sap, some bore into wood, some feed on seeds or cones.  How an insect feeds can affect its response.  To stick with an illustration I’m more familiar with, we can look at insect response to plant drought stress.  Bark beetles are widely known to key in and attack pines and other conifers under drought stress but pine tip moths prefer succulent buds and new growth and are more likely to attack well watered trees.  It’s not unreasonable to think there are similar differences with nutrition.

 

Nevertheless, as noted above, there have been attempts to come up with general theories on the effect of plant nutrition on insect resistance.  One of the most widely cited is the Growth-differential balance theory proposed by Dan Herms and Bill Mattson  (“The dilemma of plants: to grow or defend.”  Q. Rev. Biol. 67: 283-335).  A quick check on Google Scholar indicated this paper has been cited by over 1,400 other papers, which is an astounding number and speaks to its influence.  The basic premise of the theory, as suggested by the title of the paper, is that plants make a trade-off between allocating carbohydrates for growth or allocating carbohydrates for secondary defense compounds.  Dan Herms subsequently applied the theory in synthesizing the literature on woody ornamentals in his 2002 paper,  “Effects of Fertilization on Insect Resistance of Woody Ornamental Plants: Reassessing an Entrenched Paradigm.” (Environmental Entomology 31(6):923-933.).  I have heard some arborists and others use this paper to argue that we shouldn’t fertilize landscape trees at all.  The problem is they oversimplifying the theory – which is understandable, this is pretty heady stuff.  They get the ‘trade-off’ idea; if plants grow fast they produce lots of yummy stuff for bugs.  But what is often overlooked – even though Herms makes a point to say it – is that when nutrition or other plant resources are low; there is no trade-off.


This figure from Herms and Mattson illustrates the idea.  If nutrients are deficient and we fertilize a plant the plant may increase growth and secondary compounds; it’s not always an either/or situation.  The bottom-line remains the same;  nutrient deficient plants can benefit from fertilization or correcting the factors (e.g., alkaline pH) that made them deficient in the first place.

Koricheva, J. 2002. The Carbon-Nutrient Balance Hypothesis Is Dead; Long Live the Carbon-Nutrient Balance Hypothesis? Oikos 98 (3): 537-539