Do you ever sit around in the grass and watch how bees fly by, hopping from flower to flower and happily buzzing to and fro?
I sometimes do. And sometimes it strikes me how good they look. Nice wings with patterns and a sharp defined edge. Nice striped coats on their fuzzy bellies. Beautiful bags stuffed with colourful pollen. Cool skinny little legs and black shiny eyeballs. They look like they are on a mission and it looks good. They seem to know exactly what they’re doing and their bodies seem perfectly designed to make their purpose in life come true.
I recommend to click on this photo
Until you see a sick bee.
Until you see that a bee comes home to a hive that is stuffed with sick, mutated larvae.
Until you see a hive that is destroyed by mice, moths, beetles or the freezing cold.
In my previous post I’ve fully concentrated on a fatal bee disease: AFB. But, you might have felt it in your gut, this was not a complete story. Unfortunately, there are lots of other things that threat our precious bees. From freezing to death to starving to death to being chewed by pests or being poisoned by pesticides.
In this post I’m concentrating on two Hot Topics: Varroa Destructor and the mysterious effects of pesticides on bees.
Varroa Destructor is a Parasytic Mite Syndrome. At the moment varroa is one of the greatest reasons for hive loss in New Zealand, and it is also the reason why it basically impossible to be an organic beekeeper these days.
Varroa is not a disease, it is a mite – a pest, a parasite. It’s a little creature that chews on the bees and deforms them.
Mmm yum yum, chew chew, says the happy mite.
The bees die in agony.
This it how it works.
Varroa life cycle
- The varroa jumps into the brood cell during the larval stage of the bee. It jumps into the brood food. There it waits until the larva matures and stretches out. When ready, it emerges from the food and climbs into the larva by chewing a hole. The larva is bleeding. It establishes a feeding station anywhere inside the larva that suits it, and starts laying eggs.
- The first egg that hatches is always male, all the following ones are female.
- They all form their own feeding station and chew away.
- They eat body fluids, and while chewing they deform the brood.
- Often the bee simply dies and doesn’t emerge.
- The more the brood gets chewed the less survival chance. The consequence is less vigour in the hive.
- When workers chew cap open varroa comes out of the cell and spreads.
- The length of the varroa life cycle depends on the bee life cycle. Male drones take longest to emerge from their cells (24 days, whereas workers take 21 days and queens only 16). The longer they take to emerge, the longer the mite can chew and live. This is why the mites prefer drones (And this is also a reason for some beekeepers to scrape away drone cells from the hive)
Currently bees are being genetically selected to improve their hygienic behaviour. This would improve their ability to clean out the mite out of their cells, and hopefully will contribute to eradication of the pest.
Yet, before we get to that stage the most common solution for now is suppressing the mite is by a non-organic chemical treatment. Special Varroa strips are often used. Mites that have emerged from cells and start spreading throughout the hive, are the ones we can kill off. And it has proven to be successful.
The treatment we choose depends on the scale and type of our apiaries. There is a lot of discussion between commercial, organic and hobby beekeepers. Some organic beekeepers suppress the mite with organic chemicals like oxalic and thymol. Also, hobby beekeepers with hives on a small scale might choose more natural and labour-intensive ways of dealing with varroa. Some of them have been successful, others haven’t been.
The common treatment
- There are two different chemical groups for varroa strips
- You need to keep on changing between chemical groups, otherwise the mites develop resistance against the strips.
- As soon as you take strips out of the hive, varroa starts winning the battle again. But you can’t leave the strips in continuously either. They should be removed in winter and when you’re going to harvest honey. The chemicals aren’t good for human consumption. (It may sound dubious, but it is fine to feed bees “chemical honey”…..)
- Mind you: bees hate the strips. They will move away from them. The queen is likely to not relay her eggs in the area where the strips are. The longer you leave strips in the same place, the more effective the bees get in avoiding them. This is why you need to keep on moving them around inside the hive, every 6 weeks or so.
It’s not all doom and gloom. For the region where I live, Otago, New Zealand, there is a hopeful prospect. It gets very cold in winter and therefore there is the possibility that not every hive will have brood all year round. This increases the chances you kill off varroa in winter when you have been treating your hive with chemical strips.
Does this mean we should embrace the use of pesticides in beekeeping practices completely?
There are many other pesticides out there, some of them are frequently used in agricultural practices with beehives. One important group of pesticides is called neonicotinoids. They are used for a wide variety of common seeds: grass seed, rye, maize, squash, sweet corn, pumpkin and brassicas. A lot of people don’t even relate the use of plant pesticides to the welfare of bees. The plants get sprayed for “better” crop yields; and the bees help pollinating the crops. No worries?
This is a pressing topic that urgently needs more attention.
Various articles have been published and speculate about mysterious hive losses. Bees feed from the flowers of these neonicotinoid-sprayed plants: the pesticides work their way up from the seed, through the plant, into the pollen and nectar. In other words: the bees feed on (small doses of) poison. The poison attacks their central nervous system and causes disoriented behaviour.
And there are many other types of pesticides of which the effects on bees haven’t been properly researched yet. They could be highly toxic . They might reduce their immune systems, which makes them more susceptible to external threats and diseases………..
Could this be one of the reasons why we lose so many hives?
Let me know what your thoughts are, feel free to comment!
Information about pesticides obtained from Organic NZ, March/April 2013 Vol.72 No.2. The first three photos in this post kindly retrieved from Wikipedia