Running through care sheets and discussions on many websites (eg. 1) and even reading some books (eg. 2), you will find many recommendations against feeding bees and wasps to chameleons with sometimes very strange recommendations like removing the stingers or absolutely excluding them from diet and alarming about their being life threatening.
Now, what is the reality?
The research on chameleon food in the wild is rather scarce and does not give us yet a complete picture on their food composition (3) but there are lots of unpublished data and observations, that confirm one:
For many species, the hymenopterans are a crucial part of their natural diet, at least seasonally.
Pleguezuelos et al (4) reports on Chamaeleo chamaeleon feeding predominantly on bees and wasps.
I have done hundreds of fecal samples of wild Yemen chameleons (Chamaeleo chamaeleon), Meller's Chameleons (Trioceros melleri), Panther chameleons (Furcifer pardalis), Oustalet's Chameleons (Furcifer oustaleti), Socotran Chameleons (Chamaeleo monachus) and Arabian Chameleons (Chamaeleo arabicus- attached photo of fecal sample analysis): all they are full of bees and wasps, often comprising over 80% of all food analyzed both quantitatively as well as qualitatively.
There are reports of colleagues like Katrin Pawlik: "This pregnant Chamaeleo chamaeleon, I found in Andalusia / Spain in a flowering Manukka tree ate more than 40 wild bees while I watched her." (5)
And, there is video (6,7) and photography evidence (attached) of chameleons feeding on bees and wasps.
What is their nutritional value?
Well, the body as such is very light as they are flying insects and is not highly nutritional itself, but it has lots of indigestible parts and therefore it is quite good for forming the gut content and passing it through the extremely short chameleon intestine. But the great value added is the pollen, with which the bees are all dusted and the pollen pellets they wear on their legs! Additionally, they are gut-loaded by nectar and the bee bread which is a fermented mixture of pollen, honey and bee wax, which they eat in the hive. So their bodies are containing lots of sugar, and every single vitamin, every micro-element, every amino acid and even bactericide substances.
Wasps of many kinds are hunters and feed on both vegetarian food as well as bodies of animals. This way, they can be one if the few options how a processed vitamin A gets into the bodies of chameleons, as the rest vitamin A they ingest in the form of carotenoids, it means, pro-vitamins and their ability to modify it into its active form seems to be limited.
So, bees and wasps are absolutely fantastic feeders!
Do the chameleon get stung by the bees or wasps?
I have no evidence of any single sting in my 30years practice of breeding them in thousands and I do feed with bees and wasps. The only case I have seen in years was an unfortunate case when a captive young Calumma brevicorne packed a carpenter bee of a very big size (exceeding head length), it was stung into the head and died. But this was due to inadequate size of prey.
It is obvious, that bees and wasps are perfectly normal and natural food source for most chameleons. They have a very rapid strike and crunch feeding behavior, designed to rapidly incapacitate them without being stung.
Why is it they do not get stung?
IMHO it is a combination of several factors
1. Surprize (the prey is shocked and need some time to consolidate and react and it looses time for reaction until it is too late)
2. Speed (the retracting of the tongue happens slowly than projection, but anyway, is rather quick, so before the prey can react, it is crushed with the jaws)
3. Mechanical demolition (once in mouth, the prey is crushed and looses the capability to sting)
4. Hardness (the areas on head around mouth are hard so even if they want to sting, they merely can, itnis full of hard keratinous scales)
5. Size (usually the size of the prey is much smaller than the mouth length and itnis overpowered easily)
6. Evolutionary experience (it is obvious that an animal will develop tricks and techniques how to avoid a sting from the most or one of the most frequent prey items)
What about the poison?
The bee poison (Apitoxin) is a colorless transparent bitter substance with hemotoxic and cytotoxic properties, consisting of proteins.
So, it is denaturated by digestion enzymes, it means it is modified to a non-toxic product, which is then normally digested along with the remaining gut content. The content of toxic substances in the poison of other hymenopterans is diverse, but all are analogically protein-based.
So, is it OK to feed bees to chameleons in captivity?
It is technically OK, as it is natural and normal.
However, bees experience now a drastic decline of their populations globally, which is a real issue, as the ecosystems are globally deeply dependent on bees as pollinators, so some might argue about their protection and be against feeding them.
Anyway, there are harmless approaches neutral to bee populations, such as to feed old bee workers at the end of their lives or drones, that are after having fulfilled their privileged role in the Queen's harem mutilated and chased out of the hive to die.
A great alternative is to set up a beehive (or several - I have 3). One contains on average around 50.000 bees, which is enough to feed 100 chameleons for about half a year if they would not eat anything else.
Also, the influence of wild chameleons on the bee populations being their predators is really minute, as a simple calculation may reveal.
Any other complications?
We often live in heavily modified landscape full if industrial and agricultural pollution, fertilizers and even insecticides or pesticides in general. So, in such areas, the bees can be of course contaminated with these pollutants and it is advisable to abscond from feeding them.
What are the dangers for keepers and breeders?
Nowadays lots of people have allergies and the allergy on bee and wasp poison is quite common. So, before handling bees and wasps, be aware of your health state and abscond from it when too risky...
To summit up:
Bees and wasps are fantastic food items and you can easily use them as a part of the diet of chameleons.
4. Pleguezuelos, J.M., Poveda, R., and Ontiveros, D. 1999. Feeding habits of the common chameleon, Chamaeleo chamaeleon in the southeastern Iberian Peninsula. ISRAEL JOURNAL OF ZOOLOGY. 45:267-276