June 2026
Microplastics are virtually everywhere in the environment. They are deposited in nature from the incorrect disposal of waste such as plastic bottles and food wrappers, carried by runoff, eventually travelling through the air and landing on flowers. Unsurprisingly, these tiny pieces of plastic impact the bees in multiple ways. When consumed, the particles attach to pollen and gut bacteria, impacting overall weight and survival rate. New research also shows that when these microplastics reach the brain, they can affect learning and memory. Much of the research revolves around polystyrene, so perhaps we should be looking at other beehive materials.
We often hear about the wonderful effects of supplements for the bees. It's clear that the effects of some of these are truly impressive. However, there are some disappointing results from Slovenian researchers in their paper "An Assessment of the Impacts of Feeding Four Fungal Extracts
on the Lifespan and Midgut of Newly Emerged Carniolan Honey Bees". They fed young bees various extracts of fungi and found that it didn't make a blind bit of difference to the bees. The result was that the pampered bees were exactly the same as the untreated bees. Yet another reason to ask anyone touting a miracle cure to show you the research supporting their claims!
on the Lifespan and Midgut of Newly Emerged Carniolan Honey Bees". They fed young bees various extracts of fungi and found that it didn't make a blind bit of difference to the bees. The result was that the pampered bees were exactly the same as the untreated bees. Yet another reason to ask anyone touting a miracle cure to show you the research supporting their claims!
A very interesting new study, "A review of the mechanisms of acaricide resistance in Varroa destructor affecting honey bees", looks at how Varroa destructor manages to develop immunity to treatments. Those who have been keeping bees for a while will remember how Flumethrin, the active ingredient in Bayvarol, stopped working a few years ago, and now we hear the mites have developed resistance to Amitraz, as found in Apivar, in both the USA and Australia, so it can't be long before it's an issue here. The same has happened for Coumaphos and tau-Fluvalinate, although these were never approved in Ireland. While genetic factors are critical, allowing the mites find an alternative for whatever the treatment targets, we beekeepers are the ones supporting this resistance. The key error is using only a single medication all the time - this supports the mite's efforts to develop resistance. The good news is that no resistance to organic treatments like Oxalic acid or Thymol has emerged, at least not yet. So remember to alternate your treatments to ensure that the mites don't get a chance to pass any resistance on to their offspring.
Currently there are concerns about our ability to produce enough food to feed the world. We know that bees are excellent pollinators and part of their work involves supporting the production of food. The article "The impact of pollinator diversity on the productivity of Lablab purpureus (L.) sweet, an underutilised legume crop" looks at two aspects of food security, particularly in developing countries. While some crops are well-established food sources, this looks at a legume species that is usually overlooked, despite it being a good source for protein. Interestingly, carpenter bees were twice as good as honey bees at pollinating the crop. When wind-pollinated, the return was an uninspiring 170kg per hectare, but when bees were involved this jumped to a surprising 1400kg/ha. This huge 8-fold improvement emphasises the critical role bees have in providing us with food.
It's common for pesticides to indicate the LD50, the dosage at which the treatment is lethal to 50% of the population. The article "Sublethal dichlorvos exposure induces cytogenetic damage in Apis mellifera hemocytes" looked at a particular organophosphate pesticide to see how it affected bees. It turns out that the LD50 is 10µL/L but they went further and examined the impact of a sublethal dose of the treatment. It turns out that the bees are indeed seriously harmed by what should be an dose deemed safe by the pesticide manufacturer: they found extensive genetic damage to the bees. The conclusion is that any research into the effects of new products must include the impacts of sub-lethal doses.
In this month's American Bee Journal, Randy Oliver writes about how he found that testing bees for oxalic acid gave him some weird results, turning the test solution blue rather than green. It turns out the culprit is venom. Apparently some workers and queens are into "venom bathing", where they essentially coat themselves in venom. The anti-bacterial properties of venom are well known, but bees who are struggling with Varroa apply more venom, and it seems to help keep the mites at bay. So if we have bees that practice uncapping and bathe in venom, we may have bees that are super-tolerant of Varroa. As Randy says "This calls for more research"!