Category: educate

educate

Stop calling it the “murder hornet”

Recently, news outlets have been spreading fear of the “murder hornet” invading the United States. To be clear, the “murder hornet”, actually known as the Asian giant hornet (Vespa mandarinia), does not pose a direct threat to humans. While a sting from this hornet may hurt, Asian giant hornets are generally not aggressive unless provoked. Stinging is a form of protection, and like any stinging insect, the Asian giant hornet is not out to sting you.

Instead, Asian giant hornets are after much smaller prey: honey bees.  Asian giant hornets are carnivores, meaning they feed insects to their developing young. A honey bee colony, with tens of thousands of bees, is a great place to collect protein-rich food. In one foraging trip, one Asian giant hornet can kill up to 40 honey bees! As you might imagine, a whole colony of these hornets could be fatal to a honey bee colony.

In their native range of eastern and southeastern Asia, Asian giant hornets have been predating on Asian honey bees (Apis cerana) for a long time. In response, Asian honey bees have adapted a defense strategy: heat. When the hornet invader is detected, worker bees sound the alarm by shaking their abdomens. Then, in a swift, coordinated response, hundreds of honey bees swarm the hornet and contract their flight muscles, generating intense heat. Together, the worker bees heat the hornet to about 117 °F, killing the intruder. As it happens, the hornet can only withstand temperatures up to 115 °F, while Asian honey bee workers can withstand temperatures up to 118 °F. Evolution is a beautiful thing.

Sterile female worker bees perform all the tasks in the colony, including taking care of the queen (white paint mark) and defending the hive from intruders.

But, the Western honey bees (Apis mellifera) that are managed in North America have not evolved with this predator and are not as well equipped to defend themselves. This is why we need to be worried about the Asian giant hornet. Managed honey bees provide valuable economic and ecosystem services such as beekeeper livelihoods and agricultural pollination—the Asian giant hornet jeopardizes the security of these services.

While this is certainly cause for concern, panic is unwarranted. Since August 2019, the Asian giant hornet has been spotted just three times in Washington State and three times in British Columbia. Following a recent report of a honey bee colony death that resembled the work of this hornet in Washington (although it is unconfirmed), Washington State Department of Agriculture entomologists are on the hunt to stop the hornet before it spreads.

Fortunately, Asian giant hornets have not been spotted on the east coast, and it would likely take a while for them to get here. As with any introduced species, however, attempts should be made to spot the hornets early on. If you think you have seen an Asian giant hornet in Massachusetts (which is currently highly unlikely) you can report a sighting to the Massachusetts Introduced Pests Outreach Project.

Identifying Asian giant hornets: The European hornet (Vespa crabro) is often confused for the Asian giant hornet. There are three main differences between these hornets:

  1. Size The Asian giant hornet is slightly bigger than the European hornet (photos not to scale, enlarged for detail).
  2. Stripes The Asian giant hornet has regular black-orange stripes along its abdomen; the European hornet has irregular brown-yellow stripes.
  3. Head The Asian giant hornet has an orange head; the European hornet has a golden yellow head.
LEFT: Asian giant hornet, Washington State Department of Agriculture, Flickr
RIGHT: European hornet, Chris Moody, Flickr

To learn more about the Asian giant hornet, please read this USDA report instead of news articles. To learn more about how you can help mitigate the establishment of introduced species in general, check out these resources:

educate

Return of the honey bees

Isaac Weinberg

To watch my honey bee spring inspection click here!

Spring has sprung, and the bees and butterflies have begun their return to Medford. If you’re like me, you may have wondered why insect pollinators were gone in the first place. Cold temperatures and lack of flowering plants make New England winters an inhospitable place for insects, yet year after year they return. Different species use different strategies to get through the winter months. Monarch butterflies dodge the cold by migrating south for the winter. Bumble bee queens sleep through the winter in subterranean burrows. Other insects lay eggs in fall that remain dormant in winter and hatch in spring.

Honey bees are unique in that they are the only insect pollinator that is awake and active throughout the entire winter. They are able to do this because of their massive colony size of up to 50,000 bees. Honey bees bunch up in their hive like emperor penguins and spend all winter shivering by flexing their wing muscles to keep their hive warm. Even in the coldest months of winter, honey bees can keep the temperature of their colony above 90 degrees Fahrenheit! In order to have energy to shiver all winter, honey bees hoard pounds of honey and pollen in the summer and fall which they eat for energy over the course of winter.

a Varroa mite (visible in red) feeds on the fat body of a developing bee.

Recently, overwintering deaths of managed honey bee colonies in the US has been incredibly high, with almost 40% of colonies dying each winter. Over the winter it is very difficult for beekeepers to directly help colonies, since opening a hive and exposing it to the cold would be incredibly damaging. Because of this, many beekeepers to take an active hand in helping their bees in the early spring. The first cool days in spring are very dangerous. They have likely consumed all their food stores and, with few flowers yet blooming, there may be no way for them to restock. Spring is also when there are is an explosive increase in populations of Varroa destructor, a parasitic mite that latches on to honey bees and eats their fat bodies. In the spring it is often critical for beekeepers to supplement the nutrition of their colonies, and keep the mite population under control in order to have strong healthy hives during the year.

Honey bees get most of their nutrients from different flower products, they collect sugar rich nectar to make honey which adult bees use as their main source of energy, and protein rich pollen which is fed to larvae to help them grow. In order to help supplement the diets of bees, beekeepers can feed their colonies sugar solution, and synthetic pollen patties. One type of pollen patty is made using bee collected pollen and mixing it with a 1:1 sucrose:water solution until it has a clay like consistency. In the absence of pollen, other supplements like yeast, protein powder, and eggs can be mixed with sugar water to create patties. Patties can then be made available to the bees by simply placing them in the center of the beehive.

A pollen patty wrapped in freezer paper and placed in the center of a honey bee hive.

Next, many beekeepers treat for the mite Varroa destructor. Varroa is one of the biggest contributors to honey bee decline in the United States. The mite latches on to honey bees and feeds on their fat bodies, draining nutrient reserves, and spreading disease throughout a colony. The mites primarily target honey bee larvae, and reproduce by laying their eggs directly on honey bee brood. As honey bee colonies begin to rear large amounts of brood in spring mite populations also increase exponentially. For this reason, it is important to treat for mites before a colony begins its spring uptick in brood rearing. There are many ways beekeepers treat for Varroa, which vary both in their efficacy combatting Varroa and in their lethality to the honey bees themselves. One of the most common treatments are Apivar strips because they are easy to use, relatively benign for the honey bees, and deadly to the mites. The strips can be easily hung in a honey bee hive and paralyze mites, preventing them from feeding. Because the active ingredient in Apivar is an arachnicide, it acts on the spider-like mites without causing excessive harm to the honeybees, and also does not linger for long in the hive once removed.

Though winters are an energetically demanding time for honey bees, and the early days of spring can be dangerous with temperature fluctuations and limited flowers (especially in New England where we get snow in April!), beekeepers can take an active hand in ensuring colony success. By supplementing food in early spring, treating colonies for mites, and being careful to leave some honey for the bees during fall collections, beekeepers help their colonies start the year on a strong footing and remain healthy and productive all year round!