Creating a Bumblebee Habitat

Bumblebee on Astrantia flower
Bumblebee on Astrantia flower

Bumblebees Are Important Pollinators

Bumblebees are extremely important pollinators for agriculture both in the field and in greenhouses. Unlike honey bees, they are able to forage under cold, rainy, and cloudy conditions, so it is possible to see them in all kinds of weather. Even on an early chilly morning, you can see a bumblebee sleeping inside a flower blossom, waiting for some warmth to arrive.

The crops that bumblebees can pollinate include tomatoes,peppers, raspberries, blueberries, chives, cucumbers,apples, strawberries, alfalfa, blackberries, soybeans,sunflowers, beans, cherries, apricots, plums, almonds,nectarines, peaches, rosehips, eggplants, and cranberries.

Bumblebee on flower

Bumblebees are also extremely important pollinators of many flowering plants and are generalists, which means they pollinate by visiting hundreds of flowering plants.

Bumblebee Declines
There is evidence that in North America some of our bumblebee species are declining and a few are threatened with extinction. Species that seem most  vulnerable are those with smaller climate tolerances, those at the edge of their climatic niches, and later emerging species. Many species in North America and around the world, are declining at a rapid rate.

Threats

Most bumblebees nest in underground nest, or old logs or crevices. You can help the bumblebees come to your property and nest by providing a ready to move in nest, just as you would to mason bees.

I have mason home plans at Home Sweet Home for Mason Bees.

A ready to move in mason bee house
A ready to move in mason bee house

Ground Nesting

Since most bumbles nest in the ground or a dry, dark cavity, you can provide a simple ground nest with a clay pot, a saucer, some straw, piece of chicken wire, and a short piece of garden hose for an entrance. The low-flying zig zag flight of a nest-site searching queen can be seen in the spring and is very distinctive.

A mature nest of a bumblebee can contain up to 400 residents, as compared to 50,000 to 80,000 honeybees, so the nest is quite small. It should be located in the shade in a dry location. The straw used preferably should be obtained from a mouse’s nest, as a queen will be attracted to the smell. For complete instructions and diagrams, go to Hartley Botanic.

Overturn a pot and on the drainage hole on top, place a small saucer propped up so a bee can exit, but weather is kept out
Overturn a pot and on the drainage hole on top, place a small saucer propped up so a bee can exit, but weather is kept out

When Not to Kill a Hornworm

Hornworm on a pepper plant leaf

 

Tomato Hornworms are really big green caterpillars that can munch through and devastate your vegetable  garden. Giant brown moths lay pearl-like eggs on your tomato, pepper, or eggplant,  from which the big green monsters will hatch and start to eat voraciously. The juicy grass-green caterpillars can strip a plant overnight and then start demolishing the fruit.

Tomato hornworm on tomato plant

Frass & Defoliation

Most of the time I spot the signs of a hornworm before I see the actual caterpillar. The first things you will notice about a hornworms presence is denuded branches and fruits with huge sections eaten out of them. Hornworms love to eat foliage and since they are such large caterpillars, they have a big appetite which means they poop alot. Another sign is bits of frass (droppings) on the lower leaves or on the ground which are black.

Getting Rid of Hornworms

Handpicking is the best way to get rid of these nasty green monsters, but I avoid touching them. With repulsive juicy caterpillars, gloves are the best option as the caterpillars usually have a death grip on the foliage and they are difficult to pick off. Once free, I stomp on these gross pests. Or feed them to the chickens for a juicy treat!

Beneficials

Beneficials are just that: Insects that are doing their job and preying on other harmful insects that makes your job a bit easier. For example, preying mantis’s will hunt and devour lots of insects that will hurt your ornamentals and vegetables. Leave them alone to do their job!

 

So if you spot these little white worms sprouting out of the hormworm caterpillar, you do nothing as nature has taken care of it for you. These soft white growths are actually the cocoons of a special parasitoid wasp a species of braconid wasp. The adult female wasp uses her ovipositor to lay eggs just under the skin of the unlucky hornworm. As the eggs hatch, the larvae feed on the hornworm’s insides, eating the hornworm alive.

You can see a tiny wasp that just hatched out of a cocoon

Larvae chew their way through the host skin when they mature and make a cocoon. which hatches into a tiny wasp. The wasps are usually dark with four transparent wings and rarely over one-half inch long. Their size and the fact that there are over 15,000 species make them difficult to notice, much less identify. So these tiny wasps are doing you a favor and killing the hornworm caterpillar by using the body as a hatching ground for their young is kind of like ‘meals on wheels’!

This is the moth which lays the eggs on foliage that will hatch into hornworms-from Wikipedia

Each cocoon will hatch a new wasp which will lay eggs in more hornworms that are eating your veggie garden, so leave them alone!

 

See this fascinating video below to see the wasps hatching out of these cocoons.