Tag Archives: Nathaniel Walton

Insects that look like bees

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Figure 1. Hover fly with few hairs. Photo by Veronica Calles-Torrez, NDSU

By Veronica Calles-Torrez, North Dakota State University (NDSU); Esther McGinnis, NDSU; Patrick Beauzay, NDSU; Nathaniel Walton, Michigan State University Extension; Joy Landis, Michigan State University; Janet J. Knodel, NDSU


Editor’s note: This article was a joint collaboration between North Dakota State University and Michigan State University Extension.


Everyone knows that bees love to visit flowers, but not everything that you see visiting flowers or buzzing around the garden is a bee. In fact, many insects imitate bees in order to avoid unwanted attention. Whether you call them “bee-mimics,” “wanna-bees” or “yellow-stripey-things,” most are beneficial helpers in our yards and gardens. This brief guide will help you tell some of these insects apart.

Flies

Figure 2. Hairy honey bee (Apis mellifera) on sedum. Photo by Veronica Calles-Torrez, NDSU

Some flies, especially hover flies and bee flies, can be mistaken for bees because their body form, color and hair patterns, buzzing sounds and behaviors mimic bees. Flies have a set of front wings (forewings), but the hind wings are small, knob-like balancing organs called halteres, so flies appear to have only two wings (Figure 1, red circles). Bees have well-developed forewings and hind wings.

Figure 3. Hover fly. Photo by Veronica Calles-Torrez, NDSU

Flies have large compound eyes that occupy most of the head, while bees have narrow compound eyes on the sides of the head. Most flies that resemble bees have short, three-segmented antennae, while bees have longer, cylindrical antennae of 12 (female) or 13 (male) segments.


Some flies, especially bee flies, can be hairy like honey bees (Figure 2), bumble bees and digger bees, and can hover and move quickly from flower to flower while foraging, just like bees. Flies do not sting people.

Hover flies (Family: Syrphidae)

Figure 4. Bee fly. Photo by David Cappaert, Bugwood.org

Several hover fly species (Figures 1 and 3) resemble bees in coloration, behavior and size. Most hover flies are 5 to 15 millimeters long and have large heads with reddish or marbled black eyes, two clear wings and black and yellow color patterns on the abdomen and sometimes on the thorax. Some hover flies are quite hairy while others are not.


Hover flies buzz and hover like bees around flowers. They feed on pollen and nectar, often using the same flowers that bees do. Some hover fly larvae are aphid predators and provide biological pest control.

Bee flies (Family: Bombyliidae)

Figure 5. Paper wasp. Note the waist between the thorax and abdomen. Photo by Veronica Calles-Torrez, NDSU

Bee flies (Figure 4) are about 7 to 15 millimeters long and have stout bodies covered with yellow, black or brown hairs. Different species can have transparent or patterned wings. Bee flies have a long proboscis (tongue) and feed on pollen and nectar.

Wasps

Figure 6. Honey bee collecting pollen from aster flower. Note the pollen basket on its hind legs. Photo by Veronica Calles-Torrez, NDSU

Similar to bees, wasps have four developed wings, long segmented antennae and a distinctly visible narrow “waist” (Figure 5) due to a constriction between the thorax and abdomen. Bees also have a constricted waist, but it isn’t readily visible. Wasps are much less hairy than most bees (Figures 2 and 6). Wasps’ hairs are not branched, while bees’ are branched, but you will need a microscope to see this.


Most bees have special pollen-collecting hairs on their hind legs and collected pollen is easy to see (Figure 6). Leaf-cutting bees collect and carry pollen on hairs underneath their abdomens. Also, wasps have brighter colorations and patterns, and wider range of color and pattern variations than bees.

Yellowjackets, hornets and paper wasps (Family: Vespidae)

Figure 7. Eastern yellowjacket. Photo by Jon Yuschock, Bugwood.org

These insects are strikingly patterned with black and yellow. They hold their wings folded lengthwise over their bodies like a jet. Yellowjackets (Figure 7) are approximately 12 to 25 millimeters long. Their face is mostly yellow, except for black eyes and black antennae. Yellowjackets have yellow and black bands on the abdomen and usually nest in the ground.


Paper wasps (Figure 5) are approximately 25 millimeters long with black, yellow and sometimes orange markings. Nests are constructed of paper, often underneath house eaves.

Figure 8. Bald-faced hornet. Photo by Johnny N. Dell, Bugwood.org

Bald-faced hornets (Figure 8) are black with white markings and are about 15 to 25 millimeters long. The tip of the abdomen often has white markings. Nests are constructed in trees and sometimes roof peaks. Bald-faced hornets are usually aggressive and sting when their nests are disturbed.


Cicada killers (Family: Crabronidae) (Figure 9) are large wasps 20 to 50 millimeters long. They have a yellow face brick-red eyes and a black abdomen with yellow bands. Wings are lightly infused with brown and the legs are red. As its name implies, Cicada killer wasps prey on cicadas. They do not have nest guarding instincts like wasps and honey bees. These impressive looking wasps are not aggressive, but females do have stingers and can sting when they feel threatened.

Figure 9. Cicada killer wasp. Photo by Johnny N. Dell, Bugwood.org

This article was published by Michigan State University Extension. For more information, visit http://www.msue.msu.edu. To have a digest of information delivered straight to your email inbox, visit http://www.msue.msu.edu/newsletters. To contact an expert in your area, visit http://expert.msue.msu.edu, or call 888-MSUE4MI (888-678-3464).




Why are all these bugs appearing on the side or inside of my home?

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By David Lowenstein and Nathaniel Walton, Michigan State University Extension


As the shadows lengthen and days get shorter, we start to see some six-legged friends sneaking around our windows, eaves and soffits. This is a good time for a reminder about just who some of these insects are and how you can tell them apart. The fall invaders are all just following their natural inclination to seek an out-of-the-way resting place to spend the winter. Unfortunately for all parties involved, what happens next is anything but natural. The exterior side walls of our structures provide a very attractive array of nooks and crannies for these critters to sneak into. The problem is that these nooks and crannies often lead into the interiors of our human dwellings.

Who are the insects on the side of my home?

Three of these fall invading species in Michigan are all closely related insects in the order Hemiptera (true bugs). They are the boxelder bug, brown marmorated stink bug and western conifer seed bug (Table 1). It is possible to find all three on the outside of structures in late summer or fall.


Of these three insects, brown marmorated stink bug is the newest arrival to Michigan and the only one that is a garden or agricultural pest, according to Michigan State University Extension. Often confused for a stink bug, western conifer seed bug is less common than brown marmorated stink bug and typically remains unnoticed until fall. Boxelder bug is a native Michigan insect that can be quite abundant in some parts of Michigan in certain years. Boxelder bugs are not garden pests, but they can be a nuisance in homes simply due to the sheer number of them that can accumulate on windowsills and in attics during winter.


In case you are unsure whether the insects in your home are brown marmorated stink bugs, Photo 1 and Table 1 will help tell them apart. The shape of their hind legs, overall body shape and color can be used to differentiate these three fall invaders. Additional information on managing brown marmorated stink bug can be found on the Stop BMSB website.


Like many of the other insects in the order Hemiptera (true bugs), these bugs have a piercing sucking mouthpart and are capable of using it in self-defense. In other words, handle them with caution. None of these insects transmit any disease or sting. They also will not reproduce in the winter. Their presence is restricted to being a nuisance. In severe cases, high numbers of these bugs may stain furniture through external secretions.

Asian lady beetle
Photo 2. A multicolored Asian lady beetle (Coleoptera). Another common invader of structures in Michigan. Photo by Nate Walton, MSU Extension.

A fourth fall invading insect worth mentioning is the multi-colored Asian lady beetle (Photo 2). These beetles spend their summers eating aphids and other pest insects in our crop fields. In the fall, they can form large aggregations on the sides of structures as they look for a place to spend the winter. 


Unlike the three insects mentioned previously, multi-colored Asian lady beetles are beetles (Coleoptera), not true bugs. Asian lady beetles can bite but cannot spread disease. They also emit defensive secretions that have a slight odor, can stain fabrics and in rare cases have been known to cause allergic reactions.

What causes these insects to aggregate?

The summer months are a time when insects are active in gardens, trees or shrubs. As daylight lessens, insects undergo a physiological change known as diapause. This is characterized by an extended time of inactivity during which they do not reproduce and eat little or nothing. In their natural habitat, these insects spend winter beneath bark.


Stink bugs begin to aggregate on the sides of buildings and structures when there is less than 12.5 hours of daylight, approximately the second or third week of September in Michigan. South and west facing walls are most susceptible to large populations. They particularly move towards garages, sheds and sidings with small spaces or gaps that are protected from the weather. For several weeks in the fall, stink bugs and other aggregating insects may attempt to enter homes in search of a winter environment protected from moisture and cooler air temperatures.

How can I keep them out of my home?

During fall, search for spots on the outside of the house with gaps that are wide enough for insects to enter. These areas can be covered with wire mesh, screens or caulk. Window air conditioning units should be checked for gaps and covered. When there are hundreds of swarming insects on the outside of a home, leave the windows closed or check for gaps in the screen. A strong force of water can knock insects off exterior walls.


On homes with severe outbreaks, a pyrethroid insecticide can be applied to the foundation or siding. This will only kill insects that contact the insecticide and is not an effective long-term strategy. Since these fall-invading insects can fly up to several miles, it is likely more will return on the next warm day. When smaller numbers are present inside or outside, the insects can be knocked into a bucket of soapy water, vacuumed up or just left alone.

What can I do once they get inside?

Indoor trap for stink bugs
Photo 3. Indoor stink bug and boxelder bug collection trap. Photo by David Lowenstein, MSU Extension.

The best way to control indoor nuisance pests is through removal or exclusion. Inside homes, stink bugs are attracted to light and may fly towards light fixtures, resulting in an annoying buzz. A homemade light trap with light shined into a foil pan containing unscented dish soap and water can provide relief at killing stink bugs already inside the home (Photo 3). It is not recommended to apply insecticides to overwintering insects that are already inside your home. The chemicals will only kill insects that make direct contact and will not prevent additional insects from finding their way inside.


When hundreds of stink bugs are found in the home or shed, they can be vacuumed with a shop-vac. On warmer winter days, a stray stink bug or two may emerge from diapause and walk or fly around the house. By this time, all overwintered insects are already inside a home, and hand-picking is the easiest way to eliminate them.                                 


This article was published by Michigan State University Extension. For more information, visit http://www.msue.msu.edu. To have a digest of information delivered straight to your email inbox, visit http://www.msue.msu.edu/newsletters. To contact an expert in your area, visit http://expert.msue.msu.edu, or call 888-MSUE4MI (888-678-3464).




Smart Gardening: Pollination in vegetable gardens and backyard fruit

3-bottom, Citizen Journalism, Food, How-To's, , , , , , , ,
Blueberries at harvest display poor pollination. Right cluster was visited by bees while left cluster was not. Courtesy Michigan State University Extension

By Esther E. McGinnis, North Dakota State University; Nathaniel Walton and Erwin Elsner, Michigan State University Extension; Janet Knodel, North Dakota State University


Bees are important insect pollinators for bountiful home vegetable gardens and backyard fruits. Both European honey bees and native bees, such as bumble bees, help ensure fruit set and higher yields. Learning about the process of pollination can help smart gardeners attract and safeguard these important insects.

What is pollination?

Figure 1. Flower anatomy in a perfect flower. Courtesy Michigan State University Extension

Pollination is the deposit of pollen grains from the anther (male structure) onto the pistil (female structure) of the same plant species (Fig. 1). Pollen can be transferred within an individual flower or between separate flowers. Successful pollination results in the production of viable seeds and a fruit to protect them.


Most crop plants are pollinated by insects or wind. Many agronomic crops, such as wheat and corn, rely on wind pollination. In contrast, many fruits and vegetables require or benefit from insect pollination. Common insect pollinators include bees, butterflies and flies. Of these pollinators, bees are the most important in home gardens.

The role of pollinators in the vegetable garden

Common plants in the cucurbit family include cucumbers, squash, zucchini, pumpkins, watermelon and muskmelon. Most cucurbits depend on bee pollination because each plant produces separate male and female flowers rather than having both sets of reproductive parts in each flower.

Figure 2. Cucumber flowers. Female flower with ovary on left, male on right. Courtesy Michigan State University Extention

Gardeners frequently ask why they have so many flowers on their cucumbers, but no fruit set. Look closely at the flowers to answer this question. In many cucumber cultivars, the first set of flowers are all male, which do not bear fruit. Both male and female flowers will then be produced in the second wave of blooms.


If female flowers are present but no fruit develops, then the problem may be a lack of pollinators. In the short-term, you can fill the role of the bee with hand- pollination. Take a clean paintbrush and insert it into the male flower to gather pollen. Then, transfer pollen to the stigmas of an open female flower. Hand-pollination works best in the morning. For a long-term solution, create pollinator habitat near or in the garden to attract bees.


Such flowers are called “imperfect.” Bees are essential to cross-pollinate or carry pollen from the male flower to the receptive female flower.

Figure 3a. Tomato flower anthers forming a tube around the pistil. Courtesy Michigan State University Extension

The cucurbit male flower contains three to five stamens with pollen- producing anthers. The female flower produces a single style with three stigmas. The easiest way to distinguish between the two flower sexes is to look for an ovary below the yellow petals. Female flowers have a swollen ovary or fruit and male flowers do not (Fig. 2).

Figure 3b. Portion of anthers cut away to revel pistil. (Courtesy Michigan State University Extension

In contrast to cucurbits, Soloanaceae crops such as tomatoes, peppers and eggplants produce “perfect” flowers that contain male and female reproductive structures. Flower anatomy differs from the idealized image in Figure 1. Tomato anthers form a tube that completely surrounds the pistil (Fig. 3a). Figure 3b shows the anthers partially removed to reveal the pistil. Tomatoes, peppers and eggplants can be pollinated simply by wind shaking the pollen from the anthers onto the stigma. However, bumble bees can improve fruit set and size because they vibrate the flowers and shake pollen loose from the anthers.


Leafy greens (lettuce, spinach, arugula), cole crops (cabbage, broccoli, cauliflower, kale), root crops (carrots, beets, radishes, onions), legumes (peas, beans) and tuber crops (potatoes) do not require bees to produce an edible harvest.

The role of pollinators in growing fruit

Bee pollination is important for growing tree fruits and small fruits. Many tree fruits such as apples and pears are self-incompatible (Table 1). This means two separate cultivars must be planted to produce fruit. For example, a ‘Honeycrisp’ apple blossom will not set fruit if a bee deposits pollen from a second ‘Honeycrisp’ apple tree. Instead, the pollen must come from a cultivar that is genetically different and has an overlapping bloom time.

Fruits such as sour cherries are self-compatible and can set fruit in the absence of a second cultivar (Table 2). However, self-compatibility still requires bees to transfer pollen within the flower or between flowers for full pollination. The number of cherries on a tree is directly related to the number of bee visits.


Raspberries are another example of a self-compatible fruit that relies on bees for full pollination (Table 2). The average raspberry flower contains 100 to 125 pistils. To produce a normal berry that does not crumble, at least 75 to 85 of the pistils must be pollinated.

Best management practices to attract and protect pollinators

  • Plant native and other well-adapted flowering plants for season-long bloom in or near the garden.
  • Create nesting habitat for ground- and cavity-nesting bees.
  • Do not spray insecticides or fungicides on flowering plants or fruit trees just before or during bloom.
  • If pesticide applications are necessary, choose a product with the least toxicity to bees.

Resources

For more information on a wide variety of Smart Gardening topics, visit www.migarden.msu.edu or call MSU’s Lawn and Garden hotline at 1-888-678-3464.


Download a printable PDF: Smart Gardening: Pollination in vegetable gardens and backyard fruit


This work is supported by the Crop Protection and Pest Management Program 2017-70006-27175 from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.


This article was published by Michigan State University Extension. For more information, visit http://www.msue.msu.edu. To have a digest of information delivered straight to your email inbox, visit http://www.msue.msu.edu/newsletters. To contact an expert in your area, visit http://expert.msue.msu.edu, or call 888-MSUE4MI (888-678-3464).