Two Nicrophorus Beetle Species Plus . . .

Roundneck Sexton Beetle (Nicrophorus orbicollis)

Above is the roundneck sexton beetle that I photographed after capture (it was, of course, released after the photo session). You can see that the area after the head, called the thorax, but before the body, which is called the abdomen, is pure black. These beetles are attracted to moth lights, which is where I always find them. Sexton beetles are named after the people who look after a church and churchyard, and used to be gravediggers.

Tomentose Burying Beetle (Nicrophorus tomentosus)

Above is Jody's photo of a tomentose burying beetle. The thorax, between head and body, is covered with luxurious gold hair. That is how you can tell the two species apart. But there is one other behavior that tells them apart. The roundneck buries dead animals that it finds, and then feeds on them. The tomentose (also called the gold-necked carrion) digs a hole under the animal and covers the animal with leaf litter. Both species have antennae with orange-tipped clubs. They smell the bodies of the dead with those clubs, which are olfactory organs. 

Each of these beetles are in the family Silphidae which are carrion beetles. Carrion is "the decaying flesh of dead animals." Without carrion beetles, vultures, and other decomposers, we would be in a heap of trouble with dead animals piled a mile high.

All this is simply background to what fascinated Jody and I, though.  Look at my photograph of another roundneck beetle, and see if you notice a hitchhiker or two:

If you don't see them there, you will see them on Jody's tomentose: 

The little bugs on the beetles are Carrion Beetle Mites (Genus Poecilochirus). The mites are not doing a thing to the beetles except hitchhiking. This is called phoresis (one creature attaches itself to another solely to travel). The mites lay their eggs in dead animals, but they are tiny and the beetles can get them where they need to go quickly. The best, or biggest, example of phoresis  is a person riding a horse to go from one point to another. Another note about mites: they have eight legs, like spiders. But they are not spiders. They also are not insects.

Jody made a video of the beetle and mites. It may seem gruesome, but try to stick with it. The mites are not eating the beetle. They are, though, probably telling the beetle to get with it and take them to a carcass quick!

References:

• Bugguide: Species Nicrophorus tomentosus - Tomentose Burying Beetle
• Bugguide: Species Nicrophorus orbicollis - Roundneck Sexton Beetle
• iNaturalist: Carrion Beetle Mites
• National Park Service: A Symbiotic Relationship - Carrion Beetles and Mites
• Wikipedia: Phoresis

Nature Notes at Rambling Woods 2

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Nature Notes: Buzz Pollination

Last week, I spent a lot of time watching two species of bumble bees on the few blossoms of Rosa rugosa that were left. They seemed to be in a frenzy inside the blossom. In the past when I have seen this, it looked like they were rolling in the pollen in ecstasy, much like our dogs roll happily in vile things in the woods. But on this day, I saw that their high speed movement had deceived me. They seem to be gathering pollen, but in greater quantities than they would individually need.

R. rugosa does not have nectar so it may not be particularly enticing to insects. It is self-pollinating, but it needs cross-pollination by insects to set fruit, which are the rose hips with which we are familiar. Rugosa is also called the beach rose. It is not native, but is extensively used to prevent erosion on beaches and dunes in the eastern United States. It creates many nostalgic memories for those of us who grew up on the Atlantic shoreline or visiting it often.

Pollen is the sperm of flowers. It is on the anthers. The anthers may have the pollen on the outside, easily available to insects, or it may be trapped inside the anther. Bumbles eat pollen as adults, but most importantly, they feed it to the bee larvae in the hive. Rose pollen is highly favored by bees because it's rich in nutrients. But the pollen in R. rugosa is trapped inside the anthers, so the bumbles need to get that pollen outside of the anthers so they can collect it for the baby bees. 

Rugosa, as a genus, can be pollinated in one of or more of three different ways and all three methods can be used with R. rugosa:

1. Automatic or insect-mediated selfing within one flower (autogamy) 

2. Pollen transfer from flower to flower on the same plant (geitenogamy)

3. Cross-pollination (xenogamy) results when pollen is transferred from the anthers of one plant to the stigmas of the flowers of another.

When you see a bumble inside a blossom, making a loud buzz sound, perhaps even "rolling around," it is collecting the pollen from inside the anthers. The bee (only female bumbles can collect pollen) uses her flight muscles — not to fly, but to vibrate her entire body, and the vibrations release the pollen. While her body vibrates rapidly, creating that buzzing, she bites the tip of the anther to release the pollen. After the release, the bee collects it in the sacks on her legs. This entire process is called buzz pollination.

Because the activity in my videos, below, happens so fast, I have added this slide show of still photos of the activity at one R. rugosa blossom.

Buzz pollination is also required for tomatoes, potatoes, and blueberries (all New World foods). And honeybees cannot do it, only our native bumble bees can. JF says that she also sees this activity on mullein and hydrangea.

In the videos below, that I made as part of my practice of making nature videos, you will see Common Eastern Bumble Bees (Bombus impatiens) and one Tricolored Bumble Bee (Bombus ternarius) buzz collecting pollen from R. rugosa. The tricolored bee has the orange band. Unfortunately, I deleted the sound. The buzzing is much louder than you normally hear, and it reminded me of angry bees. But they were not angry, they were simply in "overdrive."

The bees, though different species, did not seem to mind sharing a blossom with others. One bumble here or there would run off (especially the Common Eastern Bumble). On the other hand, it also did not look as if they enjoyed each other's company. Sometimes there was a slight tussle when another bee entered the flower. Sometimes there was not.

References:

1. Kevan, PG; "Pollination in Roses", University of Guelph, Guelph, ON, Canada (pdf file)
2. NOBANIS – Invasive Alien Species Fact Sheet Rosa rugosa  (pdf file)
3. Deep Look: This Vibrating Bumblebee Unlocks a Flower's Hidden Treasure (PBS video)
4. Buzz Pollination (Wikipedia article)

View more Nature Notes

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John Missed Finding a Bee

Orange-tipped Wood-digger bee
(Anthophora terminalis)

On June 22, 2020, I found an Orange-tipped Wood-digger bee (Anthophora terminalis). You have to understand a few things to understand how much excitement this caused. John, my husband, and I found bugs both common and uncommon in Orleans County. He had great eyes and I worked the camera. We hiked our land as much as possible to find more. But he died. And now, because of arthritic knees, I haven't been able to walk about searching for bugs like we used to do. With a cane or walker and a chair, I can set myself down near promising areas and shoot. It's actually a good way to get a phenology and inventory of creatures that are in a very small area. You can find dozens if you sit long enough. But without my beloved John, it is as sad as it is comforting to go on a bug hunt.

 

The bee in the these photos settled in front of me for a brief moment and I managed to get eight shots off before it left, only two of which were usable. I knew it was not a bumble bee but had no idea what it was. I always submit my insect shots to iNaturalist, where members (community scientists and professional scientists of all kinds) identify plants and animals. When a renowned Vermont bee expert identified my bee that day, I whopped. Loudly.

 

No one before June, 2020, had found this species so far north in Vermont. I submitted the find to bugguide.net for confirmation, and it came in overnight from a world-renowned international bee expert.

 

These photos now document the first reporting of this bee in Orleans County. iNaturalist had eight other sightings in other Vermont counties that season. I am in the company of the great community scientists that I so admire. 

 

I was sad that John missed out on the excitement. He was such an enthusiastic part of these quests, and he would have been proud of this find. But despite his death, my knees, the pandemic, and the tragedy of fellow Americans suffering under racism and hate, I have learned that sometimes something wonderful like this can still happen. Sometimes, I can smile again.

Read more Nature Notes here.

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