I'm trying to identify a beetle I took video of in July (around 2010) in the Muskoka region of Ontario, Canada. Attached below is a still frame.

I've done some googling and was thinking this was a Milkweed Leaf Beetle because of the orange and black stripes. This beetle however has an interestingly marked green head, and Milkweed Leaf Beetles appear to only have a black head.

I'm especially curious to know if the smaller insects on this beetles back are its young, or some type of parasite.

orange and black beetle with mites

I've just posted the original video to youtube. It's right here: Beetle Video

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    $\begingroup$ Nice photo - could you give a bit more detail on where/when you found it? Thanks. $\endgroup$ – user438383 Jan 30 at 16:10
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    $\begingroup$ Thank-you. This is from about 10 years ago - and was shot sometime in July in the Muskoka region of Ontario, Canada. $\endgroup$ – OrbitRob Feb 1 at 2:31
  • $\begingroup$ In the future, please edit your original post. Comments are ephemeral and often overlooked, so they should not be used to convey information important to answering the question. Thanks! $\endgroup$ – tyersome Feb 3 at 0:33
  • $\begingroup$ @OrbitRob can I convince you to save a bi of your video as a gif and upload that directly to your post here? www.ezgif.com makes this process very easy. (you can upload your video, crop the length, and optimize to make the gif <2mb so SE lets you add it. Hope you consider it. thanks! $\endgroup$ – theforestecologist Feb 14 at 3:25

Thanks to pascal's answer, I looked at the genus Nicrophorus and agree that this is some member of that genus. (The spelling Necrophorus has been used in the past but is now deprecated.) The 60+ members of this genus are commonly known as burying beetles or sexton beetles from their behavior of burying dead small animals to serve as nourishment for their offspring.

However, instead of N. vespillo, I think the species might be N. tomentosus:

N. tomentosus on leaf(Photo: Judy Gallagher via Wikimedia Commons)

The most distinguishing feature seems to be the green or gold hairs on the thorax as seen clearly in the large version of OP's photo. These hairs or setae Wikpedia mentions as separating N. tomentosus from other members of the genus. A common name for the species is "gold-necked carrion beetle". Two other photos of this species are here and here.

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    $\begingroup$ Great picture. I like how the mites have placed themselves 'in colour-co-ordinated formation" on the beetle's back! Thanks for your help and FYI i've just added a link to the original video below the main photo in my question. Rob. $\endgroup$ – OrbitRob Feb 1 at 2:39
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    $\begingroup$ I compared what I could see in the OP photo with the identification key given in The Insects and Arachnids of Canada Part 13 (online here), and can confirm this specimen as Nicrophorus tomentosus. $\endgroup$ – Arthur J Frost Feb 1 at 4:03

I think I agree with mgkrebbs that this is N. tomentosus but the members of this genus are all very similar to one another. The part of your question that inquires about the "smaller insects on this beetles back" is of interest. They are not insects, they are mites.

The behavior of these mites is called "phoresis" and there is a good illustrated article here about it. The mites are simply using the beetle for transportation to food. The beetle is better than the mites at finding dead animals and is able to fly. This species of mite has evolved the lifestyle of a "hitchhiker" on the beetle. They have therefore become dependent on the beetle, but they are not a parasite, because the beetle is not harmed. In fact, there may be some benefit to the beetle, which would make this a mutualistic relationship.

  • $\begingroup$ Great info. Much appreciated! ...and FYI i've just added a link to the original video (it shows the mites moving around) below the main photo in my original question. Rob. $\endgroup$ – OrbitRob Feb 1 at 2:41
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    $\begingroup$ First clue that the mites are not the beetle's young are they've got 8 legs to the beetle's 6. $\endgroup$ – Darrel Hoffman Feb 1 at 20:42
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    $\begingroup$ re: "there may be some benefit", from the linked article: "[the mites] feed on fly larvae and nematodes, which are competitors of the beetle" $\endgroup$ – Tim Sparkles Feb 1 at 22:31

This is a beetle of the species Necrophorus vespillo (or a relative), very common beetles. It is parasitized by some mites. A similar picture as yours can be found on this page. I like it very much! We can see on the external page, that those little creatures are mites.

Necrophorus_vespillo (Picture from wikimedia commons)

  • $\begingroup$ Thanks for your help Pascal and FYI i've just added a link to the original video below the main photo in my original question. Rob. $\endgroup$ – OrbitRob Feb 1 at 2:40

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