Do Rain Beetles Bite? Uncovering the Truth About Their Behavior

folder_openColeoptera, Insecta
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Rain beetles, belonging to the family Pleocomidae, are fascinating insects that tend to emerge during rainy seasons. These insects are generally harmless and not known to bite humans, making them interesting subjects for observation.

As rain beetles stay mostly underground and are rarely encountered, their adult stage is marked by intriguing activity. After surfacing, male beetles are capable of flight, while wingless females reenter their burrows, as mentioned on WSU Tree Fruit. When discussing rain beetles, it’s important to note their mild nature and unique habits.

Adding to their mystery, rain beetles often remain hidden and are classified into different species based on their field appearances during August and September. Despite not being a significant threat to humans or plants, studying these insects can broaden our understanding of the insect world and contribute to appreciating the diversity of nature.

Rain Beetles Overview

Defining Characteristics

Rain beetles, belonging to the genus Pleocoma and family Pleocomidae, are fascinating insects. They have some unique features:

  • Large, robust, and shiny
  • Hairy: Pleocoma means abundant hair in Greek1

These beetles spend most of their lives underground as larvae, feeding on tree roots, fungi, and other organic matter1.

Geographical Distribution

Rain beetles are found primarily in North America, specifically in the western United States2. Different species of rain beetles emerge at varying times in the field2. These insects have notable characteristics concerning their emergence and behavior:

  • Pupae transform to adults in August and September2
  • Adults can live for months but do not feed2
  • Only male beetles can fly2

Comparison Table

Feature Rain Beetles Other Beetles
Diet (as larvae) Tree roots, fungi, organic matter1 Varies by species
Flight Only males can fly2 Typically both sexes
Hairiness Abundant hair1 Not a common feature

Rain Beetles Behavior and Life Cycle

Rain beetles are found only in western North America, particularly in fruit-growing areas of the Pacific Northwest1. These beetles are known for their unique behaviors, such as flying during the rain and possessing flightless females.

The life cycle of rain beetles consists of four stages: egg, larva, pupa, and adult1. Females lay eggs in the soil, after which they develop into larvae.

Larvae primarily feed on tree roots1. They burrow in the soil, consuming roots throughout their larval stage. This stage plays a significant role in their development and growth.

Once fully grown, rain beetle larvae pupate in soil chambers1. Pupation marks the transition from larva to adult, during which they undergo significant physiological changes.

Adult rain beetles are typically flightless (females) or fly during rainfall (males)1. These beetles use their antennae to detect pheromones emitted by females, guiding them to potential mates.

Here’s a brief comparison table:

Rain Beetle Stage Main Characteristics
Egg Laid in soil by females, initiates life cycle
Larva Feeds on tree roots, burrows in soil
Pupa Transforms from larva to adult in soil chambers
Adult Flightless females; males fly during rain

Some key features of rain beetles include:

  • Flightless females
  • Males that fly during rain
  • Larvae that consume tree roots
  • Burrow in soil throughout life cycle

When observing rain beetles, keep the following characteristics in mind:

  • Males use antennae to detect female pheromones
  • Follow a complete metamorphosis life cycle
  • Found in western North America
  • Primarily inhabit mountain habitats

While rain beetles possess strong mandibles, they are not known to bite humans. Their focus is mainly on their life cycle, involving laying eggs, feeding on tree roots, developing in soil chambers, and engaging in mating rituals related to rain.

Do Rain Beetles Bite

Rain beetles are known for living underground and feeding on shrub and tree roots, fungi, and other organic matter. They do not typically pose a threat to humans, as their primary focus is to find food and reproduce.

However, if you happen to encounter one of these beetles, it’s important to exercise caution. Some beetle species might bite if provoked or threatened. Let’s explore some related beetles and their potential to bite:

Examples of Beetles:

  • Stag Beetles
  • Bark Beetles
Beetle Type Bite Probability Pain Level Harmful to Humans
Rain Beetles Low N/A No
Stag Beetles Medium Low No
Bark Beetles Low N/A No

Characteristics:

  • Strong jaws
  • Sharp teeth
  • Different diet and prey preferences

In the case of the rain beetle, their jaws are not designed for biting humans. Whereas stag beetles have powerful jaws, they use them to fight other males during mating season and tend to avoid humans.

In summary, rain beetles are unlikely to bite. The risk of being bitten by other related beetles is usually minimal when handled gently.

Environment and Habitat

Rain beetles, belonging to the genus Pleocoma, are found predominantly in western North America, particularly in the Pacific Northwest1. These beetles thrive in environments with abundant organic matter, such as shrubs and fungi, which provide them energy for growth and reproduction2.

The rainfall plays a key role in the life cycle of rain beetles. Adult beetles emerge from the ground and become active during periods of heavy rain3. Additionally, rain provides the moisture needed for the fungi and other organic matter that supports their habitat4.

Some rain beetles have been found in fruit-growing areas, such as apple orchards5. These environments offer a combination of factors that benefit the beetles, including:

  • Sufficient organic matter
  • Availability of fungi
  • Shaded areas provided by shrubs and trees

Despite their presence in fruit-growing areas, there is no evidence to suggest that rain beetles pose any threat to humans or that they bite. So, you can enjoy these beetles in their natural habitat without any concern for your safety6.

Rain Beetles and Humans

Rain beetles are unusual insects that live underground for most of their lives. They emerge only under specific conditions, such as heavy rainfall. Despite being a curious and fascinating species, rain beetles don’t have a significant impact on humans.

As underground larvae, rain beetles feed on shrub and tree roots. In some cases, they can become pests, particularly if they attack the roots of fruit trees, such as apples or pears1. However, these beetles are not known to bite humans, and they are generally considered to be harmless.

Some characteristics of rain beetles include:

  • Large, robust, and shiny body
  • Abundant hair1
  • Long-lived adults that don’t feed2

When it comes to controlling rain beetles, insecticides might not be the best option. Since they spend most of their lives underground, insecticides may not reach them effectively. Instead, proper care and maintenance of fruit trees can help minimize potential damage.

It’s also worth noting that although rain beetles have abundant hair, they are not known to cause allergic reactions in humans1. Additionally, these beetles are not attracted to artificial lights, unlike some other insect species.

In summary, rain beetles are fascinating insects that live mostly out of sight. While they can sometimes be pests for certain fruit trees, they are harmless to humans and don’t pose allergy risks.

Interesting Facts and Insights

Rain beetles are a fascinating group of beetles found mostly in the western North American regions such as Washington, California, and Oregon1. They are closely related to scarab beetles and have some unique characteristics, including:

  • V-shaped scoop
  • Spiral pattern
  • Abundant hair

Rain beetles have a V-shaped scoop on their heads that helps them to dig through the soil2. Their bodies exhibit a spiral pattern, which is a striking feature they share with scarabs3. These beetles also have abundant hair, giving them a distinctive appearance4.

These beetles are known as “Pleocoma sp.”5 and are often seen in December, particularly the male rain beetles6. They have a fascinating life history, involving several stages:

  • Nymph
  • Algae
  • Grubs

The nymphs of rain beetles are usually found near bodies of water, where they feed on algae7. As grubs, these critters primarily feed on roots, fungi, and other organic matter8.

Rain beetles are known to lay their eggs near trees9 and can sometimes be a pest to fruit trees, such as apple and pear trees10. These beetles share some common habitats with mosquitoes, crabs, and other insects11.

Here’s a comparison table highlighting key differences between rain beetles and scarab beetles:

Rain Beetles Scarab Beetles
V-shaped scoop on head No V-shaped scoop
Spiral pattern on body No spiral pattern
Abundant hair Less hairy
Found in wet environments Found in diverse habitats
Primarily in western North America Widespread distribution

As mentioned, rain beetles can sometimes be problematic for fruit trees. However, they also play a crucial role in the ecosystem as a food source for other animals and by helping to recycle nutrients in the environment.

Footnotes

  1. (https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=19974) 2 3 4 5 6 7 8 9 10 11 12 13 14

  2. (https://treefruit.wsu.edu/crop-protection/opm/rain-beetles/) 2 3 4 5 6 7 8 9

  3. https://extension.umn.edu/nuisance-insects/ground-beetles 2

  4. https://hort.extension.wisc.edu/articles/beetles/ 2

  5. https://treefruit.wsu.edu/crop-protection/opm/rain-beetles/ 2

  6. https://extension.umn.edu/nuisance-insects/ground-beetles 2

  7. https://entomology.si.edu/resources/faq/geninfo/type_houseinsects.html

  8. https://bugguide.net/node/view/15497/bgpage

  9. https://entomologytoday.org/2017/12/04/rain-beetles-emerge-chasing-the-nasty-weather/

  10. https://extension.umd.edu/hgic/topics/apple-pear-wood-boring-beetles

  11. https://www.aphis.usda.gov/aphis/resources/pests-diseases/hungry-pests/the-threat/environment+

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Another Rain Beetle

 

Is this a Rain Beetle?
November 18, 2009
Just found in the pool flailing around on top of the water — it looks like the other Rain Beetle pictures on your site and thought I’d ask if that’s what this is to confirm. One picture is on top of the net I got it out of the pool with. The other is on the ground. We had rain last night and everything is still sort of wet around here today. Thanks!
Elaine
Rural Windsor, California (North of Santa Rosa)

Rain Beetle
Rain Beetle

Dear Elaine,
You are absolutely correct.  We are happy that our website was helpful with your Rain Beetle identification.  This is the second submission of Rain Beetles we are posting from yesterday.

Rain Beetle
Rain Beetle

Letter 2 – First Rain Beetle sighting of the Season

 

Subject:  Enormous May Beetle in Winter?
Geographic location of the bug:  Arnold, CA (Sierra Nevadas)
Date: 11/28/2018
Time: 09:52 AM EDT
Your letter to the bugman:  Hi there,
Two of these huge beetles were banging on my glass door before dawn today at my house in the sierra forest. They were attracted to the lights inside and my porch light,
They were hitting the glass so loudly I thought someone was knocking. And of course as soon as I opened the door to take a look, they invited themselves in. They look like May beetles but were huge, at least an inch and a half long, with fine hair all over. They were pretty noisy, slow fliers, banging into everything. I did some poking around the internet and the closest bug I could find was the European common cockchafer.
They seem like an odd bug to see in winter in the mountains (4,000ft)-temperatures here have been dipping to the 30s at night for some time. We’ve also had drenching rain over the past week. The color was much more rust/red than in the picture.
What are these giant mystery bugs? Thank you!
How you want your letter signed:  Sarah J

Hi again!
I now believe these are rain beetles.I happened to see the word “rain” on your beetle list, clicked, and there they are. Just letting you know since it seems folks seem to be looking for these. We’re getting a lot of rain here!
Thanks for this great web resource!

Rain Beetle

Dear Sarah,
We agree with your assessment that this is a Rain Beetle.  Only male Rain Beetles have wings, and they often fly during pouring rains.  There are many creatures that appear after a rain, but Rain Beetles are rather unique in that they are often only found during a rain.  Male Rain Beetles are able to locate underground females that are flightless.  Perhaps Gene St. Denis, who sends us images of Rain Beetles he collects, will have some idea of the species based on your location as populations of Rain Beetles are often quite isolated.

Letter 3 – More Rain Beetles

 

Subject: Pleocoma staff Schaufuss 1870 male
Location: 4 miles South East of Grass Valley , Nevada County, California, USA
November 23, 2016 9:31 am
On October 16th and 17th 2016 ( during rain showers ) I headed south of Grass Valley on the side of the road and collected a very nice series of Pleocoma staff Schaufuss 1870 males both days crawling on the ground ,several run over and squashed by trucks, a couple netted in the air and 6 in my homemade blacklight traps .The male staff started flying as soon as the sun went down until dawn , which was the heaviest Fights . Male sizes ranged from 27 to 32 mm . The flights for a few males lasted until 8 o’clock that morning . These guys are stocky and have ” Amazing Colors ” ! Also stopped by a couple days ago and picked up a half dozen dead / barley alive males under lites. Cheers ! Gene St. Denis Sierra Nevada Research
Signature: Gene St. Denis

Rain Beetles
Rain Beetles

Hi Gene,
All your recent images are making us envious that we have never witnessed the flight of Rain Beetles.

Rain Beetle
Rain Beetle
Rain Beetle
Rain Beetle

Letter 4 – Rain Beetle

 

Giant beetle creature! Whazzit??
Hi there. Your site is really fantastic! While flyfishing the other day (northern California area), I came across several of these HUGE beetles. Some were swimming (rather pathetically). They have wings of a sort but it seemed to never occur to them to fly. Any clue on its ID? Thanks much!
Michelle Mahood

Hi Michelle,
You have a photo of a Rain Beetle, Pleocoma species, one of the Scarab Beetle Family. According to our favorite expert Hogue: “The first measurable late fall or winter rains stimulate the adult males of this genus to emerge from their subterranean burrows, in which they have lain as pupae for more than a month. In some species a soaking rain of several inches is needed to initiate activity, but the species found at higher elevations will often fly a few minutes after the onset of the year’s first shower. In the foothill and canyon areas, the males seem to emerge in response to the rain and may be attracted to light, congregating around store fronts or dwellings during a drizzle or downpour. When searching for the burrows of the flightless female beetles, the males fly in slow sweeping patterns low over the ground and brush. … The females are seldom found outside their burrows, which may extend from 4 to 6 feet into the soil. The male apparently locates the burrow of the female by detecting a strong [musky] scent that she puts into the air. He enters her burrow to copulate, after which the female plugs the burrow’s opening with pulverized soil and digs deep in the ground. The eggs, which are laid in a spiral at the base of the burrow and packed tightly in fine soil, do not mature until the following spring or early summer. … The life cycle may last as long as ten or twelve years, with the larvae feeding on the roots of varied kinds of plants, usually hardwood shrubs or trees and in particular oaks and conifers. The mouthparts of the adults are atrophied and useless for feeding.” Your beetles were not swimming, but probably just bumbled into the stream. Thanks for a new addition to our site.

Ed. Note: We received this letter shortly after posting the Rain Beetle photo.
Rain Beetles Hello: I am a biologist studying rain beetles in California, and came across the posting of the rain beetle on your website. I would be very interested in finding out the exact locality where the beetle was seen. Would it be possible for you to contact the woman who posted the picture and question and either give her my email to contact? Thanks! -Ian
We forwarded Ian’s letter to Michelle who wrote back to us:
Thanks for passing my email along. I heard from Ian last night and sent him some whopping big high-res photos of the rain beetle — even the underside. How cool that someone is studying them! Thanks again for ID’ing my bug. You guys are EXTREMELY COOL. Best regards, Michelle

Ed. Note: We just got this letter.
(08/09/2005) identifications Hello – I was recently shown your site, and it is excellent. My specialization is longhorned beetles, and in cruising around I notice a number of incomplete or uncertain IDs for this family. I don’t know if you are interested in receiving this sort of input, but if you are, I offer the following additions to your identifications.
The Northern California Pleocoma species sent by Michelle Mahood is undescribed, having been incorrectly recorded in older literature as P. simi, which is found in southern Oregon, and closely resembles Michelle’s beetle. The species shown in the photo occurs around the Lake Shasta basin, most often in Douglas Fir and Incense cedar forest. I will be described in my upcoming revision of the genus Pleocoma.
Keep up the good work. You are a valuable resource.
Cheers Frank Hovore

Letter 5 – Rain Beetle

 

Is this a scarab beetle?
Fri, Nov 28, 2008 at 8:48 AM
Dear Folks,
Could you please help me identify the beetle in the attached pictures? The closest match I could find was a scarab beetle. For the past few weeks (November) our cats have been bringing these into the house. I can’t remember ever having seen them outside in the garden and I thought I was pretty familiar with most of the larger insects we have here in southwest Oregon.
They are a little over 1 inch long with a lot of what looks like fur on their underside and legs. I am sorry the pictures are so poor; we only have one of those point and shoot cameras without any setting to take close-ups of less than 3 feet.
Your site is where I go first whenever I come upon an unknown insect. I’m immensely grateful for the work you’ve put into this. Thank you so very much.
Elizabeth Hunter
Grants Pass Oregon

Rain Beetle
Rain Beetle

Hi Elizabeth,
Until today, we would have begun our response with “Yes this is a Scarab Beetle” and then gone on to further classify it as a Rain Beetle. We have just learned, upon visiting BugGuide, that Rain Beetles are no longer considered to be in the family Scarabaeidae, but have been classified into their own family, Pleocomidae . Only male Rain Beetles can fly. The female Rain Beetle remains buried deep underground in a burrow and must wait for a male Rain Beetle to locate her so they can mate. According to BugGuide, there is a single genus, Pleocoma, in the family Pleocomidae, and the genus has 34 species that range in: “Western Coastal North America, from Southern Washington to northern Baja California, Mexico and Utah. ” The individual species of Rain Beetle often has a very limited range. Rain Beetle Grubs feed underground on the roots of oaks and conifers. We are thrilled to have your images and letter for our archives, and we will be creating a new beetle category for Rain Beetles and moving the earlier postings out of the Scarab Beetle category.

Rain Beetle
Rain Beetle

Dear Daniel,
Thank you so much for your answer; I hadn’t really expected a response as I am sure you must be besieged with questions. This made my day!
The next time one of the cats presents me with a Rain Beetle I will try to get better pictures.
Thanks again for the terrific site.
Best regards,
Elizabeth

Letter 6 – Rain Beetle

 

Found a bug
Location: Northern Ca foothills near Auburn CA
November 13, 2011 1:58 pm
Hi, I found this bug on my doorstep this morning. It is about 2 inches long. Not sure what kind it is and if I should be concerned about the trees or house. We live in a heavily wooded area, many pines and oaks in the Sierra Nevada foothills near Auburn CA.
Can you tell us what bug this is?
Signature: Duke

Rain Beetle

Hi Duke,
Congratulations on your wonderful sighting.  This is a male Rain Beetle in the family Pleocomidae (see BugGuide), a family with a range that is limited to the west coast of North America.  Rain Beetles are a very unusual family of beetles.  Larvae live underground and feed on the roots of oaks and conifers and they can remain underground for as long as ten years.  Mating activity is triggered by rain.  Only male Rain Beetles have wings, and they will circle the ground until they locate the burrows of a flightless female.  There are many species of Rain Beetles and many have very limited ranges.  An expert is required to distinguish one species from another.  There was an excellent article in the LA Times several years ago on the Rain Beetles. 

Letter 7 – Rain Beetle

 

Beetle
Location: East San Diego County, CA
December 13, 2011 10:54 am
We found this bug on Sunday. He was hitting the windows and the door in the evening hours. We’ve seen these kind of bugs before, but only when it rains. It was damp and raining that day and 47 degrees. We are at an elevation of 4,000 ft., near the border of Mexico and California. We found it dead on a bucket the next morning.
Signature: Mark

Rain Beetle

Dear Mark,
While this is not a rare sighting, it is a somewhat unique sighting.  Your beetle is a Rain Beetle, a member of the family Pleocomidae and the genus
Pleocoma.  This is a small family that is limited to coastal regions of the west coast of North America from Washington to Baja.  This family is not known from any other parts of the world.  There is work needed on the taxonomy of the genus and it would be nearly impossible for us to provide you an exact species identification.  According to BugGuide, there are approximately 30 species identified.  Many species have very limited ranges, due in large part to the morphology of the flightless female.  One can only begin to ponder what conditions once existed that allowed the range expansion and genetic diversity that contributed to the evolution of distinct species where the female of the species is flightless and immobile.  The grubs live underground, often at great depths, feeding on the roots of oaks and conifers according to BugGuide.  You may find this May 18, 2009 Los Angeles Times article interesting.

Letter 8 – Mating Rain Beetles

 

Subject: Pleocoma shastensis Male
Location: Logging Road South of Deadhorse Summit 6 miles , Hwy 89 , Shasta County, California, USA
November 22, 2016 9:46 am
I headed up north to Dead Horse summit on Highway 89 in a radical wind and rain storm October 14th and 15th 2016 , Looking for Pleocoma shastensis Dyke 1933 . In the howling darkness south of Susanville on Highway 395 , 5 semi-tractor trailer rigs were blown over and the 5th one was right in front of me. The wind not only tipped the big rig over it lifted the Whole rig Over the highway fence and put it 40 feet from the road. Amazingly the driver was OK after crawling out and he had me call 911 for him. At times I would stop several times and wait for the gusts to pass , making the speed limit was not possible . I then continued way north past Susanville to 8 miles south of Dead horse summit and set out my home made black lite traps the next two nights and waited in the Pouring rain and howling winds. I was not disappointed ! The traps received a very nice series of males , every trap had 3 to 5 males in it. During the days I walked the Forrest service dirt roads in the immediate areas and located many more dead and dying , males from the flood conditions, as well as some still flying until Noon. It appears that the males will fly until out of energy once activated that DAY. They were not flying for several days at day break for 15 to 30 minutes at a time , as other Pleocoma do. This would explain why they have been Extremely hard to find ! Many males had been driven over by other trucks on the roads in the immediate area and I have a couple handfuls to glue and repair this winter.Male sizes were from 23 mm to 34 mm . 48 degrees to 65 during the day and Heavy rain with soaked Muddy Earth. Cheers ! Gene St. Denis Sierra Nevada Research
Signature: Gene St. Denis

Rain Beetle
Male Rain Beetle

Goodness Gene, what a harrowing experience you had.  Thanks for providing us with the images.

Rain Beetle
Male Rain Beetle
Rain Beetle
Male Rain Beetle

And , I Found a Prize !! A Gorgeous female Pleocoma shastensis was just emerged and had a dirt lid on her head like a trap door spider waiting in her hole ! Two males were on the ground headed her way . Many males had been driven over by other trucks on the roads in the immediate area and I have a couple handfuls to glue and repair this winter. Cheers ! Gene St. Denis Sierra Nevada Research

Mating Rain Beetles
Mating Rain Beetles

Hi again Gene,
Thanks again for providing so many excellent images of a rarely seen species, an even rarer sighting of a female Rain Beetle and the awesome image you have of the mating process.

Rarely seen female Rain Beetle
Rarely seen female Rain Beetle
Rarely seen female Rain Beetle
Rarely seen female Rain Beetle

Letter 9 – Bug of the Month January 2017: Rain Beetle

 

Ed. Note:  Bug of the Month
Since we just returned from our holiday, we need to select a Bug of the Moth.  Rain Beetles in Southern California have been experiencing some nice December rainfalls, so they seem a likely candidate to be featured this month.

Subject: Pleocoma octopagina
Location: Wrightwood , Burn Area Dirt Road Turnouts, San Bernardino County, California, USA
January 1, 2017 9:39 am
This December 22, 23,and 24, 2016 ,I drove down from Lake Tahoe south to the Wrightwood Burn area roads just north of San Bernardino in Southern California and back thru rain and snow storms . Meeting up with Mr.Garin Woo for the first morning , we set out our Home made Black lights and Mercury Vapor lite in high hopes of getting some hard to get Pleocoma octopagina Robertson 1970 male Rain Beetles . They have the most Antennae laminae segments or fans of the Male Pleocoma which is 8 . And we were not disappointed !! The rain flights started at 5 am and were intermittent until 6 am and then became steady until 7am and ended. Some were seen still flying around in the growing morning sun lite. We received a very nice series of Flying Large Newly Hatched Male Pleocoma octopagina . Precise Lengths of males were 22 mm to 36 mm with metal calipers . They come out in limited numbers and were quite Large and robust this year . I stayed out a couple more mornings solo . This was even in a completely and totally Burned out ( this August 2016 ) area …..” Truly Toasted “. There is strong evidence to me that the majority of this area’s Bush’s ( highly resistant somewhat to fire ) are still alive under ground and can provide food for the Pleocoma grubs . I have have photo evidence that in adjacent past fires we have clear regrowth coming out of Completely burned terrain / Bushs . The laminae are extremely Thick and robust with their prominent ” 8 fan segments ” . They are very large and strong flyers for Pleocoma males and they came in to Garin’s Mercury Vapor lite the strongest . I spent some time looking for females to no avail .On the way home in the Snow Storm I had to have it in four wheel drive from Bishop all the way home to Tahoe at 20 to 45 MPH ! Cheers ! Gene St. Denis Sierra Nevada Research
Signature: Gene St. Denis

Rain Beetle
Rain Beetle

Dear Gene,
Our editorial staff was away for the recent southern California rains, but we are thrilled that you were able to continue to supply us with Rain Beetle sighting information.

Rain Beetle
Rain Beetle
Rain Beetle Habitat
Rain Beetle Habitat

Letter 10 – More Rain Beetles: Pleocoma hovorei

 

Subject: Pleocoma hovorei La Rue 2007
Location: Paynes Creek, Tehama Co. California,USA
January 26, 2016 10:04 am
I went up to Paynes creek off of Highway 36 , west of Red Bluff on November 15, 2015 and set up my Home Made Black lights Vein Traps at 5:00 am and waited. It had and was raining @ 48 degree ambriant air temp with light winds. Soon several nice Black Pleocoma males started flying and several went into the traps and several went right by with me … with me chasing right after them in a hurry even with my net ! Soon 6:45 am sounded shut down time and I packed it up . These Shiny Black ” Little Fuzzy Butts ” were named after my Mentor from the 1960’s and 1970’s , the Late ” Frank Hovore ” a Giant of the Entomology World and One Great Man . He is missed by all. Gene St. Denis -Sierra Nevada Research- South lake Tahoe , California , USA
Signature: Gene St. Denis

Rain Beetle: Pleocoma hovorei
Rain Beetle: Pleocoma hovorei

Good Morning Gene,
We are so lucky that you continue to provide us with a diverse sampling of the unique California Rain Beetles.  We see your images are also featured on BugGuide.  We also located this marvelous YouTube video of mating
Pleocoma hovorei.

Rain Beetle: Pleocoma hovorei
Rain Beetle: Pleocoma hovorei

Authors

  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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Tags: Rain Beetle

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18 Comments. Leave new

  • I was searching for information on a beetle that we have had at our house in the winter in Twain Harte, CA. The bugs are very attracted to light and are found at the front of the house and in the garage. They fly around but seem to die quickly (in days). We have up to 10+ at a time. From what I have read, the beetles are a Rain Beetle. I have read that the flying beetles are male and live 10-12 years, but with the amount of dead beetles that we have, 10-12 years seems a long time. Can anyone give me some more information on these beetles? Does the freezing cold kill them?

    Reply
    • The 10-12 year lifespan is spent in the larval stage underground. Adult Rain Beetles live a very short time and do not feed. There are some species that fly in near freezing weather. We have loads of information on Rain Beetles on our website and we would recommend using the search engine to locate this information and the links to outside sources.

      Reply
  • What an awesome story that they were named after your mentor! They remind me of our June Bugs which are pretty awesome.
    They are glorious little beings and I love the fancy antennae and furry leggings.

    Reply
  • Gene St. Denis
    May 29, 2016 3:12 pm

    This is a unique specimen and does not represent anything described by locality , if your location information is correct . You have something new recorded for that area ! 1. We have over a dozen Unidentified Pleocoma in the central valley that need to be named and this is either one of these…….. or…. 2. something …. different . 3….only Pleocoma crinita or Pleocoma conjungens comes close in appearance with current described Species . So , it looks like I will have to spend some time looking for these ” Auburn ” specials . Let me know if you get any more for a Exact physical description . Very nice ! Gene St. Denis SNR

    Reply
    • Hi Gene,
      What’s That Bug? is very grateful for all of the information you have provided over the years regarding Rain Beetles. We hope you will continue to update us to your findings.

      Reply
  • Gene St. Denis
    November 20, 2016 7:55 am

    Daniel and Mark , after examining your Pleocoma photos I believe that you have dead male Pleocoma puncticollis or male Pleocoma australis . Mark , ( if you read this at such a late response date ) I would like some specimen examples if possible in the future or Better Yet Photos (of head and antennae in particular ) . Cheers Gentlemen ! Gene St. Denis Sierra Nevada Research P. S. I am sitting at a ‘Warm ” home in South Lake Tahoe @ 6,500 feet with a Large Mug of steaming Hot fresh French Roast Coffee , going thru Pleocoma records on the “Computer ” with a white out Blizzard ragging outside .

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  • Gene St. Denis
    November 20, 2016 8:35 am

    Daniel and hollyazevedo , if possible I would like to see some Good pictures of the Elytra and Head if possible to verify . If what Frank said is true and these match the series that I have Collected last year and last week…. then it is the ” undiscribed ” species. It is a shame that Frank didn’t get the time to Finnish it and others he was working on . It could be the illusive ” Red Staff ” or ” Pleocoma iridescenta ” , which are the nick names of a undiscribed species ! Cheers! Gene St. Denis Sierra Nevada Research

    Reply
  • Glad to see one named after Frank. Was too trained by Frank and knew him for 33 years. Sure do miss him. Was at the BioQuip open house yesterday and noticed an unidentified Pleocoma from Tehama County … am guessing that was Hovorei? May have to get one next time I am over there.

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  • So if I found one does it mean there is a partner near by?? It was in the house by the be. Will they get on humans?? Traumatized.

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  • Richard Portman
    October 2, 2018 2:20 pm

    Pleocoma season is approaching and I hope Gene St. Denis will be out there pursuing his obsession again.
    He is certainly passionate about these creatures.
    I have only seen rain beetles once. Near Simi, Ca, in the hills. It was February and raining buckets. Me and a couple other boys decided to go look for them.
    We found some! The beetles are awesome, seldom seen and so interesting.
    But I think the most fun was being out there in such a storm, when everybody else was hunkering down, and actually finding a creature we were pretty sure doesn’t exist. It opens the mind.

    Reply
  • Richard Portman
    October 2, 2018 2:20 pm

    Pleocoma season is approaching and I hope Gene St. Denis will be out there pursuing his obsession again.
    He is certainly passionate about these creatures.
    I have only seen rain beetles once. Near Simi, Ca, in the hills. It was February and raining buckets. Me and a couple other boys decided to go look for them.
    We found some! The beetles are awesome, seldom seen and so interesting.
    But I think the most fun was being out there in such a storm, when everybody else was hunkering down, and actually finding a creature we were pretty sure doesn’t exist. It opens the mind.

    Reply
  • Gene St. Denis
    December 1, 2018 6:55 pm

    I believe that you had an early flight of Pleocoma hoppingi males . And of coarse a Male Pleocoma hoppingi . Cheers ! Gene St.Denis Sierra Nevada Research

    Reply
  • Gene St. Denis
    December 7, 2018 10:56 am

    Folks , I now have some ideas about it being a male Pleocoma fimbriata ( northern sub group ) . With a head lam shoot I could pin it down . Cheers ! Geno

    Reply
  • Brenda Mackin
    May 29, 2019 9:43 pm

    My daughter and her Aunt found what looks to be a male rain beetle in Cherryvale Kansas. We have had some severe flooding lately.

    Reply

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