Ripiphoridae: All You Need to Know About These Intriguing Insects

Ripiphoridae, also known as wedge-shaped beetles, are a fascinating family of beetles with many unique characteristics. One distinct feature is their fly-like appearance, which is attributed to their short elytra (first pair of wings), leaving the large, unfolded hind wings exposed source.

These smallish, chunky beetles are easily spotted for their “bug-eyed” and hump-backed profiles, as well as their abdomens that curve under their bodies source. When visiting flowers, their exposed wings and unique stance can lead to them being mistaken for flies and wasps.

Ripiphoridae Overview

Family Ripiphoridae

Ripiphoridae is a family of beetles also known as wedge-shaped beetles due to their distinctive body structure. They belong to the order Coleoptera, class Insecta, and the phylum Arthropoda. These beetles are unique among the insect kingdom and are known for their unusual life cycle and parasitic behavior.

Classification

Ripiphoridae belong to the following taxonomic hierarchy:

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Subphylum: Hexapoda
  • Class: Insecta
  • Order: Coleoptera
  • Family: Ripiphoridae

Identification

Adult Ripiphoridae have a few key features for identification:

  • Small in size, around 6-8 mm long
  • Hump-backed, with a thick, curling abdomen
  • Short elytra (1st pair of wings)
  • Exposed, clear hind wings, sometimes bicolored with brown and yellow
  • Large, “bug-eyed” appearance

Examples of Ripiphoridae species include Ripiphorus fasciatus, which has a fly-like appearance due to its wing structure.

Numbers

There are about 450 species of Ripiphoridae beetles found worldwide. The distribution and abundance of these species may vary according to the habitat, climate, and availability of host organisms.

Comparison table

Characteristic Ripiphoridae Other Beetles
Size Small (6-8 mm) Varies
Body shape Hump-backed Often oval
Wings Short elytra Longer elytra
Hind wings Exposed and clear Usually hidden
Eyes Large, “bug-eyed” Varies

In summary, Ripiphoridae are a unique family of beetles with distinct body characteristics that set them apart from other members of the order Coleoptera. Their small size, hump-backed shape, and exposed hind wings make them easily identifiable compared to other beetles. Scientists have classified over 450 species of wedge-shaped beetles within this family, demonstrating the diversity and widespread distribution of these insects.

Physical Features

Elytra

Ripiphoridae beetles have distinctive elytra, characterized by their shortness. This feature exposes their large, unfolded hind wings, causing them to have a fly-like appearance. Elytra are often bicolored, with a brown base and a yellow rest 1.

Antennae

The antennae of these beetles vary greatly depending on the species. Some examples of antennae types include:

  • Pectinate antennae: comb-like structure
  • Flabellate antennae: fan-shaped structure
  • Monoflabellate: single fan-shaped segment
  • Biflabellate: two fan-shaped segments 2.

Distinct antennae in Ripiphoridae:

  • Ripidius: pectinate antennae found in Baltic amber 3
  • Ripiphorus: flabellate antennae

Tarsal Formula

The tarsal formula refers to the number of segments in a beetle’s leg. Although not specified for Ripiphoridae, it’s essential to understanding their physical appearance and taxonomy 4.

Flabellate Antennae

Ripiphorus species are characterized by their flabellate antennae, which are fan-like in shape and give them a unique appearance. Comparing two types of antennae found in Ripiphoridae:

Feature Pectinate Antennae Flabellate Antennae
Shape Comb-like Fan-like
Example Species Ripidius (found in Baltic amber) Ripiphorus

Life Cycle and Behavior

Larvae

Ripiphoridae larvae have two stages in their development: triungulins and planidia. The larval stage mainly feeds on their host, typically bees or wasps.

  • Triungulins: These tiny, active larvae are well-equipped for hunting their host.
  • Planidia: After the first molt, the larvae become planidia, which are endoparasites feeding on their host’s inner tissues.

Adults

Adult ripiphorids are not well-suited for feeding and have a short life span. Their primary goal is reproduction, and they are often found near bee or wasp nests to lay their eggs.

Eggs

Female ripiphorids lay small eggs near their host’s nesting sites. Upon hatching, the tiny triungulins seek out their host, which they will eventually feed upon and grow inside.

Triungulins

These are the active, first-stage larvae of Ripiphoridae and are well-adapted to locating and attaching to their host, usually ground-nesting bees or wasps.

Planidia

The second stage of larval development, planidia are endoparasites. They bore into their host’s body, eventually consuming its entire contents.

Phoresy

Ripiphoridae larvae exhibit phoretic behavior, wherein they attach themselves to adult hosts, such as bees, wasps, or flies, and hitch a ride to their host’s nesting site.

Endoparasite

As endoparasites, ripiphoridae larvae live and feed inside their host’s body, often consuming it from within as they grow.

Pheromones

Adult ripiphorids may utilize pheromones to attract mates, increasing their chances of successful reproduction.

Comparison Table of Ripiphoridae Larval Stages:

Larval Stage Features
Triungulins Active, seek out host, well-adapted for hunting
Planidia Endoparasitic, feed on host’s inner tissues, consume host from within

In summary, Ripiphoridae have a unique life cycle and behavior, beginning with their two distinct larval stages as triungulins and planidia. Adults focus on reproduction, while the endoparasitic larvae exhibit phoresy and rely on pheromones for mate attraction.

Relationship with Other Insects

Blister Beetles

Ripiphoridae share some features with Meloidae, also known as blister beetles:

  • Both beetles have a parasitic larval stage.
  • They have similar life cycles and feeding habits.

However, differences include:

  • Blister beetles produce a defensive chemical called cantharidin.
  • Ripiphoridae larvae typically parasitize bees, while Meloidae target grasshopper eggs.

Roaches

The relationship between Ripiphoridae and Blattodea (roaches) is mainly one of predation. Ripiphoridae have been known to prey upon roach eggs, helping control the population of these pests.

Wood-Boring Beetles

Macrosiagon hentz, a species within Ripiphoridae, parasitize wood-boring beetles. They lay their eggs near the host’s entrance holes. Once the Ripiphoridae larvae enter the tunnels, they consume the host’s eggs and larvae.

Mordellidae

Ripiphoridae and Mordellidae, sometimes known as tumbling flower beetles, exhibit similarities in their physical appearance and some aspects of their biology:

  • Both possess elongated bodies and heads that point downwards.
  • They share a similar habitat, often inhabiting flowers.

A brief comparison table of the mentioned relationships:

Relationship Shared Features Differences
Blister Beetles Parasitic larval stage, life cycle, feeding habits Cantharidin production, host targets
Roaches Predation N/A
Wood-Boring Beetles Parasitism N/A
Mordellidae Physical appearance, habitat N/A

Distribution and Habitat

Range

Ripiphoridae, also known as wedge-shaped beetles, belong to the superfamily Tenebrionoidea and series Cucujiformia. They are found in various parts of the world, including North America, Europe, Asia, and Australia.

  • Ripiphorinae
  • Pelecotominae

These are the two subfamilies within the Ripiphoridae family. They have different ranges and host preferences. For example, Ripiphorinae mostly parasitize bees and wasps, while Pelecotominae attack wood-boring beetles.

California

In California, Ripiphoridae species like those within the subfamily Ripiphorinae can be found in habitats where their primary hosts, bees, and wasps, are present. Examples of such habitats include meadows, forests, and urban gardens.

  • Diverse range of habitats
  • Presence of host species

These factors contribute to the distribution of Ripiphoridae in California.

Florida

The distribution of Ripiphoridae in Florida is also influenced by the availability of their host species. In this state, the beetles can be found in diverse habitats, such as forests, wetlands, and sandy coastal areas.

  • Forests
  • Wetlands
  • Coastal areas

The diverse range of habitats in Florida supports various host species, including cockroaches, which are parasitized by some Pelecotominae species.

Feature California Florida
Habitats Meadows, forests, urban gardens Forests, wetlands, coastal areas
Host species Bees, wasps Cockroaches, other wood-boring beetles
Subfamilies present Ripiphorinae Pelecotominae

Additional Information

Clickable Guide

A great resource to explore more about Ripiphoridae is the Clickable Guide that offers information on their appearance and habitat. This guide is helpful for both amateurs and naturalists alike.

BugGuide.net

BugGuide.net is another useful platform for finding accurate information about Ripiphoridae. It provides details on the physical characteristics, like:

  • Serrated female antenna
  • Male antenna pectinate or flabellate
  • Humpbacked, wedge-shaped beetles

Local Extension Office

For expert professional advice on Ripiphoridae, consider contacting your Local Extension Office. They can offer guidance tailored to your specific region.

Nomenclature

Regarding nomenclature, keep in mind that the spelling “Ripiphorus Bosc” is outdated and should be replaced with the more accurate “Ripiphoridae.”

Works Cited

It is essential to include reliable sources in your research to ensure the information is trustworthy. Some suggested resources are:

When comparing sources, consider creating a comparison table:

Source Focus Pros Cons
Clickable Guide Appearance and habitat Easy to use Limited scope
BugGuide.net Physical characteristics Detailed info Technical jargon
Local Extension Office Expert professional advice on Ripiphoridae Tailored guidance Requires contact

In summary, this section has provided you with resources to further explore the fascinating world of Ripiphoridae, including the Clickable Guide, BugGuide.net, and a Local Extension Office for professional advice. Happy exploring!

Footnotes

  1. https://edis.ifas.ufl.edu/publication/IN1069

  2. https://uwm.edu/field-station/its-a-beetle-really/

  3. https://entnemdept.ufl.edu/creatures/misc/BEES/Ripiphorus.htm

  4. https://rdl.train.army.mil/catalog-ws/view/100.ATSC/0E47612A-F13B-4BE2-AA41-3E886A40B88C-1335953260245/report.pdf

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 – Female Wedge Shaped Beetle

 

Subject:  Female Wedge Shaped Beetle
Geographic location of the bug:  Andover, NJ
Date: 08/05/2018
Time: 03:05 PM EDT
Your letter to the bugman:  Hi Daniel,
As promised, here are three shots of the female M. limbata.  I watched her for quite some time, hoping I’d see her interacting with a host bee or wasp, but no luck.  There was another male on a patch of mountain mint in the garden, which I understand is one of their preferred plants.  So, maybe before their brief lives are over, I’ll be able to observe some behaviors.
How you want your letter signed:  Deborah Bifulco

Female Wedge Shaped Beetle

Hi Deborah,
Thanks so much for sending images of a Female Wedge Shaped Beetle,
Macrosiagon limbata, to accompany the image you sent a few days ago of the male from the same species.

Female Wedge Shaped Beetle
Female Wedge Shaped Beetle

Letter 2 – Male Wedge Shaped Beetle: A new genus on What’s That Bug?!!!

 

Subject: Beautiful looking antler(ed) bee
Location: Milton, Ontario
September 1, 2013 6:35 pm
Hi
I’m starting to take macro shots of insects, I found this ’bee’ on a trip to an apple orchard, the little guy was holding a weird looking leave of one of the apple trees. I was able to take a couple of nice pictures of it, profile and front. I haven’t seen anything like this before. I was wondering if you could help me identify it
Thanks!!
Signature: DrZhark

Wedge Shaped Beetle
Wedge Shaped Beetle, genus Ripiphorus

Dear DrZhark,
We are very excited with your submission, which we believe creates a new genus on our site.  Though your insect resembles a bee, the antennae are very characteristic of certain beetles, especially Scarabs.  We did some research and quickly found a family on BugGuide known as the Wedge Shaped Beetles, Ripiphoridae, which is described as:  “Small to medium-sized beetles, sometimes found on flowers. Many have fan-like (flabellate) antennae, esp. males. Abdomen blunt. Tarsal formula 5-5-4.”  Within that family is a genus
 Ripiphorus which is described on BugGuide as:  “Body appears wasp-like…with very short elytra (looking like large tegula) and long, exposed wings…but with very un-wasp-like antennae.  Male antennae are biflabellate, i.e. with two rami (= side-branches) at each joint, and the rami usually of roughly equal size at each joint of the relatively short main axis of the antennae.”  BugGuide also notes:  “Females lay eggs on flowers (often on buds). Eggs hatch into active first stadium larvae (triungulins) which hitch a ride on bees to their nests. Once there they feed on the brood: first as internal parasites, and later in their development as external parasites…a habit otherwise almost unknown in Coleoptera(3)  Adults are very short-lived: in many species the males live no longer than a day; females may be similarly short-lived but tend emerge over a longer period” and “Females are more commonly seen than males because they visit flowers to deposit eggs; and males are shorter lived.  The genus badly needs revision; only a fraction of spp. can be confidently identified.”  We will contact Eric Eaton to see if he can add any information.

Wedge Shaped Beetle, genus Ripiphorus
Wedge Shaped Beetle, genus Ripiphorus

Daniel:
Not only do I agree with the identification, but I learned a few things about these beetles I did not know before myself!  Like, how short-lived they are.  I think the information you provide through the Bugguide page is more than thorough.  Nice work.
Eric

Thank you for your help, and running your magnificent web site.
I had no idea the beetle was rare, I only thought it was unusual. I was very lucky to have found it =).  I left it unharmed and moved on.
I have higher resolution versions of the pictures:
http://www.flickr.com/photos/99458228@N05/9639763141/
http://www.flickr.com/photos/99458228@N05/9642999006
Thanks again

Letter 3 – Mating Wedge Shaped Beetles

 

Subject:  Mating Wedge shaped beetles
Geographic location of the bug:  Andover, NJ
Date: 08/06/2018
Time: 04:24 PM EDT
Your letter to the bugman:  I was elated today when I found a male and female M.  limbata on my mint.  The male was intent on mating with the female and, initially, she rebuffed him.  Finally, she allowed him to mount her several times – I guess his fancy head-gear finally won her over.  Now, let’s see if I can catch her parasitizing a bee…
How you want your letter signed:  Deborah Bifulco

Mating Wedge Shaped Beetles

Wow Deborah,
In the words of mom “You have the patience of a saint” and your patience paid off in getting this amazing documentation of mating Wedge Shaped Beetles,
Macrosiagon limbata. You submitted the image of the male two days ago and requested an identification, and then you followed that with the image of the female yesterday, and now, bingo. 

Mating Wedge Shaped Beetles

We believe we have taken the images out of order for our posting because we wanted to open with (please forgive the pornography reference) the money shot to better appeal to our Facebook followers.  Thanks again for all of your amazing contributions to our archives over the years.  We would also encourage you to post these images to BugGuide which has a much greater reach than our own humble website, because despite six pages of images, they have no shots documenting the mating activity.  According to BugGuide:  “They go through hypermetamorphosis. The female deposits eggs on flowers frequented by bees. The first instar is a planidum, an active larva capable of climbing on a bee or bumble bee (their hosts). They are transported to the bee nest where they behave as parasitoids. The following instars don’t have legs and feed on the bee larvae and stored pollen and nectar.”

Pair of Wedge Shaped Beetles

Thanks!  I was pretty excited to be able to watch and photograph this – made the humid 90 F day seem suddenly bearable.  I’m quite interested in their reproductive cycle and wonder if I will be able to see the larval stage?  I’ve definitely got to do some digging to get more information on these fascinating little beetles.  It doesn’t seem like there is a lot of information about them.
Thanks for the suggestion on submitting the photos to bugguide – I will definitely do that.
And thanks for being as excited as I was to see this!
Deborah Bifulco

Letter 4 – Wedge Shaped Beetle

 

two-toner
Location: Jamestown, RI
August 22, 2011 3:06 pm
This little guy was visiting the mountain mint 8/19/11.
Signature: PeeGee

Wedge Shaped Beetle

Dear PeeGee,
At first we thought this looked like a Tumbling Flower Beetle in the family Mordellidae, but when we couldn’t find a match on BugGuide, we broadened our search, and eventually identified it as a Wedge Shaped Beetle,
Macrosiagon dimidiata, which we found on BugGuide where this information is provided:  “Adults said to like to feed on Mountain-mint, Pycnanthemum spp.(1)  Larvae, like other members of the genus, are parasitoids of Hymenoptera.”  BugGuide expands on that with this remark:  “Females lay eggs on flowers, larvae hitch a ride from one of its hosts (Hymenoptera) and parasitize the brood.”  We are creating a brand new Beetle subcategory to house your submission.

Letter 5 – Wedge-Shaped Beetle

 

Subject: What is it?
Location: New Jersey
July 13, 2014 8:46 pm
I saw this bug sipping the nectar of a butterfly weed plant – asclepias.
Thanks so much for your help!
Signature: Bridget

Wedge-Shaped Beetle
Wedge-Shaped Beetle

Dear Bridget,
We now do most of our research online, but in the case of your unusual beetle, we turned to our brand new copy of Beetles of Eastern North America by Arthur V. Evans and we quickly identified your beetle as
Macrosiagon flavipenne, one of the Wedge-Shaped Beetles in the family Ripiphoridae.  According to Evans:  “Adult Ripiphrids live for only a few days and information on their lives is fragmentary.  They rest on low grasses or flowers and meet in mating swarms.  The comblike antennae on the male persumably increase its ability to locate females emitting sexual pheromones. …  All species undergo hypermetamorphosis.  Early instars feed internally on the larvae of other insects, whereas the later stages feed externally on their hosts. …   Macrosiagon larvae parasitize wasps in several families, including Vespidae, Sphecidae, Crabronidaeand Tiphidae.  Of the species Macrosiagon flavipenne, Evans writes:  “Abdomen black (male) or red (female). … Adults active in summer, found mainly on flowers.”  There is a differing spelling of the species name on BugGuide, where it is listed as Macrosiagon flavipennis.  BugGuide also notes:  “Females lay eggs on flowers. Eggs hatch into an active larva that attaches itself to visiting wasp. It is carried back to wasp nest where it burrows into a host larva.”

Wedge-Shaped Beetle
Wedge-Shaped Beetle

Thank you so much for identifying the beetle. I’ve been trying to figure it out for days. You’re the best!

Letter 6 – Wedge Shaped Beetle

 

Subject:  Feathery Tiara
Geographic location of the bug:  Andover, NJ
Date: 08/03/2018
Time: 03:14 PM EDT
Your letter to the bugman:  Hi Daniel,
I found this very festive beetle (I think?) on my common milkweed today.  I’ve gone through several searches for beetles with feathery antenna  and can’t find anything that quite matches this little guy.  The overall look of it makes me think it might be a nymph form of something.  Hoping you can ID it for me.
How you want your letter signed:  Deborah Bifulco

Wedge Shaped Beetle: Macrosiagon limbata

Dear Deborah,
This is a Wedge Shaped Beetle in the family Ripiphoridae, and thanks to this image on BugGuide, we have identified it as
Macrosiagon limbata.  This is a new species in a very underrepresented genus on our site.  According to BugGuide: “Adults on flowers of goatweed (Capraria), elderberry (Sambucus), thoroughwort (Eupatorium), beebalm (Monarda), goldenrod (Solidago), mountain mint ( Pycnanthemum),” and “They go through hypermetamorphosis. The female deposits eggs on flowers frequented by bees. The first instar is a planidum, an active larva capable of climbing on a bee or bumble bee (their hosts). They are transported to the bee nest where they behave as parasitoids. The following instars don’t have legs and feed on the bee larvae and stored pollen and nectar.”  Of the family, BugGuide notes:  “bee/wasp parasites lay eggs on/near flowers, sometimes inside flower buds. Larvae attach to visiting bees and are taken back to nest, where they are internal parasites of larval hymenoptera, in some cases only in early stages. Some are reported to feed on leaves in later stages. Adults are short-lived.”  Thank you for this marvelous addition to our archives.

Thank you so very much for the ID!  I found the genus in my Beetles of Eastern NA after you gave me the id and read up a little on them.  Fascinating, and I feel so very fortunate to have seen one.  I need to start keeping a yard list of all the insects I’ve seen here. Thank you again, and have a great weekend.  I’m off to see what I can find in the garden…

You are most welcome Deborah.  There is a pretty good record of your sightings on WTB?  You can use the search engine with your name to bring them all up.

Authors

    by
  • 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.

  • 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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