Forcepflies: All You Need to Know

Forcepflies, often recognized by their distinctive physical features and unique behavior, hold a notable position within the insect world.

These insects, though small in size, have garnered attention from entomologists and researchers due to their limited species count and the mysteries surrounding their life cycle.

As a member of the insect order Mecoptera, Forcepflies have characteristics that set them apart from other insects, making them a subject of intrigue and study.

In this article, we will explore the Forcepflies, shedding light on their taxonomy, behavior, and significance in the broader context of insect biodiversity. 

Forcepflies
Forcepfly

Taxonomy and Classification

The term “Forcepflies” refers to insects belonging to the family Meropeidae.

This family is a part of the Mecoptera order, which encompasses various insects, including scorpionflies.

However, what makes Forcepflies particularly interesting is the limited number of species within the Meropeidae family.

Currently, there are only three recognized living species: Merope tuber, Austromerope poultoni, and the recently discovered Austromerope braziliensis.

This limited distribution and species count make the family a focal point for entomological studies.

Forcepflies are also known as “earwigflies.” Despite the name, they are not related to earwigs and do not exhibit behaviors associated with earwigs, like entering human ears.

The name likely stems from their appearance and the elongated structures in males that might resemble earwig pincers to the untrained eye.

Appearance and Physical Characteristics

Forcepflies, despite their small stature, possess a set of distinctive physical features that make them easily identifiable to those familiar with their appearance.

  • Body Structure: One of the most noticeable characteristics of Forcepflies is their flattened, yellowish-brown bodies. This flattened morphology is not just an aesthetic trait but serves a functional purpose, allowing them to navigate and reside in tight spaces beneath logs and bark.
  • Wings: Their wings are another defining feature. They are divided into multiple rectangular cells, separated by a plethora of cross-veins. This intricate wing pattern is not only visually striking but is also a key identifier for the species.
Forcepfly

Sexual Dimorphism

Male and female Forcepflies exhibit certain differences in their physical appearance.

Both genders possess the characteristic flattened body and veined wings

However, the males stand out due to their elongate, slender clasping structures at the end of their abdomen, known as claspers.

These claspers are unique to Forcepflies and play a crucial role in their mating rituals. In contrast, the female’s abdomen is shorter and tapers to a narrow tip.

Distribution and Habitat

Forcepflies, though limited in species count, are spread across different regions, each species having its own specific habitat.

  • Merope tuber: This species is the only living member of the family Meropeidae found in North America. Its distribution spans the east from Ontario to Georgia and extends westward to Kansas.
  • Austromerope poultoni: This species has its habitat in Western Australia. Its discovery added to the intrigue surrounding the Forcepflies due to its distinct location.
  • Austromerope braziliensis: A relatively recent discovery, this species has added to the known biodiversity of Forcepflies. Its specific distribution and habitat details are subjects of ongoing research.

Preferred Habitats

Irrespective of their species, Forcepflies show a preference for residing under logs, bark, and leaf litter.

Their proximity to stream or river banks is also a commonality among their habitats.

This preference can be attributed to the moisture and protection these environments offer,  making them ideal for the Forcepflies’ survival.

Merope Tuber. Source: Machado R, Kawada R, Rafael JCC BY 3.0, via Wikimedia Commons

Behavior and Lifestyle

Forcepflies, like many insects, exhibit a set of behaviors that are crucial for their survival and reproduction.

Stridulation

Stridulation is a behavior where insects produce sound by rubbing certain body parts together.

In the case of Forcepflies, this behavior serves dual purposes.

Firstly, it is a mechanism to attract potential mates. By producing specific frequencies and patterns of sound, male Forcepflies signal their presence and fitness to females.

Secondly, stridulation acts as a deterrent for potential predators. The sounds produced can be perceived as threatening or alarming, causing predators to reconsider their approach.

Mating Rituals

The mating process in Forcepflies is intricate and involves specific behaviors from both males and females.

The male’s elongated clasping structures, or claspers, play a pivotal role in this.

These claspers help the male grip the female during copulation, ensuring successful mating. 

The unique design of these claspers is believed to have evolved to facilitate a secure grip, given the Forcepflies’ specific mating positions and the challenges posed by their habitats.

Unknown Life History

Despite the knowledge accumulated about Forcepflies, significant gaps remain, especially concerning their life history and larvae.

The exact processes of their development, from egg to adult, remain elusive.

This lack of information is primarily due to the insect’s secretive nature and the challenges posed by their preferred habitats.

Austromerope brasiliensis. Source: Machado R, Kawada R, Rafael JCC BY 3.0, via Wikimedia Commons

Significance of Forcepflies in Scientific Research

Given their unique characteristics and the mysteries surrounding them, Forcepflies have become a focal point in entomological research.

The discovery of species like Austromerope braziliensis has underscored the gaps in our understanding of Forcepflies and their distribution.

Moreover, one of the most intriguing aspects of Forcepflies is the unknown details of their life cycle.

While certain stages, like the adult phase, are well-documented, the larval stages remain a mystery.

This gap in knowledge has spurred numerous research initiatives aimed at uncovering the developmental processes of Forcepflies.

Understanding their life cycle is not just about academic curiosity; it has broader implications.

It can provide insights into the ecological roles Forcepflies play, their interactions with other species, and the specific environmental conditions crucial for their survival.

Lastly, the male genitalia of Forcepflies, specifically the claspers, are of particular interest due to their unique design and function.

The claspers are used to grip the female during copulation.

The design of these claspers is not arbitrary; they have evolved to ensure successful mating. 

Given the challenges posed by their preferred habitats, such as under logs and leaf litter, a secure grip during mating becomes crucial.

It’s plausible that females may prefer males with certain clasper characteristics, leading to the evolution of the current design through sexual selection.

Merope tuber Forcepfly. Source: Ilona LoserCC BY-SA 4.0, via Wikimedia Commons

Conclusion

Forcepflies are a unique group of insects that have captured the attention of entomologists and nature enthusiasts alike.

Their limited species count, with only three recognized living species worldwide, has made them a key focus of research initiatives.

Their unique behaviors, such as stridulation for mate attraction and predator deterrence, are fascinating.

However, there remain significant gaps in our understanding, especially concerning their life history and larval stages.

As research continues, these enigmatic creatures promise to offer more insights into insect evolution, behavior, and the delicate balance of ecosystems.

Reader Emails

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

Letter 1 – Forcepfly: Rare Sighting

Subject: Mystery flying insect
Location: Merrimack, NH, USA
October 3, 2012 8:23 pm
I found this insect on the by an outdoor light at night. I live in a heavily wooded rural area next to a lake in Merrimack, New Hampshire, USA. I found this caught in a vacant spider web and wasn’t going to interfere until i saw its abdomen. It looked like it has 8 legs?!

is this a mutation of some sort? because in one of these images you can clearly see the cerci, so they can’t be elongated cerci. It actively moved each of the ”7th & 8th” legs independently. Any ideas what this may be?
Signature: Jace Porter

Forcepfly

Dear Jace,
This is a very exciting posting for us.  This is a new species, a new category, and a totally unknown group of insects for us.  This is a Forcepfly in the family Meropeidae which we identified on BugGuide.  It most closely resembled a Scorpionfly to us and they are classified in the same order, Mecoptera. 

We learned on BugGuide that Forcepflies are also called Earwigflies and that there are only “2 spp. worldwide, one in North America, another in sw. Australia.”  We also learned that:  “The family was widespread during the Jurassic from Australia to Antarctica and over the Americas; the extant members are relics that survived at the edges of that ancient range.” 

The species is Merope tuber and according to BugGuide:  “Very little is known about biology or behavior. Larvae have never been discovered. The flattened appearance suggests that the adults probably spend much of their time close to the ground hiding in cracks and crevices.”  Finally, they are “uncommon to rare in collections and seldom encountered.”

Forcepfly

The forcep clasping structures at the tip of the abdomen indicate that this is a male.

Forcepfly

According to the NCSU Insect Museum website:  “Merope tuber is native to the eastern deciduous forests in North America and occurs from southeastern Canada (Ontario) south to Florida, west to Iowa and Kansas (1, 3). The Florida Natural Areas Inventory lists the species as very rare and vulnerable to extinction.

Very little is known of its life history and the larvae have not yet been recognized.  The larvae of the earwigfly could provide important information about the evolutionary relationships in holometabolous insects (4). The undergraduate Entomology club at Cornell has established the species as their mascot and have made it their goal to find and describe the larval stage!” 

The Cornell Undergraduate Entomology Club Website states:  “They are generally rare and secretive insects, but adult specimens are still occassionally collected near streams or at blacklight traps. However, Meropeid larvae have never been found or identified.

We at Snodgrass and Wigglesworth, therefore, have adopted Merope tuber as our official mascot and made it our mission to locate and describe the larval stage of Merope, as this would be a valuable contribution to the annals of entomology. ”

Thank you! This is very exciting for me too.  Do you have any tips on how I could preserve this?  Or any organizations I may donate this to for further study?
Thanks again,
Jace Porter

Update
I found the female forcepfly and I believe it may be pregnant. I would like to study it until it lays its eggs and incubate until the larvae hatch. I know its never been done, but do you have any helpful tips?

Hi again Jace,
We would recommend contacting your local Museum of Natural History or perhaps the Cornell Undergraduate Entomology Club to donate the specimen.  We would love to post a photo of the female Forcepfly.

Thanks for the suggestions. I have contacted Cornell and await a response, unfortunately though she flew away after I opened the lid to her terrarium while I was trying to get a picture. 🙁 Live insects can be stubborn photo subjects. 

They tend to stay in my area at night when I have our outside light on, so i’ll keep my eye out for her and hope I can safely capture her again, and this time I’ll get a picture before capture.

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.

    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.

    View all posts

2 thoughts on “Forcepflies: All You Need to Know”

  1. Thank you! This made my day. I appreciate the quick response. It’s very exciting to know I have found a rare species. I will be preserving this specimen.

    Reply

Leave a Comment