Conquering the Clegs: Your Essential Guide to Horseflies on the Isle of Mull

The Isle of Mull is a truly spectacular destination, famed for its rugged cliffs, silver-sand beaches, and dramatic mountains. While the Scottish midge often gets a bad rap, many seasoned outdoor enthusiasts consider the horsefly, or “cleg,” to be the real challenge of the Scottish summer. These persistent insects can turn a peaceful walk into a “maddening dance of swatting and cursing”. But don’t let them deter you! With the right knowledge and preparation, you can enjoy Mull’s natural beauty comfortably and safely.

Understanding Horseflies: The Basics

What are Horseflies (Clegs)?

Horseflies are robust insects, easily recognized by their large eyes and sometimes patterned wings. In the UK, the Notch-horned cleg-fly is a common species, dark grey with mottled wings and distinctive iridescent eyes. They can be quite large, with some species reaching over an inch in length.

Only female horseflies bite, as they need blood to produce their eggs. Unlike mosquitoes that pierce the skin, horseflies use scissor-like mouthparts to cut the flesh, creating a painful wound from which they lap up blood. This is why their bites are so immediately sharp and can sometimes bleed.

Where and When Do They Appear?

You’ll typically find horseflies near water sources like rivers, lakes, or marshes, and in areas with livestock. On Mull, this means long grasslands, wetlands, and damp woodlands.

They are most active during the day, particularly in warm and humid conditions. Horseflies are strong flyers and are highly attracted to movement, warmth, and the carbon dioxide we exhale. They often approach silently from behind and wait in shady spots. Many people only feel the bite as the fly is already leaving.

A close-up view of a horsefly (cleg), showing its distinctive large eyes and patterned body.

Horsefly Season on Mull

Horseflies typically emerge with the Scottish summer, with their activity peaking from May through September. Their most active period is generally June to September. While May, June, and late August to September are often recommended as good times to avoid the highest concentrations of midges, horseflies can still be very present during these months.

Your Proactive Protection Plan: Don’t Get Bitten!

Effective prevention is your best defense. It’s a combination of smart clothing, the right repellents, and a few behavioral tweaks.

1. Dress for Success: Strategic Clothing Choices

1. Cover Up: Wear long-sleeved tops, long trousers, and closed-toe shoes to create a physical barrier.
2. Light Colours: Horseflies are drawn to dark, fast-moving objects, so light-coloured clothing can make you less conspicuous.
3. Tightly Woven Fabrics: Choose materials that are tightly woven, making it harder for flies to bite through.
4. Head Net: A midge head net or hood, worn over a hat, is excellent for protecting your face, head, and neck. Insects, including horseflies, can be incredibly persistent around your eyes, ears, nose, and mouth.
5. Permethrin-Treated Clothing: For an extra layer of defense, consider clothing treated with permethrin (e.g., Insect Shield). This EPA-registered technology provides built-in, long-lasting insect protection for up to 70 washes and is invisible and odorless. You can buy pre-treated apparel or apply permethrin spray to your own clothing and outdoor gear.

2. Repellents: Your First Line of Chemical Defense

Choosing the right insect repellent is crucial.

1. Picaridin (Saltidin/Icaridin) – Our Top Pick:
   • Smidge (developed in Scotland) contains 20% Saltidin® (Picaridin) and is scientifically proven to provide up to 8 hours of sweat-proof protection against horseflies, midges, mosquitoes, and ticks.
   • It works by blocking insects’ ability to find you and makes your skin unpalatable to them.
   • Smidge is gentle on the skin, non-sticky, has a pleasant citrus aroma, and won’t damage plastics or metals (making it safe for your phone, camera, and other gear!).
   • It’s water-based, includes moisturizer, and is safe for children over 24 months, pregnant, and breastfeeding individuals.
   • The WHO, Public Health England, Health Protection Scotland, and the CDC all recommend Picaridin as an effective alternative to DEET.
2. DEET – A Powerful Alternative:
   • DEET is a common and highly effective ingredient in many repellents. The EPA has concluded that DEET is safe when used as directed.
   • However, DEET can damage certain plastics (like credit cards, glasses frames, phone cases) and synthetic fabrics. It can also leave a sticky residue and may feel unpleasant on the skin.
3. Other Options:
   • Citrepel® has shown efficacy against horseflies, midges, and other biting insects, offering up to 8 hours of protection.
   • Avon Skin So Soft has gained a reputation in Scotland for its effectiveness against midges, reportedly even used by the Royal Marines, though its efficacy against horseflies is less explicitly documented.

Application Tips:

1. Always apply repellent to exposed skin and clothing.
2. For liquid repellents, spray onto your hands first, then rub onto exposed skin, carefully avoiding direct spray on the face.
3. If using sunscreen, apply it first and allow it to absorb before applying repellent.
4. Reapply as needed, especially after heavy sweating or prolonged swimming.

Our Pick

Avon Skin So Soft

Avon Skin So Soft Original Dry Oil Body Spray with Jojoba 150 ml – Pack of 2

Buy Now

We earn a commission if you make a purchase, at no additional cost to you.

3. Behavioral Avoidance: Smart Strategies

1. Avoid Breeding Grounds: Horseflies are prevalent near water sources (rivers, lakes, marshes) and in long grasslands and damp woodlands. Try to avoid lingering in these specific environments, especially during summer.
2. Stick to Paths: When hiking, adhere to marked paths rather than venturing into tall grass or thick bushes, where insect populations are often denser.
3. Minimize Attractants: Horseflies are drawn to sweat. Strong perfumes, scented soaps, shampoos, and deodorants can also attract various insects. Opt for fragrance-free personal care products when outdoors.
4. Calm Movement: Horseflies are highly attracted to movement. While instinctive, frantic flailing or desperate swatting may actually invigorate their pursuit rather than deter them. A calm, steady retreat may prove more effective.
5. Seek Shelter: If insect populations become overwhelmingly high, retreating indoors or to a screened tent can provide a much-needed respite. Keeping windows and doors closed or utilizing fine netting can prevent insects from entering indoor spaces.

If You Get Bitten: Immediate First Aid & Treatment

Despite your best prevention efforts, a horsefly bite can still happen. Knowing how to respond effectively is crucial for managing discomfort and preventing complications.

Recognizing a Horsefly Bite

Horsefly bites are widely known for their immediate and intense pain. Within minutes, the affected area typically develops into a red, raised, and swollen lump. Itchiness is also a very common accompanying symptom. Due to the horsefly’s scissor-like mouthparts that cut the skin, bites can sometimes result in bleeding at the site. It’s also important to note that horsefly bites may take a longer time to heal compared to other insect bites.

Step-by-Step Immediate First Aid

1. Clean the Area Thoroughly: As promptly as possible, wash the bite area with soap and warm water. This is fundamental in reducing the risk of a secondary infection.
2. Apply Cold Compress: To alleviate swelling and pain, a cloth soaked in cold water or an ice pack (always wrapped in a cloth to protect the skin) should be placed on the bite for at least 10 to 20 minutes.
3. Elevate the Area: If the bite is located on a limb, keeping the affected area elevated can further assist in reducing swelling.

Over-the-Counter Remedies for Symptom Relief

1. Painkillers: Non-prescription painkillers such as paracetamol or ibuprofen can be taken to manage pain and reduce swelling. Always follow package instructions.
2. Antihistamines: Oral antihistamines are effective in reducing swelling and alleviating the intense itching commonly associated with horsefly bites.
3. Topical Creams: A mild hydrocortisone cream can be applied to the affected area to reduce itching and swelling. An antiseptic spray may also be used to help reduce irritation.

Crucial “Don’ts”: What to Avoid for Safe Healing

1. DO NOT SCRATCH! This is perhaps the most critical instruction. Scratching the bite can break the skin, which significantly increases the risk of secondary bacterial infection.
2. DO NOT Use Unproven Home Remedies: Avoid attempting to treat the bite with unverified home remedies, such as bicarbonate of soda, vinegar, or petroleum jelly, as these are unlikely to be effective and may even worsen the situation. While calamine lotion may offer temporary soothing, it can dry and potentially exacerbate itching in the long run.
3. Horseflies do NOT leave stingers.

When to Seek Help: Recognizing and Managing Complications

While most horsefly bites resolve without serious complications, it is essential to recognize when medical attention is necessary.

Signs of a Developing Infection

1. Increased redness (which may be harder to discern on brown or black skin).
2. The skin around the bite feeling warm to the touch.
3. Escalating pain or increased swelling.
4. The presence of pus or fluid emanating from the bite.
5. A spreading rash that extends away from the bite, which could signal cellulitis.

If the infection or wound appears to be worsening, or if it has not resolved within seven days, professional medical advice should be sought. A pharmacist can offer valuable guidance, recommend appropriate over-the-counter treatments such as antihistamines and steroid creams, and, if deemed necessary, may be able to provide antibiotics for an infected bite. It is also advisable to consult a general practitioner (GP) if an infant under 1 year old has sustained an insect bite.

Identifying Severe Allergic Reactions (Anaphylaxis)

1. Sudden swelling of the lips, mouth, throat, or tongue.
2. Rapid or struggling breathing, wheezing, or a sensation of choking or gasping for air.
3. A tight feeling in the throat or difficulty swallowing.
4. Changes in skin color, such as the skin, tongue, or lips turning blue, grey, or pale (this may be more easily observed on the palms of hands or soles of feet for individuals with black or brown skin).
5. Sudden confusion, drowsiness, dizziness, weakness, or fainting.
6. A widespread rash that is swollen, raised, or intensely itchy (hives).
7. Nausea, vomiting, or diarrhea.

When to Consult Medical Services

1. Pharmacist: Consult for advice on over-the-counter treatments, such as antihistamines and steroid creams, or if there is a suspicion that the bite has become infected.
2. General Practitioner (GP): A GP visit is recommended if the bite is on a child under 1 year old, if symptoms are worsening, if a high temperature or swollen glands develop, or if multiple bites have been sustained.
3. Call NHS 111 (Non-Emergency): Contacting NHS 111 is appropriate for advice regarding a child under 5 years old, or if there is a history of severe allergic reactions to insect bites.
4. Call 999 (Emergency Services): Dial 999 immediately for an ambulance if an individual experiences any symptoms of a severe allergic reaction (anaphylaxis), particularly sudden swelling of the face or airways, severe breathing difficulties, or loss of consciousness. If the person carries an adrenaline auto-injector (Epipen), it should be administered without delay.

Enjoying the Isle of Mull Safely and Comfortably

The Isle of Mull is an undeniably stunning destination, offering unparalleled natural beauty and diverse outdoor adventures. While horseflies (clegs) are an acknowledged part of the Scottish summer experience, their presence should not deter you from exploring this captivating island.

By understanding their behavior, implementing effective prevention strategies, and knowing how to respond to bites, you can significantly mitigate the impact of these insects. Embrace these practical recommendations—from making strategic clothing choices and utilizing effective repellents to knowing when and how to seek medical attention—and you’ll be well-equipped to navigate the “wee beasties” of the Scottish summer.

This comprehensive approach empowers you to take control of your outdoor experience, ensuring your adventure is memorable for all the right reasons. A prepared traveler is a happy traveler, ready to fully immerse themselves in the magic of the Isle of Mull!