Butterflies and Moths With Clear Wings – A Unique Form of Camouflage
Butterflies and moths with transparent or clear wings represent a unique group of insects that use camouflage to their advantage While most butterflies and moths have brightly colored, patterned wings, some species have evolved partial or complete wing transparency as a way to evade predators
Clear wings provide an exceptional form of camouflage, allowing these insects to essentially become invisible against their natural backgrounds When at rest among leaves, branches or brush, their see-through wings render them practically undetectable to birds, lizards and other predators
This article will explore some of the most fascinating butterflies and moths with clear wings, examining their adaptations and behaviors. It will also look at the benefits and limitations of clear wings versus traditionally colored wings in butterflies and moths.
Why Clear Wings Provide Effective Camouflage
Butterflies and moths with transparent wings inhabit primarily densely vegetated tropical and woodland regions. Against the complex backdrops of foliage, clear wings allow them to blend in seamlessly and avoid notice.
The levels of transparency vary – some species have wings that are completely transparent, while others have small or moderate opaque patterns on otherwise translucent wings. Even partial transparency provides excellent camouflage amidst the intricate shapes and shadows of leaves and branches.
In addition to transparency, some clearwing species have wings with vein patterns that reinforce the resemblance to vegetation. The venation looks similar to that of leaves, further enhancing the camouflage effect.
Limitations of Clear Wings
While clear wings provide predator evasion advantages, they also have some limitations compared to traditionally colored wings.
Pigmentation on wings allows butterflies and moths to absorb heat from sunlight. This facilitates thermoregulation – controlling internal temperatures as they fly around in changing conditions. Clear wings are less efficient for thermoregulation, which could present challenges in maintaining optimal body temperatures.
Additionally, some research indicates transparent wings may be more fragile and prone to damage in wet jungle conditions. The structural integrity could deteriorate faster.
Nevertheless, the overall benefits of the camouflage effect appear to outweigh the disadvantages of clear wings for species that have evolved this adaptation.
Notable Clearwing Butterfly Species
Some of the most fascinating transparent-winged butterflies include:
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Thick-tipped Greta: Common in Central America, these butterflies have almost completely transparent wings except for black wing tips and white stripes. They absorb toxins from plants, making them poisonous to predators.
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Glasswing Butterfly: Mostly found in Central and South America, the aptly named glasswing butterfly has entirely see-through wings with opaque black accents along the edges. They migrate short distances in search of food.
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Big Greasy: Native to Australia, these very large butterflies have transparent forewings and hindwings with mostly opaque black edges. Males are noticeably bigger than females.
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Confusa Tigerwing: Inhabiting high mountain elevations up to 7,000 feet in South America, this species has clear wings with brown and black accents. They feed on toxic plants, becoming inedible to predators.
Notable Clearwing Moth Species
Some moths are just as adept at the clearwing camouflage strategy, including:
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Hummingbird Clearwing: Found across much of North America, these moths mimic hummingbirds in appearance and flight patterns. They have transparent wings with bold red borders.
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Snowberry Clearwing: Common in North America, larvae of this hairy species feed on Snowberry plants, which also provide nectar for adults. Their wings have distinct black venation against transparency.
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Six-belted Clearwing: Named for abdominal stripes, these slender moths copy wasps in shape, size and coloration. They have mostly transparent wings with minimal black borders.
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Scarlet-tipped Wasp Mimic: Another wasp copycat, this South American moth has glass-like wings with red body tipping. At just 1.2 inches wingspan, it’s one of the smallest clearwing moths.
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Banyan Tussock Moth: Native to tropical Asia, these moths have opaque black hindwings but forewings that are nearly completely transparent. They can damage fruit crops.
A Masterful Form of Disguise
Butterflies and moths with see-through wings provide some of the most fascinating examples of camouflage in the insect world. Using transparency to disappear against complex backgrounds, they illustrate the amazing adaptations species can evolve to avoid predators and survive in their environments. There is still much to learn about these elusive clearwing insects.
Morphogenesis and cytoskeletal organization of developing scale cells
To investigate developmental processes of wing and scale development, we performed dissections of G. oto pupae at different time points (Fig. 2). As in other species of Lepidoptera, the early pupal wing consisted of a thin bilayer of uniform epithelial tissue and by 16 h APF, numerous epidermal cells had differentiated to produce parallel rows of sensory organ precursor (SOP) cells (the precursors to the scale and socket cells) (Fig. 2B,C). At this early stage of wing development, we observed that the clear wing region harbored a lower density of SOP cells relative to the opaque wing region (Fig. 2B,C). In a 400 μm2 area, the density of SOP cells in the clear region was 65.2±7.0, compared with the density of SOP cells in the opaque region of 169.2±15.7 (t=−10.4629 d.f.=4, P=0.0003, N=3 pupae). We can therefore infer that early into wing development, SOP cell patterning is differentially regulated between clear and opaque regions, which impacts the adult wing scale density and the amount of wing membrane surface exposed in different parts of the wing.
Pupal wing development and cytoskeletal organization of scales in clear and opaque regions. (A) Representative of a G. oto pupa ∼5 days after pupal formation (APF), (A′,A″) developing up to the melanic stage ∼7 days APF, just prior to eclosion. (B,C) Early wing development 16 h APF stained with DAPI (nuclei) in (B) a clear wing region and (C) an opaque wing region. The clear region contains a reduced number of sensory organ precursor (SOP) cells (the precursor cells to the scale and socket cells) relative to the opaque region. Scale bars, 20 μm. SOP cells are false-colored magenta for better viewing. (D–I) Fluorescently labeled scale cell membrane (wheat germ agglutinin; WGA, magenta) and F-actin (phalloidin, green), comparing clear wing regions (D,F,H) to opaque wing regions (E,G,I). (D,E) At 30 h AFP, WGA and phalloidin staining reveal early scale buds extending from the wing epithelium and loosely organized parallel actin filaments. (F,G) At 48 h APF, scales have grown and changed in morphology. Short actin filaments have reorganized and formed smaller numbers of thick, regularly spaced parallel bundles under the cell membrane surface. (F) In the clear wing region, scale cells alternate between triangular shapes and bristles. (H,I) At 60 h APF, developing scales have become more elongated. (H) The triangular-shaped scales in the clear wing region have proceeded to generate two new branches, which fork and elongate bidirectionally. (I) In the opaque region, scales are longer and have developed serrations at the tips. Scale bars, (D–I) 10 μm.
Next, we investigated cellular and cytoskeletal organization during scale growth in clear and opaque wing regions (Fig. 2D–I). We found that general aspects of scale development in G. oto follow those previously reported in several butterfly and moth species by Dinwiddie et al. (2014), with some notable distinctions for modified scale growth in the clear wing regions of G. oto. By 30 h APF, the SOP cells have divided to produce the scale and socket cells (Fig. 2D,E). The scale cell body lies internally within the wing, while the socket cell associated with each scale cell lies in a more superficial position. Phalloidin staining showed the appearance of small cylindrical scale outgrowths containing F-actin filaments, and WGA staining showed outlines of the membrane as the scale outgrowths begin to project and elongate beyond the wing surface. At this stage, budding scales in the clear wing region appeared morphologically similar to the unspecialized opaque scales: roughly elongated balloon-shaped with numerous small actin rods fanning out from the pedicel to the apical tip of the scale (Fig. 2D,E). By 48 h APF, scale cell extensions have grown and elongated (Fig. 2F,G). The actin filaments have reorganized into smaller numbers of thick, regularly spaced bundles along the proximal–distal axis of the scale just under the surface of the cell membrane. Fluorescent staining revealed larger bundles of F-actin in the adwing (facing the wing membrane) side of the scales relative to the abwing side (Movie 1). At this stage, scales in different regions of the wing had taken on dramatically different morphologies. Scales in the clear region had elongated in a vertical orientation and obtained two types of alternating morphologies: short and triangular, or long and bristle-like outgrowths (Fig. 2F). In the opaque region, scales had taken on a round and flattened morphology, with ground scales shorter than the cover scales (Fig. 2G). By 60 h APF, scale projections were even more elongated (Fig. 2H,I). The triangular scales in the clear wing region had proceeded to generate two new branches, which forked and elongated at the tips bidirectionally, while bristle-like scales had elongated and curved (Fig. 2H). In the opaque region, scales were longer, wider and flatter, and had developed serrations at the tips (Fig. 2I).
Scale measurements in clear and opaque wing regions of adult G. oto
We investigated features of scale density, scale morphology and the amount of wing surface exposed in adult G. oto. We focused on two adjacent regions on the dorsal surface of the forewing for consistency: a clear region within the discal cell and an opaque region that consists mainly of black scales near the cross-vein (indicated by the red box in Fig. 1F). The clear wing region contained two types of alternating scale morphologies – bristle-like scales and narrow, forked scales – while within the opaque wing region, scale morphologies resembled ‘typical’ butterfly pigmented scales – flat and ovoid with serrations at the tips (Fig. 1K,L). The mean (±s.d.) density of scales in the adult wing were significantly lower within the clear region, with 98.2±18.1 scales per mm2 in males and 102.3±17.2 in females, compared with the opaque region with 374.3±22.2 scales per mm2 in males and 358.1+19.6 in females (t=−30.9, d.f.=4, P<0.0001 for male sample comparison, t=−21.9, d.f.=4, P<0.0001 for female sample comparison; Fig. 1N). In the clear region, forked scales were significantly smaller in size (498±39 μm2) compared with the bristle-like scales (831±183 μm2), while in the opaque region, scales were the largest (3467±382 μm2) (Fig. 1O). Finally, the amount of exposed wing membrane was significantly different between wing regions, with an average of 81.6±2.7 and 82.2±4.3% of exposed membrane in the clear wing regions of males and females, respectively, compared with 2.6±1.1 and 1.4±0.7% membrane exposed in opaque regions of males and females, respectively (t=78.9423, d.f.=4, P<0.0001 for male sample comparison, t=48.3854, d.f.=4, P<0.0001 for female sample comparison, Fig. 1P).
Butterfly or Moth?
FAQ
What kind of moth has clear wings?
Hummingbird Moth (Clearwing Moth) At first sight, it’s easy to mistake a hummingbird moth for a tiny hummingbird. It feeds on the nectar of flowers, hovering with the body stationary, its transparent wings beating so fast as to be nearly invisible, and a long proboscis protruding beaklike into the blossom.
What kind of butterfly has clear wings?
Glasswing butterflies (one pictured) sport mostly transparent wings that help the insects hide from predators.
What is the saying about moths and butterflies?
The moth prefers the moon and detests the sun, while the butterfly loves the sun and hides from the moon.
What are the moths that look like butterflies?
The false tiger moth (Dysphania militaris) is one of the moth species most commonly mistaken for a butterfly, perhaps due to its bright coloration, which is reminiscent of some swallowtail butterflies.
What do clearwing moths look like?
Clearwing moths have transparent wings that lack scales. Unlike other moths, their front and back wings are hooked together by curved spines, resembling wasps, which is a form of protective mimicry.
Where do clear-winged butterflies and moths live?
These types of species live all over the world and they often spark the interest of researchers. Most butterflies and moths have pigmented wings and this helps for quick species identification. A smaller group of butterflies and moths have clear wings.
Why do butterflies and moths have clear wings?
A smaller group of butterflies and moths have clear wings as a distinct trait. These species use this feature to escape predators by employing camouflage. Most butterflies and moths have pigmented wings, which aids in quick species identification.
Are butterfly and moth wings transparent?
Many aquatic organisms, including jellies and fish, are transparent. But transparent butterfly and moth wings are so arresting that merely catching a glimpse of one typically causes a human to lunge for a camera or at least point it out to their friends. These enigmatic, transparent butterfly wings have not been studied comprehensively.
What do clearwing butterflies look like?
Clearwing butterflies, part of the clearwing genus, are known for their transparent wings with a yellow tint. Males have transparent forewings with black margins and brown tinged lower forewings, while females have a more pronounced yellow tint.
What do moths with clear wings mimic?
Moths with clear wings are known to mimic mockingbirds. Almost all types of moths with clear wings have visible contrasting black veins and possibly colorful margins. These types of moths are difficult to spot or might even look confusing to their predators.