Written by Kutlwano Mokoena
Founder of Evergreen Hideout Agricultural Services (NPO: 2024 / 380375 / 07), specialising in regenerative biology and the ecological role of decomposers.
Quick Guide to Net-Winged Beetles
Net-winged beetles belong to the family Lycidae. Their distinctive wing patterns and chemical defences make them interesting insects to encounter in gardens and natural environments.
Many species display bright orange, red, yellow and black patterns that warn predators of their chemical defences.
Many Lycid larvae live in decaying wood and feed on nutrient-rich fluids associated with fungal decomposition.
🌿 My First Encounter with a Net-Winged Beetle
I first spotted a Net-Winged Beetle in February 2025, during the height of summer in Soshanguve. At the time, I was working at St Francis Primary School, where I had been running a gardening project since the beginning of the year.
I was inspecting the guava tree near the edge of the school garden, checking its leaves for signs of pest damage, when something bright caught my attention.
As I turned over a large, healthy guava leaf, I noticed a flash of orange and black against the deep green surface. At first, I thought it was a piece of plastic or a fallen flower petal. Looking closer, I discovered a small beetle, approximately 2 cm long, with distinctive ridged wing covers and striking colours.
What I observed: The beetle was relatively still, resting on the guava leaf in the warm morning sunshine. When I gently nudged it with a blade of grass, it responded by slightly raising its wings. I also noticed a faint chemical odour. This behaviour made me curious about its defensive adaptations, particularly reflex bleeding.
The encounter stood out for three reasons:
- Connection to decomposition: Many Lycid larvae develop in decaying wood and are associated with fungal activity. Although spotting an adult beetle does not prove that a particular fungal network is present, it highlights the importance of maintaining suitable organic habitats around gardens.
- Garden biodiversity: Finding an unfamiliar insect on the guava tree reminded me that a garden supports far more life than the vegetables and fruit trees we deliberately cultivate. Our no-spray approach also gave us an opportunity to observe beneficial and less familiar insects without immediately disturbing them.
- An educational opportunity: I called the learners over to have a closer look. They were fascinated and a little nervous. I explained how bright colours can warn predators that an insect is chemically defended. They took photographs on their phones and named it "Spotted" before I gently guided it back onto the guava leaf.
📍 Location: St Francis Primary School, Soshanguve, Pretoria — on a guava tree leaf
📅 Date: February 2025
🌤️ Conditions: Hot summer morning, approximately 32°C, with high humidity
🌱 Activity: Inspecting the guava tree for pest damage and leaf health
Identifying Net-Winged Beetles: The Structure of Their Wings
The name "Net-Winged Beetle" comes from the distinctive surface pattern of its elytra, the hardened or modified forewings that protect the flight wings underneath.
These wing covers have raised longitudinal ridges crossed by smaller transverse ridges, creating a net-like appearance. This pattern is one of the most recognisable features of the family Lycidae.
Unlike many beetles with heavily hardened wing covers, Lycids generally have relatively soft-bodied structures. Their distinctive appearance and lightweight build are associated with their active adult lifestyles, which may include visiting flowers for nectar.
Chemical Defences: Why Net-Winged Beetles Are Brightly Coloured
Net-winged beetles do not rely entirely on speed or physical protection to escape predators. Many species use chemical defences alongside their conspicuous colours.
One of their defensive behaviours is known as reflex bleeding. When threatened, a beetle can release defensive fluid from joints in its body. This fluid may contain unpleasant-smelling and distasteful compounds that discourage predators from eating it.
Some Lycid species produce or contain compounds known as methoxypyrazines, which contribute to their characteristic odours and chemical defence.
Their bright colours are an example of aposematic coloration. Rather than hiding from predators, these insects advertise that attacking them may be an unpleasant experience.
In some cases, multiple chemically defended species evolve similar warning signals, a phenomenon known as Müllerian mimicry. This shared appearance can help predators learn to avoid them.
Larval Ecology: The Connection Between Net-Winged Beetles and Fungal Decomposition
The adult beetle is only one part of the Lycidae life cycle. Their larvae have a very different lifestyle and are commonly associated with moist, decaying organic material.
Many Lycid larvae are flattened and have specialised body structures that help them move through narrow spaces in decaying wood and other organic habitats.
Rather than feeding on healthy living plants, many species obtain nutrients from fluids associated with fungal decomposition. Fungi break down complex materials such as lignin and cellulose in dead wood, helping return nutrients to the surrounding environment.
This relationship illustrates why decaying wood and undisturbed organic matter are important parts of natural ecosystems. They provide food and shelter for numerous organisms involved in decomposition.
For gardeners, the lesson is simple: not every piece of decaying wood or leaf litter needs to be removed. Where practical, retaining suitable organic habitats in designated areas can support biodiversity and the organisms involved in natural nutrient cycling.
Frequently Asked Questions About Net-Winged Beetles
Are Net-Winged Beetles harmful to garden plants?
Generally, no. Net-winged beetles are not known as significant vegetable garden pests. Adults may visit flowers for nectar, while many larvae develop in decaying wood and other organic habitats.
How can I encourage Net-Winged Beetles in my garden?
Maintain suitable natural habitats by retaining some decaying wood, leaf litter and organic matter in appropriate areas. Avoid unnecessary pesticide applications and allow parts of the garden to support natural biodiversity.
Why are Net-Winged Beetles orange and black?
Their contrasting colours are an example of aposematic coloration. These warning signals help predators recognise that the beetles may be chemically defended and unpleasant to eat.
Why was the beetle resting on a guava tree leaf?
Adult beetles may rest on leaves and other vegetation. They may also visit nearby flowers for nectar. The guava leaf provided a resting place, although the observation alone cannot establish exactly why the beetle chose that particular spot.
Should I touch a Net-Winged Beetle?
It is better to observe these insects without handling them unnecessarily. Some species release defensive fluids when disturbed. If you need to move one, use a leaf or another gentle method rather than handling it directly.
Conclusion: What a Net-Winged Beetle Can Teach Us About Garden Biodiversity
Net-winged beetles offer an interesting glimpse into the relationships that sustain natural ecosystems. Their warning colours and chemical defences demonstrate how insects protect themselves, while their larval association with decaying wood highlights the importance of decomposition.
For gardeners, these observations are a reminder that healthy growing spaces need more than productive plants. Organic matter, suitable habitats and a diversity of organisms all contribute to the ecological processes that support a garden.
My encounter with this beetle on a guava leaf at St Francis Primary School in February 2025 was a memorable experience. What initially looked like a small flash of colour became an opportunity to teach learners about insect defence, biodiversity and the less visible relationships that exist within a garden.