Have you ever wondered about the tiny creatures buzzing, crawling and flying around you? Insects comprise most animal species on Earth and play vital roles in ecosystems.
Insects are by far the most diverse group of animals on the planet. Scientists have identified and described over 1 million insect species so far, but estimates suggest there could be 5-10 million species in total. That means around 75% of all animal species are insects!
Their diversity allows them to inhabit almost every land habitat, from tropical rainforests to deserts. Due to their small size, insects can evolve rapidly and exploit many ecological niches over millions of years. Their success is evident in their abundance, with 1 gram of soil containing around 1 million individual insects.
Despite their small stature, insects have sophisticated internal systems that allow them to survive. Their outer skeleton or exoskeleton made of chitin provides protection but also limits growth, so insects moult and shed their skin as they mature. Inside, you’ll find a complex system of tracheae that deliver oxygen directly to tissues, unlike our lungs.
A three-part body plan of head, thorax and abdomen houses six jointed legs, compound eyes and other appendages. Reproduction varies between species, but external fertilisation is common, with females laying eggs that hatch into young nymphs or larvae.
The Importance of Insects
Insects perform crucial roles in ecosystems that would collapse without them. As pollinators, insects like bees, butterflies, and moths fertilise around 90% of wild plant species and 75% of global food crops. Scavengers like dung beetles recycle nutrients and reduce disease. Predators such as ladybirds control pest populations.
Insects also provide an essential food source for birds, bats, reptiles and other animals higher up the food chain. Their biomass far exceeds that of all humans and livestock combined. Clearly, the tiny insect world supports and sustains life everywhere it thrives.
Some insect species have evolved extraordinary social behaviours. Ants, bees, wasps and termites live in large colonies with distinct castes performing different tasks. Ant colonies can contain millions of individuals cooperating flawlessly without leaders. Worker ants clean, feed larvae, ventilate the nest and act as living construction equipment.
Honeybees perform waggle dances to communicate food sources to one another. Termites build towering mounds through cooperation, housing populations larger than some human cities. Indeed, social insects embody teamwork like no other animals on Earth.