Thrips are tiny insects often found on plants, known for their ability to cause damage.
The Actual Size of Thrips
Thrips are remarkably small, with most adult individuals typically measuring around 1 to 2 millimeters in length. To visualize this, imagine a tiny dark sliver or a piece of long-grain rice, as they are often no larger than the thickness of a sewing needle. While the majority are minute, some larger predatory species can reach up to 14 or 15 millimeters, though these are less common and typically found in tropical regions. Their diminutive size means that people often notice the damage they cause to plants before they actually spot the insects themselves. The exact size can also vary significantly between the approximately 7,700 described species of thrips.
Identifying Thrips
Adult thrips typically have slender, elongated, and somewhat cigar-shaped bodies, with coloration ranging from translucent white or yellowish to various shades of brown or black, though some species exhibit brighter hues like reddish-orange. Younger thrips, known as nymphs or larvae, are often paler in color, such as yellow or green, and lack wings. A key characteristic of adult thrips is their two pairs of narrow, strap-like wings, uniquely fringed with fine hairs, which fold flat over their backs when at rest, often making them appear wingless. While thrips can move by crawling, they may also leap or fly short distances when disturbed, although they are not considered strong fliers. Observing their movement as an “animated line” or shaking plants over a white surface can help reveal their presence.
Implications of Their Small Size
The small stature of thrips has significant consequences for their behavior and impact on plants. Their minute bodies allow them to effectively conceal themselves in tight spaces, such as inside flower buds, within leaf crevices, or on the undersides of leaves. This ability to hide makes them challenging to detect, allowing infestations to establish. Some species can even burrow between the upper and lower surfaces of leaves, further aiding their concealment. Their size also dictates their unique feeding mechanism; thrips use their asymmetrical mouthparts to pierce the outer layer of plant cells and then suck out the internal contents or sap. This feeding process results in damage that can seem out of proportion to their size, appearing as stippling, silvery or bronzed streaks, discoloration, or distorted growth on leaves, flowers, and fruits. Additionally, their small size combined with their fringed wings enables them to be carried long distances by air currents and wind, facilitating their widespread dispersal between plants and even across geographic regions.