Ladybugs are often seen as beneficial insects, known for their role in consuming garden pests like aphids. Despite their generally positive perception, a common question arises regarding their interaction with humans: can ladybugs bite?
Understanding Ladybug Bites
Ladybugs possess mandibles, which are small jaw-like structures they primarily use for feeding on soft-bodied insects. While native ladybug species are less likely to bite humans, the invasive Asian lady beetle (Harmonia axyridis) is more prone to this behavior. A ladybug bite generally feels like a minor pinch or a sharp pinprick. It is usually not painful enough to break human skin, and bleeding is rare.
For most people, a ladybug bite results in only mild, temporary irritation, such as a small, raised red bump that may itch for a short period. This reaction typically resolves within a few hours or a day or two. However, some individuals can experience a mild allergic response, which might present as increased redness, swelling, or itching at the bite site. In very rare cases, severe allergic reactions, including respiratory symptoms like difficulty breathing or swelling of the face, lips, or throat, have been reported due to proteins found in their bodies or defensive secretions.
The Asian lady beetle, in particular, can secrete a yellowish-orange, foul-smelling fluid called hemolymph from its leg joints when stressed. This reflex bleeding is a defensive mechanism and can irritate the skin or stain surfaces. If this fluid comes into contact with the eyes, it may lead to conjunctivitis, also known as pink eye. While ladybug bites are not known to transmit diseases or parasites to humans, it is always advisable to wash the affected area with soap and water to prevent any secondary irritation or infection.
Reasons for Ladybug Bites
Ladybugs do not bite humans aggressively; their biting behavior is typically defensive or exploratory. One reason a ladybug might bite is if it feels threatened or trapped, such as when it is accidentally squeezed or pressed against the skin. This can trigger a defensive response, prompting the insect to use its mandibles.
Sometimes, a ladybug might bite simply out of curiosity or in an attempt to explore its surroundings. They may mistake human skin for a food source, such as aphids, or be seeking moisture or salt. This exploratory biting is particularly noted in Asian lady beetles, especially during dry spells or periods of food scarcity.
Overwintering periods, particularly in the fall, can also lead to increased ladybug encounters and potential bites. As temperatures drop, ladybugs, especially Asian lady beetles, seek warm, sheltered places to hibernate, often congregating indoors. When large numbers gather, the likelihood of incidental contact and subsequent biting increases.
Minimizing Ladybug Encounters
To reduce the likelihood of ladybug bites and indoor infestations, sealing potential entry points into homes is effective. Inspect and seal cracks around windows, doors, pipes, and utility lines. Gaps in siding, foundation cracks, and tears in window or door screens should also be repaired. These measures prevent ladybugs from entering in search of overwintering sites.
If ladybugs are found indoors, it is best to remove them gently rather than crushing them. Crushing can cause them to release their foul-smelling hemolymph, which can stain walls, fabrics, and carpets. Vacuuming them up is an effective and clean method of removal; simply empty the vacuum canister outdoors immediately after. Alternatively, a piece of duct tape (sticky side out) wrapped around a hand can be used to gently pick them up for relocation.
For those seeking to deter ladybugs from specific areas, natural repellents can be considered. Ladybugs are reportedly averse to strong scents like those from bay leaves, cloves, and certain essential oils such as peppermint, citronella, or lavender. Placing these items near windows and entry points, or using them in sprays, may help discourage their presence. Planting chrysanthemums (mums) around the exterior of a home in the fall can also act as a natural deterrent.