Identifying Box Elder Bugs — Appearance and Behavior

Box elder bugs are common pests known for their distinctive appearance and behavior. Understanding how to identify them can help in managing and controlling their presence. Here’s a guide to recognizing box elder bugs:

Appearance

1. Coloration
   • Primary Colors: Box elder bugs are primarily black with orange or red markings. The vibrant colors can be found on the body and wings.
   • Patterns: They often have an orange or red border along the edges of their black wings and a pattern of orange or red spots or lines on their back.
2. Size and Shape
   • Size: Adult box elder bugs typically measure between 1/2 to 5/8 inch (12-14 mm) in length.
   • Shape: They have a flattened, oval-shaped body. Their shape and size contribute to their distinctive appearance.
3. Wings
   • Appearance: When at rest, the box elder bug’s wings are usually folded flat over their back. The wings have a characteristic black color with orange or red markings.
   • Flight: While they can fly, box elder bugs are not strong fliers and tend to move around by walking or flying short distances.
4. Antennae and Legs
   • Antennae: They have long, slender antennae that are typically orange or red.
   • Legs: Their legs are black with orange or red segments, matching their overall color pattern.
5. Nymphs
   • Appearance: Nymphs (young box elder bugs) are smaller and lack wings. They are usually red with black markings and gradually develop the adult coloration as they mature.

Behavior

1. Habitat and Infestation
   • Preferred Plants: Box elder bugs are often found around box elder trees (Acer negundo), but they can also infest other types of maple trees and various shrubs and plants.
   • Seasonal Activity: They are most active during the fall and early spring when they seek shelter indoors to overwinter or during the warmer months when they reproduce.
2. Feeding Habits
   • Diet: Box elder bugs feed on the seeds, leaves, and stems of box elder and other maple trees. Their feeding can cause minor damage to plants but is generally not harmful to trees.
   • Sucking Mouthparts: They use their piercing-sucking mouthparts to extract sap from plants.
3. Wintering Behavior
   • Indoor Infestations: As temperatures drop, box elder bugs may seek refuge inside homes and buildings. They are commonly found in attics, wall voids, and other sheltered areas.
4. Reproduction
   • Eggs: Box elder bugs lay their eggs in clusters on the underside of leaves or on plant stems. The eggs are small, red or orange, and turn darker as they develop.
   • Lifecycle: They undergo incomplete metamorphosis, progressing through egg, nymph, and adult stages.
5. Movement
   • Seeking Warmth: During cooler months, they may congregate on sunny sides of buildings or on the exterior walls, seeking warmth. Inside homes, they can be found on windowsills, walls, and ceilings.

Managing Box Elder Bugs

1. Sealing Entry Points: Ensure that windows, doors, and other entry points are properly sealed to prevent them from entering your home.
2. Removing Infestations: Use a vacuum to remove box elder bugs from indoor areas. Dispose of the vacuum bag immediately to prevent reinfestation.
3. Exterior Treatment: Apply insecticides around the perimeter of your home and on the exterior walls to reduce outdoor populations and prevent them from entering.

Understanding the appearance and behavior of box elder bugs helps in identifying them and implementing effective control measures to manage and reduce their presence in and around your home.