Broad-Headed Bug – Alydus eurinus

Broad-Headed Bug – Alydus eurinus
Family Alydidae – Broadheaded Bugs
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Live adult bugs photographed in the wild at Winfield, Illinois, USA

There are approximately 29 species of broadheaded bugs in North America. This species, Alydus eurinus, is the most abundant of the broad-headed bugs and is usually found on bush clover (Lespedeza capitata). The nymphs are remarkable ant mimics, while the adults resemble spider wasps (Pompilidae). As a second line of defense, both nymphs and adults exude chemicals known as allomones (butyric and hexanoic acids) from the metathoracic scent glands characteristic of true bugs.

Wings are similar to leaf-footed bugs

Broad-headed bugs feed on developing seed of many hosts including trees, shrubs, vines, weeds and many cultivated crops. They may also feed on the stems and foliage when seed are not present. Both nymph and adult stink bugs pierce plants with their needlelike mouthparts and suck sap from pods, buds, blossoms and seeds. The degree of damage depends on the developmental stage of the plant when it is attacked. Immature fruit and pods become deformed as they develop. Seeds are often flattened and shriveled.

Later-developing cultivated plants become more attractive when these initial wild hosts dry down, and their proximity allows easy access for stink bug colonization in crops. Shortly after egg deposition and hatching, emerging nymphs are gregarious in habit and remain on or near the egg mass. As they develop, they begin to feed and disperse.

This shot better shows the spurs on the tibia that betray this bug's kinship to the leaf-footed bugs.


  1. Troy Bartlett, et al, Family Pentatomidae  
  2. North Carolina State University Cooperative Extension Stink Bugs 
  3. Line, Les. The Audubon Society Book of Insects. Harry N Abrams, 1983.

Order Hemiptera: True Bugs number almost 5,000 species in North America, and 40,000 worldwide. They have mouthparts formed into a beak, adapted for sucking plant juices or the liquefied insides of their animal prey.
Suborder Auchenorrhyncha – Cicadas & Planthoppers
Suborder Sternorrhyncha – Aphids, scales, mealybugs, jumping plant lice