Children of the sixties may remember the animated television classic, “It's the Great Pumpkin, Charlie Brown” based on Charles Schultz’s comic strip. Linus’s attempt to find the most sincere pumpkin patch, the one in which the Great Pumpkin arises on Halloween, meets with disappointment when the Great Pumpkin fails to appear. Each autumn with the passion of Linus, Bug of the Week visits the goldenrod patch to catch a glimpse of one of the insect world’s rarest and most bizarre killers, the wedged-shaped beetle. You will recall in last week’s episode of Bug of the Week we met two stealthy predators that dealt death by ambush to unsuspecting pollinators visiting goldenrod. Unlike Linus and his pumpkin patch, this week our goldenrod patch rewarded us with a glimpse of the wonderful wedge-shaped beetle.
Effects on bees and wasps
Now, something called a wedged-shaped beetle may sound harmless, but if you are a bee or wasp this beetle is peril for your progeny. Here’s why. The female wedge-shaped beetle visits the blossoms of goldenrod to eat nectar and pollen knowing full well that the same blossoms will be visited by myriad bees and wasps during the course of the summer and autumn. Within the blossoms, she deposits eggs that hatch into strange, active larvae called a triungulins. Triungulins lurk in the flower until a hapless bee or wasp wanders too near. The small larva then scrambles onto the body of the bee or wasp and, like an unwelcome hitchhiker, the triungulin rides back to the nest. Within the nest the triungulin bores into an unfortunate bee or wasp babe and feeds. After molting, it bores out of its host and with tenacious mouthparts, attaches to the skin of the doomed victim. After molting several times while consuming it host, the larva changes into a pupa. From the pupa emerges the adult beetle that will return to flowers to complete the cycle of life. Visit your favorite goldenrod patch. Perhaps it will be worthy and you will catch a glimpse of the great, fantastic wedge-shaped beetle.
Bug of the Week thanks Dr. Nancy Breisch for sharing her expertise and knowledge about stinging insects. For more information on yellow jackets and their stings, please visit the following web sites.