Hypena opulenta UPDATE
The presentation below (oec_hypena_with_notes.pdf) and accompanying videos are from a talk given to the Ottawa Entomology Club on March 18, 2021 by me (Naomi Cappuccino, author of this site) titled "Biological control of dog-strangling vine: will Hypena opulenta ever eat enough?" The presentation provides a post-release update on Hypena opulenta, the results of some student projects on predators of Hypena, and my optimistic and not-so-optimistic perspectives as to whether Hypena will eventually be a successful biocontrol agent for DSV.
Images without photo credits are mine. Email me ([email protected]) if you would like to use them and I can provide you with the originals.
Images without photo credits are mine. Email me ([email protected]) if you would like to use them and I can provide you with the originals.
oec_hypena_with_notes.pdf | |
File Size: | 12383 kb |
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Cardinal rejecting Hypena opulenta (video below)
We put Hypena caterpillars as well as several other local caterpillar species in dishes in bird feeders and observed bird behaviour. We used mealworm larvae, which are sold in pet stores as food for birds and reptiles, as a palatable control. The cardinal in this video eats the last of three mealworms in the dish and then eyeballs the three Hypena caterpillars that remain from several angles before flying off. Even though Hypena caterpillars look like a tasty treat, birds (at least the cardinals, chickadees and sparrows that came to our feeders) are uninterested in them. That's good news for biocontrol of DSV, as birds are a major source of mortality for caterpillars.
We put Hypena caterpillars as well as several other local caterpillar species in dishes in bird feeders and observed bird behaviour. We used mealworm larvae, which are sold in pet stores as food for birds and reptiles, as a palatable control. The cardinal in this video eats the last of three mealworms in the dish and then eyeballs the three Hypena caterpillars that remain from several angles before flying off. Even though Hypena caterpillars look like a tasty treat, birds (at least the cardinals, chickadees and sparrows that came to our feeders) are uninterested in them. That's good news for biocontrol of DSV, as birds are a major source of mortality for caterpillars.
Cardinal handling Hyles euphorbiae caterpillar:
The video below shows a cardinal whacking the toxic gut contents out of a spurge sphinx (Hyles euphorbiae) caterpillar before eating it. It drops the caterpillar in the dish several times and then whacks it against the side of the dish. The spurge sphinx feeds on toxic host plants (cypress spurge and leafy spurge) but does not sequester the plant toxins for its own defense. Instead, it regurgitates the toxic and irritating gut contents onto attacking predators. The cardinal in the video knows exactly how to handle a caterpillar that feeds on a toxic plant and may have a gut full of toxins but is otherwise edible. In contrast, the cardinal in the first video (possibly the same individual bird) did not even touch Hypena opulenta before rejecting it.
The video below shows a cardinal whacking the toxic gut contents out of a spurge sphinx (Hyles euphorbiae) caterpillar before eating it. It drops the caterpillar in the dish several times and then whacks it against the side of the dish. The spurge sphinx feeds on toxic host plants (cypress spurge and leafy spurge) but does not sequester the plant toxins for its own defense. Instead, it regurgitates the toxic and irritating gut contents onto attacking predators. The cardinal in the video knows exactly how to handle a caterpillar that feeds on a toxic plant and may have a gut full of toxins but is otherwise edible. In contrast, the cardinal in the first video (possibly the same individual bird) did not even touch Hypena opulenta before rejecting it.