As you’ll be able to see, feminine dobsonflies are magnificent, however males are actually one thing particular with their huge sickle-shaped mandibles. Cautious observations of mano-a-mano encounters between male dobsonflies reveal that their tremendous massive jaws are utilized in fight to dislodge opponents from substrates the place potential mates is likely to be current. These mandibles are ineffective in capturing prey and each female and male dobsonflies, which have highly effective jaws, should not predatory as adults. As adults their weight loss plan is probably going a liquid one.
Juvenile dobsonflies go by the identify of hellgrammites and reside a life aquatic. These fierce predators roam the interstitial areas between stones and vegetation on the backside of quickly flowing streams, the place they seize and dine on immature mayflies, stoneflies, and caddisflies. Expertise tells me that their highly effective jaws can ship a memorable chew to unsuspecting people trying a seize. Hellgrammites are a key indicator of stream well being and never present in polluted waters. Fish adore them and they’re wonderful bait. Like many aquatic bugs, hellgrammites have gills lining the margins of the stomach enabling them to extract oxygen from their watery habitat. In an uncommon developmental twist, additionally they have spiracles, respiratory ports, which permit them to acquire air on land. This adaptation is crucial to their amphibious life type as they climb out of the water to construct pupal chambers on land beneath stones, logs, or different moist protected constructions. It’s possible you’ll encounter grownup dobsonflies within the morning close to lighted buildings, as each sexes are drawn to gentle. After mating, feminine dobsonflies deposit eggs on vegetation overhanging water. Hatchlings drop to the stream under to roam the benthos looking for prey. Larval improvement can take from one to 3 years. Over the subsequent a number of weeks as you wander the banks of freshwater streams and rivers in our area, or go to constructions with nighttime illumination close to waterways, hold a watch open for these marvelous giants of the insect world.
Bug of the Week thanks Nolan for offering pictures that had been the inspiration for this episode. The fantastic publications “Behavioral Observations on the Dobsonfly, Corydalus cornutus (Megaloptera: Corydalidae) with Photographic Proof of the Use of the Elongate Mandibles within the Male” by T. J. Simonsen, J. J. Dombroskie, and D. D. Lawrie, and “Featured Creatures, widespread identify: japanese dobsonfly (grownup), hellgrammite (larva), scientific identify: Corydalus cornutus (Linnaeus) (Insecta: Megaloptera: Corydalidae: Corydalinae)” by D. Corridor, and “Comparative Thermoregulation of 4 Montane Butterflies of Completely different Mass” by Bernd Heinrich, had been used as references for this episode. Many due to Nolan Jenkins for offering the cool picture of the huge-jawed male dobsonfly.