Golden Digger Wasp
Sphex ichneumoneus
July 29, 2012
Big Oak Flat Information Station
Golden Digger Wasps are invading Big Oak Flat! Don't be alarmed, these beneficial insects are not aggressive and will not bother you unless provoked. A colony of several dozen burrows was discovered in the Big Oak Flat Information Station parking lot median. These fascinating wasps could be seen actively digging, bringing a tiny ball of sand to the surface and spreading it out in a patchwork of tan over the grey gravel median. The Golden Digger Wasp is a gorgeous and colorful insect with golden hairs decorating its black head and thorax. A black tip caps its red-orange abdomen and matching legs. As deadly (to other insects) as they are beautiful, it didn't take long before these wasps were observed bringing prey to their nests. Wasp venom is designed to paralyze other insects and these wasps hunt crickets or grasshoppers. They bring the immobilized prey back to the nest to supply their larva with food. The larva will spend the winter in the burrow, emerging next summer to repeat the cycle. For being such an efficient predator, the adult wasp is actually a vegetarian, feeding only on flower nectars and other plant fluids. Not only do these wasps help control pest insects, but they are pollinators too!
Feathers
August
Keep an eye out for feathers on the trail as the birds of Yosemite are replacing their flight feathers this time of year. This process is called molting and it allows the birds to replace damaged or worn feathers. Although birds molt every year, not all feathers are replaced at once and some species take several years to replace their full set. This pattern of old and new feathers is a handy way for researchers to estimate the age of a bird.