Signs of Aestivation Break

Along with the changing leaves and the cooler temperatures comes the waking of HWA. It’s fall, and this is the time of year when HWA begins to grow and develop after going through its period of summer dormancy known as aestivation. Just yesterday we saw the first signs of aestivation break on some of our trees outside our lab at Cornell. In the photo on the left, you can see two of these signs: segmentation of the adelgid’s body, and lightening of its color as the pinkish hemolymph (insect blood!) shows through the space between those segments. These photos show samples at 100x magnification under a dissecting microscope in the lab, but soon you’ll be able to see signs of aestivation break with a hand lens or magnifying glass in the field.

Aestivation break signals the time for us to begin planning and implementing biocontrol releases around the state. In the fall we release our Laricobius beetles, which will feed on HWA throughout the fall, winter, and into the spring. Aestivation break is one of HWA’s major life stages that we track as part of our Phenology Project. Our network of volunteers around the state helps us understand how HWA behaves across climate gradients in New York and helps us know where and when to release our biocontrol bugs. In addition, aestivation break signals that the food collection sites that we rely on for feeding our lab colony will be ready to go soon, ensuring that our Laricobius beetles will have a fresh meal heading their way. Things may be cooling down outside, but in the lab we’re just getting warmed up!