Nature Notebook – Diapause
Where have all the insects gone? They are spending the winter in diapause. All life activities and development stop during this period. When the temperature and, more importantly, the light-to-dark ratios of sunlight are just right they will resume their development. In order to minimize the effects of winter, the insects will first migrate vertically. They will move from higher places to lower, more protected places such as under leaf litter.
Many species will then enter a different life stage before starting diapause (i.e. adults lay eggs, larvae form pupae). A keen-eyed observer may spy the hardened egg case of a mantid on a bush or the messy clump of cattail fluff in which the cattail larva is resting. Looking for these signs of life can turn a winter walk into a treasure hunt.