Some species have bivoltine life cycles and exhibit two modes of calling activity. This figure shows the calling seasons for a ground cricket, Eunemobius carolinus (blue), and a field cricket, Gryllus rubens (red), for northern Mississippi. Both are bivoltine but there are differences in the life cycles reflected by the adult calling seasons. E. carolinus overwinter in the egg stage. The first adults appear in late May and early June and reproduction produces a second generation of adults in October and November. G. rubens overwinter as late instart juveniles and therefore have a head start in early spring. Adult rubens begin calling and reproduce in May and April. A second generation matures in August and September.

I think understanding insect life cycles and the rhythms of their signals may provide a huge benefit in monitoring changes in ecosystems. Insects are perhaps the most important group of animals in every terrestrial ecosystem. They are small, occur in large numbers, and are typically a vital part of the ‘food pyramid’ (web) in most ecosystems. Also, many species are habitat specific and because they have a relatively short generation time, effects to the ecosystem may be more readily (rapidly) observed by monitoring changes in insect populations. Finally, many species produce loud, species-specific signals that are easily recognized. I believe that in the near future an automated census technique will be developed to monitor acoustic animals.