Context: 1 trillion cicadas from two different broods are expected to begin appearing in the Midwest and Southeast regions of the United States at the end of April.
About Cicadas
More about the news:
- It's the first time since 1803 that Brood XIX, or Great Southern Brood, and Brood XIII, or the Northern Illinois Brood, will appear together in an event known as a dual emergence.
- Temperature determines when they emerge.
- The soil needs to reach 17.78 degree Celsius, about 6 inches deep, and with the rainfall they come out.
- Are they harmful?
- Cicadas don't bite or sting, nor do they carry any diseases.
- The bugs are beneficial to the environment, acting as natural tree gardeners.
- The holes they leave behind when they emerge from the ground help aerate the soil and allow for rainwater to get underground and nourish tree roots in summer.
- The slits they make in trees can cause some branches to break, and the leaves then turn brown in a process known as ‘flagging,’ which is a kind of natural pruning.
- When the branch grows again, the fruits it yields will tend to be larger.
- Two groups of periodical cicadas:
- Those that emerge every 13 years and those that emerge every 17 years.
- For most of their lives, cicadas live underground and then emerge once the soil reaches optimum temperature.
Cicadas:
- Common name: Cicadas
- Scientific name: Cicadoidea
- Type: Invertebrates
- Diet: Herbivore
- Average lifespan in the wild: Up to 17 years
- Size: 0.75 to 2.25 inches
- Cicada: family of more than 3,000 species of sound-producing insects.
- They are found in tropical and temperate areas worldwide and occur in deserts, grasslands, forests.
- Nearly 60 species are found in Europe, the Middle East, and parts of Africa.
- Typical characteristics:
- They typically live in trees, feeding on watery sap from xylem tissue, and laying their eggs in a slit in the bark.
- The vast majority of species are active during the day as adults, with some calling at dawn or dusk.
- Only a rare few species are nocturnal.
- One exclusively North American genus, which spend most of their lives as underground nymphs, emerge in predictable intervals of 13 or 17 years.
- The annual cicadas are species that emerge every year.
- Temperature regulation:
- Desert cicadas control their temperature by evaporative cooling.
- When their temperature rises above about 39 °C (102 °F), they suck excess sap from the food plants and extrude the excess water through pores.
- Such a rapid loss of water can be sustained only by feeding on water-rich xylem sap.
- By evaporative cooling, desert cicadas can reduce their bodily temperature by some 5 °C.
- Conversely, many other cicadas can voluntarily raise their body temperatures as much as 22 °C (40 °F) above ambient temperature.