He estimated how many species of insects lived on each plant species in England, and then extrapolated that figure across the whole planet. âIf we say 400,000, we shall, perhaps, not be very wide of the truth,â he wrote. Today, scientists know the Westwood figure is far too low.
Symptoms: A chronic dry cough that's worse at night, disturbing sleep, and sometimes with wheezing and shortness of breath. Causes: An irritating night cough is often the first sign of asthma, especially in children, but you can develop it at any age. It's also a sign asthma is worsening or not being well controlled.
A dry, hacking cough may develop toward the end of a cold or after exposure to an irritant, such as dust or smoke. There are many causes of a nonproductive cough, such as: 1  Viral illnesses. 2  After a common cold, a dry cough may last several weeks longer than other symptoms and often gets worse at night. Infections. 2  An infection of the lungs or upper airway passages can cause a cough. 3  A productive cough may be a symptom of pneumonia, bronchitis, sinusitis, or tuberculosis. 4  Chronic lung disease.