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.
Other causes of a dry cough. A persistent cough can be due to causes related to respiratory and digestive systems including: 1  Airway irritation (bronchospasm). 2  Aortic aneurysm. 3  Asthma and allergies. 4  Chronic obstructive pulmonary disease (COPD, includes emphysema and chronic bronchitis). 5  Congestive heart failure.