Everyone will be familiar with this substance found on creeping thistle, Cirsium arvense, yesterday on Phase 2. But do you know what causes it? Look out for the answer next week....
I'm sure everyone is familiar with this substance, known as 'cuckoo-spit', but what is less widely known is the causal organism - the larvae of a froghopper called Philaenus spumarius. This froghopper is one of the most common in the UK and is also known as the Common or Meadow Froghopper.
The foamy cuckoo-spit is produced by the larvae of the froghopper as protection against predators and to provide adequate moisture and temperature regulation whilst the larvae are in development. The larvae feed inside the foam mass throughout their development and emerge as adults when the 'cuckoo-spit' has completely dried out after around 2 months.
Being members of the insect Order Hemiptera (the true bugs), they go through incomplete metamorphosis - meaning there are three stages in the lifecycle instead of four (as in other Orders such as butterflies and moths and beetles). There is no pupal stage in this life cycle.
The imago (adult) insects themselves are around 5-7mm long and can be seen from June - September. They are extremely variable in their appearance, ranging from black to almost completely white in colour and with various patternings. The female froghoppers lay their eggs (up to 350 per female) on the foodpalnt of the larvae, which is also variable and includes grasses and herbaceous plants.