A new scientific study has found dramatic" and "alarming" declines in insect populations. In German nature reserves, flying insect populations have declined by more than 75% over the duration of the 27-year study. "The flying insect community as a whole... has been decimated over the last few decades," said the study. "Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services." Co-author Caspar Hallman said he and his colleagues were "very, very surprised" by the results. "These are not agricultural areas, these are locations meant to preserve biodiversity, but still we see the insects slipping out of our hands," he told CNN. Entomologists have long had evidence of the decline of individual species, said [researcher] Tanya Latty. However, few studies have taken such a broad view of entire insect populations. Latty says the importance of insects - which make up around 70% of all animal species - is underestimated. "Insects pollinate the crops we eat, they contribute to pest control. They're even crucial in waste control - most of the waste in urban areas is taken care of by ants and cockroaches." Insects, she says, are "crucial" to biodiversity, and "we exist because of biodiversity." Indeed, "ecosystem services provided by wild insects have been estimated at $57 billion annually in the USA," the study says, quoting an earlier study. Some 80% of wild plants rely on insects for pollination; 60% of birds rely on insects as a food source, according to the study.