Reading: Sentence Completion: Question 2

For centuries, agricultural researchers assumed that bees were the primary pollinators of most flowering crops, largely because bees are active during daylight hours and therefore easy to observe and count. Recent field studies using infrared time-lapse cameras have overturned this assumption, revealing that moths and other nocturnal insects visit flowers far more frequently after dark than had previously been recorded, and in some hedgerow habitats deliver a share of successful pollination roughly equal to that of daytime bees. This discovery has drawn fresh attention to a threat increasingly facing night-flying pollinators: artificial light at night, a phenomenon ecologists commonly refer to using the abbreviation ALAN, which covers the glow produced by streetlamps, illuminated signage and household security lighting.

Moths navigate partly by orienting themselves relative to the moon and stars, keeping these distant light sources at a constant angle as they fly in a straight line. A nearby streetlamp disrupts this system because the insect attempts to maintain the same constant angle to a light that, unlike the moon, is close enough for its position to shift noticeably as the moth moves past it; the result is the familiar spiralling flight that traps a moth circling a bulb for hours rather than foraging among flowers. Researchers studying hedgerows near artificial lighting found that moth activity on illuminated flowers fell by roughly one third compared with flowers in darker stretches of the same hedgerow, and that the pollination of certain plant species dependent on nocturnal visitors declined correspondingly.

In response, several conservation trials have tested amber-coloured LED streetlamps, which emit light at wavelengths less disruptive to insect vision than the blue-rich white LEDs increasingly common in street lighting. Early results from a two-year trial in rural Cornwall suggest that switching to amber lighting, combined with shielding fixtures so that light is directed downward rather than outward, can measurably reduce the disorientation effect while still meeting road-safety lighting standards.

Complete the sentences below. Choose NO MORE THAN TWO WORDS from the passage for each answer.

1. Bees were long assumed to be the main crop pollinators partly because they are active during ____________________.
2. Ecologists commonly use the abbreviation ____________________ to describe artificial light produced at night by sources such as streetlamps and signage.
3. When navigating by the moon or stars, a moth keeps the light source at a constant ____________________ as it flies.
4. Because a streetlamp is far closer than the moon, a moth trying to hold the same angle to it ends up performing the ____________________ that traps it near the bulb.
5. In the hedgerow study, moth activity on illuminated flowers fell by roughly ____________________ compared with flowers in darker areas.
6. Some conservation trials have tested replacing white streetlamps with ____________________ LED streetlamps.
7. The two-year lighting trial described in the passage took place in rural ____________________.