Artificial Light at Night Prolongs Juvenile Development Time in the Black Field Cricket, Teleogryllus Commodus

A growing body of evidence exists to support a detrimental effect of the presence of artificial light at night (ALAN) on life-history and fitness traits. However, few studies simultaneously investigate multiple traits and the life stages at which changes manifest. We experimentally manipulated ALAN intensities, within those found in the natural environment, to explore the consequences for growth, survival, and reproductive success of the field cricket, Teleogryllus commodus. We reared crickets from egg to adult under a daily light-cycle consisting of 12 hr bright daylight (2,600 lx) followed by either 12 hr darkness (0 lx) or dim-light environments (1, 10, or 100 lx). We found egg hatch, adult survival, and reproductive measures were largely comparable for all treatments. However, juvenile development time (number of days from egg to adult) was on average 10 days (14%) longer and adults were also larger when crickets were exposed to any light at night (1, 10, or 100 lx). Our data demonstrate that chronic lifetime exposure to ALAN can modulate the timing of life-history events and may disrupt phenology to a similar extent as other abiotic factors.