Effect of red clover-only diets on house crickets (Acheta domesticus) growth and survival

This study evaluated the potential of red clover as a sole diet for house crickets (Acheta domesticus, AD) and the effect of ensiling or drying red clover biomass on growth, survival and water consumption of AD. Wild AD were caught near Uppsala, Sweden, and reared in a climate-controlled room under a 12-h light regime. One day-old third-generation cricket nymphs (n=2,880) were used in a 56-day feeding trial. The experimental diets (n=8) were early-cut (pre-bloom) and late-cut (late-bloom) red clover, preserved as frozen-fresh, dry-silage, haylage and hay, and a control diet. All clover diets were fed as sole diets with salt block available ad libitum in every treatment. Feed dry matter intake, feed conversion ratio ( FCR, kg feed dry matter per kg weight gain), number and weight of crickets and water consumption were recorded every five days. FCR was higher for late-cut than early cut-red clover, but overall cricket weight and survival rate did not differ between cutting times (P=0.939). FCR, weight and survival were not affected by forage conservation method. Total feed consumption was highest for red clover hay. Crickets fed red clover diets had lower (P<0.01) weight and higher FCR than crickets fed the control diet, but their survival rate was not different from that of control crickets during the first 25 days of life. Water consumption of AD fed the control diet was about half that reported for pigs and poultry. Crickets fed on fresh red cover had lower (P=0.04) water consumption compared with crickets fed dried or ensiled red clover, but ensiling did not reduce water consumption compared with hay. Red clover cannot be recommended as a sole feedstuff for AD, but early and latecut red clover had similar effects. The possibility to partly include late cut red clover in cricket diets is interesting from an ecosystem service perspective since the flowering crop will provide feed for declining populations of bees and other pollinators