Handsome red foxes will deposit the remains of small mammals like shrews in piles of scat.
Fur and bones in scats are telltale signs that a small mammal is well on its way down the decomposition cycle.
In central New Jersey the pastoral plain of Hillsborough is home to the magnificent Duke Estate. This haven of meadows, breath- taking landscapes, and wildlife is a model for modern ecological stewardship founded on the legacy of a visionary captain of American industry, J. B. Duke, and his beloved daughter Doris. While wandering trails at Duke Farms on a brilliant autumn afternoon, I was delighted to see dozens of small scats (a polite term for piles of animal dung) populated with marvelous bugs making meals of these smelly remains. Almost every scat I happened upon had a couple of broad-headed bugs lapping at the juicy tucker of the still fresh dung. Most of the scats contained fur and bones, remnants of small ground dwelling mammals like mice and shrews. One of the farm program managers related that the landscape was rife with foxes, the likely suspects for the many scats scattered around the countryside. In autumn and winter shrews and mice are prime elements of the fox’s diet.
By feeding on dung, broad-headed bugs help recycle nutrients in food webs; nasty work but somebody has to do it.
A freshly deceased shrew begins its journey through the decomposition cycle.
So much for foxes and shrews, what was the deal with the bugs? Like brown marmorated stink bugs, kudzu bugs, and harlequin bugs, many broad-headed bugs are plant feeders. Some are pests of crop. However, on several occasions broad-headed bugs have been recorded feeding on carrion and dung. One clever study found broad-headed bugs are attracted to rotting flesh of fish and shrimp used to attract carrion feeding butterflies. What strange contrivances entomologists ply in their trade! In previous episodes we met other dung feeders including butterflies and dung beetles, but discovery of dung feeding true bugs (Heteroptera) caught me by surprise. Carrion and dung are rich sources of nutrients, particularly nitrogen and minerals necessary for the growth and development of insects. Apparently, broad-headed bugs also benefit by feeding on nutrient rich dung. By consuming dung and carrion, broad-headed bugs participate in the nasty but valuable role of recycling nutrients in terrestrial food webs. While the fox may have tamed the shrew, broad-headed bugs help to recycle the shrew.
If travels take you through central New Jersey and you have some time to spare, make a stop at Duke Farms to enjoy their beautiful landscape and gardens and take a moment to inspect the fox’s scat. You never know exactly who might be recycling the remains.
References
Bug of the Week thanks Gordon and Sheri for providing the inspiration for this episode. Two interesting articles “Heteroptera Attracted to Butterfly Traps Baited with Fish or Shrimp Carrion” by J. E. Eger Jr., H. Brailovsky and T. J. Henry, and “Extra-Phytophagous Food Sources of Hemiptera-Heteroptera: Bird Droppings, Dung, and Carrion” by Peter H. Adler and A. G. Wheeler, Jr. were used to prepare this story. Many thanks to Tom Henry for identifying the gorgeous broad-headed bugs filmed in this episode and to the friendly folk at Duke Farms for providing background information.