Sap beetles feed on sap: sap oozing from trees, sap oozing from plants damaged by other insects and occasionally are found living with bees. One of the sap beeltes,Glischrochilus fasciatus, is called the picnic beetle, because it is attracted to odors of fruit juices, wine, beer and other fermenting beverages. Thus, they are commonly found at picnics. Picnic beetles are not good drinkers. They are commonly found drowning their sorrows in beverage cups, making drinking more difficult for the humans.
The picnic beetles live as larvae in decayed and fermenting plant material. In late summer and fall, large numbers can invade picnic grounds and dimish the outdoor dining pleasure. Picnic beetles overwinter as adults and emerge in early spring. Picnic beetles are usually secondary pests of fruits and corn. They invade sites that have been damaged by other insects. They can carry fungal spores that promote spoilage of the fruit
This beetle was attracted to the sap of a recently cut maple trees, just as the sap started to run, one warm day in spring.
Picnic Beetle, Glischrochilus fasciatus
Living With Insects Blog 
How do I keep them from coming on my body?????????