A trap for monitoring Coleoptera and phoretic mites associated with dung.

A trap designed for monitoring Coleoptera associated with dung communities is described. A modification of the trap is described that can be used to determine associations between beetles and phoretic mites. The literature relating to dung communities (Kumar and Lloyd 1976) is rapidly expanding for two reasons. Dung microhabitats provide a readily available community for investigation. In addition, the concept of manipulating dung communities by introducing exotic coprophagous and predaceous beetles was first utlized in Hawaii over 50 years ago. The beetles, introduced primarily from Africa, were meant to supplement the existing beetle fauna and compete with dung breeding fly pests. Similar projects are currently sponsored by the USDA in southern US and by the CSIRO in Australia (Waterhouse 1974). Several traps have been designed (Howden 1955; Newton and Peck 1975) that used modified pitfalls to collect beetles attracted to dung. Fincher (1968) described an automatic trap for monitoring flight activity of dung beetles. However, these traps do not allow dung to be naturally colonized. Only a near natural system can reveal the interactions of dung inhabiting beetles at the community level. Pitfall traps are useful for habitat comparisons and mass collections, but various problems can occur when analyzing communities (Adis 1979). Some special problems occur when using pitfall traps to study beetle populations in dung. For example, Hammond (1976) has summarized kleptoparasitic behavior by dung beetle species that are attracted to the brood balls or dung balls of other species. Kleptoparasitic species are attracted to pitfalls in unnaturally large numbers possibly due to the disturbed dung. Other species are repelled from pitfalls and the net result is a biased sample. To avoid these pitfalls, a trap has been designed that can be naturally colonized, operated by one person and partially sorted in the field. Similar but less portable traps have been used by colleagues in South Africa (Endrody-Younga, pers. comm; Stickler 1976). The trap described below can be modified to sample the phoretic mites attached to many dung beetles. The trap consists of an outer ring one meter in diameter and 16cm high (Fig. 1-2). The four equal pieces forming the outer ring were placed in a circle and buried to a depth of 8cm. Two side cylinders (16cm diameter and 16cm high) were placed between pieces of the ring on opposite sides. The side cylinders were sunk flush with the soil surface to function as holders for buckets that fit snugly into the cylinders. Both cylinders had a half cylinder placed behind it and buried to a level equal to that of the outside This content downloaded from 157.55.39.220 on Fri, 02 Sep 2016 05:35:57 UTC All use subject to http://about.jstor.org/terms 390 BERNON: DUNG TRAPS ring forming a continuous wall of uniform height. Soil was placed flush with the wall to form a gradual angle of approach to the trap. The two pieces of the ring between each side cylinder were joined together with a clamp. A center cylinder (40cm diameter and 15cm high) was sunk flush with the soil surface inside the trap. A plastic bucket with attached nylon ropes fit snugly into the center cylinder. The carrying ropes were attached as shown in Fig. 2 and fell to the sides of the bucket when in place. Plastic disks were placed over the side pitfalls and secured with stones. All cylinders and pieces of the outside wall were made from 18 gauge steel. To set a trap, the center bucket was filled with sifted moist sand that had been tightly packed in place. The pitfall buckets were packed with a small amount of sand in a similar way. The center bucket was placed in the cylinder and the carrying ropes dropped to the sides. Cow dung was primarily used and collected fresh shortly before use. The dung was dropped from a shovel about two meters above the center of the bucket, forming a naturally shaped pad. Beetles colonized the dung by either flying directly into it or crawling along the soil flush with the outside ring, dropping to the inside ground level and continuing toward the dung. The plastic disks over the pitfalls prevented beetles from falling into the buckets before reaching the dung. Any beetles that removed dung in a horizontal direction, usually in the form of a dung ball, would move the dung against the ring and along it until they dropped into a pitfall. Beetles remaining in the dung were recovered by placing any surface dung left after a sampling interval in a standard fun:~~~~~~~e,t Z v r