Our study marks the first efforts by BugCamp to quantify insect diversity in Ryerson Woods. BugCamp was started in 1996 as a middle school primer for generating enthusiasm about insect diversity. Throughout the summer of 1998, our group sampled insect diversity of Ryerson Woods on a weekly basis, using three different collecting techniques in each of three different sized fields. The purposes of our investigations were to 1) uncover differences in insect diversity among different sized fields, 2) uncover differences within each throughout the summer, and 3) to generate enthusiasm for insect diversity among our middle school students.

In the first year, general collecting was carried out by the students and museum staff, and a reference collection was created for Ryerson Woods. In the summer of 1998, "BugCamp" continued with grant support from the Nancy Ryerson Ranney Leadership Grants Program, the National Science Foundation, and Field Museum in-kind support. A group of teen age students from Ancona School in Chicago was selected to learn about insect biology. From June 22 through July 30 the students had presentations from museum staff, conducted weekly collections at Ryerson Woods, and followed up by processing the collections as directed by museum scientists.

To efficiently sample a wide variety of insects, we employed three collecting techniques -- pitfall traps, sweeping, and malaise traps. The same three fields were samples in 1997, 1998, and 1999.

Large Field
This first site was about 10 acres just west of the parking lot and adjacent to second growth forest on the North. This field consisted of various prairie grasses and forbs, and is seeded and partially mowed each year.

Medium Field
This field was a grassy area east of the Project Cabin and north of the main entry road. It is about 2 acres and has not been seeded with prairie species.

Small Field
This area was about a 1/8th acre opening in the second growth forest just north of the barn parking lot.

Once per week, students sampled each field using the three collecting techniques described. Students curated their own collections from each day by labelling their samples and pinning a subset of their specimens. Dave Pollock (Field Museum) then identified the insects to order and family. Identifications continue as we work some of the most common insects down to species. All specimens are deposited in the Field Museum.

Pitfall Traps
The three most commonly found ground dwelling insects in pitfall traps included the families Formicidae, Carabidae, and Staphylinidae which comprise the ants, ground beetles, and rove beetles, respectively (fig 1). Ground dwelling insects were clearly dominated by the ants (family Formicidae). In three weeks' worth of pitfall trap collection, a total of 287 ants were collected, greatly surpassing the second and third most common carabids (30) and staphylinids (26).

Pitfall traps from the three different fields showed no detectable heterogeneity. That is, these three families occurred in similar proportion among the three fields. Ants dominated the ground dwelling fauna, apparently a result of their efficient mass foraging. Throughout the summer, the numbers of ants collected differed slightly. The week ending July 14 showed a marked decrease in ant abundance, from 103 to 68. On July 23, the number of ants rebounded to 116.

Figure 1. Pitfall traps produced very large numbers of ants. Data are presented is pooled across all three field types, because there was no detectable difference between them.

Sweeping
Sweep netting revealed an interesting result. Two suborders of insects, the Heteroptera and the Homoptera, are very similar in life history. These so-called "true bugs" feed exclusively on plants and dominate the fields in large numbers. However, sweep netting revealed that different sized fields are dominated by a different suborder. In large fields, Heteroptera are more abundant than Homoptera (Figure 2). In the small and medium fields the reverse is true, and Homoptera were much more abundant than Heteroptera (Figure 3). Also interesting is the fact that Heteroptera numbers peaked on July 14, while the Homoptera peaked July 7, just one week earlier.

Figure 2. In the large field, Heteroptera occurred more frequently than Homoptera.

Figure 3. In contrast to the large field (Figure 2), Homoptera occurred more frequently than Heteroptera in the smaller two fields.

Malaise Traps
Malaise traps revealed a distinct difference among fields in terms of insects present. In the large field, among the three most common families collected in the large field, hover flies (family Syrphidae) were most abundant on July 1, then rapidly declined by July 7 and throughout the rest of the summer (Figure 4). In contrast, sweat bees (family Halictidae) were present in low numbers on July 1, slightly increased on July 7, then slowly decreased throughout the rest of the summer. The third most commonly encountered insect during, the flower beetles (family Chrysomelidae), followed a pattern similar to the Halictidae. Most of the Chrysomelidae collected were members of the genus Diabrotica (see Discussion below).

Figure 4. Malaise trapping in the large field produced a large number of Chrysomelidae, Syrphidae, and Halictidae.

In the small field, Halictidae were clearly the most abundant flying insects (Figure 5). Interestingly, Chrysomelidae were virtually absent (Figure 5), indicating their strong preference for the large field. The Syrphidae were present in much lower numbers than the Halictidae.

Figure 5. In the small field, Halictidae were the most frequently collected flying insects. In contrast to the large field (Figure 4), Chrysomelidae are virtually absent.

These results constitute a preliminary analysis of objectives 1 and 2 (Introduction). We attempted to uncover some general trends to do with differences among fields and throughout the summer. In addition to documenting changes, some miscellaneous encounters are worth noting here:

The most abundant beetle collected by sweeping and in Malaise traps in the large field was Diabrotica cristata. This beetle is a member of the family Chrysomelidae, and accounts for the main reason this family was one of the most abundant collected in Malaise traps (see above). Because the grubs of this species feed on roots, it may be a potentially important insect to monitor for the health of the prairie. Why D. cristata was so abundant at Ryerson Woods remains a question of central interest to us. Future BugCamp data will hopefully uncover some correlations to do with the high numbers of these beetles.

The most abundant fly was a small species of the family Syrphidae. These were very numerous in sweeps, but its taxonomy has not been resolved. These flies are also called hover flies on account of their maneuverability in the air.

The most disturbing find was made by student Will Jobe. Will found a large moth pupa which on emergence was a Gypsy Moth. Evidently the Lake County staff are already aware that these moths are present.

The most unusual beetle is a single Wedge-shaped beetle, family Rhipiphoridae. The genus Rhipiporus has 36 species mostly in the western states. Those studied are parasites of bee larvae.

In addition to documenting differences among the three fields over the summer of 1998, an equally important third objective was to generate enthusiasm about insect diversity in middle school students. We believe this objective to be an assured success. Curators from the Field Museum were selected to give special topic lectures on their research centering on insects or their relatives.

One common experience was a greater fascination with arthropods. The great diversity of forms collected impressed the students, as did the great numbers of that were collected over a brief time. The field work was stimulating and enjoyable, even on hot and humid days.

Our ability to teach students how to identify insects was hampered by the sheer diversity of insects. By the end of the course, most students could identify their collections to order. To teach them how to identify insects to family would require several years, we depended on the abilities of Dave Pollock for identification and data entry. In addition to the diversity of insects, students also gained a better appreciation for the patient work of curating a collection of insects. Specimens had to be labeled with care in order to ensure their scientific value. Some specimens are small and fragile, and had to be handled with the greatest care. Over time, students began to uncover more questions than answers, asking such questions as "how can insects of the same family look so different".