1
Zoology 484 Aquatic Entomology Exam II
Name ________________________
Figure 3 is from the Hoeinghaus et al. paper (Carbon flow in large-river food webs):
Figure 3. 1st and 99th percentile contribution estimates of sources supporting upper-level consumers in each food web.
Bars are means (±1 SD) for each food web of 1st and 99th percentile estimates calculated independently for each consumer
species.
1. What is the main source of carbon in low-gradient rivers? 5
Aquatic C3 plants
2. What is the main source of carbon in high-gradient rivers? 5
Seston / FPOM
3. Which river type had the highest contribution from seston/FPOM? Why? 10
Reservoirs; phytoplankton production highest in lake ecosystems
2
4. Which river concept explained energy sources in 10 tributaries of the Parana River, in
Hoeinghaus et al.’s (2007) study? 5
Flood pulse concept = low gradient rivers; riverine productivity for reservoirs
Figure 1 below is from Lytle and Poff (2004): Adaptation to natural flow regimes:
Figure 1. Hydrograph of the Green River, Utah, USA from 1929 to 2000. Before the Flaming Gorge Dam was completed in 1963 (arrow), the river experienced
floods from spring snowmelt and droughts during autumn and winter. Damming truncated the flow extreme s, causing both floods and droughts to become
less frequent and smaller in magnitude. Data from US Geological Survey.
5. What does this figure show? 5
Loss of high flows and variability in flows after dam was constructed.
6. What would be the effects of the hydrologic alterations show above in Figure 1, on aquatic insects
in the Green River? 5
Insects that use pulses as a cue for life history events would not get cue; reproduction decreased or
cease
7. What five insect orders compose the majority of benthic stream invertebrates? 5
Diptera, trichoptera, ephemeroptera, coleopteran, plecoptera
3
8. Why is the insect diversity in streams so much higher than in lakes? 10
Increased DO, more habitat type and niches available, increased variety of nutrient sources as
allochthonous and autochthonous sources
9. What are five examples of morphological adaptations of aquatic insects for current? 5
Many potential answers
Table 1. Physical characteristics of the three intensively moni·
tored streams in the Sugar Creek watershed, Clinton and Madi·
son counties, Illinois.
Cover
Parameter
Low
Medium
High
Catchment area, ha
Row crop iu watershed, %
Stream length, m
Forest in 15-m buffer, %
Average wetted width, m
Substrate composition, %
Gravel
Sand
Silt
Temperature
Average, oc
Minimum, oc
Maximum, oc
Degree days
220
90
4707
6
2
369
89
12300
22
4
250
82
5208
31
3
17
55a:j:
58
26
16b
35
51
14b
10.9
0.0
28.7
2442
10.9
0.0
26.1
3121
8.3
0.3
27.0
1346
28
Table 1 above is from the Stone et al. (2005) paper: macroinvertebrate communities in agriculturally
impacted southern Illinois streams: patterns with riparian vegetation, water quality, and in-stream
quality.
10. Which stream sites had the highest silt? Why? 5
Low cover, decreased riparian vegetation results in increased siltation from ag fields.
11. What were the dominant macroinvertebrates in all of Stone et al.’s (2005) streams? 5
diptera
12. How do you select a sampling device for a particular site? 5
Based on target organisms, habitat at sites,
4
13. What is the marine paradox, and why does it occur? 10
Few insects in marine ecoystems – why? Few available niches available – other marine invertebrates
filled niche space previously. Physiology not able to adapt to high salinity water.
Answer one of these #14 questions please:
14. Why would insects drift during the night vs. the day? 5
Predator avoidance
14. What is a major difficulty with studying insect life history? 5
Tedious and time-consuming to study, lack of taxonomic information for many taxa, larvae have to
be reared in lab.
15. What are five functional feeding groups for aquatic insects? 5
Predator, scraper, collector-gatherer, filter-feeder, shredders
16. What is an advantage of using the functional feeding group method for analyzing aquatic insect
communities? 10
Allows linking ecosystem functions to assemblage level analyses.