RESEARCH
Life History, Secondary Production, and Ecosystem
Significance of Acridid Grasshoppers in Annually
Burned and Unburned Tallgrass Prairie
C. K. Meyer, M. R. Whiles, and R. E. Charlton
ABSTRACT Secondary production of the acridid community on Konza Prairie Biological Station, Kansas, was estimated to evaluate its
significance to energy and nutrient cycling in annually burned and long-term unburned tallgrass prairie. A drop-trap and vacuum device
were used to sample acridids on three watersheds in both the burned and unburned prairies during the 1998 and 1999 growing seasons.
Production of common species was estimated using the instantaneous growth method, and consumption and egestion were estimated using
ecological efficiencies. Total acridid abundance, biomass, and production estimates showed a trend of higher values on burned than on
unburned watersheds during both years with significantly higher biomass and production on burned watersheds during 1998 (P < 0.05).
Higher biomass and production on burned watersheds was primarily a result of higher values for graminivorous taxa. Forb-feeder and
grass-feeder production was more similar on unburned than on burned watersheds, although responses of individual species varied greatly
between the two watershed types and years. Grass-feeders and forb-feeders consumed an estimated 0.4-4.7 g ash-free dry mass (AFDM) m2 yr-1 of grass and 0.7-2.1 g AFDM m-2 yr-1 of forbs, respectively, depending on watershed type and year. Results indicate that acridids are
important in nitrogen cycling. However, their relative importance to energy and nutrient cycling in tallgrass prairie varies with plant
responses to burning and may be influenced by ungulate grazing.
A
rthropods can play significant roles in ecosystems as
primary consumers that remove and recycle a portion of
primary production, thereby influencing material and energy cycling and primary producers (e.g., Reichle et al. 1969, Van
Hook 1971, Schowalter 1981, Swank et al. 1981, Lightfoot and
Whitford 1990). The importance of arthropod primary consumers
can be assessed by quantifying energy and nutrient transfers within
a system (e.g., Wiegert and Petersen 1983). For example, some nutrients in plants are removed by arthropod herbivores and eventually returned to the soil through egestion, excretion, and death and
decomposition. In turn, changes in soil nutrients can influence primary productivity, plant species composition, and physiological
responses of plants to the environment (e.g., Schowalter 1981, Blair
1997, Blair et al. 1998).
In grasslands, the impact of ungulate herbivores on energy and
nutrient cycling and plant communities has received attention recently (e.g., Hartnett et al. 1997, Collins and Steinauer 1998, Knapp
et al. 1999), but impacts of other primary consumers, such as
arthropods, are not as well studied. Grasshoppers are conspicuous
primary consumers in most grasslands; their importance in removing aboveground biomass and accelerating nutrient turnover has
been demonstrated in some systems (e.g., Blumer and Diemer 1996)
but remains poorly quantified in others. Rodell (1977) suggested
that the ecological role of grasshoppers in grasslands could be assessed by examining the amount of energy in the form of grasshopper biomass, energy flow through grasshopper populations during
a given time interval, and the influence or control that grasshoppers
exert on other organisms in an ecosystem. Estimates of grasshopper
secondary production may be best for examining these factors.
52
Secondary production is biomass created by heterotrophic organisms over the course of time, regardless of its fate (Benke 1984).
This includes, but is not restricted to, biomass that is retained within
the population as growth, is lost from the population through predation and other mortality factors, and is used for egg production.
Production has been termed the ultimate measure of success because
it integrates many factors associated with fitness such as abundance,
biomass, growth rates, reproductive rates, and survivorship (Benke
1993). Factors limiting secondary production include food quantity and quality, temperature, habitat complexity, biotic interactions,
and stress (Benke 1984). Although abundance and biomass are
static measures, production is a rate that represents the flow of
materials and energy, thereby linking populations with their ecosystems (Benke 1993). Secondary production estimates also can be
used, along with estimates of ecological efficiencies, to estimate
amounts of food resources consumed and egested by consumers
(e.g., Benke and Wallace 1980).
Fire is an historically important regulating factor in tallgrass prairie
that has a profound impact on plant communities (Hulbert 1973,
Collins and Steinauer 1998, Knapp et al. 1998a), but the impacts of
fire on primary consumers, especially arthropods, are less understood. Evans (1984, 1988a, 1988b) examined the impacts of annual burning on grasshoppers on the Konza Prairie Biological Station (KPBS) in Kansas and found that annual spring burning had a
variety of impacts including (1) grasshoppers hatched several weeks
earlier on burned watersheds compared with unburned, (2) fire
adversely affected survivorship of forb-feeding but not grass-feeding grasshoppers because it favored grasses, and (3) fire influenced
plant species richness resulting in a positive relationship between
AMERICAN ENTOMOLOGIST • Spring 2002
plant and grasshopper species richness. Additionally, Nagel (1973)
found greater abundance and biomass of arthropods on burned
areas compared with unburned in a Kansas tallgrass prairie.
Andersen et al. (1989) investigated the impacts of fire in Illinois sand
prairie habitats and found that arthropod biomass was significantly
higher on long-term unburned sites compared with burned sites 1
yr after burning. Biomass increased on burned watersheds 2 and 3
yr after burning. These studies suggest that fire has an impact on
grassland arthropods such as grasshoppers, and that mechanisms
and patterns probably vary temporally, spatially, and among taxa.
The objective of this research was to quantify the ecological significance of the acridid grasshopper community in a native tallgrass prairie ecosystem. To accomplish this, we estimated acridid secondary
production on KPBS and used production estimates and ecological
efficiencies to examine the role of acridids in nutrient and energy
cycling. We examined the significance of these primary consumers in
the context of a long-term experiment examining the influence of fire
on the tallgrass prairie ecosystem, utilizing long-term unburned and
annually burned watersheds. Based on previous investigations, we
predicted that these abundant herbivores would play a significant
role in energy and nutrient cycling. We also hypothesized that the
significance of these grasshoppers to energy and nutrient cycling (e.g.,
their production) would be enhanced in burned areas because of the
positive impact burning has on primary production and that the
relative contributions of forb and grass-feeding species to total grasshopper production would track changes in plant communities that
are associated with burning (e.g., higher production of grass-feeders
on annually burned watersheds).
Materials and Methods
Study Site. The study was conducted during 1998 and 1999 at
KPBS, an ≈3,500-ha tract of native tallgrass prairie, located 10 km
south of Manhattan, KS (39o 05’ N, 96o 35’ W), in the Flint Hills
physiographic region. KPBS is owned by the Nature Conservancy
and maintained by the Kansas State University Division of Biology.
Mean monthly temperatures range from –4°C in January to 27°C
in July (Knapp et al. 1988a). Annual precipitation is highly variable
but averages 835 mm, with most occurring during the growing season. Dominant vegetation includes the warm season, perennial grasses
Andropogon gerardii Vitman, Schizycharium scoparium (Michaux),
and Sorghastrum nutans (L.). Primary production at KPBS is relatively high but exhibits much annual variation (Knapp et al. 1998b).
Knapp et al. (1998a) provide a detailed description of the study site.
KPBS is divided into watersheds that receive various prescribed
burn and large ungulate [Bos bison (L.) and cattle] grazing treatments. Knapp et al. (1998a) summarized the role of burning and
grazing on tallgrass prairie. In general, watersheds that are burned
annually are dominated by warm-season grasses and have a relatively sparse forb community, whereas long-term unburned watersheds have a higher abundance of forbs and woody vegetation. For
this study, annually burned and long-term unburned watersheds
were used, neither of which was grazed. Annually burned watersheds examined were K1A, K1B, and 1D during 1998, and 1C,
K1B, and 1D during 1999 (Fig. 1). Watershed K1A was replaced by
1C during 1999 because K1A was not burned that year. Long-term
unburned watersheds examined were K20A, 10A, and 20B (n = 3 of
each treatment during each year).
Grasshopper Abundance and Life Histories. In 1998, three
samples were taken in the interior of each watershed; one upland,
one midslope, and one lowland. In 1999, sampling effort was increased to four samples per watershed because acridid numbers
appeared lower and more variable than during 1998. Quantitative
samples were collected every other week from mid-May to mid-June
followed by weekly sampling through the end of September in 1998.
AMERICAN ENTOMOLOGIST • Volume 48, Number 1
Fig. 1. Konza Prairie Biological Station showing experimental watersheds used during this study. Annually burned watersheds are burned
every year, and unburned watersheds had not been burned for at least
4 yr before 1998. K1A was used only during 1998, and 1C was used
only during 1999.
Sampling intensity was increased to weekly during 1998 in order to
ensure collection of accurate life history information. In 1999, sampling occurred weekly from mid-May through September. Samples
were collected at night when grasshoppers were inactive.
Samples were taken with a drop-frame that was a 50 cm tall plastic
cylinder that sampled a 0.25-m2 area. The frame was mounted on two
≈4.5 m long poles so that sampled areas were not disturbed as the investigators approached. A cone constructed of nylon mesh (1.0 mm) was
fastened to the top of the frame, and a center hole (24 cm diameter) was
cut to fit a vacuum tube. The vacuum device was a modified Craftsman
24 cm3, 2-cycle gasoline powered leaf blower (model no. 358.797931,
Chicago, IL) reversed for suction. A fine mesh bag designed for use in
swimming pool vacuums was placed inside the suction tube to collect
insects as they were collected from the sampled area. Following collection, the collection bag was everted and emptied into a labeled plastic
bag. Samples were placed on ice and frozen until processed.
Contents of each sample were sorted, and all acridids were removed and measured (total body length). Most specimens were identified to the lowest possible taxon and assigned to an instar based
on Coppock (1962), Blecha (1974), Otte (1981), and Capinera and
Sechrist (1982). Because of our inability to differentiate between
nymphs of Mermiria, they were reported as Mermiria spp. Similarly,
some Melanoplus nymphs could not be identified to species and
were reported as Melanoplus spp. Feeding group assignments (grassfeeders and forb-feeders) were based on a previous investigation in
the Flint Hills region of Kansas by Campbell et al. (1974). Melanoplus
spp. [primarily M. bivittatus (Say) on KPBS] are generalists that feed
on both forbs and grasses and were included in the forb-feeder
category for most analyses because they show a preference for forbs
when they are available (Bailey and Mukerji 1976, MacFarlane and
Thorsteinson 1980).
53
During 1998, additional qualitative samples were collected to
facilitate close examination of acridid life histories on burned and
unburned watersheds. These samples were collected with a canvas
sweep net, processed in the same manner as quantitative samples,
and used to supplement numbers collected in quantitative samples.
The timing of egg hatching for each common species in 1998 was
estimated by recording the date when first instars of each species were
collected in either quantitative or qualitative samples. In the few cases
where second instars were the first individuals collected, we used a
conservative estimate that first instars were present 1 wk before first
collection dates for second instars (e.g., Khan and Aziz 1974, Kemp
and Dennis 1989). Activity periods were documented by repeated
capture of each species throughout the season until it was no longer
collected. Intensive sampling continued until the end of September.
Biomass and Secondary Production. Instar-specific and adult
male and female ash-free dry mass (AFDM) was estimated for each
species. Individuals were dried for 3-4 d at 55°C in a drying oven,
cooled in a desiccator for 6 h, and weighed to obtain dry mass.
Individuals then were placed in a muffle furnace (550°C) for 2 h,
cooled in a dessicator, and weighed again to obtain ash mass. The
difference between dry mass and ash mass was recorded as AFDM.
Predictive length-mass equations were developed for those species in which enough individuals of a variety of size classes had been
collected. For this procedure, body length (mm) was measured from
the frons to the tip of the abdomen. Length values were natural log
(ln) transformed and then regressed against ln-transformed AFDM.
Regressions then were used to develop the following predictive equation for each common taxa:
AFDM = a · (L)b,
where a = y intercept, L = length, and b = slope. Significant relationships (P < 0.05) were used to develop predictive equations, and
biomass estimates were obtained by applying length-mass relationships to size-specific abundance data.
Secondary production was estimated using the instantaneous
growth method (see Benke 1984). Instantaneous growth rates were
calculated as follows:
G = ln(Wf /Wi)/t,
where G = daily growth rate, Wf = average individual mass after time
t, Wi = initial average individual mass, and t = time in days. For
nymphs, we used average mass of first instars for Wi and average
mass of fifth instars for Wf, and estimated development time (t)
from size-frequency plots of individual taxa on each watershed type.
For adults, we used average mass of early-season adults for Wi and
average mass of late season adults for Wf; periods of adult presence
(t) were estimated from size-frequency plots. Production was then
calculated as follows:
P = G · B · t,
where P = production, G = daily growth rate, B = average biomass
during the development time interval, and t = number of days in the
interval. Because nymphs and adults have substantially different growth
rates, nymph, adult male, and adult female production were calculated separately and then summed to estimate total annual production.
Nitrogen and Carbon Analyses. Because it is an important limiting nutrient in tallgrass prairie (Blair et al. 1998), we focused our
nutrient analyses on nitrogen. Phoetaliotes nebrascensis (Thomas),
one of the dominant grass-feeding acridids in the tallgrass prairie
(Campbell et al. 1974, Evans 1988a), was used as a model for examining nitrogen relationships. Ten nymphs, eight adult males, and
seven adult females of this species were collected with a sweep net
from burned and unburned watersheds on KPBS during 1999 and
analyzed for C and N content. Frass was collected from another
series of late instars from burned and unburned watersheds during
1999 by allowing captives (10 from each watershed type) to defecate
54
in sterile jars immediately following capture. Grasshoppers and frass
were freeze-dried under high vacuum for ≈3 d and then homogenized with a mortar and pestle. Material was analyzed with a Carlo
Erba (NA 1500, Milan, Italy) C/N analyzer to detect percentages of
carbon and nitrogen. Percentages for P. nebrascensis and frass from
burned and unburned watersheds were used for all species of acridids
in cycling estimates, and these values were in the range of those
reported for a variety of taxa (Robel et al. 1998). For plant tissues,
we used 1.0% N for grass and 2.0% N for all forbs, based on an
average for common forbs on KPBS (Turner et al. 1995).
Consumption and Egestion Estimates. Using production estimates, the following relationship was used to estimate plant consumption by acridids:
C = P/(AE · NPE),
where C = consumption, P = secondary production, AE = assimilation efficiency, and NPE = net production efficiency (Benke and
Wallace 1980). For AE estimates, we used 50% for all species, based
on laboratory studies with P. nebrascensis (Meyer 2000), and an
average of literature values for other insect herbivores (Scriber and
Slansky 1981, Slansky and Scriber 1982). This value is higher than
those reported for many grasshopper species and, thus, our consumption and egestion estimates are probably conservative. We used
40% for NPE, the efficiency at which assimilated material is converted to production. This value is an average of those reported for
various North American grasshoppers (Smith 1959; Smalley 1960;
Wiegert 1965; Van Hook 1971; Bailey and Riegert 1973; Duke and
Crossley 1975; Bailey and Mukerji 1976, 1977). Consumption estimates for graminivorous species and for forb-feeders were summed
separately and compared with 10-yr averages of annual net primary
production (ANPP) of grasses and forbs on burned and unburned
watersheds on KPBS (Knapp et al. 1998b). Egestion was estimated
as the difference between consumption and assimilation.
Statistical Analyses. Slopes of length-mass regressions were compared using analysis of covariance (ANCOVA) (SAS Institute 1988)
and the Tukey multiple comparison procedure at α = 0.05 (Zar
1996). Mean abundance, biomass, and production values for acridids
on burned and unburned watersheds during each year (n = 3 of
each treatment during each year), and between the two study years,
were compared with analysis of variance (ANOVA, α = 0.05) procedures (SAS Institute 1988). Values were ln-transformed (ln [x+1])
prior to analysis to normalize data and eliminate heteroscedasticity
(Zar 1996). ANOVA procedures also were used to test for differences in N contents of life stages of P. nebrascensis and frass from
P. nebrascensis collected on burned and unburned watersheds, but
these data did not exhibit heteroscedasticity and thus were not
transformed. Multiple comparisons among life stages were made
using Duncan’s least significant difference means separation procedure.
Results
Grasshopper Life Histories. Of the abundant acridid taxa encountered on KPBS during 1998, six were grass-feeders, three were
obligate forb-feeders, and three were generalists that feed on both
grasses and forbs (Fig. 2). The first acridids to hatch during 1998
were Melanoplus keeleri (Thomas) and Syrbula admirabilis (Uhler)
on burned watersheds by the first week of May, and M. bivitattus
and Orphulella speciosa (Scudder) on burned and unburned watersheds by mid-May (Fig. 2). In contrast, Hypochlora alba (Dodge)
first instars did not appear until 3 June (both burned and unburned
watersheds) and Melanoplus femurrubrum (De Geer) first instars
were not present on unburned watersheds until 1 July. Boopedon
auriventris McNeill appeared in mid-May and showed no difference
in phenology between the two watershed types. Most species examined had a life cycle of ≈4 mo from hatching to senescence. The
AMERICAN ENTOMOLOGIST • Spring 2002
Fig. 2. Phenology of common acridids collected on annually burned and long-term unburned watersheds on Konza Prairie Biological
Station during 1998. Lines extend from hatching to senescence of each taxon. aGrass-feeder. bForb-feeder. cGeneralist.
earliest species to hatch (i.e., M. keeleri and S. admirabilis) completed
their life cycles and senesced by early to mid-September, whereas
species that hatched later (e.g., M. femurrubrum) persisted through
most of September (Fig. 2).
Burning considerably influenced egg hatching time of some
acridid species (Fig. 2). First-instar Campylacantha olivacea
(Scudder), M. keeleri, and S. admirabilis appeared ≈1-1.5 mo earlier; Hesperotettix speciosus (Scudder) and P. nebrascensis 2-3 wk
earlier; and M. femurrubrum and Mermiria spp. ≈1 wk earlier on
burned than on unburned watersheds. Of the most abundant
acridids encountered on KPBS during 1998, seven appeared at
least 1 wk earlier on burned than on unburned watersheds (Fig.
2). In contrast, Ageneotettix deorum (Scudder) appeared earlier
on unburned watersheds, and others (H. alba, O. speciosa, M.
bivittatus) showed no appreciable difference in phenology between
watershed types (Fig. 2).
Length-Mass Relationships. Length-mass relationships for common acridids on KPBS were all highly significant (P < 0.01), with r2
values ranging from 0.91 to 0.98 (Table 1). Intercept values ranged
from 0.004 for Mermiria spp. to 0.031 for C. olivacea and H. alba,
and slopes ranged from 2.25 (P. nebrascensis) to 2.96 (Mermiria
spp.). Some significant differences among slopes were evident (P <
0.05), indicating differences in body proportion changes during
development among taxa (Table 1).
Abundance, Biomass, and Secondary Production. Overall abundance, biomass, and production of acridids on KPBS generally
were higher during 1998 than 1999, and total production was
significantly higher in 1998 than 1999 (P = 0.04) (Fig. 3). During
both years, there was a trend toward greater acridid abundance on
burned watersheds, and total acridid biomass and production were
significantly higher in burned watersheds than unburned during
1998 (P = 0.01 and 0.02, respectively). This was primarily a result
of higher values for grass-feeders on burned watersheds; grassfeeder biomass and production both were significantly higher on
burned watersheds compared to unburned during 1998 (P <
AMERICAN ENTOMOLOGIST • Volume 48, Number 1
0.001). There was a similar but nonsignificant pattern during 1999
(P = 0.4 and 0.1 for biomass and production, respectively). Averaged over the two study years, grass-feeders accounted for 71, 81,
and 66% of total abundance, biomass, and production on burned
watersheds, respectively, compared with 56, 51, and 39% of abundance, biomass, and production on unburned watersheds, respectively (Fig. 3).
Acridid nymphal cohort production to biomass (P/B) values
ranged from 3 to 6 for all taxa, and growth rates ranged from 0.049
+ 0.007 d-1 (mean + 1 SE) in burned watersheds to 0.054 + 0.003 d-1
in unburned. Despite differences in phenologies associated with burn
treatments, there were no significant differences in growth rates of
individual taxa between watershed types.
Among individual taxa, grass-feeding species generally were more
productive on burned watersheds, whereas forb-feeder and general-
Table 1. Parameter estimates from regressions of ln-tranformed
mass (mg) versus ln-tranformed body length (mm) for acridids
collected at Konza Prairie Biological Station during 1998
Species
n
Range, mma
ab
bc
r2
Campylacantha olivacea
15
6.0-23.0
0.031
2.58a
Hesperotettix speciosus
27
5.0-25.2
0.017
2.80b
0.96
0.98
Hypochlora alba
13
9.6-20.6
0.031
2.57a
0.91
Melanoplus bivittatus
26
7.0-40.0
0.011
2.94a
0.97
Melanoplus spp.
19
8.0-25.6
0.020
2.71ab
0.96
Mermiria spp.
24
7.0-44.0
0.004
2.96c
0.97
Orphulella speciosa
31
4.0-21.0
0.025
2.55a
0.97
Phoetaliotes nebrascensis
36
4.0-31.5
0.057
2.25d
0.97
Syrbula admirabilis
10
4.7-33.6
0.012
2.66ab
0.97
Slopes followed by the same letters are not significantly different (ANCOVA, P > 0.05).
aShortest and longest specimens used for each species.
by intercept.
cSlope of line.
55
(Table 4). Forb-feeders consumed 4.2 and 0.9% of forb ANPP on
burned and unburned watersheds, respectively, in 1998; and 1.3
and 0.7% during 1999, respectively (Table 4).
Consumption estimates for grass-feeders during 1998 were
equivalent to 1 and 0.3% of N in ANPP on burned and unburned
watersheds, respectively, during 1998; and 0.2 and 0.1%, respectively, during 1999 (Table 5). For forb-feeders, the values for burned
and unburned were 4.2 and 0.9%, respectively, during 1998; and
1.3 and 0.7%, respectively, during 1999 (Table 5).
Egestion estimates followed patterns of production and consumption, with higher total values during 1998 (Tables 4 and 5). Estimates for grass-feeders consistently were higher in burned watersheds compared with unburned, whereas those for forb-feeders were
more similar between watershed types.
Fig. 3. Abundance (individuals/m2), biomass (g AFDM/m2), and
production (g AFDM m-2 yr-1) estimates for forb-feeding (includes the
generalists Melanoplus spp.) (shaded portions of bars) and grassfeeding acridids (unshaded portions of bars) in annually burned and
long-term unburned watersheds (n = 3 of each) on Konza Prairie
Biological Station during 1998 and 1999. Values are means + 1 SE.
Abundance and biomass are averages for the 5-mo growing season
(May-September). Asterisks above bars indicate significant differences
for total grasshoppers (P < 0.05) between watershed types within a
year (ANOVA with ln-transformed values). Asterisks within bars
indicate significant differences for that feeding group between watershed types within a year.
ist production was more variable across watershed types (Table 2).
Mermiria spp. and O. speciosa, both grass-feeders, had significantly
higher production on burned watersheds during 1998 and 1999 (P
< 0.05). However, one grass-feeder, P. nebrascensis, was a dominant
contributor to production on unburned watersheds during both
years. A generalist, M. bivittatus, also did not follow expected trends
and had significantly higher production on burned watersheds during 1998 (P < 0.05), but was the dominant contributor in unburned
watersheds in 1999.
Substantial shifts in dominant taxa on each watershed type were
evident between 1998 and 1999. For example, Mermiria spp. was
the dominant contributor to production in burned watersheds in
1998, but ranked only fifth during 1999. Likewise, H. alba dropped
from the third most productive taxon in unburned watersheds during 1998 to seventh in 1999 (Table 2).
Nutrient Analyses and Consumption and Egestion Estimates.
Phoetaliotes nebrascensis nymphs had significantly lower amounts
of nitrogen (N) than adults (P < 0.05, Table 3), and the average N
content for all life stages and both sexes was 12.5% (Table 3).
Nymphal frass from unburned watersheds was 2.5% + 0.27 N, which
was significantly higher than frass from burned watersheds (1.7 +
0.13% N). Carbon content varied little between nymphs, adults, and
sexes, with an average of ≈50% for all life stages (Table 3).
Based on production estimates, grass-feeders consumed 1.0 and
0.3% of grass ANPP on burned and unburned watersheds, respectively, during 1998; and 0.2 and 0.1%, respectively, during 1999
56
Discussion
Grasshopper Life Histories. Life history patterns during 1998
indicated that burning influenced the timing of egg hatching on
KPBS. Prior investigations also have noted that fire influences hatching phenology. The influence of fire has been attributed to differences in solar penetration, and thus soil temperature, between burned
and unburned areas during spring (Knutson and Campbell 1976,
Evans 1988a). Patterns we observed were generally consistent with
those of prior studies. For example, Evans (1988a) found that grasshoppers generally hatched 1-2 wk earlier on burned areas, as was
the case for most species during this study. In fact, some species
exhibited an even greater difference in hatching time between burned
and unburned during our study. However, four species showed no
positive response to burning treatment, and one other, A. deorum,
appeared ≈1 wk earlier on unburned watersheds.
Trends of hatching times on burned and unburned watersheds
were not linked to feeding preference, because there were no consistent patterns among feeding groups. Rather, different responses
among taxa likely were linked more to other factors (e.g., distribution and movement patterns) that we did not examine. Grasshoppers often have patchy distributions (Capinera and Sechrist 1982),
and it is possible that some species we examined appeared to contradict the trend of earlier hatching on burned watersheds because
individuals were not found until some time after they had hatched
(e.g., they were initially concentrated in areas of the watershed that
were not sampled). Acridid nymphs will move appreciable distances
in response to host plant distributions (e.g., Richards and Waloff
1954, Dempster 1955), and movements by early instars on KPBS
could have influenced patterns of some taxa. Nonetheless, most
taxa that we examined showed a trend of earlier hatching on burned
areas, and this is consistent with prior studies.
Campbell et al. (1974) studied a similar acridid assemblage in a
tallgrass prairie site located within 15 km of KPBS, and the phenology of many taxa examined during the two studies differed considerably. However, they did not differentiate between burned and unburned areas, so a comparison of burning effects between studies is
impossible. Campbell et al. (1974) found that C. olivacea hatched in
early June, whereas we observed first instars by mid-May in burned
areas and at the end of June in unburned areas. They found that H.
speciosus hatched at the end of April, which is ≈1 mo earlier than we
observed in burned areas, and nearly 2 mo earlier than in unburned.
They also reported that H. alba, Mermiria spp., M. femurrubrum,
and M. bivittatus all hatched ≈1-2 wk earlier, and S. admirabilis
hatched >1 mo later than we observed. The disparity between the
two studies demonstrates that grasshopper populations in a given
region can show considerable annual variability, and much of this
may be linked to annual differences in weather patterns (e.g., Joern
and Pruess 1986, Capinera 1987, Collins and Glenn 1997). However, potential differences in land management cannot be ignored
AMERICAN ENTOMOLOGIST • Spring 2002
Table 2. Production estimates (mean mg AFDM m-2 yr-1 [+SE]) and % contribution to total production for common acridids in
annually burned and long-term unburned watersheds (n = 3 of each watershed type) on Konza Prairie Biological Station during 1998
and 1999
Burned
Unburned
Taxon
Production
% of total
409.8 + 166*
30
Taxon
Production
% of total
93.4 + 47
28
1998
Mermiria spp.a
Orphulella
speciosaa
Phoetaliotes nebrascensisa
bivittatuscb
256.7 + 76*
19
Melanoplus
54.8 + 16*
16
Melanoplus bivittatusb
210.0 + 97*
15
Hypochlora alba c
47.9 + 28
14
Phoetaliotes nebrascensisa
190.2 + 28
14
Hesperotettix speciosusc
40.9 + 21
12
105.0 + 91
8
Melanoplus spp. b
33.0 + 21
10
Syrbula admirabilisa
85.8 + 91
6
Mermiria spp. a
32.7 + 13*
10
Melanoplus spp. b
54.8 + 48
4
Orphulella speciosaa
14.5 + 5*
Hypochlora alba c
31.3 + 33
2
Campylacantha olivacea c
Campylacantha olivacea c
16.1 + 7*
1
Syrbula admirabilisa
Hesperotettix
speciosusc
1
14.0 + 17
1,359.7 + 434*
Total
4
1.9 + 0.3*
4
333.2 + 111*
1999
Phoetaliotes nebrascensisa
93.9 + 68
28
Melanoplus bivittatusb
94.2 + 15
45
75.1 + 35*
22
Phoetaliotes nebrascensisa
56.4 + 46
27
Melanoplus bivitattusb
63.5 + 40
19
Syrbula admirabilisa
Melanoplus spp. b
37.9 + 13
11
Melanoplus spp. b
Mermiria spp.a
36.7 + 23*
11
Campylacantha olivacea c
Hesperotettix speciosusc
24.1 + 30
7
Hesperotettix speciosus
3.2 + 4
1
Hypochlora alba c
Orphulella
speciosaa
Syrbula admirabilisa
Orphulella
Total
9.0 + 10
c
6
7.6 + 9
4
19.6 + 14
9
6.1 + 7
3
1.9 + 2*
1
speciosaa
334.4 + 39
4
12.9 + 8
207.9 + 75
AFDM, ash-free dry mass.
* Indicates means are significantly different (P < 0.05) between watershed types during the same year (ANOVA with ln-transformed values).
aGrass-feeder.
bGeneralist.
cForb-feeder.
(e.g., Evans 1988b, Fielding and Brusven 1993, Baldi and Kisbenedek
1997, Chambers and Samways 1998).
Grasshopper Length-Mass Relationships. Few studies have generated predictive length-mass equations for grasshoppers or other
groups of terrestrial insects, despite their obvious utility for estimating biomass. Relationships we found between length and mass were
similar to those for aquatic insects (see review by Benke et al. 1999)
and terrestrial insects in general (Rogers et al. 1976). However,
Rogers et al. (1976) did not report length-mass regressions that
were specific to grasshoppers. Rather, they developed an equation
for terrestrial insects that included representatives from seven orders and ≈60 families. Therefore, the usefulness of their equation
for specific groups is limited. Compared with the relationships we
developed, mass predictions using the equation from Rogers et al.
differ by 13-22% for most acridid species and up to 190% for Mermiria
spp. In general, the slope of the equation from Rogers et al. is too
high for most species we examined, because it overestimated mass.
However, it underestimated mass for M. bivittatus and Mermiria
spp., because they are relatively heavy-bodied. The value of using
taxon-specific relationships is further underscored by the significant
differences we observed among slopes of length-mass regressions
for KPBS acridids.
Secondary Production Estimates. We know of no other secondary production estimates for grasshopper communities in tallgrass
prairie, but our estimates are in the range of grasshopper populations and communities studied elsewhere. Smalley (1960) estimated
that production of a single species (Orchelimum fidicinium Rehn &
Hebard) in a Georgia salt marsh was ≈2 g m-2 yr-1 dry mass (DM),
AMERICAN ENTOMOLOGIST • Volume 48, Number 1
and Van Hook (1971) estimated that Melanoplus sanguinipes (F.)
production in a Tennessee grassland was about 5.3 g DM m-2 yr-1.
Both of these estimates exceed values for the total community
that we examined on KPBS. However, our estimates are higher
than some others. Wiegert (1965) found the production of a
Michigan community of acridids ranged from 72 to 123 mg DM
m-2 yr-1 in an old field and was 880 mg DM m-2 yr-1 in an alfalfa
field. Bailey and Riegert (1973) estimated that production of
Encoptolophus sordidus (Scudder) was ≈250 mg DM m-2 yr-1 in
a Saskatchewan grassland. The Michigan and Saskatchewan estimates may be lower than ours because they are from more northern latitudes where colder temperatures and shorter growing seasons may limit grasshopper productivity. However, relationships
between invertebrate community production and temperature
often are unclear (see review by Benke 1993), and other biotic
Table 3. Tissue analysis (% nitrogen and carbon) of Phoetaliotes
nebrascensis nymphs (n = 10), adult males (n = 8), and adult females
(n = 7) collected on Konza Prairie Biological Station during 1999
(values are means + SE)
Life stage/sex
Nymphs
Males
Females
Average
%N
10.9
13.8
13.4
12.5
+ 0.2a
+ 0.1b
+ 0.1b
+ 0.3
%C
49.0
49.6
51.0
49.9
+
+
+
+
0.2
0.5
0.4
0.7
Means in a column followed by the same letters are not significantly different
(ANOVA, P > 0.05).
57
Table 4. Production, consumption, and egestion estimates for acridid grasshoppers in annually burned and long-term unburned
watersheds on Konza Prairie Biological Station during 1998 and 1999
Year/Treament/
Group
Production
g m-2 yr-1
ANPPa
g m-2 yr-1
Consumption
g m-2 yr-1
% ANPP consumed
Egestion
g m-2 yr-1
1998 Burned
Grass-feeders
0.94
450
4.70
1.0
2.35
Forb-feeders
0.42
50
2.10
4.2
1.05
Grass-feeders
0.15
290
0.75
0.3
0.38
Forb-feeders
0.18
100
0.90
0.9
0.45
Grass-feeders
0.21
450
1.05
0.2
0.53
Forb-feeders
0.13
50
0.65
1.3
0.33
Grass-feeders
0.07
290
0.35
0.1
0.18
Forb-feeders
0.14
100
0.70
0.7
0.35
1998 Unburned
1999 Burned
1999 Unburned
All values are ash-free dry mass.
Acridids are grouped by feeding preference; Melanoplus spp. (generalists) are grouped with forb-feeders.
aAnnual net primary production (ANPP) values are 10-yr averages for grasses and forbs in burned and unburned watersheds on KPBS (Knapp et al. 1998b).
and abiotic factors such as moisture and forage quality may be
more or equally important.
General patterns of acridid production we observed reflected
vegetational patterns and climate at KPBS. Overall higher production by grass-feeders during this study was not surprising because
previous investigations have shown that graminivorous taxa generally outnumber forb-feeders on KPBS (Evans 1984, 1988a, 1988b).
Lower total acridid production on KPBS during the second year of
this study likely was linked to unusually wet conditions during the
spring of 1999 (year 2), because grasshopper populations in temperate areas generally are more successful during hot, dry years
(Capinera 1987, Capinera and Thompson 1987). Early spring rains
can cause high nymphal mortality (Capinera 1987), and young
grasshoppers are prone to fungus infection under these conditions
(Parker 1930, Pickford and Riegert 1964).
Abundance, biomass, and production sometimes can show different patterns. Static measures such as abundance and biomass
only reflect numbers and mass of organisms that are present on any
particular sampling date and, therefore, do not reflect all that is
integrated into production, such as growth rates and life cycle length.
For example, Lugthart and Wallace (1992) and Whiles and Wallace
(1995) found that abundance and production estimates for a stream
invertebrate community showed different patterns through a disturbance and recovery sequence. However, they examined an entire
invertebrate community that included taxa with body sizes that
ranged across orders of magnitude and life cycles ranging from
polyvoltine to merovoltine. All acridids that we examined on KPBS
were univoltine and relatively similar in size; therefore, patterns reflected by abundance, biomass, and production estimates were similar during our study.
Burning Effects on Production. Our results indicate that burning
increases total acridid production, and that fire influences individual
taxa differently. Based on abundance estimates, Evans (1984, 1988a,
1988b) showed that grasshopper community structure on KPBS
was different in burned and unburned areas, and this was attributed to changes in plant community structure brought about by
fire. He reported that forbs, and thus forb-feeding grasshoppers,
were more abundant on unburned areas, whereas grasses and grass58
feeders dominated in burned areas. We also observed a trend toward greater abundance, biomass, and production of total grassfeeders on burned watersheds, although forb-feeder responses were
variable. Patterns observed for individual taxa were less clear and, in
some cases, contradicted expected patterns. For example, M.
bivittatus (generalist/forb-feeder) and C. olivacea (forb-feeder) had
significantly higher production on burned watersheds during 1998.
Further, M. bivittatus was the dominant contributor to production
in unburned watersheds and C. olivacea was completely absent from
burned watersheds during 1999. Thus, although overall patterns of
acridid production resembled predictions based on responses of
plant communities (e.g., higher grass-feeder production in burned
watersheds where grasses are increased), trends among individual
taxa, particularly forb-feeders, were variable. The variable responses
we observed may reflect the cyclical nature of prairie grasshopper
populations that others have reported (e.g., Joern and Pruess 1986,
Joern and Gaines 1990).
Differential responses of acridid species within feeding groups
may have been related to differences in plant community structure
and acridid feeding patterns at a finer scale than we examined. All
acridids at KPBS that we considered grass-feeders feed on a wide
variety of grasses. For example, S. admirabilis feeds on 12 different
grass species (Campbell et al. 1974). Similarly, most forb-feeders
and generalists we examined also feed on a variety of different host
plants. Thus, if the abundance or quality of one or more food plants
were low in a watershed during a given year, there potentially would
be other host plants available.
Despite the apparent “head start” by some acridids on burned
watersheds, we found no evidence that earlier hatching was linked
to higher production. Patterns of abundance, biomass, and production indicated that differences in abundance, and thus biomass, accounted for differences in production of individual taxa, suggesting
that differences in production were most linked to factors influencing fecundity and/or survivorship. In fact, average instantaneous
daily growth rates during 1998 and 1999 were ≈10% higher on
unburned watersheds compared with burned, primarily because of
shorter developmental periods in unburned watersheds. A longer
period of activity would be expected to increase production in some
AMERICAN ENTOMOLOGIST • Spring 2002
Table 5. Nitrogen amounts and fluxes associated with grasshopper production, consumption, and egestion in annually burned and
long-term unburned watersheds on Konza Prairie Biological Station during 1998 and 1999
Year/Treatment/
Group
N in acridids
g m-2 yr-1
N ANPPa
g m-2 yr-1
N consumed
g m-2 yr-1
%N consumed
g m-2 yr-1
N egested
1998 Burned
Grass-feeders
0.118
4.5
0.047
1.0
0.040
Forb-feeders
0.053
1.0
0.042
4.2
0.018
1998 Unburned
Grass-feeders
0.019
2.9
0.008
0.3
0.010
Forb-feeders
0.023
2.0
0.018
0.9
0.011
Grass-feeders
0.026
4.5
0.011
0.2
0.009
Forb-feeders
0.016
1.0
0.013
1.3
0.006
1999 Burned
1999 Unburned
Grass-feeders
0.009
2.9
0.004
0.1
0.005
Forb-feeders
0.018
2.0
0.014
0.7
0.009
Acridids are grouped by feeding preference; Melanoplus spp. (generalists) is grouped with forb-feeders.
N consumed is shown as g m-2 yr-1 and as percentage (%) of total annual net primary production consumed.
aAnnual net primary production (ANPP) values are 10-yr averages for grasses and forbs in burned and unburned watersheds on KPBS (Knapp et al. 1998b).
cases, particularly for polyvoltine taxa. However, the acridids we
examined have only one generation per year, and the density of
individuals at a given location most influenced annual production.
Further, survivorship of nymphs on KPBS that hatch earlier in the
year on burned watersheds, when moister and cooler conditions
prevail, likely is low (e.g., Parker 1930, Pickford and Riegert 1964,
Capinera 1987).
Shifts in dominance that we observed within watershed types
during the two study years further underscore the dynamic nature of grasshopper populations. For example, Mermiria spp.
went from the dominant contributor to production in burned
watersheds in 1998 to fifth in 1999, and H. alba dropped from
the third highest contributor in unburned watersheds during
1998 to seventh in 1999. Other studies have documented substantial annual fluctuations in grasshopper populations (e.g.,
Joern and Pruess 1986, Joern and Gaines 1990), and these studies and ours suggest that long-term investigations may be necessary for accurate assessments of populations and the factors that
influence them.
Consumption, Egestion, and Nutrient Cycling. Our estimates
of consumption by acridids are similar to those from other studies. Most prior studies have estimated that grasshopper consumption is <5% of ANPP. For example, Wiegert (1965) found that a
Michigan grasshopper community removed ≈0.5% of ANPP in an
old field and ≈2.5% of ANPP in an alfalfa field. Bailey and Mukerji
(1977) estimated consumption by M. bivittatus and M.
femurrubrum was 1.65 and 1.74% of ANPP, respectively. Our
estimates indicate that consumption is highest on burned watersheds and that for grasses and forbs it can range up to 1 and 4%
of ANPP, respectively. Because fire substantially reduces forbs
(Knapp et al. 1998b), percent consumption of forb ANPP is disproportionately higher on burned watersheds. These results indicate that burning indirectly influences the relative importance of
acridids to energy and nutrient cycling on KPBS by altering the
availability of food plants.
Our results suggest that acridid grazing is less important than
that of bison, which are maintained to remove ≈20% of ANPP on
KPBS, but can vary substantially with burn history and year. Unlike
AMERICAN ENTOMOLOGIST • Volume 48, Number 1
grazing by invertebrate communities, grazing by bison on KPBS is
well studied, and these large grazers have a significant impact on
material and energy cycling as well as plant community structure
(Knapp et al. 1999). Our consumption estimates suggest direct impacts by acridids may be less evident, with the possible exception of
forb-feeders in burned areas. Bison preferentially graze grasses
(Hartnett et al. 1997), whereas we estimated the most significant
impacts of acridids, in terms of percent of plant tissues removed,
were on forbs. Further, bison grazing promotes forb production
by reducing competition with grasses (Knapp et al. 1999). Thus, it
appears that bison and acridids are having their largest impact on
different components of the tallgrass prairie plant community, and
that there may be complex interactions between burning, plant
communities, grazing by bison, and grazing by acridids. For example, burning increases the relative significance of grazing by
forb-feeding acridids, but burned watersheds also are grazed preferentially by bison (Coppedge and Shaw 1997), which in turn
favors forb production, thus potentially diluting the impact of
forb-feeding acridids, in terms of percent ANPP removed. We did
not examine bison-grazed areas during our study, but our results
suggest that future studies should examine grasshopper production and consumption within the context of both burning and
ungulate grazing treatments.
Arthropod grazers can have important impacts on energy cycling that transcend consumption. For example, arthropods such as
grasshoppers that chew their food often can remove more plant
material than they actually ingest. Varying amounts of this “green
fall” occur when parts of the plant are severed and dropped to the
ground, and this can vary from 10% (White 1974) to 480%
(Andrzejewska et al. 1967) of ingestion. Based on laboratory studies of P. nebrascensis collected from KPBS (Meyer 2000), acridids
sever and drop an amount equivalent to 3% of what they ingest as
nymphs and between 17 and 40% of what they ingest as adults.
However, these values were obtained under stable laboratory conditions (e.g., no wind or rain) and are likely higher under field conditions. Based on these laboratory estimates, removal of ANPP in
1998 could have been as high as 1.4% of grass ANPP by grassfeeders and as much as 5.9% of forb ANPP by forb-feeders in
59
annually burned watersheds. Even when corrected for dropped
material, these estimates still do not account for the additional impacts of damage to plants during grazing (e.g., Tukey 1970,
Schowalter et al. 1986).
Nitrogen-flux through acridids on KPBS represents a significant
pathway for this limiting nutrient. Annual N inputs on KPBS from
bulk precipitation are 1-2 g m-2 yr-1, and litter-fall represents 0.5-2.0
g m-2 yr-1 (Blair et al. 1998). Nitrogen loss due to volatilization
during fire ranges from 1 to 4 g m-2 yr-1, and loss through stream
and groundwater ranges from 0.018 to 0.036 g m-2 yr-1 (Blair et al.
1998). Thus, N moving through acridid biomass (0.027 to 0.171 g
m-2 yr-1, depending on watershed type and year), and N consumed
by acridids (0.018 to 0.089 g m-2 yr-1) represent appreciable portions in this ecosystem. Additionally, 0.014-0.058 g m-2 yr-1 N is
returned to the soil as frass. Acridids also represent N available to
higher trophic levels, because they are consumed by many invertebrate and vertebrate predators in the tallgrass prairie. Nitrogen in
acridid biomass that is not consumed returns to the soil through
death and decomposition. Blair et al. (1998) estimated that plant
detritus on KPBS contained only ≈0.4% N, which is much lower
than our estimates of acridids and their frass. Dead arthropods
and frass are relatively nutritious and labile compared with plant
detritus, and have been shown to stimulate nutrient cycling (e.g.,
Swank et al 1981, Anderson and Ineson 1983, Seastedt and
Crossley 1984).
In summary, results of this study demonstrate that acridids are
an important and dynamic component of the tallgrass prairie. Further, this group is only one of many diverse groups of herbivorous
insects found in tallgrass prairie, and the combined effects of all
groups obviously would be greater than that of acridids alone. Our
results do not indicate that acridids in tallgrass prairie are limited by
primary production, or that acridid grazing is equal to that of ungulates. Rather, our results suggest that the relative importance of
acridids varies with plant community responses to burning, and
could potentially interact with the influence of ungulate grazers.
Future studies that examine grasshopper and plant communities in
finer detail, and across different grazing and burning treatments,
will further our understanding of the significance of these ubiquitous consumers in prairie ecosystems.
Acknowledgments
We thank J. M. Blair, D. C. Margolies, B. L. Brock, and P. A. Fay
(Kansas State University, Manhattan) for assistance with all facets
of this research. Logistical support was provided by V. Ganti, B.
Stone-Smith, A. Gesche, J. Jonas, M. Callaham, S. G. Baer, G. Hoch
(Kansas State University), and A. D. Huryn (University of Maine,
Orono). A. C. Benke (University of Alabama, Tuscaloosa) and an
anonymous reviewer provided comments that greatly improved the
manuscript. Funding for this research was provided by the Kansas
State University Department of Entomology and an NSF Long-Term
Ecological Research grant awarded to the KSU Division of Biology.
This is contribution no. 01-351-J from the Kansas Agricultural
Experiment Station.
References Cited
Anderson, J. M., and P. Ineson. 1983. Interactions between soil arthropods
and micro-organisms in carbon, nitrogen and mineral element fluxes
from decomposing leaf litter, pp. 413-432. In J. E. Lee, S. McNeill, and
I. H. Rorinson (eds.), Nitrogen as an ecological factor. Blackwell,
Oxford.
Anderson, R. C., T. Leahy, and S. S. Dhillion. 1989. Numbers and biomass
of selected insect groups on burned and unburned sand prairie. Am.
Midl. Nat. 122: 151-162.
Andrzejewska L. 1976. The effect of intensive fertilization on the struc60
ture and productivity of meadow ecosystems. 10. The influence of
mineral fertilization on the meadow phytophagous fauna. Pol. Ecol.
Stud. 2: 93-109.
Bailey, C. G., and M. K. Mukerji. 1976. Consumption and utilization of
various host plants by Melanoplus bivittatus (Say) and M. femurrubrum
(De Geer) (Orthoptera: Acrididae). Can. J. Zool. 54: 1044-1050.
Bailey, C. G., and M. K. Mukerji. 1977. Energy dynamics of Melanoplus
bivittatus and Melanoplus femurrubrum (Orthoptera: Acrididae) in a
grassland ecosystem. Can. Entomol. 109: 605-614.
Bailey, C. G., and P. W. Riegert. 1973. Energy dynamics of Encoptolophus
sordidus costalis (Scudder) (Orthoptera: Acrididae) in a grassland ecosystem. Can. J. Zool. 51: 91-100.
Baldi, A., and T. Kisbenedek. 1997. Orthopteran assemblages as indicators of grassland naturalness in Hungary. Agric. Ecosyst. Environ. 66:
121-129.
Benke, A. C. 1984. Secondary production of aquatic insects, pp. 289-322.
In V. H. Resh and D. M. Rosenberg (eds.), The ecology of aquatic
insects. Praeger, New York.
Benke, A. C. 1993. Concepts and patterns of invertebrate production in
running waters. Edgardo Baldi Memorial Lecture. Verh. Int.
Vereiningung Limnol. 25: 15-38.
Benke, A. C., and J. B. Wallace. 1980. Trophic basis of production among
net-spinning caddisflies in a southern Appalachian stream. Ecology
61: 108-118.
Benke, A. C., A. D. Huryn, L. A. Smock, and J. B. Wallace. 1999. Lengthmass relationships for freshwater macroinvertebrates in North America
with particular reference to the southeastern United States. J. N. Am.
Benthol. Soc. 18: 308-343.
Blair, J. M. 1997. Fire, N availability, and plant response in grasslands: a
test of the transient maxima hypothesis. Ecology 78: 2359- 2368.
Blair, J. M., T. R. Seastedt, C. W. Rice, and R. A. Ramundo. 1998. Terrestrial nutrient cycling in tallgrass prairie, pp. 222-243. In A. K. Knapp,
J. M. Briggs, D. C. Hartnett, and S. L. Collins (eds.), Grassland dynamics: long-term ecological research in tallgrass prairie. Oxford University Press, New York.
Blecha, K. 1974. Identification of nymphs and adults of the common
grasshoppers (Acrididae) inhabiting the Flint Hills native tallgrass
prairie near Manhattan, Kansas. M.S. thesis, Kansas State University,
Manhattan.
Blumer, P., and M. Diemer. 1996. The occurrence and consequences of
grasshopper herbivory in an alpine grassland, Swiss central Alps. Arctic Alpine Res. 28: 435-440.
Campbell, J. B., W. H. Arnett, J. D. Lambley, O. K. Jantz, and H. Knutson.
1974. Grasshoppers (Acrididae) of the Flint Hills native tallgrass prairie in Kansas. Research Paper no. 19. Agricultural Experiment Station,
Kansas State University, Manhattan.
Capinera, J. L. 1987. Population ecology of rangeland grasshoppers, pp.
162-182. In J. L. Capinera (ed.), Integrated pest management on rangeland: a shortgrass prairie perspective. Westview, Boulder, CO.
Capinera, J. L., and T. S. Sechrist. 1982. Grasshoppers (Acrididae) of
Colorado: identification, biology, and management. Colorado State
University, Fort Collins, CO.
Capinera, J. L., and D. C. Thompson. 1987. Dynamics and structure of
grasshopper assemblages on shortgrass prairie. Can. Entomol. 119:
567-575.
Chambers, B. Q., and M. J. Samways. 1998. Grasshopper response to a
40-year experimental burning and mowing regime, with recommendations for invertebrate conservation management. Biodiver. Conserv.
7: 985-1012.
Collins, S. L., and S. M. Glenn. 1997. Effects of organismal and distance
scaling on analysis of species distribution and abundance. Ecol. Appl.
7: 543-551.
Collins, S. L., and E. M. Steinauer. 1998. Disturbance, diversity, and
species interactions in tallgrass prairie, pp. 140-159. In A. K. Knapp, J.
M. Briggs, D. C. Hartnett, and S. L. Collins (eds.), Grassland dynamics: long-term ecological research in tallgrass prairie. Oxford University Press, New York.
Coppedge, B. R., and J. H. Shaw. 1997. Bison grazing patterns on seasonally burned tallgrass prairie. J. Range Manage. 51: 258-264.
Coppock, S., Jr. 1962. The Grasshoppers of Oklahoma (Orthoptera:
AMERICAN ENTOMOLOGIST • Spring 2002
Acrididae). Okla. State Univ. Process. Ser. P-399.
Dempster, J. P. 1955. Factors affecting small-scale movements of some
British grasshoppers. Proc. R. Entomol. Soc. Lond. A Ser. 30: 145-150.
Duke, K. M, and D. A. Crossley, Jr. 1975. Population energetics and
ecology of the rock grasshopper, Trimerotropis saxatilis. Ecology 56:
1106-1117.
Evans, E. W. 1984. Fire as a natural disturbance to grasshopper assemblages of tallgrass prairie. Oikos 43: 9-16.
Evans, E. W. 1988a. Grasshopper (Insecta: Orthoptera: Acrididae) assemblages of tallgrass prairie: influences of fire frequency, topography,
and vegetation. Can. J. Zool. 66: 1495-1501.
Evans, E. W. 1988b. Community dynamics of prairie grasshoppers subjected to periodic fire: predictable trajectories or random walks in
time? Oikos 52: 283-292.
Fielding, D. J., and M. A. Brusven. 1993. Grasshopper (Orthoptera:
Acrididae) community composition and ecological disturbance on
southern Idaho rangeland. Environ. Entomol. 22: 71-81.
Hartnett, D. C., A. A. Steuter, and K. R. Hickman. 1997. Comparative
ecology of native versus introduced ungulates, pp. 72-101. In F. Knopf
and F. Samson (eds.), Ecology and conservation of Great Plains vertebrates. Springer, New York.
Hulbert, L. C. 1973. Management of Konza Prairie to approximate prewhite-man fire influences. Third Midwest Prairie Conference Proceedings, Manhattan, KS.
Joern, A., and S. B. Gaines. 1990. Population dynamics and regulation in
grasshoppers, pp. 415- 482. In R. F. Chapman and A. Joern (eds.),
Biology of grasshoppers. Wiley, New York.
Joern, A., and K. P. Pruess. 1986. Temporal constancy in grasshopper
assemblages (Orthoptera: Acrididae). Ecol. Entomol. 11: 379- 385.
Kemp, W. P., and B. Dennis. 1989. Development of two rangeland grasshoppers at constant temperatures: development thresholds revisited.
Can. Entomol. 121: 363-371.
Khan, H. R., and S. A. Aziz. 1974. Effect of temperature and humidity on
the incubation and hopper development periods of Eyprepocnemis
alacris Serville (Orthoptera: Acrididae). Acrida 3: 47-53.
Knapp, A. K., J. M. Briggs, D. C. Hartnett, and S. L. Collins (eds.). 1998a.
Grassland dynamics: long-term ecological research in tallgrass prairie.
Oxford University Press, New York.
Knapp, A. K., J. M. Briggs, J. M. Blair, and C. L. Turner. 1998b. Patterns
and controls of aboveground net primary production in tallgrass prairie, pp. 193-221. In A. K. Knapp, J. M. Briggs, D. C. Hartnett, and S.
L. Collins (eds.), Grassland dynamics: long-term ecological research in
tallgrass prairie. Oxford University Press, New York.
Knapp, A. K., J. M. Blair, J. M. Briggs, S. L. Collins, D. C. Hartnett, L. C.
Johnson, and E. G. Towne. 1999. The keystone role of bison in North
American tallgrass prairie. BioScience 49: 39-50.
Knutson, H., and J. B. Campbell. 1976. Relationships of grasshoppers
(Acrididae) to burning, grazing, and range sites of native tallgrass
prairie in Kansas. Proc. Tall Timbers Conf. Ecol. Anim. Control Habitat Manage. 6: 107-120.
Lightfoot, D. C., and W. G. Whitford. 1990. Phytophagous insects enhance nitrogen flux in a desert creosotebush community. Oecologia
82: 18- 25.
Lugthart, G. J., and J. B. Wallace. 1992. Effects of disturbance on benthic
functional structure and production in mountain streams. J. N. Am.
Benthol. Soc. 11: 138-164.
MacFarlane, J. H., and A. J. Thorsteinson. 1980. Development and survival of the twostriped grasshopper, Melanoplus bivittatus (Say) (Orthoptera: Acrididae), on various single and multiple plant diets. Acrida
9: 63-76.
Meyer, C. K. 2000. Life history and secondary production of grasshoppers
(Orthoptera: Acrididae) in a Kansas tallgrass prairie. M.S. thesis, Kansas State University, Manhattan.
Nagel, H. G. 1973. Effect of spring prairie burning on herbivorous and
non-herbivorous arthropod populations. J. Kans. Entomol. Soc. 46:
485-496.
Otte, D. 1981. The North American Grasshoppers. Harvard University
Press, Cambridge, MA.
Parker, J. R. 1930. Some effects of temperature and moisture upon
AMERICAN ENTOMOLOGIST • Volume 48, Number 1
Melanoplus mexicanus mexicanus Saussure and Camnula pellucida
Scudder (Orthoptera). Univ. Mont. Agric. Exp. Stn. Bull. 223.
Pickford, R., and P. W. Riegert. 1964. The fungus disease caused by Entomophthora grylli Fres., and its effects on grasshopper populations in
Saskatchewan in 1963. Can. Entomol. 96: 1158-1166.
Reichle, D. E., M. H. Shanks, and D. A. Crossley, Jr. 1969. Calcium,
potassium and sodium content of forest floor arthropods. Ann. Entomol.
Soc. Am. 62: 57-62.
Richards, O. W., and N. Waloff. 1954. Studies on the biology and population dynamics of British grasshoppers. Anti-Locust Bull. 17: 1-182.
Robel, R. J., C. A. Desjardins, and K. E. Kemp. 1998. Nutrient and energetic characteristics of grasshoppers of different life stages. Prairie
Nat. 30: 37-48.
Rodell, C. F. 1977. A grasshopper model for a grassland ecosystem. Ecology 58: 227-245.
Rogers, L. E., W. T. Hinds, and R. L. Buschbom. 1976. A general weight
vs. length relationship for insects. Ann. Entomol. Soc. Am. 73: 106109.
SAS Institute. 1988. SAS user’s guide: statistics. SAS Institute, Cary, NC.
Schowalter, T. D. 1981. Insect herbivore relationship to the state of the
host plant: biotic regulation of ecosystem nutrient cycling through
ecological succession. Oikos 37: 126-130.
Schowalter, T. D., W. W. Hargrove, and D. A. Crossley, Jr. 1986. Herbivory in forested ecosystems. Annu. Rev. Entomol. 31: 177-196.
Scriber, J. M., and F. Slansky, Jr. 1981. The nutritional ecology of immature insects. Annu. Rev. Entomol. 26: 183-211.
Seastedt, T. R., and D. A. Crossley, Jr. 1984. The influence of arthropods
on ecosystems. BioScience 34: 157-161.
Slansky, F., Jr., and J. M. Scriber. 1982. Selected bibliography and summary of quantitative food utilization by immature insects. Bull. Entomol.
Soc. Am. 28: 43-55.
Smalley, A. E. 1960. Energy flow of a salt marsh grasshopper population.
Ecology 41: 672-677.
Smith, D. S. 1959. Utilization of food plants by the migratory grasshopper Melanoplus bilaturus (Walker) (Orthoptera: Acrididae), with some
observations on the nutritional value of the plants. Ann. Entomol. Soc.
Am. 52: 674- 680.
Swank, W. T., J. B. Waide, D. A. Crossley, Jr., and R. L. Todd. 1981. Insect
defoliation enhances nitrate export from forest ecosystems. Oecologia
51: 297- 299.
Tukey, H. B., Jr. 1970. The leaching of substances from plants. Annu. Rev.
Plant Physiol. 12: 305-324.
Turner, C. L., J. R. Kneisler, and A. K. Knapp. 1995. Comparative gas
exchange and nitrogen responses of the dominant C4 grass Andropogon
gerardii and five C3 forbs to fire and topographic position in tallgrass
prairie during a wet year. Int. J. Plant Sci. 156: 216- 226.
Van Hook, R. I., Jr. 1971. Energy and nutrient dynamics of spider and
orthopteran populations in a grassland ecosystem. Ecol. Monogr. 41:
1-26.
Whiles, M. R., and J. B. Wallace. 1995. Macroinvertebrate production
in a headwater stream during recovery from anthropogenic disturbance and hydrologic extremes. Can. J. Fish. Aquat. Sci. 52: 24022422.
White, E. G. 1974. Grazing pressures of grasshoppers in an alpine tussock
grassland. N.J. J. Agric. Res. 17: 357-372.
Wiegert, R. G. 1965. Energy dynamics of the grasshopper populations in
old field and alfalfa field ecosystems. Oikos 16: 161- 176.
Wiegert, R. G., and C. E. Petersen. 1983. Energy transfer in insects. Annu.
Rev. Entomol. 28: 455-86.
Zar, J. H. 1996. Biostatistical analysis, 3rd ed. Prentice-Hall, Englewood
Cliffs, NJ.
C. K. Meyer is in the Department of Agronomy and Horticulture,
University of Nebraska, Lincoln, NE 68583-0724. M. R. Whiles is in
the Department of Zoology, Southern Illinois University, Carbondale,
IL 62901-6501 (send reprint requests to [email protected]).
R. E. Charlton is in the Department of Entomology, Kansas State
University, Manhattan, KS 66506-4004.
B
61