Cedar Creek Natural History Area

Insects of Cedar Creek

Order ORTHOPTERA

ACRIDINAE
The Slant-faced Grasshoppers feed exclusively on grasses and are primarily early to mid-summer species. They will be considered roughly in order of abundance. Ageneotettix deorum is an abundant and ubiquitous mid-summer species. It is most common in xeric-weedy fields. Aeropedellus clavatus is a common early-summer species with clubbed antennae. It is rare to absenct in xeric fields but occurs in fair numbers in mesic-prairie and grassy fields containing Poa. Pseudopomala brachyptera is reported to feed on big and little bluestem, but it has been taken in fields containing neither of these grasses. It is absent from extremely xeric fields and is most common in prairie fields. It fluctuates considerably in abundance from year to year. Orphulella speciosa, the Pasture Grasshopper, occurs in small numbers in prairie and weedy fields but is generally absent from brome and Poa fields. Chorthippus curtipennis is common in savanna and mesic grassy swales. Chloealtis conspersa is an uncommon inhabitant of dry oak woods and savanna. The remaining species in this subfamily are infrequently collected. Orphulella pelidna has been taken sparingly from prairie and savanna. Eritettix simplex overwinters as a nymph and is found as an adult only in extremely xeric fields in early summer. I suspect it may feed on Aristida. Dichromorpha viridis is a rare visitant? to the Area that frequents marshes and the coarser grasses around ponds and lakes.

OEDIPODINAE
The Banded-wing Grasshoppers are conspicuous but are seldom swept in large numbers. They inhabit primarily xeric-weedy fields, are extremely wary, and readily take flight when one approaches with a net. Males of most of these colorful species evidence courtship with hovering flight and 'crackling' wings. This group will be considered chronologically.

Pardalophora apiculata is a large, green, leopard-spotted species with pink wing discs that is conspicuous in most fields in late spring. Arphia conspersa is a smaller, dark-bodied, yellow-winged species also occuring in most fields during the same period. Chortophaga viridifasciata prefers luxuriant growth near marsh edges. Xanthippus corallipes-latefasciatus is a large leopard-spotted, yellow-winged species found only in xeric fields in the SE corner of the Area. It has not been seen in several years.  All of these species overwinter as half grown nymphs.

The two most common late-summer species of Banded-wings are Spharagemon collare (pale body, yellow wings, orange legs) and Arphia pseudonietana (dark body, red-peach wings, dark legs). Both are widespread but A. pseudonietana is more common in mesic fields than in xeric ones. Dissosteira carolina, the Black-winged Grasshopper, is commonly seen along gravelly roadsides and at gopher mounds in fields. The remaining Oedipodinae of late-summer are only infrequently collected. Psinidia fenestralis occurs only in extremely xeric fields with sparse vegetation cover and near blowouts in savanna areas. The very similar Trachyrhachys kiowa has only been taken from a few weedy fields in 1989-1991. Camnula pellucida, the Clear-winged Grasshopper, is probably a visitant to the Area and has only been collected from a few fields in 19900-91. This species is abundant in northern Minnesota and can be a pest of cereal crops. Encoptolophus sordidus is an uncommon species of early fall and has been taken from weedy Poa fields and prairie. Spharagemon bolli is an uncommon species of savanna and open woodland.

Stethophyma gracile is a rare species of marshes. It reportedly feeds on Carex and has been variably assigned to the Acridinae and Oedipodinae. This species is extremely wary and difficult to capture. It quickly descends into the vegetation upon spotting an intruder. Only a single specimen collected.

CYRTACANTHACRIDINAE
Schistocerca emarginata, the Bird-winged Grasshopper, is the only representative of this subfamily. It is a large tan species and an excellent flier. It has a deliberate flight and will frequently fly to Bur Oak trees and has been observed feeding on oak leaves. Leadplant, Amorpha canescens, appears to be a preferred host plant of the nymphs. This species has been taken or observed in most fields--many lacking leadplant, but it is most common in dry prairie and savanna.

MELANOPLINAE
Most of the Spur-throats belong to the genus Melanoplus, but a miscellany of other species will be considered first. Phoetaliotes nebrascensis, the Big-headed Grasshopper, is a late-season species that is fairly common in most fields, but perhaps best represented in brome fields. Hypochlora alba (pale green with red antennae) is a specialist on Artemisia ludoviciana and has only been taken from a few fields and savannas containing its host plant. Last collected in 1996.  Both of these species are nearly always brachypterous. Hesperotettix viridis-pratensis is a forb feeder (Solidago rigida?) of xeric prairie and has only been taken in sand prairie and savanna in 1991-93.
*Booneacris glacialis-canadensis is a black and green brachypterous species found in northern Minnesota.

Melanoplus femurrubrum, the Red-legged Grasshopper, is the most common and widely distributed of all the Acrididae of CCNHA. Probably no field lacks this species, but it is extremely rare in xeric and mesic prairie. M. sanguinipes, the Lesser Migratory Grasshopper, is abundant in SV but uncommon to absent elsewhere. It can be a pest of cereal crops in the northern and western portions of the state. M. keeleri-luridus is common and widely distributed but is most common in weedy-brome fields and mesic prairie. A preferred host plant may be perennial ragweed, Ambrosia coronopifolia? M. angustipennis is widely distributed but is only common in xeric fields in the SE corner of the area. I suspect it feeds on Helianthus and other rough prairie forbs. M. dawsoni is a brachypterous species (black and yellow banded abdomen) that occurs in modest numbers in prairie fields but is most common in the savanna region south of Fish Lake. M. bivittatus, the Two-striped Grasshopper, prefers mesic grasslands but is taken in modest numbers from a variety of fields. It can be a crop pest. M. confusus is an early summer species that has been taken sparingly from several weedy-xeric fields. Two uncommon species of xeric fields are M. flavidus and M. foedus . M. differentialis can be a crop pest in southern Minnesota, but is uncommon at Cedar Creek where it seems to prefer luxuriant growth at pond and marsh edges.

M. borealis is an uncommon marsh inhabitant, but this habitat is inhospitable for collecting, and it may in fact be found to be quite common with appropriate collecting. M. fasciatus is an uncommon open woodland inhabitant that reportedly feeds on Blueberry.  M. islandicus is another very rare species of woodland.  M. punctulatus is an uncommon inhabitant of tamarack swamp and also pine plantations? Individuals are routinely seen in late summer on tamaracks surrounding Beckman Lake. This species is cryptically colored to blend with the lichen covered bark, and I suspect it may feed on the lichen. I have seen females oviposit in rotten logs in this boggy environment.

Some outstate species of Melanoplus not collected at Cedar Creek include:  M. walshii, M. viridipes, M. gracilis, and M. undet taken at limestone cliffs in Whitewater State Park, Olmsted Co.

ADDENDUM:  POPULATION REGULATION
Grasshopper populations are generally quite large on the sandy soils of Cedar Creek and the surrounding Anoka Sand Plain. However, I suspect that they rarely if ever compete for resources (see Ritchie, 1992; for a differing view). Populations seem to be more strongly influenced by meteorologic conditions. They thrive under hot-dry conditions and are suppressed by cool-wet ones. Grasshopper predators/parasites abound and they may have some influence as well. Probably birds (kingbirds, meadowlarks, cranes, etc.) are the most important vertebrate predators. Asilidae (Robber Flies) feed on nymphs and adults; but most insects attack egg pods in the soil. This group includes some Bombyliid Flies (Systoechus, Anastoechus), Meloid (Epicauta pennsylvanica) and Carabid (Percosia obesa) Beetles, and probably other Carabids and Staphylinids. Sarcophagid Flies (Acridiophaga sp) parasitize nymphal and adult grassshoppers as do some Nematodes.