8.20: web.pol/buffelgrass control with grasshoppers:
. some grasshoppers will eat buffel grass .
. if there was an easy way to catch them,
they could both eat the buffelgrass and serve as food,
as they do in many places -- including japan .
. this is an economical way to get grass-fed meat .
Warm and dry spring conditions encourage nymphal growth.
An early spring followed by cloudy, damp weather
encourages diseases that sicken and kill hoppers.
A long, hot summer ensures a plentiful food supply
and encourages early maturity of grasshoppers and a long egg-laying period.
On the other hand, a cool summer and early fall
slows down grasshopper maturity and reduces time for laying eggs.
Grasshoppers are drawn to monocultures
and dislike nitrogen-fixing crops like legumes and sweet clover.
. all birds love grasshoppers .
. instead of being caterpillars, they develop in an egg,
and hatch as jumping grass or forb [flowering non-grass] eaters;
in a few more weeks they can fly .
The most widely eaten insects in japan are inago
(the grasshopper, Oxya velox F.),
which is preserved by boiling in soy sauce.
-- a luxury item in supermarkets throughout the country, including Tokyo.
Catching inago is done in rice paddies in autumn
. with rice in overproduction, why not let inago feed on the excess,
thus increasing the population of the grasshopper?
perhaps the prefer their rice;
they also like cooking wasps, suggesting it might be just a sport .
insect hazards
Some insects secrete toxins, produce toxic metabolites
or sequester toxic chemicals from foodplants
(Blum, 1978; Duffey, 1980; Wirtz, 1984).
Defensive secretions that may be reactive, irritating or toxic
include carb-oxylic acids, alcohols, aldehydes, alkaloids, ketones, esters,
lactones, phenols, 1,4-quinones, hydrocarbons and steroids, among others.
Phytochemicals sequestered by various insects include
simple phenolics, flavin, tannins, terpenoids, polyacetylenes,
alkaloids, cyanogens, glucosinolates and mimetic amino acids.
Insects are also a source of
injectant, ingestant, contactant and inhalant allergens (Wirtz, 1984; Gorham, 1991 ),
and some insects serve as vectors or passive intermediate hosts of
vertebrate pathogens such as bacteria, protozoa, viruses or helminths (Gorham, 1991).
More attention should be directed toward
assessing these risk factors in the edible insect groups.
The long history of human use suggests, however, with little evidence to the contrary,
that the insects intentionally harvested for human consumption
do not pose any significant health problem.
The Nematomorph hairworm (Spinochordodes tellinii)
develops inside land-dwelling grasshoppers and crickets
until the time comes for the worm to transform into an aquatic adult.
. the mature hairworms brainwash their hosts by producing proteins
causing them to seek out and plunge into water.
Family Anthomyiidae
. -- Members of the family Anthomyiidae are medium in size,
about a quarter-inch (6 mm) long and closely resemble the common housefly.
One species is reported to parasitize grasshoppers .
Acridomyia canadensis Snyder
is the only species of family Anthomyiidae in North America
known to parasitize grasshoppers.
It has been classified as an ÒimportantÓ parasite in Canada
and mentioned as ÒoccurringÓ in Montana and Idaho (Rees 1973).
This fly is known to parasitize at least 16 species of grasshoppers
within all 3 grasshopper subfamilies of the family Acrididae,
the slantfaced, the spurthroated, and the bandwinged grasshoppers.
Melanoplus bivittatus and M. packardii
are reported as this parasite's preferred host species.
. flesh flies, family Sarcophagidae,
are important parasites of grasshoppers in North America.
. their eggs hatch within the uterus
and the female deposits a live larva on the host via larviposition:
the female flips a larva from the tip of her abdomen onto the grasshopper.
The larva quickly penetrates the host's body through an intersegmental space
and begins feeding on the body fluids and tissue .
. species Servaisia falciformis (Aldrich) = Protodexia =Sarcophaga falciformis (Aldrich),
possesses a sharp ovipositor that is used to insert a larva
into the large muscle of the hind leg of the grasshopper.
. mature larva exits through a hole in the grasshopper body wall
and pupates in the soil. These flies target last-stage nymphs and adults
and are generally considered the most effective group of grasshopper parasites
. 3 species of Tachinid flies are considered important parasites
in the United States and Canada .
Acemyia tibialis is the principal tachinid parasite of grasshoppers
and has been reported from Melanoplus bivattatus and M. sanguinipes.
Canadian reports indicate parasitism ranges between 16 and 65 percent
(Rees 1973). Ceracia dentata (Coquillett)
and Hemithrixion oestriforme Brauer
and Bergenstamm have been reported from grasshoppers collected in the United States
and Canada with parasitism rates ranging between 1 and 5 percent (Rees 1973).
. tangle-veined flies (family Nemestrinidae)
are medium-sized, stout-bodied, fast fliers that can hover persistently.
. of six North American species, 2 are parasites of grasshoppers
Neorhynchocephalus sackenii (Will.)
and Trichopsidea (= Parasymmictus) clausa (Osten Sacken) (Smith 1958)
. they favor rangeland and Òidle acresÓ habitats .
Ageneotettix deorum (Scudder), Camnulla pellucida (Scudder),
Metator pardalinus (Saussere), and Aeropedellus clavatus (Thomas)
are preferred hosts of
N. sackenii with parasitization rates between 30 and 95 percent .
. solitary wasps (family Sphecidae) consisting of eight subfamilies,
most of which nest in wood, construct mud cells, or burrow in the soil.
Twenty-nine species are recorded as parasitizing grasshoppers
in Canada and the United States (Rees 1973).
. Trombidiidae is the most important of three known families of mites
that have been reported as parasites of grasshoppers and locusts.
Red mites have been universally observed attached to the wings of their host.
Adult mites appear early in the spring and begin searching for grasshopper egg-pods.
Mites remain in the pods feeding on individual eggs
until the mites become sexually mature.
Mating takes place in the egg-pod, but eggs are laid in cells in the soil.
Larvae emerge after 28 to 30 days and actively seek a suitable host.
Larvae usually attach at the base of the wings on adults.
. mites had little if any effect on the grasshopper hosts;
[they are mostly egg predators .]
Grasshopper nymphs eat vegetation contaminated with the eggs of
the Mermithidae species of Nematodes;
The infective nematode larva is released from the egg
during the digestive process.
The larva eventually penetrates through the host's gut wall into the body cavity,
where it remains for 4 to 10 weeks.
The mature larva exits the host (usually killing it) late in the summer
and overwinters in the soil.
Known North American distribution is limited to the
upper Midwest, Northeast, and small, restricted areas in the Western United States.
Moisture in the microhabitat, probably in the form of free water,
is required for successful development of nematodes.
When the required conditions occur,
the incidence of infestation in localized areas can exceed 60 percent .
. the Gordiacea class of roundworms (Nematomorpha)
are known as horsehair worms or Gordian worms. closely resemble nematodes
. they are opportunists that attack many hosts
-- incidental parasites of grasshoppers and Mormon crickets .
Adults are free living and aquatic.
Larvae are parasitic in crustaceans, grasshoppers, crickets, and beetles.
Females lay thousands of eggs in long, gelatinous strings in water.
Upon hatching, larvae seek an immature form of aquatic insect as the primary host.
Later the larvae become terrestrial
and seek a secondary host (usually a cricket, grasshopper, or beetle),
where they feed and continue to develop.
The mature larva exits the host (causing death)
and returns to an aquatic habitat (ponds, animal watering troughs,
intermittent pools, streams, or similar area),
where it reaches sexual maturity.
. There are 856 species of Asilidae (robber flies) in North America;
26 are reported as predators of grasshoppers
Six species exhibit a definite preference for grasshoppers (Rees 1973).
. Two species of family Anthomyiidae have been reported as
predators of grasshopper eggs
Female Òdigger waspsÓ (family Sphecidae)
prefer grasshoppers as provisions for their nests
and are sometimes mentioned as efficient grasshopper predators
(Lavigne and Pfadt 1966).
A typical species of this group, Prionyx parkeri Bohart and Menke,
requires about 1 hour to capture, cache, and lay an egg on an adult grasshopper.
Upon hatching, the wasp larva begins to consume the live grasshopper,
which remains paralyzed.
These wasps are generally rare in most grasshopper habitats,
but there is a report in Idaho (Newton 1956) of three Tachysphex spp.
reducing a population of Oedaleonotus enigma (Scudder) by 84 percent.
. The wolf spider, Schizocosa minnesotensis Gertsch,
and a jumping spider, Pellenes sp., are two species of nonweb-builders
that are often quite abundant on rangeland
and are reported as predatory on various rangeland grasshopper species.
The black widow spider, Latrodectus mactans (F.),
is also a common rangeland predator of grasshoppers in Wyoming and Idaho.
. Adult mites appear early in the spring and begin searching for grasshopper egg-pods.
Mites remain in the pods feeding on individual eggs
until the mites become sexually mature.
