Order: Diptera

Vol. 3: Insects

Species accounts

No common name

Dasypogon diadema

FAMILY

Asilidae

TAXONOMY

Asilus diadema Fabricius, 1781, Italy.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Adults are large (about 0.6 in [15 mm]) and sexually dimorphic; males have black abdomen and blackish wings, and females have black abdomen with red markings and brownish wings and are usually larger. Eggs are white, long, oval, and are laid in groups of 1–6 in cocoons made with sand grains glued together and covered inside with a silky lining. Larvae are white to yellowish, elongate, cylindrical, and tapering at each end. Pupae have transverse rows of elongate spines or bristles arising dorsolaterally, and abdominal segment 9 has 1–4 pairs of strongly sclerotized terminal caudal hooks.

DISTRIBUTION

Central region of Mediterranean Europe.

HABITAT

Open, dry, and sandy areas such as steppes, partly eroded hill slopes, sandy hollows, weedy grass plots, dunes, dry meadows, pastures, and olive groves.

BEHAVIOR

Males continuously look for females. Females are more territorial, remaining longer at their foraging positions perched upwards on stems, or sometimes on the ground. They only fly if they see potential prey or if males disturb them. During periods of inactivity, they hang on stems of flowers and grasses or under leaves.

FEEDING ECOLOGY AND DIET

Larvae feed on larvae of scarab beetles (order Coleoptera, family Scarabeidae), and adults mostly on hymenopterans, including honey bees (Apis mellifera). With their long, thin legs, the strong spur at the apex of the foretibiae, and long proboscis, they are well adapted for subduing wasps and bees without being stung. After catching a prey in flight, they look for an appropriate perching site before sucking the prey’s contents.

REPRODUCTIVE BIOLOGY

Mating is initiated after a short struggle, when the male grasps the female’s ovipositor with his genital claspers. Final mating position is end-to-end. The female then flies with the male in copula looking for a suitable place to land. After mating, the female lays the eggs in clutches in the soil, protected inside sand cocoons. The four larval instars and the pupa live in the soil.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

None known.

Dasypogon diadema

Austrosimulium pestilens

364	Grzimek’s Animal Life Encyclopedia

Vol. 3: Insects

New World primary screwworm

Cochliomyia hominivorax

FAMILY

Calliphoridae

TAXONOMY

Lucilia hominivorax Coquerel, 1858, French Guiana.

OTHER COMMON NAMES

English: American primary screwworm; Spanish: Gusano barrenador del ganado.

PHYSICAL CHARACTERISTICS

Adults are 0.4–0.6 in (10–15 mm) long, metallic blue to bluish green, with three longitudinal black stripes on the thorax. Face and eyes are orange-brown; palps are short and threadlike, and antennae are plumose to their tips. The larvae are whitish, about 0.4–0.5 mm (10–12 in) long, and have large posterior spiracles, each with three straight slitlike apertures surrounded in part by a prominent dark-pigmented peritreme. They have a ring of spinules on each segment, which gives them the appearance of a screw.

DISTRIBUTION

Native to tropical and subtropical areas of the Americas. The screwworm has been eradicated from the southern United States and Mexico and most of Central America. There is a seasonal spread of the screwworm into the temperate regions of Argentina, Uruguay, and Paraguay during spring and summer, and it is occasionally reported from Chile and southern Argentina from imported animals. It was imported to Libya in North Africa around 1988 and eradicated three years later.

Helaeomyia petrolei

Cochliomyia hominivorax

Order: Diptera

HABITAT

Tropical and subtropical areas; cannot overwinter where soil freezes.

BEHAVIOR

Mature larvae are negatively phototropic (they move away from light), and this behavior facilitates burrowing in the soil to pupate. Adult flies disperse to find mates and oviposition sites. In tropical environments, females tend to disperse only 6.2–12.4 mi (10–20 km) when there is a high density of animals; in arid environments with lower densities of animals, screwworm flies have traveled as far as 186 mi (300 km). In more arid areas, screwworm flies travel along water courses, and in mountainous areas, along the course of valleys, where the climate is warmer and moisture and animal density higher.

FEEDING ECOLOGY AND DIET

Larvae are obligate ectoparasites (external parasites that cannot complete their cycle outside of their host) of mammals and will infest warm-blooded livestock, wildlife, and humans; they are unable to breed in carrion. A cut, abrasion, or other wound in the skin is required for the larvae to invade the host tissue, where they feed on the living tissue. Adults imbibe water and nectar and fluids of exposed wounds.

REPRODUCTIVE BIOLOGY

Individual females lay batches of 200–300 eggs in compact masses on the skin at the edges of fresh wounds or areas where there is a bloody or mucous discharge. Even wounds the size of a tick bite are sufficient to attract oviposition. The eggs hatch in 14–18 hours. Within a day of hatching, the maggots start to feed, burrowing into the living tissue, where they bunch together to feed with their posterior spiracles exposed. In 5–9 days, larvae are fully developed and leave the host to pupate in the soil for about seven days. After 3–5 days of emergence, adult flies are ready to mate. Male screwworm flies will mate several times, while females usually mate only once. Under ideal conditions, the life cycle is completed in 24 days.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

The screwworm is an economically important pest of domestic cattle. Wounds infested by screwworm larvae become increasingly attractive to fly species whose larvae breed on dead organic material, and also to gravid females of the primary screwworm, thus making the syndrome self-perpetuating in endemic areas, where the result is usually the death of the host.

Yellow fever mosquito

Aedes aegypti

FAMILY

Culicidae

TAXONOMY

Culex aegypti Linnaeus, 1762, Egypt.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Small in comparison to other mosquitoes, between 0.1–0.15 in (3–4 mm) long, black with a white lyre-shaped patch of scales

Grzimek’s Animal Life Encyclopedia

365

Order: Diptera

Vol. 3: Insects

Aedes aegypti

Arachnocampa luminosa

on its thorax and white rings on the legs; wings translucent and bordered with scales. The eggs are white when freshly laid but soon turn black.

DISTRIBUTION

Originally from Africa but has spread by human activity to all tropical and subtropical regions of the world between 45°N and 35°S latitudes.

HABITAT

The yellow fever mosquito is peridomestic, breeding in or near human dwellings in hot, humid areas, and is particularly abundant in towns and cities. Females are early morning or late afternoon feeders but can take a blood meal at night under artificial illumination. Human blood is favored over that of other animals, with preference for the ankle area. Adults usually rest in dark or dimly lit closets, cabinets, or cupboards during the day. Larvae are aquatic.

or even 4–10 days if it is warm enough, the larvae reach the pupa stage, which is usually of short duration. Pupae rise to the surface of the water, where the top of the pupal case opens and the new adult emerges. The species is summer-active in higher latitudes and active all year in tropical areas. Adults are killed by temperatures below freezing and do not survive well at temperatures below 41°F (5°C). On average, females live up to a month, but males die sooner.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

Aedes aegypti is the most important domestic vector of the viruses that cause human dengue and urban yellow fever, and for the chikungunya virus in Asia.

BEHAVIOR

At rest, the insect turns up its hind legs in a curved fashion and usually cleans them by rubbing one against the other, or crosses them and alternately raises and lowers them.

FEEDING ECOLOGY AND DIET

Males of mosquitoes do not bite humans or animals of any species; they live on fruit juices. By contrast, the females need a blood meal in order to induce the maturation of their eggs. The larvae feed on plankton they filter from the water.

No common name

Cyrtodiopsis dalmanni

FAMILY

Diopsidae

TAXONOMY

Diopsis dalmanni Wiedemann, 1830, Java, Indonesia.

OTHER COMMON NAMES

REPRODUCTIVE BIOLOGY

Females lay eggs singly on damp surfaces or clean water held in small containers such as old automobile tires, drums, jars, natural water-retaining cavities in plants, and tree holes. The eggs can resist desiccation for up to one year, and they will hatch when flooded by water. After a few weeks from hatching,

None known.

PHYSICAL CHARACTERISTICS

The most striking characteristic of flies in this family is the position of the eyes on the tip of lateral stalks, which gives them the common name “stalk-eyed flies.” In males of Cyrtodiopsis

366	Grzimek’s Animal Life Encyclopedia

Vol. 3: Insects

dalmanni, the length from one compound eye to the other is nearly the length of the body; females have shorter eye-stalks.

DISTRIBUTION

Widespread in Southeast Asia.

HABITAT

Found among forest-floor detritus in damp and well-shaded areas near streams in primary or secondary forests.

BEHAVIOR

The long and rigid eye-stalks are used for improved visual orientation and, in males, for sexual competition. The forelegs, adapted for gripping, are used in combats with rivals. The extreme eye-stalk structure requires special foreleg movements to clean the eyes.

FEEDING ECOLOGY AND DIET

Larvae feed on plants. Feeding habits of the adults are still unknown.

REPRODUCTIVE BIOLOGY

Adults stop grazing in the evening, and males stake out rootlets dangling from stream banks. On a disputed rootlet, males face off eye to eye, and the one with the shorter eye span backs down. Several females are found together with a long stalkeyed male and show continuous sexual receptivity and high rates of multiple mating. Males with exaggerated eye spans can mate with as many as 24 partners in half an hour. After emergence from the puparium, stalk-eyed flies go through a pumping process for about 15 minutes to unfold the eye stalks to their full length simultaneously with the wings.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

None known.

Petroleum fly

Helaeomyia petrolei

FAMILY

Ephydridae

TAXONOMY

Psilopa petrolei Coquillet, 1899, California.

OTHER COMMON NAMES

English: Oil fly.

PHYSICAL CHARACTERISTICS

Adults are small (0.08 in [2 mm]), and their bodies are black and pruinose except cheeks and sides of face, which are grayish. Eyes are hairy and wings are hyaline and tinged with gray on their costal (anterior) half. Larvae are elongate, reaching a length of 0.3–0.4 in (7–10 mm). They breathe through spiracles on their posterior end, which are surrounded by four supporting fans of setae; the fans rest upon the surface of the oil and keep the spiracles above the surface.

DISTRIBUTION

California oilfields.

Order: Diptera

HABITAT

This is the only insect known from which larvae develop in seepages of crude oil.

BEHAVIOR

Larvae swim slowly, usually near or on the surface of the oil, although they can submerge for a considerable length of time. Adults remain near petroleum pools, hiding in the cracks in the soil, flying about and over the pools, and landing on the margin or on some projecting stone or stick within the pool. They can walk on the surface of the oil as long as no body part other than the tarsi comes in contact with the oil.

FEEDING ECOLOGY AND DIET

The larvae feed on dead insects that have become trapped in the oil pools.

REPRODUCTIVE BIOLOGY

Mating behavior and oviposition are still undescribed. When ready to pupate, the larva leaves the oil and pupates on grass stems on the margins of the pool.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

Crude oil is usually regarded as a very effective insecticide. Thus, petroleum flies are of interest to biotechnologists because they can provide information regarding the ability of organisms to resist the toxic effects of aromatic and petroleum compounds.

Tsetse fly

Glossina palpalis

FAMILY

Glossinidae

TAXONOMY

Nemorhina palpalis Robineau-Desvoidy, 1830, Congo River.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Adults are yellowish to brown, with a forward-projecting, piercing proboscis and a hatchet-shaped cell in the center of each wing. The arista arising from the third antennal segment has branched setae. Both sexes have dichoptic eyes. Larvae breathe through a pair of posterior spiracles and in the third stage via a pair of lateral lobes, which contain three air chambers and open through numerous spiracles.

DISTRIBUTION

Western Africa.

HABITAT

Local patches of dense vegetation along banks of rivers and lakes in arid terrain, and also in dense, wet, heavily forested equatorial rainforest.

BEHAVIOR

Larvae show negative phototaxis (avoiding light) and are positively thigmotactic (seeking contact with surfaces).

Grzimek’s Animal Life Encyclopedia

367

Order: Diptera					Vol. 3: Insects

Gasterophilus intestinalis

Glossina palpalis

FEEDING ECOLOGY AND DIET

Adults feed on the blood of any vertebrate they encounter, including reptiles—especially monitor lizards and crocodiles— birds, and mammals. They are not responsive to the conventional vertebrate host odors that other tsetse flies respond to. This species generally feeds while inside dense humid forest habitats, where trailing hosts by sight is easier than by olfaction.

causes nagana in horses and cattle and sleeping sickness in humans.

New Zealand glowworm

REPRODUCTIVE BIOLOGY

Female tsetse flies reproduce by adenotrophic viviparity, which involves the retention of a single egg that develops to the third larval stage before being deposited. The egg within the uterus hatches in 3–4 days, giving rise to the first-stage larva. The larva feeds from secretions of a pair of uterine glands from the mother. Just before depositing her larvae at the third instar, the adult female actually weighs less than her offspring. The larvae are deposited on the soil and burrow down, where they pupate for 4–5 weeks. The young adult emerges from the puparium using its ptilinum, which it also uses to move up through the soil. Having emerged, both sexes seek a host to gain a blood meal. Males are not fully fertile until several days after emergence, and females are able to mate two to three days after emergence. The first larval offspring is deposited about 9–12 days after the female emerges. Due to the length of development, tsetse flies are relatively long-lived, up to 14 weeks for females, with males having shorter lives of around 6 weeks. Hence the rate of reproduction is extremely slow compared to other dipteran species.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

This species is an important vector of West African trypanosomiasis via the protozoan Trypanosoma brucei gambiense, which

Arachnocampa luminosa

FAMILY

Keroplatidae

TAXONOMY

Bolitophila luminosa Skuse, 1891, New Zealand.

OTHER COMMON NAMES

English: New Zealand fungus gnat, glowing spider bug; Maori: Titiwai.

PHYSICAL CHARACTERISTICS

All stages, except for the eggs, glow. The eggs are small and white and turn brown before larvae emerge. Eggs are coated with a sticky substance and adhere to the substrate. Larvae go through five instars and reach a body length of 1.2–1.6 in (30–40 mm). They are brown but with transparent skin, allowing bluish green light to shine through. Adults are slightly larger than a mosquito, about 0.50 in (15 mm) in length.

DISTRIBUTION

New Zealand.

HABITAT

Damp, sheltered areas with hanging surfaces, dark for a good portion of the day and protected from winds, such as caves; usually associated with streams.

368	Grzimek’s Animal Life Encyclopedia

Vol. 3: Insects

BEHAVIOR

During the day larvae hide in crevices, and during the night they enter their silk tubes and hunt. Bioluminescence is used to attract food in larvae and mates in adults; the hungrier a larvae is, the brighter it glows. If no male is waiting on a female’s pupa when the female is ready to emerge, the female will glow brighter and will flash its lights on and off. The flight of adults is slow, and their habits are mostly crepuscular or nocturnal. They are often found on low vegetation, under overhanging rocks and trunks, and along banks of streams.

FEEDING ECOLOGY AND DIET

Glowworm larvae are voracious hunters with large mandibles. They spin a delicate web of horizontal silk tubes from special labial glands in their heads. This web is attached to rocks and branches and suspended from the tubes; they hang from silk threads covered with globules of sticky mucous that can reach 20 in (50 cm). Insects that are attracted to the light of the larvae become caught in the sticky mucous of these “fishing lines.” Vibrations are sent up the line and sensed by the larva, which then begins to swallow the line. Certain chemicals within the mucous paralyze the prey, which is finally bitten and killed by the larva. New Zealand glowworms can be cannibalistic, with the larvae often eating other larvae or even adults that happen to fly into the fishing lines. They also feed on mosquitoes, moths, stoneflies, sand flies, caddisflies, midges, ants, spiders, millipedes, and even snails. Adults have reduced mouthparts and do not feed.

REPRODUCTIVE BIOLOGY

Females ready to hatch begin to emit light while still inside the pupa. This attracts males, which land on the pupa and fight with each other in an attempt to dislodge each other from the pupa’s surface. This ensures that only the strongest males mate

Order: Diptera

with the females as soon as they hatch. Upon emerging from the pupa, males live for three to five days and females for one or two days. Females lay the eggs one at a time in clusters of 30–40, usually on muddy banks, and can lay as many as four clusters. The eggs hatch after three weeks, and the larvae emerge emitting light and immediately begin to build their homes. The larval stage lasts roughly 6–12 months. When it is time to pupate, the larva arranges its sticky fishing lines into a protective, circular barrier and then hangs in the middle of this circle. Pupation takes about 12 days.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

Caves with gatherings of glowworms constitute a tourist attraction.

Spider bat fly

Basilia falcozi

FAMILY

Nycteribiidae

TAXONOMY

Nycteribia falcozi Musgrave, 1925, Australia.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Adults lack wings and their body is compressed dorsoventrally, so that head and legs arise from the dorsal surface of the tho-

Basilia falcozi

Pseudacteon cur vatus

Tipula paludosa

Grzimek’s Animal Life Encyclopedia

369

Order: Diptera

rax, giving them a spiderlike appearance. They have long legs with strong claws. The pupae are shining black and flattened.

DISTRIBUTION

Australia.

HABITAT

Ectoparasites on cave-dwelling bats of the family Vespertilionidae.

BEHAVIOR

Adults stay on host except to deposit pupae in roost.

FEEDING ECOLOGY AND DIET

Hematophagous.

REPRODUCTIVE BIOLOGY

Females deposit fully developed pupae singly, gluing them to vertical substrata (e.g., cave walls and trees) in the vicinity of the host bat roosts. This process may be repeated several times during the female’s lifetime. Emergence of the adult is triggered by the warmth or contact of a roosting bat.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

None known.

Horse bot fly

Gasterophilus intestinalis

FAMILY

Oestridae

TAXONOMY

Oestrus intestinalis De Geer, 1776, type locality not specified (probably Sweden).

OTHER COMMON NAMES

English: Nit fly; German: Magenfliege, Magendasselfliege.

PHYSICAL CHARACTERISTICS

Adults resemble honeybees in appearance and size (about 0.7 in [18 mm]). They have a hairy head and predominantly yellowbrown hairs dorsally, and whitish ones laterally on the thorax. The abdomen is tricolored, bearing long white hairs on the second segment, predominantly black ones on the third and fourth segments, and dark yellow hairs on the posterior parts. The light yellow eggs are attached to the hair of the host. Larvae are reddish brown and when mature usually around 0.8 in (20 mm) in length. They have two bands of coarse spines with blunt tips per segment (except in the last segment).

DISTRIBUTION

Originally from the Old World, horse bot flies today are virtually cosmopolitan, having spread with humans and their horses around the world.

HABITAT

Associated with their hosts.

BEHAVIOR

Adults are diurnal (active in the daytime) with peak activity occurring in the early afternoon in warm, sunny weather.

Vol. 3: Insects

FEEDING ECOLOGY AND DIET

Adult mouthparts are greatly reduced; adults do not feed and rely on stored body fats. Larvae infest the digestive tract of horses and other domestic animals such as mules and donkeys, where they feed on tissue in the horse’s stomach or gut lining as well as on nutrients from the horse’s food. Newly hatched larvae occasionally invade human skin but die in a few days.

REPRODUCTIVE BIOLOGY

Adults are short-lived; females have a life span of one day. Mating occurs in the vicinity of horses where solitary hovering males will establish and defend a territory. They are also known to aggregate at hilltops and other elevated landmarks to mate, where males hover and aggressively pursue passing objects. Males make contact with a female on the wing, couple, and fall to the ground, where copulation is completed. Females lay eggs around the knees of walking, trotting, or standing horses; if this action induces the horses to gallop, the females will pursue them until they stop and then immediately resume oviposition. When the horse licks the area, the heat and wetness from its tongue causes the eggs to hatch. The larvae then enter the mouth and travel to the stomach, where they attach themselves with strong mouth hooks to the walls. Third-stage larvae remain attached for 9 to 11 months before exiting within the horse’s feces. Pupation takes place on the ground, lasting for 3–5 weeks.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

Because of their parasitic habit in horses, larvae are more easily found than adults. They cause hide spoilage, ulceration, hemorrhage, severe debilitation, and even death in horses in cases of severe infestations.

Fire ant decapitating fly

Pseudacteon curvatus

FAMILY

Phoridae

TAXONOMY

Pseudacteon curvatus Borgmeier, 1925, Brazil.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Small, about the size of their host ant’s head, with relatively large eyes, a humped-back thorax, and a hypodermic needleshaped ovipositor in females. In the field, they appear as minute, fuzzy specks hovering over host ants.

DISTRIBUTION

South America from Brazil to Argentina.

HABITAT

Widely distributed in the natural range of their hosts.

BEHAVIOR

Females are attracted to disturbed mounds, mating flights, or foraging trails of their hosts. Females in attack mode hover 0.1–0.4 in (3–10 mm) above the ants and orient to their movements. Males are not attracted to the ants.

370	Grzimek’s Animal Life Encyclopedia

Vol. 3: Insects

FEEDING ECOLOGY AND DIET

Adults feed on nectar, and the larva on the inner tissues of its host ant’s head.

REPRODUCTIVE BIOLOGY

Males and females have multiple matings. The females lay eggs in fire ants of the Solenopsis saevissima species-complex. The female stays in front of a chosen worker ant and then quickly moves to the side of the ant and injects a single egg into its thorax. The larva migrates to the head capsule of the worker and passes through three instars, during which time the worker ant appears to behave normally. Just before pupation, the tissue inside the ant’s head capsule is consumed, killing the ant in the process. Larval and pupal development each takes 2–3 weeks. The ant’s head usually falls off, and the pupa completes its development inside the head capsule, at which point the adult fly emerges from its oral cavity. Sex in this species is apparently determined environmentally, as males are produced from smaller ant workers, whereas females are produced from larger ant workers. Adults are active all year, except during the winter months in the more temperate regions of their range.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

Possible biological control agent for red imported fire ants in the United States. Although the percentage of ants that the flies are able to parasitize and kill is low, they have a large effect on their host’s competitive interactions with other ants. The presence of ant decapitating flies disrupts colony-level foraging in the ants, which retreat to their nests, leading to as much as a 50% decrease in resource acquisition.

Order: Diptera

BEHAVIOR

After mating, females look for a blood meal in open spaces, seldom entering buildings. Following the blood meal, females rest in trees and shrubs prior to oviposition.

FEEDING ECOLOGY AND DIET

Larvae filter drifting food with their fan-like mouthparts. Adult females require a blood meal before the first batch of eggs is laid. They are pool feeders, imbibing blood from a droplet created from cutting the skin.

REPRODUCTIVE BIOLOGY

Eggs are laid into fresh running water and sink to the bottom, where they can remain quiescent for at least five years on a damp stream bed, until they hatch with the next flood. Larvae construct well-formed silken cocoons when ready to pupate; the pupal stage lasts about two days. Adults usually emerge during daylight hours and float to the surface in a bubble of air. Males tend to emerge before females and form highly visible mating swarms associated with trees close to the water. Females enter these swarms, are captured, and mate, after which they seek a blood meal. Egglaying swarms are diffuse and occur throughout the daylight hours. Females fly low over the stream and dip their abdomens into the water surface. Adult flies may live up to three weeks.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

Considered a nuisance pest in Australia; females bite cattle, dingoes, goats, horses, humans, and marsupials such as kangaroos and wallabies.

Dawson River black fly

Austrosimulium pestilens

FAMILY

Simuliidae

TAXONOMY

Austrosimulium pestilens Mackerras and Mackerras, 1948, Queensland, Australia.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Adults are small, black, and humped-back, about 0.04 in (1 mm) in length. Eyes are holoptic (in contact with each other) in males and dichoptic (separated) in females. The larvae are 0.008–0.2 in (0.2–4.5 mm) in length, pale with irregular mottling. They have a pair of large cephalic fans on the head, a proleg (false leg) in the thorax, and another one at the tip of the abdomen, armed with a circlet of spines that anchors the larvae to submerged substrates. Pupae have a pair of breathing organs called spiracular gills that look like a collection of threads attached to the back of the head, which enable them to breathe while permanently submerged.

DISTRIBUTION

Queensland and northern New South Wales in Australia.

HABITAT

Larvae require oxygenated, running waters, and they live in both stony and weedy streams. Adults appear along the larval river or streams courses and the surrounding countryside.

Chevroned hover fly

Allograpta obliqua

FAMILY

Syrphidae

TAXONOMY

Scaeva obliqua Say, 1823, United Sates.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Eggs are white, elongate, and oval. The mature larvae are 0.35 in (8–9 mm) in length, elongate and flattened on the dorsum, green with two narrow whitish longitudinal stripes and with transversely wrinkled tegument-bearing papillae. They have mouth hooks on the anterior end of the tapering head, and two posterior respiratory tubes fused together. The pupae are green, darkening at maturity. Adults are 0.25 in (6–7 mm) in length. They have a yellow face, yellow thoracic stripes, and four longitudinal, oblique, yellow stripes or spots on the fourth and fifth abdominal segments. Eyes are holoptic (in contact with one another) in males and dichoptic (separated) in females.

DISTRIBUTION

Canada south to Argentina.

Grzimek’s Animal Life Encyclopedia

371

Order: Diptera

Allograpta obliqua

Tabanus punctifer

HABITAT

Found in areas with flowering plants sheltered from wind.

BEHAVIOR

Adults are excellent fliers and can hover and fly backward.

FEEDING ECOLOGY AND DIET

Adults often visit flowers for nectar or may be seen around aphid colonies feeding on honeydew secreted by the aphids. Larvae prey on aphids, but if there are no aphids, they can subsist on plant materials such as pollen.

REPRODUCTIVE BIOLOGY

Adults occur throughout the year in temperate areas, and during spring and summer in the cooler areas of their range. The eggs are laid singly on the surface of a leaf or twig that bears aphids. They hatch in 2–8 days. The larval stage takes 5–20 days, and larvae fasten themselves to a leaf or twig when ready to pupate. The pupal stage takes 8–33 days.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

This flower fly is considered to be beneficial to humans, because adults are agents in the cross pollination of some plants, and the larvae are predators of aphids that attack citrus, subtropical fruit trees, grains, corn, alfalfa, cotton, grapes, lettuce and other vegetables, and ornamentals. When larval populations are high, they may consume 70–100% of the aphid populations.

Vol. 3: Insects

Big black horse fly

Tabanus punctifer

FAMILY

Tabanidae

TAXONOMY

Tabanus punctifer Osten Sacken, 1876, Utah.

OTHER COMMON NAMES

English: Klegs, green heads.

PHYSICAL CHARACTERISTICS

Adults are stout and broad-headed, 0.35–1.1 in (9–28 mm) in length, with bulging and brightly colored eyes, gray thorax, black abdomen, and blackish wings. Larvae are cylindrical and have a longitudinally striated tegument.

DISTRIBUTION

Canada from British Columbia south to California, encompassing the western United States from Kansas south to Texas.

HABITAT

Adults are especially common around ponds, streams, and marshes, where the larvae live in shallow water or moist soil.

BEHAVIOR

Adults land stealthily on exposed skin in order to feed.

FEEDING ECOLOGY AND DIET

Adults feed mainly on nectar and flower pollen, and females need a blood meal before they can lay eggs. They have mouthparts adapted for tearing and lapping, and they suck blood mainly from livestock but also from humans. Larvae are predacious, feeding on insect larvae, snails, and earthworms.

REPRODUCTIVE BIOLOGY

Eggs are laid in 3–4 layer masses of 100–1,000 eggs each, covered with a jellylike material, on leaves, rocks, or debris overhanging water or on moist areas. Upon hatching, the larvae fall into the water or onto moist soil, where they undergo 3–4 instars. When ready to pupate, they move to the margin of the pool or drier areas of their habitat.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

Considered a nuisance pest for horses and mules because of the painful bites of females, which occasionally also bite humans.

Mediterranean fruit fly

Ceratitis capitata

FAMILY

Tephritidae

TAXONOMY

Trypeta capitata Wiedemann, 1824, East Indies (probably in error).

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Adults range from 0.14–0.2 in (3.5–5 mm) in length. The wings are semiopaque, broad, and patterned with yellow, and the eyes

372	Grzimek’s Animal Life Encyclopedia

Vol. 3: Insects

Order: Diptera

Ceratitis capitata

Cyrtodiopsis dalmanni

are iridescent and multicolored. Males are distinguished by a pair of spatulate projections on the frons, and females by a prominent ovipositor. Larvae are white and cylindrical, with a narrowed anterior end and flattened caudal end, and reach 0.3–0.35 in (7–9 mm) in length. Pupae are cylindrical, approximately 0.12 in (3 mm) in length, and dark reddish brown.

DISTRIBUTION

Native to Africa. Within the last 100 years, has spread throughout most of the world, from Portugal, Spain, Italy, Greece, Jordan, Turkey, parts of Saudi Arabia and most countries along the North African coast as far away as the Americas, the Hawaiian islands, and Australia, mainly due to transportation of infested fruit. It was eradicated from Mexico using the Sterile Insect Technique, which has also been employed effectively in Guatemala, Chile, California, and Florida.

HABITAT

vae emerge from the fruit and drop to the ground, where they pupate in soil 1–2 in (2.5–5 cm) below the surface. The adults emerge from the pupa approximately 10 days later. They exhibit a “lek” mating system, in which males settle nonrandomly on particular host or nonhost trees and defend individual leaves as mating territories. While on territory, males emit a pheromone attractive to females and, following female arrival, perform a brief courtship display involving wing and head movements before mounting the female.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

The mediterranean fruit fly is a major agricultural pest in temperate and subtropical regions worldwide, attacking over 200 varieties of cultivated fruit crops.

Found wherever appropriate host trees (including citrus, peach, and guava, among many others) grow.

BEHAVIOR

Adults can fly only short distances, but winds may carry them a mile or more away.

FEEDING ECOLOGY AND DIET

Larvae feed within the flesh of fruits where eggs are laid, and adults on exposed sweet substances such as fruit, honeydew, or plant sap.

REPRODUCTIVE BIOLOGY

Eggs are laid beneath the skin of a suitable fruit in batches of 1–10. Females will lay approximately 300 or more eggs during their lifetime; these hatch into first-instar larvae after 2–3 days. The larvae live and feed within the host fruit, undergoing two molts in 6–10 days. When ready to pupate, the third-instar lar-

European marsh crane fly

Tipula paludosa

FAMILY

Tipulidae

TAXONOMY

Tipula paludosa Meigen, 1830, Europe.

OTHER COMMON NAMES

English: Leatherjacket (larvae), marsh crane fly; German: Lästlinge Wiesenschnake; Italian: Tipula dei prati.

PHYSICAL CHARACTERISTICS

Adults resemble giant mosquitoes and have a grayish brown body, about 1 in (2.5 cm) in length, two narrow wings, and

Grzimek’s Animal Life Encyclopedia

373

Order: Diptera

very long (0.7–0.9 in [17–25 mm]) brown legs. Larvae are gray, 1.1 in (30 mm) in length, and are known as leatherjackets because of their tough leatherlike skin. Pupae are brown, spiny, and about 1.3 in (33 mm) in length.

DISTRIBUTION

Native to northern Europe; introduced into western Canada and United States.

HABITAT

Found in wet areas of lawns, pastures, fields of forage crops, and grassy banks of drainage ditches, in regions of mild winters, cool summers, and rainfall averaging about 23.5 in (600 mm).

BEHAVIOR

Adults are weak fliers. They are attracted to lights and may enter houses and buildings.

FEEDING ECOLOGY AND DIET

Young larvae feed on humus and rotting vegetable matter, germinating cereal seeds, roots of Gramineae (grass), and the collar area of some young aerial plants.

Vol. 3: Insects

REPRODUCTIVE BIOLOGY

The marsh crane fly completes one generation per year. Adults are abundant in late August and early September, and each female can lay up to 280 black, shiny eggs, mainly at night, from mid-July to late September. Eggs are laid on the soil surface or at depths of less than 0.4 in (1 cm), and hatch 11–15 days following oviposition. Larvae are found in the upper 1.1 in (30 mm) of soil, throughout the fall and during warm periods in winter. They grow rapidly in spring and reach their full length of about 1.6 in (40 mm) by April or May, pupating approximately in mid-July. Pupae remain underground for about two weeks before working their way to the surface, where the empty pupal case is often left protruding from the soil by the emerging adult. Adults emerge after sunset and mate immediately. Males live about 7 days; females 4–5.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

Of economic importance due to larvae, which can strip the root hairs and girdle the stems of bareroot stock in commercial tree nurseries.

Resources

Books

Colless, D. H., and J. F. McAlpine. “Diptera.” In The Insects of Australia: A Textbook for Students and Research Workers, vol. 2 (CSIRO), 2nd ed. Carlton, Australia: Melbourne University Press, 1991.

Evenhuis, N. L. Catalogue of the Fossil Flies of the World (Insecta: Diptera). Leiden, Netherlands: Backhuys Publishers, 1994.

—. Litteratura Taxonomica Dipterorum (1758–1930). 2 vols. Leiden, Netherlands: Backhuys Publishers, 1997.

Foote, B. A., F. C. Thompson, G. A. Dahlem, D. S. Dennis, T. A. Stasny, and H. J. Teskey. “Order Diptera.” In Immature Insects, vol. 2, edited by F. W. Stehr. Dubuque, IA: Kendall/Hunt Publishing, 1991.

Haupt, J., and H. Haupt. Fliegen und Mücken: Beobachtung, Lebensweise. Augsburg, Germany: Naturbuch-Verlag, 1998.

McAlpine, J. F., et al., eds. Manual of Nearctic Diptera. 3 vols. Ottawa, Canada: Research Branch, Agriculture Canada, 1981–1989.

Oldroyd, H. The Natural History of Flies. New York: W.W. Norton and Company, 1965.

Organizations

Arbeitskreis Diptera. Dr. Frank Menzel (Leiter), ZALF e.V., Deutsches Entomologisches Institut, Postfach 100238, Eberswalde, D-16202 Germany. Phone: [phone]. Fax: [phone]. E-mail: [e-mail] Web site: <http:// www.ak-diptera.de>

Dipterists’ Forum. Liz Howe, Ger-y-Parc, Marianglas, Benllech, Gwynedd, LL74 8 NS United Kingdom. Web site: <http://www.dipteristsforum.org.uk/>

North American Dipterists’ Society. E-mail:

[e-mail]

The Malloch Society. Graham Rotheray, Research Coordinator, Royal Museums of Scotland, Chamber Street, Edinburgh, EH1 1JF United Kingdom. E-mail: [e-mail]

Other

“BIOSIS.” Resource guide: Diptera [May 28, 2003]. <http:// www.biosis.org/zrdocs/zoolinfo/grp_dipt.htm>.

“The Diptera Site.” Systematic Entomology Laboratory, ARS, USDA: Department of Systematic Biology, National Museum of Natural History [May 28, 2003]. <http:// www.sel.barc.usda.gov/diptera/diptera.htm>.

“Diptera. Tree of Life Web Project.” 2001 [May 28, 2003].

<http://tolweb.org/tree?group=Diptera&contgroup=

Endopterygota>.

Web version of the “Catalog of the Diptera of the Australasian and Oceanian Regions.” September 23, 1999 [May 28, 2003]. <http://hbs.bishopmuseum.org/aocat/aocathome

.html>.

Natalia von Ellenrieder, PhD

374	Grzimek’s Animal Life Encyclopedia