Female Midges Research Articles

Pseudosmittia aizaiensis, a new species of orthocladiinae (Diptera, Chironomidae) from human province of China

Male and female adult midges ofPseudosmittia aizaiensis sp.n. are described and illustrated with figures of morphological characters. The inferior volsella of gonocoxite with large lobes, the long but equal width gonostylus, and the small projection in basal part of outer margin are the characters that may separate this species from others. One larva of this genus is purely aquatic in habitat and is associated with Cricotopus bicinctus,Cardiocladius capucinus andPolypedilum sp. in the same algae debris (Spirogyra sp.) of the Dunghe River. Further, the larva's very short SI and SII bifids, its 5 pairs of lateral teeth on mentum and its absence of premandible brush are the characters that may also separate this species from any known species of this genus.

Variability of the grass Phragmites australis in relation to the behaviour and mortality of the gall-inducing midge Giraudiella inclusa (Diptera, Cecidomyiidae)

Variability within and between shoots of the grass Phragmites australis proved to be important for both survival (successful gall induction) and reproduction (larval weight) of the gall-inducing midge Giraudiella inclusa. The ovipositing females and the migrating first instar larvae chose a predictable microhabitat within shoots and within internodes characterized by a high nutritional quality (nitrogen, mineral content, sugar, water) and reduced palnt defense properties (silicate). Clutch size increased with the shoot diameter, larval scramble competition could not be detected. Female shoot selection was random, although the chances of successful gall induction greatly differed between shoots. Thick and intact shoots (≥6 mm) led to a high larval mortality. But thick shoots destroyed apically by stem-mining caterpillars (of the noctuid moth Archanara geminipuncta) had on average large gall clusters. Accordingly, the adjustment of the clutch size to the shoot diameter resulted in an advantage for the gall midge females only when shoots were thin and short (i.e. stressed by water and nutrient deficiency) or heavily damage (i.e. stressed) by caterpillars. Thus, the monophagous gall maker G. inclusa did not compensate for all features of intershoot variation of P. australis, although grasses are well-known for their simple plant architecture and their low diversity and low concentration of secondary compounds.

Rearing of Culicoides nubeculosus (Diptera: Ceratopogonidae) by natural or artificial feeding in the laboratory

A technique for the mass rearing of Culicoides nubeculosus in the laboratory is described. Female midges were fed either on fresh or deep-frozen, defibrinated cattle blood (-70°C) through latex membranes, or on anesthetized white mice. Feeding rates of up to 90% were obtained on the latex membrane, whereas only 41% of the midges fed on mice. The best oviposition rates of > 50% were achieved after feeding either on the latex membrane with fresh cattle blood or on mice. An average of > 100 eggs per female were deposited. The highest larval hatching rate was observed after feeding with fresh blood; about half of the larvae developed to the adult stage. A reproduction index was defined for the colony based on the feeding rate, oviposition rate, larval hatching rate and development to the adult stage. The highest reproduction index was obtained when the midges were fed on fresh cattle blood through the membrane.

Quantitation of the blood meal ingested by Culicoides arakawae (Diptera: Ceratopogonidae).

Measurements were made to determine the quantity of blood ingested, in relation to the concentrated blood meal, by Culicoides arakawae (Arakawa) maintained in the laboratory. Blood taken in a single meal by a female midge was calculated from the contents of hemoglobin, nitrogen, and iron within 15 min after engorgement. Ingested blood calculated from chemical analyses (ca. 0.36 mg) was ca. 2.5-fold heavier than that estimated from the increase of the body weight. Quantitation of the blood ingested can assist in the estimation of the number of gametocytes of Leucocytozoon caulleryi (Mathis & Leger) ingested by C. arakawae .

DIURNAL OVIPOSITION ACTIVITY IN GRAIN SORGHUM BY CONTARINIA SORGHICOLA (COQUILLETT) (DIPTERA: CECIDOMYIIDAE)

AbstractDiurnal oviposition activity and preference for panicles at various stages of anthesis by female sorghum midge, Contarinia sorghicola, were investigated on grain sorghum in central and southern Queensland during 1981–82. Peak activity was recorded between 0800 h and 1100 h, the time of maximum midge numbers being slightly modified by daily temperature. Ovipositing midges preferred panicles at mid‐anthesis, while panicles prior to and finishing anthesis were the least attractive. We define criteria for optimum pest population assessment.

Evidence for a female sex pheromone in the brassica pod midge Dasineura brassicae

ABSTRACT. The responses of Dasineura brassicae Winn. (Diptera, Cecidomyiidae) to odours from both male and female midges and from their host (Brassica napus) and non‐host (Vicia faba) plants were studied using a Y‐tube olfactometer. Female but not male D. brassicae are attracted to crushed B. napus leaves but not to those of V. faba. Males are attracted to live virgin females, to crushed virgin and mated females and to hexane washes of females, suggesting that the female produces a sex pheromone that attracts males. Males were also attracted to hexane washes of female ovipositors, but not to washes of the bodies of females without ovipositors, suggesting that the ovipositor is the site of pheromone release or production. Males were not attracted to live mated females or to other live or crushed males and mated females were not attracted to other mated females.

Adult Sorghum Midge (Diptera: Cecidomyiidae) Nonpreference for a Resistant Hybrid Sorghum

Adult density and oviposition of sorghum midge, Contarinia sorghieola (Coquillett), on a resistant and susceptible sorghum, Sorghum bicolor (L.) Moench hybrid, were assessed under field conditions at College Station, Tex., during 1983 and 1984. Approximately 33% more female midges visited flowering panicles of a susceptible hybrid than those of a resistant hybrid. Moreover, ca. 25% more female midges were collected on flowering panicles of either hybrid that had not previously been infested with midges compared with panicles that had already been exposed to midges. Number of eggs laid in spikelets by 20 caged females per panicle, or by naturally occurring females in the field, was from 4- to 5-fold greater for midges infesting a susceptible than a resistant hybrid. Differences in number of eggs and egg-infested spikelets of the two hybrids were consistent in a free-choice or no-choice situation. These results indicated that nonpreference for oviposition was much more important than nonpreference for adult visitation as a component of nonpreference resistance of the agronomically improved sorghum hybrid AT×2755 × T×2767.

Sorghum Midge (Diptera: Cecidomyiidae) Adult Ovipositional Behavior on Resistant and Susceptible Sorghum Hybrids

Ovipositional behavior of adult sorghum midge, Contarinia sorghicola (Coquillett), on a midge-resistant (‘AT×2755 × T×2767’) and a midge-susceptible (‘AT×2752 × T×430’) sorghum hybrid was compared under field conditions at College Station, Tex., in 1983. Searching time, interval between two oviposition attempts, and number of flowers searched were recorded for a total of 320 adult female midges during four occasions. Probing time and frequency of ovipositional success were recorded for a total of 258 adult midges during 10 occasions. Adult midges searched flowers of the resistant hybrid more rapidly than flowers of the susceptible hybrid; however, probing/ovipositional time was longer for females on the resistant hybrid. Ovipositional efficiency of the sorghum midge female was 4-fold less on flowers of the resistant hybrid than those of the susceptible hybrid.

Changes in behaviour, flight tone and wing shape in nematode-infestedChironomus (Insecta, Diptera)

The flight tones generated by wing beat frequencies of adult female and male non-biting midges,Chironomus anthracinus, infested by a species ofLimnomermis are very similar (mean values 219.9 and 228.9 Hz respectively), intermediate between normal females (205.1) and males (363.1), but closer to that of the uninfested females. Similarly, the wing shape of parasitized individuals appears intermediate resembling the female more than the male. Statistically wing width and surface area in the parasitized adults resemble those of females and differ significantly from those of normal males. The wing length of the parasitized midges, however, is more like that of males, but there is no statistically significant difference between the groups. Malnutrition of the larvae caused by competition with the parasite seems to result in wing shortening superimposed on sexual differences. All parameters of wing shape are negatively correlated with flight tones. Weight and musculature of the parasitized individuals have also been investigated, but only where worms were present in the thorax was a change found in the flight tones. The flight tone changes served no apparent biological function for the parasitized midges, but the worms apparently benefit from behavioural changes of the infected host, thereby reaching habitats where fresh hosts for its larvae may be available.

Mechanism of Resistance in Sorghum Variety AF-28 to Contarinia sorghicola (Diptera: Cecidomyiidae)

Counts of sorghum midge, Contarinia sorghicola (Coquillett), adults visiting florets of the resistant sorghum, Sorghum biocolor (L.) Moench. (variety AF-28), and the susceptible variety Sart were not significantly different. More eggs (17-fold) were laid in ‘Sart’ florets than in florets of AF-28. When eggs were artificially inserted into the florets of both varieties, there were no significant differences in numbers of adult midges that emerged, or in days for development from egg to adults between the two varieties. Thus, AF-28 showed resistance due to nonpreference for oviposition by the female sorghum midge.

Effects of Resistant Sorghum Hybrids on Sorghum Midge (Diptera: Cecidomyiidae) Biology

Fewer ovipositing female sorghum midges, Contarinia sorghicola (Coquillett), were found on flowering panicles of two resistant grain sorghum hybrids, ATx2755 x RTx2767 and ATx2761 x RTx2767, than on susceptible hybrids, ATx2752 x RTx430 and ATx3042 x RTx2737, on a few occasions during the 1981 growing season. However, these differences in adult abundance occurred erratically and did not follow any apparant pattern. It was doubtful that the resistance of these hybrids could be attributed to an effect on the number of ovipositing midges. Determination of the number of progeny produced per female that oviposited in panicle spikelets of susceptible and resistant hybrids was complicated by competition between midges at high population densities. An interference index was used to compensate for this competition. Midges infesting resistant hybrids produced 50 to 60% fewer progeny per female than midges infesting susceptible hybrids, regardless of midge density. This percentage of reduction became ineffectual in preventing economic damage to resistant hybrids as midge densities reached high levels. There was a slight, but nonsignificant, increase in the developmental time of midges infesting resistant sorghum hybrids. These results suggest that the effects of midge resistant sorghums would be cumulative in reducing midge density through time.

Interaction of Male and Female Midges, Anarete pritchardi Kim, Leading to Coupling1

The movement of female and male midges, Anarete pritchardi Kim, in a swarm prior, during and following coupling was described in five cases. Along with two couplings described in an earlier paper, a possible cue of interaction leading to coupling was identified, namely a sharp turn of the female, a sharp turn of the male, then followed by the convergence of flight paths. The male then eased up to the female to make contact.

Turning Motion of Individual Midges, Anarete pritchardi, in Swarms1

Behavior patterns of forward motion and turns of male and female midges, Anarete pritchardi Kim in swarms of different sizes was analyzed. The mean speed of a pass, the path between turns, is higher in males than in females. The speed of males was not influenced by size of swarm, but that of females was reduced in swarms of larger size. Turns were of varied sharpness. Turns of 90–120° and 150–180° were more frequent than those of 60–90° and 120–150°. This bimodal distribution was shown in both sexes and various swarm sizes, and was independent of the orientation of midges in relation to the sun, the location of midges over the marker, and the position of midges in the swarm.

Resistance to sorghum midge (Contarinia sorghicola Coquillet) in grain sorghum

Standardized levels of infestation of sorghum midge Contarinia sorghicola Coquillet were used to compare the levels of resistance in sorghum cultivars (Sorghum bicolor) in glasshouse experiments at Biloela in Central Queensland. Sorghum heads were reduced to 250 florets and ten female midges were caged over each head on three consecutive days during anthesis. Two breeding lines from the U.S.A., IS 12608C and IS 12664C were superior (P < 0.01) to Alpha and KS 19 in percentage seed set and number of midge progeny produced. The percentage seed set was 50, 54, 22, 12 for IS 12608C, IS 1664C, Alpha and KS 19, respectively. The Indian line Q 13828 was susceptible. Testing with a standardized level of infestation is a useful technique for screening parents in a breeding program aimed at incorporation of midge resistance into agronomically useful hybrid cultivars.

The biology of Leptoconops (Styloconops) spinosifrons (Carter) (Diptera, Ceratopogonidae) in the Seychelles Islands, with descriptions of the immature stages.

The important breeding area of Leptoconops (Styloconops) spinosifrons in the Seychelles Islands is the flat or backwardly sloping shelf of the storm beach, between high tide mark and the vegetation fringing the back of the beach. Larvae, pupae, adult males and adult females are associated with the beach sand. The egg, larval, pupal and adult stages are described. The physical nature of the beach sand was analyzed and an account is given of other organisms living in the sand. The head capsule of the larva is very modified and the larvae feed on organic material and microorganisms in the sand. The larvae of Leptoconops are the dominant insect larvae in this environment. The adult midge does not disperse far from the breeding place. Females were captured on sticky traps placed over the beach up to a height of 120 cm but not at, or above, 240 cm in both wind traps and on sticky traps. Female midges were captured coming to bite man on the beach and also up to a distance of 400 m inland, but they were not found on beaches that were not suitable breeding places. There was a marked increase of biting activity in the late afternoon, especially in the 2 hr before sunset, although midges were captured coming to bite near the breeding places throughout the day. This species is an established biting nuisance on tropical beaches around the Indian Ocean.

Studies on a Method of Radioactive Tagging of a Gall Midge, Dasyneura brassicae Winn. (Dipt., Cecidomyiidae)

AbstractAs mentioned in an earlier paper (Sylvén, I970) specimens of the Brassica Pod Midge, Dasyneura brassicae Winn., can be efficiently tagged by treating midge-infested pods with 32P. The results of the experiment dealt with in the present article indicate that about I-I I/2 μCi of 32P per g fresh weight of the pods is for this purpose an appropriate contamination level. This amount gives a high labelling effect, and seems to have no drastic influence upon the body size or the egg production of the female midges developed from larvae in the pods treated.

THE MORPHOLOGY OF THE MALE AND FEMALE REPRODUCTIVE SYSTEMS OF THE MIDGE, CHIRONOMUS PLUMOSUS L.

In both the male and female adult midge, the posterior three abdominal segments are modified for the reproductive function, and the musculature of these segments is modified accordingly. Main features of the male internal reproductive system are testes consisting of one sperm tube each, in which spermatogenesis is complete, and a glandular ejaculatory duct of four sections. The muscles of the posterior pregenital segments are modified for torsion. The muscles of the terminalia are described. Those of the ninth segment are greatly modified for the genital function. The female has numerous three-chambered polytrophic ovarioles extending radially from a common central egg passage in the ovary, and there is a single accessory gland. The muscles of the female terminalia are described. The reproductive system of several specimens parasitized by a nematode worm is discussed.

OBSERVATIONS AND EXPERIMENTS ON THE HESSIAN FLY (MAYETIOLA DESTRUCTOR SAY)

Experiments showed that a stem midge collected locally on couch grass (Agropyron repens) and similar midges collected on wheat, barley and rye were of the same species, i. e. the hessian fly, Mayetiola destructor Say. There were three main flights per year, with some overlapping of the generations. In experiments, Aegilops ovata, Triticum compactum, T. dicoccoides, T. durum, T. spelta and T. turgidum were successfully used as host plants besides wheat, barley, rye and couch grass. Individual female midges when moved from plant to plant gave rise to families on the different host plants; similarly, succeeding generations of midges were able to breed on various host plants other than those from which they themselves were reared. Oviposition also took place on plants on which larvae failed to establish themselves.Wheat seemed more favourable for the hessian fly than couch grass, and more midges were reared from young plants than from mature ones.Unisexual families occurred in about half the experiments. The following parasites were bred: Trichacis didas Walker, Eupteromalus? hemipterus Walker, Platygaster sp., Chrysocharis sp. and Tetrastichus sp.

ON THE BIOLOGY OF THE GALL‐MIDGES (CECIDOMYIDAE) ATTACKING MEADOW FOXTAIL GRASS (ALOPECURUS PRATENSIS), INCLUDING THE DESCRIPTION OF ONE NEW SPECIES

Summary. Three midges do serious damage to the seeding of meadow foxtail grass; they are Dasyneura alopecuri (Reuter), Stenodiphsis geniculati Reuter and Contarinia merceri n.sp. All three occur almost wherever the grass is grown. The distribution and bionomics of these midges are dealt with; D. alopecuri has one brood a year, S. geniculati has two, while C. merceri usually has one but occasionally may have two. “Blindness” or empty husks in meadow foxtail grass is due very largely to attacks of C. merceri, which midge does the most extended damage. Keys are given for the separation of larvae, pupae and adults. Control measures are discussed and a method of keeping sheep on the grass until a certain safety date, i.e. a date when the crest of emergence of the female midges is over, is strongly advocated in districts where the bionomics is known.

XLI.—Scent-organs (?) in female midges of the Palpomyia group

XLI.—<i>Scent-organs (?) in female midges of the</i> Palpomyia <i>group</i>