Female Sawflies Research Articles

The genome sequence of Tenthredo livida Linnaeus, 1758

We present a genome assembly from an individual female sawfly, Tenthredo livida (Arthropoda; Insecta; Hymenoptera; Tenthredinidae). The genome sequence has a total length of 348.40 megabases. Most of the assembly (98.94%) is scaffolded into 10 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 45.27 kilobases in length.

Detection of a mass breeding site of the elm sawfly-zigzag <i>Aproceros leucopoda</i> Takeuchi, 1939 (Hymenoptera: Argidae) in Voronezh

During entomological monitoring, three species of sawflies were observed in the plantings of small-leaved elm Ulmus pumila Linnaeus (1753), rough U. glabra Hudson (1762) and smooth U. laevis Pallas (1784) in Voronezh. Slight overeating by the elm sawfly Cladius ulmi (Linnaeus, 1758) (Tenthredinidae) was found throughout the study area on three species of elms. Mines of the elm mining sawfly Fenusa ulmi Sundevall, 1847 (Tenthredinidae) were found only on the rough elm in the Northern district of the city. Isolated damage to the leaves of U. pumila by the zigzag sawfly Aproceros leucopoda Takeuchi, 1939 (Argidae) was noted in all districts of the city, U. glabra – only in two points of the Northern district. In early July 2023, a hearth with a high number of zigzag sawflies on U. pumila was discovered in the park of the Sovetsky district, in which 90% defoliation on U. pumila was recorded by early August. The flight of the imago of A. leucopoda on the territory of three parks and squares of the Sovetsky district was marked in the first decade of July. The female sawfly was caught on a city bus with the starting point of the route near the found hearth with a high number of sawflies, which confirms the transfer of the imago of the zigzag sawfly within the city by public transport.

Insect egg deposition induces defence responses inPinus sylvestris: characterisation of the elicitor

Egg deposition by the phytophagous sawfly Diprion pini L. (Hymenoptera, Diprionidae) is known to induce locally and systemically the emission of volatiles in Scots pine (Pinus sylvestris L.) that attract the egg parasitoid Chrysonotomyia ruforum Krausse (Hymenoptera, Eulophidae). The egg parasitoids kill the eggs and thus prevent damage to the plant from feeding sawfly larvae. The elicitor inducing the pine's response is known to be located in the oviduct secretion which the female sawfly applies to the eggs when inserting them into a slit in the pine needle using the sclerotized ovipositor valves. In this study we have characterized the elicitor. The elicitor was still active when isolated from the oviduct and applied directly to slits made in the pine needles. However, as soon as the oviduct secretion was dissolved in Aqua dest. and stored for 3 h at room temperature or kept frozen at -80 degrees C, its activity was lost. In contrast, oviduct secretion kept its eliciting activity, when dissolved in Ringer solution (pH 7.2) both after storage at room temperature and after freezing. The activity of the elicitor vanished after treatment of the oviduct secretion with proteinase K, which destroyed all proteins. This suggests that the elicitor in the oviduct secretion is a peptide or protein, or a component bound to these. SDS-PAGE revealed a similar, but not identical protein pattern from hemolymph and oviduct secretion. Hemolymph itself has no eliciting effect. The elicitor in the oviduct secretion is only active when transferred to slit pine needles, since its application on undamaged needles did not induce the emission of attractive volatiles.

Impact of the parasitoid Lathrolestes ensator (Hym., Ichneumonidae, Ctenopelmatinae) as antagonist of apple sawfly Hoplocampa testudinea (Hym., Tenthredinidae)

Abstract: Lathrolestes ensator (Brauns) was the only parasitoid species reared from larvae of apple sawfly Hoplocampa testudinea (Klug) collected in Dutch orchards. The life history parameters of apple sawfly and its parasitoid L. ensator were investigated in field and semi‐field experiments. Usually, the adult parasitoids emerge in synchrony with the preferred host stage, the second instar sawfly larvae. Parasitoid females carried 120–175 eggs, but never laid more than half this number. The mortality of sawfly eggs and larvae varied from 75 and 99%. The eggs and mining larvae are most vulnerable, as the older larvae survive for 90% on average. Three factors at least determine how many of the descending larvae become adult sawfly or parasitoid next spring. The failure of descending larvae to construct a cocoon varied from 7 to 31% and was highest in clay soil. Probably a similar mechanical hindrance prohibited more emerging adults, of both sawfly and L. ensator, from attaining the surface in heavier soils next spring. Relatively more sawfly prepupae than parasitoids died in the cocoon stage, from fungus disease or other causes, but more parasitoids than hosts stayed in prolonged diapause. Mainly due to this last factor, the overall result was a decrease of the parasitoid : host ratio during the first season underground. A life table based on survival rates during various life stages yields a net reproductive rate of up to 2.4 daughters per female sawfly. It indicates that 60% of the sawfly larvae need to be parasitized to stop population growth, or correspondingly less when more than 75% of the host eggs and young larvae are killed by predators or other causes.

Pheromone components of the wheat stem sawfly: identification, electrophysiology, and field bioassay.

Volatiles collections and cuticular extracts of the wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), were analyzed by coupled gas chromatographic-electroantennographic detection (GC-EAD) in order to detect possible pheromone components of this species. Volatiles collections from male and female sawflies contained the same 13 GC-EAD-active compounds that stimulated both male and female antennae. GC-EAD-active compounds were identified by mass spectrometry, and the identities were verified by acquiring or synthesizing authentic standards with identical GC retention times and mass spectra. 9-Acetyloxynonanal gave the strongest EAD response. Additional GC-EAD-active compounds included 13-acetyloxytridecanal, aldehydes with 9-16 carbon chain lengths, acids with 8-10 carbon chain lengths, and phenylacetic acid. The last was instantly detectable by human nose when several males were allowed to interact, but not from isolated insects. On a per-insect basis, grouped males overall released higher amounts of the GC-EAD-active compounds than grouped females. Notable quantitative differences between the sexes were relatively higher amounts of 9-acetyloxynonanal, phenylacetic acid, and tetradecanal from males and hexadecanal from females. In the absence of an absolute, qualitative difference between sexes, these relative differences might be important for sex recognition. Field bioassay demonstrated the attractiveness of 9-acetyloxynonanal for male and female C. cinctus. The major compounds of male and female cuticular extracts showed no GC-EAD activity, but ozonolysis of extracts gave dramatically increased amounts of GC-EAD-active material. Hence, double-bond-containing cuticular compounds are suggested as precursors of the aldehydic pheromone components.

Quantitative high-resolution gas chromatographic determination of stereoisomeric composition of chiral volatile compounds in the picogram range by ec-detection

A gas chromatographic method using electron capture detection for determination of the stereochemical composition of chiralolatile compounds, e.g., pheromones, at the picogram level is described. Substances of interest are analyzed as pentafluorobenzoate derivatives on fused silica capillary columns coated with CP Sil-88. This method was developed primarily for the quantitative analyses of stereoisomerism of the pheromone precursor, diprionol, in female sawflies,Neodiprion sertifer. It was possible to separate the stereoisomers showing (2S, 3S, 7R) and (2S, 3S, 7S) configurations. Resolution of the (2S, 3S, 7S)- and (2S, 3R, 7R)-diastereomers was high enough to allow the quantification of these stereoisomers. A quantitative analysis of the diprionol production in individualN. sertifer females yielded 7.5-9.7 ng/female.

Is Leaf Size Important for a Leaf-Galling Sawfly (Hymenoptera: Tenthredinidae)?

We evaluated the importance of leaf size in determining oviposition choice (i.e., gall densities), gall (and larval) size, and larval survivorship for a population of leaf-galling sawflies, Pontania sp. nr. pacifica Marlatt, on arroyo willow, Salix lasiolepis Bentham. Our results did not support the hypothesis that female sawflies prefer to oviposit in developing willow leaves that will be larger when they are fully expanded. Although leaves with four to seven galls had bigger leaf areas than leaves with one to three galls, the size of the mature leaf did not appear to be an important factor determining which leaves were selected for oviposition among the leaves available. The data did not support the prediction that larger leaves produce Pontania sp. galls (and larvae) that are substantially bigger than those on smaller leaves; gall size was only weakly correlated with leaf area ( r ≤ 0.253). We hypothesized that survivorship of Pontania sp. larvae would be positively related to leaf size, but the result was opposite. In total, larval survival was weakly biased toward smaller leaves, primarily because of lower mortality from natural enemies. Mortality from two species of inquilines was positively related to leaf area, whereas mortality from two ectoparasitoids showed inconsistent relationships to leaf area. The absence of strong directional selection illustrates that it would be unlikely for female sawflies to evolve a leaf size choice strategy based on maximizing survival rates of their offspring.

An apterous female sawfly (Hymenoptera: Symphyta) from Papua New Guinea

Abstract. A new species of sawfly, Cladomacra terricola, belonging to the family Pergidae, is described from an apterous female from mid‐montane Papua New Guinea. The profoundly modified thorax of the female is compared with the thorax of other wing‐reduced and macropterous Hymenoptera. The ovipositor is greatly reduced and lacks the typical, symphytan, saw‐like valves. The ordinal, family, subfamily and generic classification of C. terricola is discussed. Diagnostic features of the pergid subfamilies Pterygophorinae, Euryinae and Perreyiinae are reviewed. The egg and larva of C. terricola are described. Egg brooding by the female is reported. Larvae of C. terricola may feed on dead plant material in forest litter.

Persistence and Accumulation of Fenitrothion Residues in Jack Pine Foliage and Their Effect on the Swaine Jack Pine Sawfly, Neodiprion swainei (Hymenoptera: Diprionidae) 1

Fenitrothion persists in jack pine foliage and with repeated annual treatments (275 g/ha) accumulates in needles but not in bark. These residues are associated with high larval mortality of the Swaine jack pine sawfly, Neodiprion swainei , the differences between treated and controls increasing with the number of fenitrothion appliations. The mean cocoon width of survivors and the fecundity of female sawflies were significantly lower on treated foliage. Conifer needles may be micro-sinks for organophosphorus insecticides. Persistent residues may cause unexpected perturbations in the population dynamics of certain non-target fauna.

Influence of Sex Pheromones on Mating Behavior and Populations of Virginia Pine Sawfly 1 , 2

Rise and decline in populations of Neodiprion pratti (Dyar) have been attributed most frequently to the influence of natural control factors. However, data obtained from 1963 through 1970 indicate that population densities are due to the sex attractiveness of the female sawfly. It was shown that the female emits a potent sex pheromone which was apparently necessary for mating. Unmated females oviposited only 17% of their egg potential, whereas mated females oviposited more than 90% of their total egg complement. Severe tree defoliation occurred when more than 50% of the females mated.

Biosystematics and Morphology of Symphyta. Ii. Biology of Gall-Making Nematine Sawflies1 in the California Region

Female sawflies in 3 genera of tenthredinid Hymenopterain the subfamily Nematinae (Phyllocolpa, Pontania, and Euura) incite a gall (procecidium) on Salicaceae during oviposition by injecting modified colleterial fluid. The resulting callus is a true tumor, and the incitant host plant specifically ranges from broad (Phyllocolpa) to species-specific (Euura). There are degrees of plant susceptibility to gall formation and insect inciting capability. Phyllocolpa engender an open gall along the leaf margins of Populus and Sali.v, Pontania create a variety of closed cecidia on the leaves of Salix, and Euura form closed bud, petiole, and stem galls on Salix. Diapause of stem-galling Euura apparently is controlled by the plant. Defense mechanisms and host specificity of sawflies, and parasitoid and inquiline complexes, gall structure, and relationship between species group of host plant and gall maker as shown by gall form, ovipositor structure, and larval behavior are discussed.

Oviposition Behaviour of the Jack-pine Sawfly, Neodiprion americanus banksianae Roh., as Indicated by an Analysis of Egg Clusters

This study was undertaken as part of a broader investigation of the behaviour of the jack-pine sawfly, Neodiprion americanus banksianae Roh. The greater part of the investigation was directed towards an understanding of larval group-feeding behaviour, but in order to clarify the situation in which this insect begins larval life, large numbers of egg clusters were analysed with special attention paid to the positional relations of egg-bearing needles. Such analysis has permitted certain inferences on the oviposition behaviour of this insect and this indirect information is of value in view of the difficulties experienced in efforts to induce this species to oviposit under laboratory conditions for direct observation. Fortunately, egg clusters obtained from the field are well adapted to descriptive measurement and analysis, for in order to lay its full complement of eggs the adult female sawfly must select as many as 20 to 30 needles, thus leaving behind it a readily measured record of its egg-laying behaviour.

Insect Enemies

MR. EALAND has done good service in publishing his book on insect enemies. The work is cast in popular form, which fact may in the eyes of some detract from its merits; but, as the author justly observes, “unless and until those who have no scientific training are told of the activities of insects in language which they can understand, they can hardly be expected to be other than phlegmatic concerning the work of entomologists. The best “methods of dealing with these enemies of mankind may be revealed by the comparatively few economic entomologists, but the great work of eradication can, in many cases, only be accomplished by the active co-operation of the general population.” In accordance with the views here expressed, the insect pests of forest, orchard, flower and vegetable garden, farm crops, domestic animals, household, and warehouse are briefly but not inadequately dealt with, a final chapter being devoted to insects that are directly injurious to man. The treatment is naturally not exhaustive, and it may be doubted whether the remedial measures proposed are in all cases set forth in sufficient detail to be of much practical service unless the directions for use are supplemented from other sources; An appendix gives useful information as to the preparation of insecticides, thopgh not as to the precise method of employing them. A few errors have escaped the author's notice; “Trochilium apiformis” is an awkward collocation, and in Fig. 7 the representations of male and female sawfly are reversed.