Neodiprion Swainei Research Articles

Isozymes of the sawflies Neodiprion and Diprion similis: Diagnostic characters and genetic distance

No isozyme markers distinguish between any two of the following, Neodiprion swainei, N. rugifrons or N. dubiosus . Assuming independent sorting of the ACO-A, GPD and SDH loci, N. swainei can be distinguished from the other two with a probability of 99.23% if these three loci are all used. The results from Nei's genetic distance calculation for 13 Neodiprion spp. are generally similar to previous work using morphological and geographic characters, except that: (a) N. taedae linearis and N. pratti are not as close to N. rugifrons as believed; (b) N. nanulus nanulus and N. fulviceps are closer to the other North American species in the lecontei group than they are to the Eurasian N. sertifer , and (c) there is no pattem of relationship between the sertifer group species studied.

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.

Chemical Basis for Feeding Adaptation of Pine Sawflies Neodiprion rugifrons and Neodiprion swainei

Larvae of two pine sawflies, Neodiprion rugifrons Midd. and Neodiprion swainei Midd., consume only old foliage of jack pine, Pinus banksiana Lamb., and leave juvenile foliage intact early in the growing season. The chemical basis for this unique adaptation is a feeding deterrent chemical, 13-keto-8(14)-podocarpen-18-oic acid, which was isolated from juvenile foliage. The content of this deterrent chemical decreases as the foliage begins to mature until needles become acceptable to Neodiprion swainei larvae by August (60-day-old foliage) and to second-generation Neodiprion rugifrons by September (90-day-old foliage). The precise timing of larval acceptance of juvenile foliage indicates a highly specific relationship between these insects and their host tree based on the composition of chemicals in the foliage.

POTENTIAL OF ANTIFEEDANTS TO CONTROL LARVAL FEEDING OF SELECTED NEODIPRION SAWFLIES (HYMENOPTERA: DIPRIONIDAE)

AbstractAntifeedants for controlling larval feeding of several Neodiprion sawflies were evaluated in laboratory and field studies. Nine commercially available insect antifeedants and a hexane extract of the juvenile foliage of jack pine, Pinus banksiana Lambert, were tested on larvae of six species. In laboratory bioassays larvae exhibited varying sensitivity to antifeedants; generally species with monophagous or restricted oligophagous feeding habits were most sensitive. In the laboratory the Swaine jack pine sawfly, Neodiprion swainei Middleton, had severely restricted feeding, development, survival, and fecundity. Triphenyltin hydroxide was toxic to N. swainei and to European pine sawfly, N. sertifer (Geoffroy). In field tests certain antifeedants disrupted N. swainei feeding and development. The colonial behavior of larvae often was disrupted and solitary larvae fell from trees or wandered on twigs. Colony disruption by most antifeedants was temporary and many larvae resumed feeding.

Influence of Semipurified Constituents of Juvenile Jack Pine, Pinus banksiana, Foliage and Other Pine-derived Chemicals on Feeding of Neodiprion swainei and N. rugifrons Larvae1

Fractionated extracts of foliage of juvenile jack pine, Pinus banksiana Lambert, were investigated as antifeedants for larvae of the Swaine jack pine sawfly, Neodiprion swainei Middleton, and N. rugifrons Middleton. A partially purified fraction exhibiting strong antifeedant activity was obtained from aqueous extracts by a selective extraction procedure and by TLC. This fraction had similar TLC development and IR spectral absorption as an antifeedant component in a hexane extract of juvenile foliage. N. swainei showed variable feeding preference to non-host foliage and oleoresin extracts. Several non-oxygenated monoterpenes common in pine needle oil did not inhibit larval feeding. Terpene acetates also were inert. The resin acid, 1-pimaric, did not inhibit N. rugifrons feeding; d-pimaric acid and abietic acid were not active at low concentration (1%), but deterred larval feeding at a higher concentration (20%). Larvae were strongly deterred by tall oil fatty acids and certain oxygenated monoterpenes. Feeding of both sawflies was inhibited by certain quinoidal compounds; larvae were most sensitive to 2-methyl-3-phytyl- 1,4-naphthoquinone > 5-hydroxy-1,4-naphthoquinone > 1,4-naphthoquinone > 2-methyl-1,4-naphthoquinone > 2-hydroxy-1,4-naphthoquinone.

Deterrent(s) in Jack Pine, Pinus banksiana, Influencing Larval Feeding Behavior and Survival of Neodiprion swainei and N. rugifrons1,2

Neodiprion swainei Middleton and N. rugifrons Middleton actively reject current season (juvenile) foliage of jack pine, Pinus banksiana Lamb., early in the growing season and their development is aberrant on an exclusively juvenile foliage diet. In bioassay, larval feeding was inhibited by extracts of juvenile foliage. Solvent extracts of higher polarity were most active as antifeedant(s). Antifeedant(s) also occur in mature foliage in lower concentrations. N. rugifrons was more sensitive to the antifeedant(s) than N. swainei. Other sawfly species were slightly deterred or not affected by juvenile foliage extracts: viz. N. nanulus nanulus Schedl, N. taedae linearis Ross, N. pratti paradoxicus Ross, and N. sertifer (Geoffroy). Larvae of N. swainei rejected young juvenile foliage even after it had been extracted in hexane. Bioassay of serial dilutions revealed that antifeedant activity was greatest in the aqueous fraction (AF) (following extraction) and the non-volatile fraction (following distillation) hexane extracts of juvenile foliage. Mature jack pine foliage sprayed with AF inhibited feeding, development, and survival of N. swainei and thus acted as a physiological inhibitor to larvae.

Influence of Needle Maturity on Larval Feeding Preference and Survival of Neodiprion swainei and N. rugifrons on Jack Pine, Pinus banksiana1

Neodiprion swainei Middleton and N. rugifrons Middleton exhibit differential feeding behavior on jack pine. Current season (juvenile) foliage becomes increasingly acceptable for larval feeding as it matures; N. swainei reared on juvenile foliage had extended larval stadia, reduced size, and higher mortality than larvae reared on mature foliage; fecundity differences were not significant. Free carbohydrates (CHO) in juvenile jack pine foliage collected early in the growing season (June–July) were quantitatively lower (ca. 50%) than in mature foliage; total CHO content was slightly higher in juvenile foliage. Late in the growing season (October) juvenile foliage contained slightly less (ca. 90%) free CHO than mature foliage. Total amino acids were qualitatively similar in both juvenile and mature foliage collected June–July and October. The quantity of certain amino acids was greater in juvenile foliage.

THE NEUROENDOCRINE ORGANS OF LARVAE OF NEODIPRION LECONTEI, N. SWAINEI, AND DIPRION HERCYNIAE (HYMENOPTERA: DIPRIONIDAE)

AbstractLarvae and eonymphs of the diprionid sawflies Neodiprion lecontei (Fitch), Neodiprion swainei Midd., and Diprion hercyniae (Htg.) were dissected and stained to demonstrate the nervous system and endocrine organs. Morphologically and anatomically the endocrine organs in both larvae and eonymphs of all three species are very similar. The cephalic structures comprise lateral and medial neurosecretory cells in the brain which discharge their secretions through a single pair of nerves (NCC) to the corpora cardiaca. The NCC divide before they enter the corpora cardiaca sending a branch to the corresponding corpus allatum. No other nervous connections with these organs are apparent.Paired neurohaemal organs occur in each thoracic segment, forming distinct dilations on slender nerves arising from the ventral cord connectives. They receive secretions from groups of lateral neurosecretory cells in the thoracic ganglia.Each abdominal ganglion has three neurohaemal organs associated with it, a single small spherical structure antero-medially, and paired lateral organs of a diffuse structure, overlying the base of each segmental nerve. They are less conspicuous than the thoracic organs and have different staining properties.

SEQUENTIAL SAMPLING FOR EGG CLUSTERS OF THE SWAINE JACK PINE SAWFLY, NEODIPRION SWAINEI (HYMENOPTERA: DIPRIONIDAE)

AbstractA sequential sampling method for egg clusters of the Swaine jack pine sawfly, Neodiprion swainei Middleton, is described.

A COMPARISON OF DISCRIMINATION AND OF DENSITY RESPONSES DURING OVIPOSITION BY EXENTERUS AMICTORIUS AND E. DIPRIONIS (HYMENOPTERA: ICHNEUMONIDAE), PARASITES OF NEODIPRION SWAINEI (HYMENOPTERA: DIPRIONIDAE)

AbstractThe oviposition behavior of Exenterus amictorius Panzer, an introduced parasite of pre-spinning eonymphs of the Swaine jack pine sawfly, Neodiprion swainei Middleton, was studied in a series of field experiments over a 5-year period in the Province of Quebec. The ability of this parasite to discriminate against hosts with previously deposited progeny varied significantly: discrimination was lacking at the beginning of the host’s spinning period, but was rapidly acquired and persisted to the end of the spinning period. The relationships were described by negative power functions of the form Iδ = aX−b, where Iδ = Morisita’s Index of Dispersion, and X = the number of days from the beginning of the host’s spinning period. The response of E. amictorius to changing host densities, however, was positive at all host densities and described by functions of the form Y = aXb, where Y = number of parasite progeny per host and X = number of hosts dropping into funnel traps at 2-day intervals during the spinning period. Over 67% of the variation in the number of progeny deposited by E. amictorius during a field experiment in 1969 was explained by changes in adult parasite density, and an additional 19% by changes in host numbers. This indicates strongly that the observed change in discrimination against previously deposited progeny bears no direct relationship to either host or parasite density. It was suggested that the change might be influenced either by a reduction in the parasite’s egg complement in time, or by an associative learning process.The density response of an indigenous parasite, Exenterus diprionis Rohwer, was comparatively much weaker and it seemed to lack the adaptive changes in discrimination against previously deposited progeny possessed by E. amictorius. Although attacks of the one species occurred independently of the other, in the event of multiparasitism E. amictorius always survived because of its faster rate of development in the host. The role of discrimination and of density response in the dominance of E. amictorius among the Exenterus spp. attacking N. swainei, and its successful establishment on a variety of North American diprionids, is discussed.

Some effects of photoperiod on the development of Neodiprion swainei Midd.

Uninterrupted development of Neodiprion swainei Midd. occurs if feeding larvae are reared under 16.5- to 19-h photophases. Experimental evidence indicates that the limitations placed on N. swainei by its host specificity, diapause requirements, and developmental rates effectively rule out more than one generation per year. Because of the photoperiodic control of diapause, it is unlikely that the insect can develop under natural conditions without a prepupal diapause.

Coleopterous predators of the Swaine jack-pine sawfly, Neodiprion swainei Middleton (Hymenoptera: Diprionidae)

Thirty-four species of elaterids were collected in jack-pine stands. Eighty-six percent of the elaterid larvae (wireworms) collected from soil samples belonged to the genus Ctenicera which were effective predators of the Swaine jack-pine sawfly, Neodiprion swainei Middleton. The peak activity of wireworms occurred in late May and June which coincided with a high abundance of sound sawfly cocoons in the soil. Wireworms destroyed a constant proportion of cocoons with increasing cocoon densities indicating a density-independent response. Populations of wireworms also appeared independent of sawfly cocoon populations. It may be concluded that wireworms played only a minor role in the life system of N. swainei.Five of the 15 species of adult carabids, captured in jack-pine stands, were found to prey upon sawfly cocoons. These were Pterostichus punctatissimus Rand, P. adstrictus Esch., P. coracinus Newn., P. pensylvanicus Lec., and Sphaeroderus lecontei Dej. The peak activity of adult carabids coincided with peak abundance of sawfly cocoons in the soil. Adult carabids destroyed an increasing proportion of cocoons at higher cocoon densities indicating that they may be playing an important role in the life system of N. swainei.

ACTIVITY PATTERNS OF PARASITOIDS ON THE SWAINE JACK PINE SAWFLY, NEODIPRION SWAINEI (HYMENOPTERA: DIPRIONIDAE), AND PARASITOID IMPACT ON THE HOST

AbstractField studies enabled the identification of some limiting factors to which parasitoids were exposed in exploiting the sawfly host, Neodiprion swainei Middleton, and aspects of their quantitative and qualitative impact on the host population. Emergence patterns and flight activity of parasitoids in the spring indicated that larval parasitoids were vulnerable to hyperparasitism by cocoon parasitoids. Although cocoon parasitoids were limited by a shortage of time in which to exploit the host in the spring they still reduced the overwintered host population by 66% in 1969. All forms of predation caused less than 10% sawfly mortality so parasitoids formed the major mortality factor in the spring. Sawfly in prolonged diapause appeared to be immune from cocoon parasitoid attack and thereby efficiency of these parasitoids was limited. However, cocoon parasitoid activity was selective on sawfly that would normally have emerged early in the season and thus delayed the average development of the host population. The complex food web based on the sawfly host provided a sensitive buffering mechanism to produce a degree of stability in the host–parasitoid interaction. The composition of the parasitoid faunae before and after establishment in N. swainei populations of the introduced Pleolophus basizonus (Gravenhorst) indicates the rapidity with which the parasitoid became influential in the complex.

The Swaine Jack Pine Sawfly, Neodiprion swainei , 1 Life System: Evaluating the Long-Term Effects of Insecticide Applications in Quebec 2

The long-term effects of an aerial application of the insecticide phosphamidon (0.25 lb insecticide in 0.2 gal water per acre) in 1965 against Neodiprion swainei Middleton in Quebec was assessed as part of a study on the population dynamics of this insect. Populations in sprayed areas in a 5-year period following application averaged 280 times lower than mean populations for a 15-year period in unsprayed areas. Since the maximum amplitude in the latter was only 68×, it was concluded that the insecticide caused a profound long-term disruption in the equilibrium density. However, a different trend was observed in an area which received accidental drift of a presumably small quantity of insecticide during the 1965 operation. Survival rates in 7 of 8 sawfly age intervals following insecticide application were lower than in unsprayed areas, and resulted in a 33× lowering of populations in the 1st post-spray year. However populations returned to nearly pre-spray levels following substantial increases in survival rates in all of 10 measured age intervals in the 1st post-spray year, and have oscillated in synchrony with populations in the unsprayed controls since that time (N. swainei trends are weakly oscillatory with a periodicity of about 8 years). This suggested that the population was strongly regulated in the face of considerable population stress, since neither emigration or immigration appeared to have played a significant role in the observed population changes. The applicability of these results to proposals previously advanced for testing the presence of regulation in populations through convergence experiments is discussed. In practical terms, a considerable reduction in insecticide concentrations in future operations against the sawfly is foreseen.

The effect of sunlight on the nuclear-polyhedrosis virus of Neodiprion swainei with measurement of the solar energy received

The quantitative and qualitative effects of solar energy on partially purified nuclear-polyhedrosis virus of Neodiprion swainei were studied. The data were based on bioassays on first- and second-instar Neodiprion swainei larvae. Inactivation of the virus by sunlight was pronounced, and it varied, depending on length of exposure. Recommendations are made to overcome the inhibiting effect of solar energy in field applications of virus.

THE EFFECT OF PREY DEFENSE ON THE FUNCTIONAL RESPONSE OF PODISUS MODESTUS (HEMIPTERA: PENTATOMIDAE) TO DENSITIES OF THE SAWFLIES NEODIPRION SWAINEI AND N. PRATTI BANKSIANAE (HYMENOPTERA: NEODIPRIONIDAE)

AbstractExperiments were carried out to determine the functional response of Podisus modestus (Dallas) to densities of two colonial species of jack pine sawfly, Neodiprion swainei (Middleton) and N. pratti banksianae (Rohwer). Two types of functional response curve were exhibited by the pentatomids, a domed response curve and a negatively accelerated curve.The domed response was caused by the more effective defense reactions of the sawfly larvae at higher densities.An equation is proposed for the domed response curve. The implications of the domed functional response are discussed in relation to the social behavior of these sawflies.

Parasitiods Utilizing the Same Host: Adaptive Nature of Differences in Size and Form

Eleven hymenopterous parasitoid species commonly exploit one sawfly host, Neodiprion swainei. A comparison of the area of forewing, structure of ovary, and length of ovipositor of some of these species is revealing. The three guilds of parasitoids that attck the larval, eonymphal, and cocoon stages of the host, respectively, face different problems in host exploitation. Females of the larval parasitoid guild have large egg production and large wings. They are adapted to exploit a relatively abundant, easily discovered stage of the host, but their progeny are subject to high mortality while in the host. Females of the cocoon parasitoid guild have small wings and low egg production. They seek a scarcer, well—concealed stage of the host, and their progeny sufer less mortality. Members of the eonymphal parasitoid guild show intermediate characteristics. Among the cocoon parasitoids, the species have different ovipositor lengths, presumably allowing them to utilize segments of the host population, either different size classes or hosts that are buried at different depths in the forest litter. Comparison of ovipositor lengths indicates how similar the species can be in size, and therefore larval food exploitation, before competitive displacement prevents coexistence.

Relationship between Parasitism and Predation of Diprionid Sawflies1

Parasitization was greater in the periphery of colonies of Neodiprion swainei Middleton and N. pratti banksianae Rohwer (Hymenoptera: Diprionidae) than in the center of colonies. Because the pentatomid Podisus modestus (Dallas) (Heteroptera) usually attacked sawfly larvae on the periphery of colonies, its effect on the population of sawflies was curtailed because many of the attacked larvae were already parasitized. Pentatomid predators may play an important role in these parasite-host systems.

Diapause in the Swaine jack-pine sawfly, Neodiprion swainel, as influenced by temperature and photoperiod

Larvae of Neodiprion swainei Midd. were reared to the adult stage under temperatures of 15, 22 and 30°C and photoperiods of ( L D ): 10 14 , 12 12 , 14 10 , 16 8 , 18 6 hr . Diapause was prevented when the larvae were subjected to a long photoperiod. The higher the temperature the greater the number of individuals not entering diapause at a long photoperiod. A varying percentage of individuals may enter a short diapause similar to a summer diapause. Some cocooned larvae may also stay in prolonged diapause for an undetermined period, regardless of temperature-photoperiod conditions.

SUSCEPTIBILITY OF DAHLBOMINUS FUSCIPENNIS (CHALCIDOIDEA: EULOPHIDAE) TO THE MICROSPORIDIAN THELOHANIA PRISTIPHORAE

AbstractIt was observed that the parasite Dahlbominus fuscipennis Zett. was infected when developing in microsporidian-infected pupae of Neodiprion swainei Midd., Neodiprion lecontei Fitch, Neodiprion pratti banksianae Roh., and Pristiphora erichsonii Htg. The microsporidian was observed in the whole gut epithelium, fat body, and cerebral ganglial cells of the parasite. The parasitoid was infected only after the hosts had completed their winter diapause or at any time in non-diapausing species.