Host Plant Stimuli Affecting Oviposition Behavior of the Eastern Spruce Budworm

Abstract

The host selection of the female spruce budworm Choristoneura fumiferana (Clem.), Tortricidae, for oviposition is influenced both by the shape and the composition of the substrate. Needle extracts were bioassayed using artificial twigs. The active compounds are soluble in organic solvents and steam distillable. Synthetic D‐α and L‐β pinene occurring naturally in the extracts proved to be oviposition stimulants. The optical isomer L‐α pinene did not show any activity. Ablation experiments led to the conclusion that chemoreceptors for the host attractants and the stimulants are located on the antennae and probably also on the maxillary and labial palpi. Zusammenfassung BEEINFLUSSUNG VON WIRTSPFLANZENREIZEN AUF DAS EIABLAGE‐VERHALTEN DES NORDAMERIKANISCHEN TANNENKNOSPENWICKLERS Die Weibchen von Choristoneura fumiferana bevorzugen für die Eiablage ein nadeiförmiges Substrat. Dabei spielen die mechanorezeptiven Sinneshaare auf den Ovipositor‐Papillen vermutlich eine entscheidende Rolle. Petrolätherextrakte der Nadeloberflächen, Methanolextrakte und Wasserdampfdestillate ergaben eine erhöhte Eiablage auf damit behandelten künstlichen Nadelzweigen. Die aktiven Extraktfraktionen waren nur in organischen Lösungsmitteln löslich. Für die Attraktivität und stimulierende Wirkung der Extrakte müssen verschiedene Substanzen verantwortlich sein, α‐ und β‐Pinen wurden mit Hilfe des Gaschromatographen in den aktiven Fraktionen nachgewiesen. Synthetisches D‐α und L‐β Pinen waren beide aktiv. Dagegen ergab L‐α Pinen bei den geprüften Konzentrationen keine erhöhte Eiablage. Mit Hilfe von Ablationsexperimenten (Amputation, Überziehen mit Paraffin) wurde versucht, die Chemorezeptoren für die attraktiven und stimulierenden Stoffe zu lokalisieren. Dabei ergab sich, dass die Geruchsrezeptoren auf den Antennen und vermutlich auch auf den Labial‐und Maxillarpalpen für die Wirtswahl von Bedeutung zu sein scheinen.

Spruce budworm biological and nutritional performance responses to varying levels of monoterpenes

“…In the literature (Städler 1974, Chen et al 2002, Grant et al 2007), α-pinene has been reported as budworm oviposition stimulant, but our results showed that this monoterpene, at concentrations found in the foliage, proved toxic to sixth-instar larvae, incurring 20% mortality. To reduce the toxic effect of α-pinene, spruce budworm decreases the digestibility D (Tab.…”

Effects of Sulfur Dioxide on Volatile Terpene Emission from Balsam Fir

“…moths to their host trees. 9 After dispersal of many such forest insects, the process of finding a host tree is critical for their survival. It is conceivable that increased levels of attractive terpenes could contribute towards the success of this process.…”

Leaf age heterogeneity among selected Populus clones: 1 Influences on feeding and oviposition preferences of adult Chrysomela scripta F (Coleoptera: Chrysomelidae): 2 Correlations of preferences with foliar phenolic glycoside profiles

“…The selection of a host for ovlposltlon by many herbivorous insects is also largely due to the presence or absence of specific plant chemicals (Stadler 1974, Renwlck 1989). …”

“…In general, both olfactory and contact chemoreceptors are Involved in oviposition host selection behavior. Chemoreceptors for ovipositional cues may be located on the antennae, tarsi, maxillary and labial palps, and the ovipositor (Stadler 1974, Renwick 1989. Actual sampling of the leaf chemistry may involve such behaviors as drumming with the foretarsl, leaf scratching with the forelegs, examining with the palpi, or walking on the leaf surface , Renwlck 1989.…”

“…Chemoreceptive cells that are sensitive to sinigrin, an oviposition stimulant, have been identified on tarsal hairs of adult female cabbage root flies, Delia brassicae Bourche (Stadler 1978). Chemoreceptors located on the antennae, the maxillary and labial palpi, and possibly on the ovipositor of female eastern spruce budworm, Choristoneura fumiferana (Clemens), are involved in the reception of chemical stimuli (Stadler 1974). …”