We conducted a review of published literature reporting relationships between the size of plant m... more We conducted a review of published literature reporting relationships between the size of plant modules and the abundance or performance of gall insects. Insects in the family Tenthredinidae were recently reviewed and thus omitted from this review. The abundance or performance of approximately half of 53 species examined was positively related to plant module size. However, negative and parabolic relationships were found for all major insect families with sample sizes > 5 (i.e., Adelgidae/Aphididae, Cynipidae and Cecidomyiidae for abundance and Adelgidae/Aphididae for performance). This suggests that relationships between plant module size and the abundance or performance of non-tenthredinid gallers, although often positive, are best characterized as variable.
QUIRING, D. T. 1992. Rapid change in suitability of white spruce for a specialist herbivore, Zeir... more QUIRING, D. T. 1992. Rapid change in suitability of white spruce for a specialist herbivore, Zeiraphera canadensis, as a function of leaf age. Can. J. Zool. 70: 2132 -2138. Field studies were carried out over 2 years to determine the effect of age of white spruce (Picea glauca) leaves on the development of the spruce bud moth, Zeiraphera canadensis Mut. & Free. (Lepidoptera: Tortricidae). In both years developing buds remained suitable for first-instar larvae for only 4 -5 days after bud burst, after which survivorship decreased significantly. Individuals that survived on flaring shoots were smaller than those placed on newly burst buds. Although leaf contents of water, nitrogen, and several minerals were inversely related to leaf age, only declines in N and P content were associated with the rapid change in host suitability. Differences in N and P contents were small, however, suggesting that the rapid decline in host suitability was also due to the influence of other, unmeasured factors. When larvae were placed on foliage of the same age, their. survival was similar on trees in half-sib families with high or low susceptibility to Z. canadensis. Thus, variations in susceptibility of white spruce to Z. canadensis might be associated with differences in host-plant phenology but are not due to differences in nutritional quality. This study demonstrates that the phenological window for establishment of newly emerged folivores may be shorter than is commonly thought. QUIRING, D. T. 1992. Rapid change in suitability of white spruce for a specialist herbivore, Zeiraphera canadensis, as a function of leaf age. Can. J. Zool. 70 : 2132-2138. Des Ctudes sur le terrain ont Ct C entreprises au cours d'une pCriode de 2 ans afin de determiner l'effet de 1'8ge des feuilles de I'Cpinette blanche (Picea glauca) sur le dkveloppement de la tardeuse de 1'Cpinette Zeiraphera canadensis Mut. et Free. (Lepidoptera: Tortricidae). Au cours des 2 annCes, les bourgeons en dkveloppement se sont avkrCs appropriks h l'alimentation des lames de premier stade seulement pendant 4-5 jours aprks leur ouverture, aprks quoi la sumie des larves a diminuC significativement. Les individus qui ont servCcu sur le feuillage aprks 1'Ctalement des pousses Ctaient plus petits que ceux qui avaient CtCs placCs sur des bourgeons qui venaient d'Cclore. Le contenu des feuilles en eau, en azote et autres minCraux Ctait inversement proportionnel h 1'8ge des feuilles, mais seuls les diminutions de N et de P pouvait expliquer que l'h6te cesse rapidement de convenir h l'herbivore. Les variations du contenu en N et P Ctaient peu importantes cependant, ce qui indique que la diminution rapide de l'attrait alimentaire de l'h6te Ctait Cgalement influencie par d'autres facteurs non mesurCs. Des larves placCes sur des feuilles de mCme 8ge d'arbres h demi apparent& (d'une seule lignCe commune) trks susceptibles ou peu susceptibles d'heberger des Z. canadensis, avaient des taux de suwie semblables. Les variations dans la susceptibilitk des kpinettes h porter ou non des Z. canadensis sont probablement associees h des variations dans la phknologie des plantes h6tes plut6t qu'h des variations dans leurs propriCtCs nutritives. Cette Ctude dkmontre que l'intervalle au cours duquel s'ktablissent les folivores fraichement Cclos est probablement plus court qu'on ne le croit generalement.
Carroll, A.L., Lawlor, M.F. and Quiring, D.T., 1993. Influence of feeding by Zeiraphera canadensi... more Carroll, A.L., Lawlor, M.F. and Quiring, D.T., 1993. Influence of feeding by Zeiraphera canadensis, the spruce bud moth, on stem-wood growth of young white spruce. For. Ecol. Manage., 58: 41-49.
... 28 Dineen Drive, Fredericton, New Brunswick E3B 6C2, Canada—Phone: (506) 447-3339; Fax: (506)... more ... 28 Dineen Drive, Fredericton, New Brunswick E3B 6C2, Canada—Phone: (506) 447-3339; Fax: (506) 453-3538; chris.hennigar@unb ... Dead trees were not assessed for defoliation and were identified by examining discoloration and dryness under sections of bark (MacLean and ...
The pale-winged gray moth, Iridopsis ephyraria (Walker), a native geometrid moth species found ac... more The pale-winged gray moth, Iridopsis ephyraria (Walker), a native geometrid moth species found across eastern North America, has recently caused severe defoliation of eastern hemlock trees, Tsuga canadensis (L.) Carrière, in south-central Nova Scotia, Canada. Field studies were carried out to develop sampling techniques that could be used to predict subsequent defoliation of mature hemlocks, which are too large to sample by conventional methods. Densities of newly emerged, first-instar larvae, estimated by sticky tape traps, explained 77% of the subsequent current-year shoot defoliation by I. ephyraria. Egg densities from foam oviposition traps and mid-instar larval densities from beating sheets were weakly and usually non-significantly related to defoliation. Therefore, foam oviposition traps could be used to qualitatively estimate egg densities of I. ephyraria, but first-instar larvae must be sampled with sticky tape if accurate predictions of hemlock defoliation are desired.
Herbivory by Zeiraphera canadensis Mut. & Free. (Lepidoptera: Tortricidae), an early season foliv... more Herbivory by Zeiraphera canadensis Mut. & Free. (Lepidoptera: Tortricidae), an early season folivore of white spruce [ Picea glauca (Moench) Voss], has been associated with a shift in the timing of bud burst by its host during the subsequent year. We tested the hypothesis that a herbivory-induced shift in the phenology of bud development improves the window for colonisation of white spruce buds by Z. canadensis. Feeding on cortical tissue of elongating shoots caused the destruction of apical buds and an interruption of apical dominance in the year following herbivory. White spruce compensated for damage with the activation of dormant buds; mainly at proximal positions along shoots. As a result, half of all active buds on previously damaged branches were located immediately adjacent egg sites (i.e. previous year's bud scales), whereas <10% of active buds on intact shoots were situated there. More than 40% of newly emerged larvae colonised the basal buds of damaged shoots versus just 10% for intact shoots. Previous herbivory also influenced the initiation of bud burst. All buds flushed 2 days earlier on damaged shoots and date of bud burst was inversely correlated to bud density, indicating that short damaged shoots with large numbers of buds were stronger sinks for nutrients required for bud development. Egg hatch was best synchronized with early bursting buds on damaged branches. As a consequence, 89% of firstinstar larvae successfully colonised buds on damaged branches while only 55% were successful on undamaged branches. Improved survival of larvae in the year following herbivory was a direct result of the evolved response by white spruce to the interruption of apical dominance. The pattern of herbivory by Z. canadensis may have evolved as a strategy to enhance the quality of white spruce for their offspring.
ABSTRACT Using field surveys, we established sampling procedures for estimating defoliation resul... more ABSTRACT Using field surveys, we established sampling procedures for estimating defoliation resulting from elm spanworm, Ennomos subsignaria (Hübner) (Lepidoptera: Geometridae), feeding on mature sycamore maple, Acer pseudoplatanus L. (Aceraceae), in St. John&#39;s, Newfoundland and Labrador. We also determined whether densities of E. subsignaria eggs, egg masses, early- or late-instar larvae could predict the amount of defoliation at the end of the larval feeding period. Defoliation estimates acquired by sampling branches from only the lower, mid or upper crown explained ≥80% of the variation in tree-level defoliation, suggesting that density–defoliation relationships established using defoliation data from any crown level would also be useful for predicting tree-level defoliation. In linear regressions, egg and egg mass densities explained ≤20% of variation in defoliation and thus only provide a crude relative estimate of the amount of defoliation that will occur. Early- and late-instar larval density in the lower crown explained 53 and 29%, respectively, of the variation in defoliation in the lower crown, where defoliation levels were highest. Thus monitoring early-instar density in the lower crown should provide pest managers with reliable information for decisions regarding whether to apply suppression tactics while allowing enough time to implement these tactics, if necessary.
The Canadian Entomologist 128: 67-78 (1996) A 2-year field study was carried out to locate and id... more The Canadian Entomologist 128: 67-78 (1996) A 2-year field study was carried out to locate and identify eggs, determine the temporal distributions of eggs and larvae, and assess the impact of Strobilomyia laricis and S. viaria on Larix laricina. Eggs of S. laricis were beige with a patterned surface and usually laid one per cone in the bud scales at the base of the cone. Eggs of S. viaria were white and smooth and usually laid one per cone between the ovuliferous scales of the cone. Strobilomyia laricis oviposited from mid-to late May and S. viaria from late May to mid-June, each species initiating oviposition at a different stage of cone phenology. Peak egg densities of S. laricis were 25 and 65% higher than those of S. viaria in 1990 and 1991, respectively. Larvae of both species completed development at the same time, from mid-June to early July. The mean number of scales eaten per cone did not differ between species; one larva damaged a mean of 8.4 scales per cone in 1990 and 10.7 scales per cone in 199 1. As the number of scales per cone increased, the mean number of scales eaten increased and the mean percentage of scales eaten decreased. Cone crops were light in both years. In 1990, the only year we were able to differentiate cone maggot larvae, 44% of cones were damaged by S. laricis and only 16% by S. viaria. Together, S. laricis and S. viaria damaged 60 and 67% of the cones and destroyed 38 and 50% of the potential seed crop in 1990 and 199 1, respectively. McClure, M., D.T. Quiring et J.J. Turgeon. 1996. Ponte, distribution temporelle et impact de Strobilomyia laricis Michelsen et S. viaria (Huckett) (Diptera: Anthomyiidae) sur le mklkze laricin, Larix laricina (Du Roi) K. Koch. The Canadian Entomologist 128: 67-78.
Page 1. Evidence of an Oviposition-Deterring Pheromone in the Alfalfa Blotch Leafminer, Agromyza ... more Page 1. Evidence of an Oviposition-Deterring Pheromone in the Alfalfa Blotch Leafminer, Agromyza frontella (Rondani) (Diptera: Agromyzidae)l JEREMY N. McNEIL AND DAN T. QUIRING Departement de Biologie, Universite Laval, Quebec, PQ GlK 7P4, Canada Environ. ...
Entomologia Experimentalis Et Applicata, Oct 7, 2007
The trichome-bearing wild potatoes Solanum berthaultii (Hawkes) and Solanum tarijense (Hawkes) (S... more The trichome-bearing wild potatoes Solanum berthaultii (Hawkes) and Solanum tarijense (Hawkes) (Solanaceae) have noted resistance to leaf-feeding insect herbivores; however, little is known about their resistance to tuber-feeding herbivores. This study evaluates resistance in tubers of these two species to attack by the potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae). Tubers from a range of accessions were presented to recently emerged neonate tuber moth larvae. Resistance to neonates varied between accessions and was generally higher in accessions of S. tarijense . The contribution to observed resistance of periderm vs. cortex factors was assessed by perforating tuber periderm in paired-tuber experiments. Across species and accessions, an average of 62% of resistance was attributed to periderm-related factors. All larvae entered tubers through the eyes. Unidentified cortex-related factors affected larval development time and pupal weight. Sprouting compromised resistance by reducing the protective value of the periderm. The degree of sprouting also decreased larval development times and increased pupal weights in one of two accessions examined. These results demonstrate the potential of S. berthaultii and S. tarijense as sources of tuber-resistance and identify accessions of both species with notably high periderm-based protection. Levels of periderm resistance were not correlated to levels of cortex resistance and represent an independent resistance source compatible with the food value of crop potato.
We conducted a review of published literature reporting relationships between the size of plant m... more We conducted a review of published literature reporting relationships between the size of plant modules and the abundance or performance of gall insects. Insects in the family Tenthredinidae were recently reviewed and thus omitted from this review. The abundance or performance of approximately half of 53 species examined was positively related to plant module size. However, negative and parabolic relationships were found for all major insect families with sample sizes > 5 (i.e., Adelgidae/Aphididae, Cynipidae and Cecidomyiidae for abundance and Adelgidae/Aphididae for performance). This suggests that relationships between plant module size and the abundance or performance of non-tenthredinid gallers, although often positive, are best characterized as variable.
QUIRING, D. T. 1992. Rapid change in suitability of white spruce for a specialist herbivore, Zeir... more QUIRING, D. T. 1992. Rapid change in suitability of white spruce for a specialist herbivore, Zeiraphera canadensis, as a function of leaf age. Can. J. Zool. 70: 2132 -2138. Field studies were carried out over 2 years to determine the effect of age of white spruce (Picea glauca) leaves on the development of the spruce bud moth, Zeiraphera canadensis Mut. & Free. (Lepidoptera: Tortricidae). In both years developing buds remained suitable for first-instar larvae for only 4 -5 days after bud burst, after which survivorship decreased significantly. Individuals that survived on flaring shoots were smaller than those placed on newly burst buds. Although leaf contents of water, nitrogen, and several minerals were inversely related to leaf age, only declines in N and P content were associated with the rapid change in host suitability. Differences in N and P contents were small, however, suggesting that the rapid decline in host suitability was also due to the influence of other, unmeasured factors. When larvae were placed on foliage of the same age, their. survival was similar on trees in half-sib families with high or low susceptibility to Z. canadensis. Thus, variations in susceptibility of white spruce to Z. canadensis might be associated with differences in host-plant phenology but are not due to differences in nutritional quality. This study demonstrates that the phenological window for establishment of newly emerged folivores may be shorter than is commonly thought. QUIRING, D. T. 1992. Rapid change in suitability of white spruce for a specialist herbivore, Zeiraphera canadensis, as a function of leaf age. Can. J. Zool. 70 : 2132-2138. Des Ctudes sur le terrain ont Ct C entreprises au cours d'une pCriode de 2 ans afin de determiner l'effet de 1'8ge des feuilles de I'Cpinette blanche (Picea glauca) sur le dkveloppement de la tardeuse de 1'Cpinette Zeiraphera canadensis Mut. et Free. (Lepidoptera: Tortricidae). Au cours des 2 annCes, les bourgeons en dkveloppement se sont avkrCs appropriks h l'alimentation des lames de premier stade seulement pendant 4-5 jours aprks leur ouverture, aprks quoi la sumie des larves a diminuC significativement. Les individus qui ont servCcu sur le feuillage aprks 1'Ctalement des pousses Ctaient plus petits que ceux qui avaient CtCs placCs sur des bourgeons qui venaient d'Cclore. Le contenu des feuilles en eau, en azote et autres minCraux Ctait inversement proportionnel h 1'8ge des feuilles, mais seuls les diminutions de N et de P pouvait expliquer que l'h6te cesse rapidement de convenir h l'herbivore. Les variations du contenu en N et P Ctaient peu importantes cependant, ce qui indique que la diminution rapide de l'attrait alimentaire de l'h6te Ctait Cgalement influencie par d'autres facteurs non mesurCs. Des larves placCes sur des feuilles de mCme 8ge d'arbres h demi apparent& (d'une seule lignCe commune) trks susceptibles ou peu susceptibles d'heberger des Z. canadensis, avaient des taux de suwie semblables. Les variations dans la susceptibilitk des kpinettes h porter ou non des Z. canadensis sont probablement associees h des variations dans la phknologie des plantes h6tes plut6t qu'h des variations dans leurs propriCtCs nutritives. Cette Ctude dkmontre que l'intervalle au cours duquel s'ktablissent les folivores fraichement Cclos est probablement plus court qu'on ne le croit generalement.
Carroll, A.L., Lawlor, M.F. and Quiring, D.T., 1993. Influence of feeding by Zeiraphera canadensi... more Carroll, A.L., Lawlor, M.F. and Quiring, D.T., 1993. Influence of feeding by Zeiraphera canadensis, the spruce bud moth, on stem-wood growth of young white spruce. For. Ecol. Manage., 58: 41-49.
... 28 Dineen Drive, Fredericton, New Brunswick E3B 6C2, Canada—Phone: (506) 447-3339; Fax: (506)... more ... 28 Dineen Drive, Fredericton, New Brunswick E3B 6C2, Canada—Phone: (506) 447-3339; Fax: (506) 453-3538; chris.hennigar@unb ... Dead trees were not assessed for defoliation and were identified by examining discoloration and dryness under sections of bark (MacLean and ...
The pale-winged gray moth, Iridopsis ephyraria (Walker), a native geometrid moth species found ac... more The pale-winged gray moth, Iridopsis ephyraria (Walker), a native geometrid moth species found across eastern North America, has recently caused severe defoliation of eastern hemlock trees, Tsuga canadensis (L.) Carrière, in south-central Nova Scotia, Canada. Field studies were carried out to develop sampling techniques that could be used to predict subsequent defoliation of mature hemlocks, which are too large to sample by conventional methods. Densities of newly emerged, first-instar larvae, estimated by sticky tape traps, explained 77% of the subsequent current-year shoot defoliation by I. ephyraria. Egg densities from foam oviposition traps and mid-instar larval densities from beating sheets were weakly and usually non-significantly related to defoliation. Therefore, foam oviposition traps could be used to qualitatively estimate egg densities of I. ephyraria, but first-instar larvae must be sampled with sticky tape if accurate predictions of hemlock defoliation are desired.
Herbivory by Zeiraphera canadensis Mut. & Free. (Lepidoptera: Tortricidae), an early season foliv... more Herbivory by Zeiraphera canadensis Mut. & Free. (Lepidoptera: Tortricidae), an early season folivore of white spruce [ Picea glauca (Moench) Voss], has been associated with a shift in the timing of bud burst by its host during the subsequent year. We tested the hypothesis that a herbivory-induced shift in the phenology of bud development improves the window for colonisation of white spruce buds by Z. canadensis. Feeding on cortical tissue of elongating shoots caused the destruction of apical buds and an interruption of apical dominance in the year following herbivory. White spruce compensated for damage with the activation of dormant buds; mainly at proximal positions along shoots. As a result, half of all active buds on previously damaged branches were located immediately adjacent egg sites (i.e. previous year's bud scales), whereas <10% of active buds on intact shoots were situated there. More than 40% of newly emerged larvae colonised the basal buds of damaged shoots versus just 10% for intact shoots. Previous herbivory also influenced the initiation of bud burst. All buds flushed 2 days earlier on damaged shoots and date of bud burst was inversely correlated to bud density, indicating that short damaged shoots with large numbers of buds were stronger sinks for nutrients required for bud development. Egg hatch was best synchronized with early bursting buds on damaged branches. As a consequence, 89% of firstinstar larvae successfully colonised buds on damaged branches while only 55% were successful on undamaged branches. Improved survival of larvae in the year following herbivory was a direct result of the evolved response by white spruce to the interruption of apical dominance. The pattern of herbivory by Z. canadensis may have evolved as a strategy to enhance the quality of white spruce for their offspring.
ABSTRACT Using field surveys, we established sampling procedures for estimating defoliation resul... more ABSTRACT Using field surveys, we established sampling procedures for estimating defoliation resulting from elm spanworm, Ennomos subsignaria (Hübner) (Lepidoptera: Geometridae), feeding on mature sycamore maple, Acer pseudoplatanus L. (Aceraceae), in St. John&#39;s, Newfoundland and Labrador. We also determined whether densities of E. subsignaria eggs, egg masses, early- or late-instar larvae could predict the amount of defoliation at the end of the larval feeding period. Defoliation estimates acquired by sampling branches from only the lower, mid or upper crown explained ≥80% of the variation in tree-level defoliation, suggesting that density–defoliation relationships established using defoliation data from any crown level would also be useful for predicting tree-level defoliation. In linear regressions, egg and egg mass densities explained ≤20% of variation in defoliation and thus only provide a crude relative estimate of the amount of defoliation that will occur. Early- and late-instar larval density in the lower crown explained 53 and 29%, respectively, of the variation in defoliation in the lower crown, where defoliation levels were highest. Thus monitoring early-instar density in the lower crown should provide pest managers with reliable information for decisions regarding whether to apply suppression tactics while allowing enough time to implement these tactics, if necessary.
The Canadian Entomologist 128: 67-78 (1996) A 2-year field study was carried out to locate and id... more The Canadian Entomologist 128: 67-78 (1996) A 2-year field study was carried out to locate and identify eggs, determine the temporal distributions of eggs and larvae, and assess the impact of Strobilomyia laricis and S. viaria on Larix laricina. Eggs of S. laricis were beige with a patterned surface and usually laid one per cone in the bud scales at the base of the cone. Eggs of S. viaria were white and smooth and usually laid one per cone between the ovuliferous scales of the cone. Strobilomyia laricis oviposited from mid-to late May and S. viaria from late May to mid-June, each species initiating oviposition at a different stage of cone phenology. Peak egg densities of S. laricis were 25 and 65% higher than those of S. viaria in 1990 and 1991, respectively. Larvae of both species completed development at the same time, from mid-June to early July. The mean number of scales eaten per cone did not differ between species; one larva damaged a mean of 8.4 scales per cone in 1990 and 10.7 scales per cone in 199 1. As the number of scales per cone increased, the mean number of scales eaten increased and the mean percentage of scales eaten decreased. Cone crops were light in both years. In 1990, the only year we were able to differentiate cone maggot larvae, 44% of cones were damaged by S. laricis and only 16% by S. viaria. Together, S. laricis and S. viaria damaged 60 and 67% of the cones and destroyed 38 and 50% of the potential seed crop in 1990 and 199 1, respectively. McClure, M., D.T. Quiring et J.J. Turgeon. 1996. Ponte, distribution temporelle et impact de Strobilomyia laricis Michelsen et S. viaria (Huckett) (Diptera: Anthomyiidae) sur le mklkze laricin, Larix laricina (Du Roi) K. Koch. The Canadian Entomologist 128: 67-78.
Page 1. Evidence of an Oviposition-Deterring Pheromone in the Alfalfa Blotch Leafminer, Agromyza ... more Page 1. Evidence of an Oviposition-Deterring Pheromone in the Alfalfa Blotch Leafminer, Agromyza frontella (Rondani) (Diptera: Agromyzidae)l JEREMY N. McNEIL AND DAN T. QUIRING Departement de Biologie, Universite Laval, Quebec, PQ GlK 7P4, Canada Environ. ...
Entomologia Experimentalis Et Applicata, Oct 7, 2007
The trichome-bearing wild potatoes Solanum berthaultii (Hawkes) and Solanum tarijense (Hawkes) (S... more The trichome-bearing wild potatoes Solanum berthaultii (Hawkes) and Solanum tarijense (Hawkes) (Solanaceae) have noted resistance to leaf-feeding insect herbivores; however, little is known about their resistance to tuber-feeding herbivores. This study evaluates resistance in tubers of these two species to attack by the potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae). Tubers from a range of accessions were presented to recently emerged neonate tuber moth larvae. Resistance to neonates varied between accessions and was generally higher in accessions of S. tarijense . The contribution to observed resistance of periderm vs. cortex factors was assessed by perforating tuber periderm in paired-tuber experiments. Across species and accessions, an average of 62% of resistance was attributed to periderm-related factors. All larvae entered tubers through the eyes. Unidentified cortex-related factors affected larval development time and pupal weight. Sprouting compromised resistance by reducing the protective value of the periderm. The degree of sprouting also decreased larval development times and increased pupal weights in one of two accessions examined. These results demonstrate the potential of S. berthaultii and S. tarijense as sources of tuber-resistance and identify accessions of both species with notably high periderm-based protection. Levels of periderm resistance were not correlated to levels of cortex resistance and represent an independent resistance source compatible with the food value of crop potato.
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