Boxplots of estimated number of eggs oviposited by <i>Sirex noctilio</i> in each pine species.

<p>n = 20 logs per <i>Pinus</i> species. Boxes are bounded by the first and third quartiles; the internal solid line represents the median.</p

Mean number of <i>Sirex noctilio</i> at the beginning of each life stage in experimentally-manipulated cohorts.

<p>For each treatment, dots represent the mean number of <i>S</i>. <i>noctilio</i> recovered from 9 logs (~0.07 m³ wood) that were collected in October (egg/neonate—mid-sized larval), or from a second set of 9 logs (0.07 m³ wood) that were collected in June (adult), and error bars represent standard errors. Cohorts were either protected from (filled dots) or exposed to (open dots) the naturally-occurring community of associates. The effect of exposure to associates was tested separately for each life stage. *<i>P</i> < 0.01 according to Tukey’s HSD.</p

Differences in apparent mortality (%) among life tables of <i>Sirex</i> developing in <i>Pinus sylvestris</i> by treatment for experimentally-manipulated cohorts and separately by site for natural cohorts.

<p>Each life stage was tested separately using a generalized linear model. Different letters indicate statistically significant differences (<i>P</i> < 0.05) among cohorts according to Tukey’s HSD. Lowercase letters indicate differences between experimentally-manipulated cohorts, and uppercase letters indicate differences among natural cohorts (sites).</p><p>Differences in apparent mortality (%) among life tables of <i>Sirex</i> developing in <i>Pinus sylvestris</i> by treatment for experimentally-manipulated cohorts and separately by site for natural cohorts.</p

Relationship between number of small <i>Sirex</i> larvae and endoparasitoids from the experimentally-manipulated, exposed cohort.

<p>Equation of the fitted line: y = 0.2906 + 0.1365x + 0.0016x²; adjusted R² = 0.94; <i>P</i> < 0.001. Each dot represents number of wasps recovered from one log.</p

<i>Sirex</i> spp. and parasitoid information at six sites throughout Ontario, from which natural life table cohorts were created.

<p>Estimates of <i>Sirex</i> within-tree density and parasitism are based on the number of adult wasps that emerged from 2–10 infested pines cut in 2013 or 2014.</p><p><i>Sirex</i> spp. and parasitoid information at six sites throughout Ontario, from which natural life table cohorts were created.</p

Differences in real mortality (%) among life stages of <i>Sirex</i> developing in <i>Pinus sylvestris</i>, tested separately for treatments (experimentally-manipulated cohorts) or sites (natural cohorts).

<p>Different letters indicate statistically significant differences (<i>P</i> < 0.05) among life stages according to Tukey’s HSD, tested separately for each row, using generalized linear models.</p><p>Differences in real mortality (%) among life stages of <i>Sirex</i> developing in <i>Pinus sylvestris</i>, tested separately for treatments (experimentally-manipulated cohorts) or sites (natural cohorts).</p

Boxplots of the proportion of <i>Sirex noctilio</i> eggs that survived to adulthood in each pine species.

<p>n = 16 logs for <i>Pinus banksiana</i> and <i>P</i>. <i>resinosa</i>; n = 19 logs for <i>P</i>. <i>sylvestris</i>; n = 10 logs for <i>P</i>. <i>strobus</i>. Boxes are bounded by the first and third quartiles; the internal solid line represents the median.</p

Suitability of eastern pines for oviposition and survival of <i>Sirex noctilio</i> F.

<div><p>The European woodwasp, <i>Sirex noctilio</i> F., is a pest of pines in many areas around the world. Since its introduction to North America, the distribution of <i>S</i>. <i>noctilio</i> overlaps with a known host (<i>Pinus sylvestris</i>) and hosts native to North America. Direct comparisons of suitability for oviposition and larval survival among these pines have not been made. We tested the relative suitability of four common pine species in northeastern North America (<i>P</i>. <i>sylvestris</i>, <i>P</i>. <i>resinosa</i>, <i>P</i>. <i>banksiana</i>, and <i>P</i>. <i>strobus</i>) as hosts for <i>S</i>. <i>noctilio</i> in a controlled, but <i>in situ</i> experiment. In a mixed pine forest in northern Ontario, we caged <i>S</i>. <i>noctilio</i> mating pairs on 10 freshly cut pine logs of each species, and estimated oviposition, counted adult <i>S</i>. <i>noctilio</i> (F1 generation) that emerged from logs, and calculated survivorship from egg to adult. <i>Pinus sylvestris</i> and <i>P</i>. <i>resinosa</i> were optimal hosts according to all three metrics of <i>S</i>. <i>noctilio</i> performance. <i>Pinus strobus</i> was a suitable larval host, but was not perceived as such by females, as evidenced by lower oviposition. <i>Pinus banksiana</i> was perceived as a suitable host by females, but was the least suitable larval host. Our results suggest that <i>P</i>. <i>sylvestris</i> and <i>P</i>. <i>resinosa</i> are more suitable hosts, at least in cut logs, than <i>P</i>. <i>strobus</i> and <i>P</i>. <i>banksiana</i> for <i>S</i>. <i>noctilio</i> in eastern North America.</p></div

Survivorship curves from (a) experimentally-manipulated and (b) natural <i>Sirex</i> cohorts.

<p>Different symbols correspond to different (a) treatments or (b) sites, and represent an estimate of the total population density of <i>Sirex</i> recovered from (a) 9 logs (0.07 m³ of wood) or (b) one tree (0.006–0.21 m³ of wood each), which were/was collected in October (egg—mid-sized larval stages) or in June (adult stage).</p

Number of logs and different trees (<i>Pinus sylvestris</i>) collected for <i>Sirex</i> life tables and the actual number of surviving insects recovered from each life stage.

<p>E and N refer to experimentally-manipulated and natural cohorts, respectively.</p><p>Number of logs and different trees (<i>Pinus sylvestris</i>) collected for <i>Sirex</i> life tables and the actual number of surviving insects recovered from each life stage.</p