Immature Sirex noctilio woodwasp size and sex dataset

Resource quality can have direct or indirect effects on female oviposition
choice, offspring growth and survival, and ultimately on body size and sex
ratio. We examined these patterns in Sirex noctilio Fabricus, the globally
invasive European pine woodwasp, in South African Pinus patula
plantations. We studied how tree position as well as natural variation in
biotic and abiotic factors influenced sex-specific density, larval size,
tunnel length, male proportion, and survival across development. Twenty
infested trees divided into top, middle, and bottom sections were sampled
at three time points during larval development. We measured moisture
content, bluestain fungal colonization, and co-occurring insect density
and counted, measured, and sexed all immature wasps. A subset of larval
tunnels was measured to assess tunnel length and resource use efficiency
(tunnel length as a function of immature wasp size).  Wasp
density increased from the bottoms to the tops of trees for both males and
females. However, the largest individuals and the longest tunnels were
found in bottom sections. Male bias was strong (~10:1) and likewise
differed among sections, with the highest proportion in the middle and top
sections. Sex ratios became more strongly male biased due to high female
mortality, especially in top and middle sections. Biotic and abiotic
factors such as colonization by Diplodia sapinea, weevil (Pissodes sp.)
density, and wood moisture explained modest residual variation in our
primary mixed effects models (0-22%). These findings contribute to a more
comprehensive understanding of sex-specific resource quality for S.
noctilio and of how variation in key biotic and abiotic factors can
influence body size, sex ratio, and survival in this economically
important woodwasp.