@misc{Ulrich_Werner_The_1998,
 author={Ulrich, Werner},
 editor={Polish Academy of Sciences. Institute of Ecology},
 copyright={Creative Commons Attribution BY 3.0 PL license},
 address={Dziekanów Leśny},
 howpublished={online},
 year={1998},
 language={eng},
 abstract={The sex ratio of the parasitic Hymenoptera of a beech forest on limestone near Göttingen (FRG) was studied using ground-photo-eclectors. Judged from the mean sex ratios the parasitoids could be separated into 4 groups. Parasitoids of miners and gall-makers had the highest sex ratios (30 to 40% males) and less than 5% of the species were thelytokous. The species which attack soil-living sapro- or mycetophagous Diptera as well as the parasitoids of ectophytophages had (on average) 20 to 30% males and only 1.5% of them were thelytokous. Parasitoids of sap-suckers and egg-parasitoids usually had sex ratios below 20% males and 29% of them were thelytokous. The lowest sex ratios (below 10% males) and the highest number of thelytokous species (30%) were found among hyperparasitoids and parasitoids of soil-living Staphylinidae. No clear trend was detectable between the sex ratio and the density of the species. The density fluctuations and the degree of aggregation of the species influenced the sex ratio. The data are consistent with the hypothesis that K-selected parasitoid species have higher sex ratios on average. Koinobiontic species (mostly parasitoids of gall-makers and miners) had (on average) significantly higher sex ratios if their host lives in the herb or crown layer (32% versus 21%). They also produced more males if they are univoltine (32% versus 22%) and hibernate as larvae or pupae (30% versus 17%). After a MANOVA-analysis the voltinism turned out to be the main influencing factor. There was a trend towards higher percentages of males in the summer generation.},
 type={Text},
 title={The parasitic Hymenoptera in a beech forest on limestone. 2, Study of the sex ratios and their dependence on ecological factors},
 URL={http://www.rcin.org.pl/Content/98275/PDF/WA058_90710_P2840-T46_Eko-Pol-A-Nr-3.pdf},
 volume={46},
 number={3},
 journal={Polish Journal of Ecology},
 publisher={Polish Academy of Sciences. Institute of Ecology. Publishing Office},
 keywords={sex ratio, local mate competition, parasitoids, ground-photo-eclectors, Hymenoptera},
}