Sample size for monitoring sirex populations and their natural enemies

Natural enemies associated with Sirex noctilio (Hymenoptera: Siricidae) and S. nigricornis in Ontario, Canada.

Sirex noctilio F. is an exotic woodwasp now found in eastern North America where it shares natural enemies with native woodwasps of Pinus spp. To study the extent to which native hymenopteran parasitoids and parasitic nematodes could affect woodwasp populations, 60 Pinus trees with symptoms of S. noctilio attack were felled in 2007 and 2008 in Ontario, Canada. Each tree bole was cut into 1-m s...

A survey of alfalfa aphids and their natural enemies in Isfahan, Iran, and the effect of alfalfa strip-harvesting on their populations

در طی دو سال (1384-1383) نمونه‌برداری از جمعیت شته‌های یونجه و دشمنان طبیعی آن‌ها در اصفهان، در مجموع 4 گونه شته و 58 گونه از دشمنان طبیعی آن‌ها شامل 45 گونه شکارگر، 11 گونه پارازیتوئید و 2 گونه کنه‌ی پارازیت جمع‌آوری و شناسایی شد. علاوه بر این، 5 گونه هیپرپارازیتوئید نیز جمع‌آوری گردید. در هر روز نمونه‌برداری، شش نمونه هر کدام شامل 20 بار تور‌زدن‌ به وسیله‌ی یک تور حشره‌گیری با قطر 38 سانتی‌مت...

Natural enemies of cypress tree mealybug planococcus vovae (nasonov)and their parasitoids in shiraz iran

How to sample natural populations

Strains from nature have been widely used in experimental and evolutionary studies (reviewed by Perkins and Turner 1988, Turner et al. 2001), most recently for creating phylogenetic trees which provide information on speciation (Dettman et al. 2003). Natural populations have usually been sampled by obtaining conidia from visible colonies on burned vegetation, mostly in tropical or subtropical r...

Plant invaders and their novel natural enemies: who is naïve?

Introduced exotic species encounter a wide range of non-coevolved enemies and competitors in their new range. Evolutionary novelty is a key aspect of these interactions, but who benefits from novelty: the exotic species or their new antagonists? Paradoxically, the novelty argument has been used to explain both the release from and the suppression by natural enemies. We argue that this paradox c...