Journal of Applied Entomology (2022) 146, 1302-1310

Sanne E. Bethe, Rieta Gols and Jeffrey A. Harvey (2022)
Artificially perforated holes in stems of small hogweed mimic ecosystem engineering by a moth
Journal of Applied Entomology 146 (10), 1302-1310
Abstract: Ecosystem engineers are species that manipulate the physical state of ecosystems and thereby affect the behaviour and ecology of other species. Mature larvae of the parsnip webworm, Depressaria radiella Goeze, chew holes in the hollow stems of Heracleum sphondylium L. into which they pupate. The stems are separated into several compartments that are separated by filamentous membranes. Holes excavated by webworm larvae attract several beneficial species of arthropods that use them for shelter in autumn, including the common earwig (Forficula auricularia L.) and the common rough woodlouse (Porcellio scaber Latreille). If artificially made holes mimic the engineering effect of D. radiella, they could be made to attract (local) communities of beneficial arthropods and perhaps facilitate overwintering habitat. We conducted a field experiment to determine whether artificial holes perforated into stem compartments of H. sphondylium mimic the natural situation with D. radiella. At five sites near the city of Leiden, the Netherlands, H. sphondylium plants were exposed to different treatments: a single hole perforated in the first, second or third stem compartment, or in all three compartments. After 3 weeks, arthropod numbers were counted inside and around hogweed stems. The arthropod community in the stems differed from that surrounding the stems; the latter consisted mainly of woodlice and wolf spiders, whereas in the stems, in addition to woodlice, many earwigs were found and no wolf spiders. Both artificial and webworm-excavated holes that were present at one site were used by woodlice and earwigs. The position of the holes along the stem did not affect the number of arthropods found in that segment, although the arthropods exhibited a tendency to move up the stems. The results show that artificial holes mimic webworm-excavated holes in that both attract the same species of beneficial arthropods.
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Database assignments for author(s): Rieta Gols, Jeffrey A. Harvey

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Heracleum sphondylium (weed)		Netherlands
Depressaria radiella (weed bioagent)	Heracleum sphondylium (weed)		Netherlands