Journal of Chemical Ecology (2014) 40, 418-428

Christopher A. Wheeler and Ring T. Cardé (2014)
Following in their footprints: Cuticular hydrocarbons as overwintering aggregation site markers in Hippodamia convergens
Journal of Chemical Ecology 40 (5), 418-428
Abstract: The convergent lady beetle (Hippodamia convergens) forms large overwintering aggregations at revisited montane microsites far removed from their summer foraging grounds. Although orientation responses to visual and altitudinal features of habitat can explain the arrival of migrants at the general overwintering macrosite, the role that pheromones play in the accumulation of individuals in inconspicuous hibernacula microsites is not fully understood. Through two-choice bioassays and gas chromatography and mass spectrometry, we found that H. convergens orient towards hydrocarbons previously deposited on their walking surfaces by conspecifics. n-Tricosane (C₂₃) is primarily responsible for this chemically-mediated orientation. Footprint extracts, as well as C₂₃ alone, induce the eventual accumulation in the field of migrant H. convergens at artificial hibernacula, confirming their probable role as aggregation signals. Aggregations persisted over many days when footprint extracts were applied in conjunction with the previously identified 2-isobutyl-3-methoxypyrazine (IBMP) aggregation pheromone. The C₂₃ hydrocarbon functions as a pheromone that interacts with responses to methoxypyrazines to effectively mediate formation of persistent aggregations of diapausing conspecifics at specific microsites. Also discussed is the potential effect that C₂₃ has as a persistent scent marker in establishing the traditional use of hibernacula.
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Link to article at publishers website
Database assignments for author(s): Christopher A. Wheeler, Ring T. Cardé

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
population dynamics/epizootiology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
Hippodamia convergens (predator)			U.S.A. (SW)